Acid Rain and Transported Air Pollutants:

Implications for Public Policy

May 1984

NTIS order #PB84-222967
Recommended Citation:

Acid Rain and Transported Air Pollutants: Implications for Public Policy (Washington, D. C.:

U.S. Congress, Office of Technology Assessment, OTA-O-204, June 1984).

Library of Congress Catalog Card Number 84-601073

For sale by the Superintendent of Documents

U.S. Government Printing Office, Washington, D.C. 20402
Foreword

Transported air pollutants have been the topic of much debate during the Clean Air Act deliberations of the 97th and 98th Congresses. The current controversy over acid rain—the most publicized

example of transported pollutants—focuses on the risks to our environment and ourselves versus

the costs of cleanup. Since 1980, the committees responsible for reauthorizing the Clean Air Act—the

House Committee on Energy and Commerce and the Senate Committee on Environment and Public

Works—have called on OTA many times for information about the movements, fate, and effects

of airborne pollutants, the risks that these transported air pollutants pose to sensitive resources,

and the likely costs of various proposals to control them. Over the course of the debate, OTA has

provided extensive testimony and staff memoranda to the requesting committees, and published

a two-volume technical analysis, The Regional Implications of Transported Air Pollutants, in July

1982. This report synthesizes OTA’s technical analyses of acid rain and other transported pollutants, and presents policy alternatives for congressional consideration.

OTA’s work over the last several years has enabled us to forecast with reasonable accuracy the

cost of controlling pollutant emissions, and, for each of the many pending legislative proposals,

who will pay those costs. We also know a great deal about the transport, fate, and effects of t rans -

ported air pollutants—vastly more than was known several years ago when Congress last considered the Clean Air Act. Still, it is not yet possible to accurately evaluate the damages wrought

by the pollutants or the benefits to be gained by reducing emissions, though we can say that both

the risks of harm and the costs of control are substantial.

The issue of transported pollutants poses a special problem for policy makers: assuring regional

equity while balancing concerns for economic well-being with concerns for natural and human

resources across large regions of the Nation. Scientific uncertainties surrounding many aspects of

the problem complicate the decision of whether, or when, to control transported air pollutants.

Additional complexities arise from our inability to treat costs, damages, and benefits in a uniform,

quantitative way. Moreover, in OTA’s judgment, even substantial additional scientific research

is unlikely to provide significant, near-term policy guidance, or resolve value conflicts.

How, then, can Congress address current damage, consider potential harm to recipients of transported air pollutants, yet not enforce an unnecessarily high cost on those who would be required

to reduce pollutant emissions? OTA’s analysis cannot provide an unambiguous answer to this

dilemma. It does, however, lay out some carefully weighed estimates of costs, some carefully reasoned conclusions about the nature and extent of downwind damages and risks, and several policy

options that merit consideration. We hope that this information will help to narrow the issues of

contention for this important environmental concern.

OTA is grateful for the assistance of the advisory panel, contractors, and the over 200 reviewers

who provided advice and information throughout the course of this assessment.

Director

,..

Ill
Transported Air Pollutants Advisory Panel

Norton Nelson, Chairman

New York University Medical Center

Thomas H. Brand Gene E. Likens

Edison Electric Institute Cornell University

Robert Wilbur Brocksen Anne LaBastille

Electric Power Research Institute Adirondack Park Agency

Jack George Calvert Donald H. Pack

National Center for Atmospheric Research Private Consultant

David Hawkins Carl Shy

National Resources Defense Council, Inc. University of North Carolina

Edward A. Helme George H. Tomlinson, II

National Governors’ Association Domtar, Inc.

Richard L. Kerch

Consolidation Coal

Principal Contractors

Brookhaven National Laboratory

Kathleen Cole, Duane Chapman,

Clifford Rossi

Energy & Resource Consultants

Environmental Law Institute

Barbara J. Finalyson-Pitts,

James N. Pitts, Jr.

Additional Contributors

A. S. L. & Associates

Sanford Berg

Daniel Bromley

Thomas Crocker

Energy & Environmental Analysis, Inc.

Yacov Haimes

Perry Hagenstein

David Harrison

Walter Heck

IR & T Corp.

Brand L. Niemann

Oak Ridge National Laboratory

E. H. Pechan & Associates

Perry J. Sampson

Jack Shannon

The Institute of Ecology

Steven Olson

James Reagan

Larry Salathe

John P. Skelly

SRI International

TRC Environmental Consultants

Michael P. Walsh
OTA Proiect Staff—Transported Air Pollutants Assessment

John Andelin,

Science, Information,

Assistant Director, OTA

and Natural Resources Division

Robert W. Niblock, Oceans and Environment Program Manager

Robert M. Friedman, Project Director

Rosina M. Bierbaum, Assistant Project Director

Patricia A. Catherwood, Research Analyst

Stuart C. Diamond, * Editor/Writer

George C. Hoberg, Jr., * Polic y Analyst

Valerie Ann Lee, Policy Analyst

Contributing Staff

Linda Garcia Iris Goodman Nancy Greenbaum Jennifer N. Marsh

Administrative Staff

Kathleen A. Beil Jacquelynne R. Mulder Kay Senn
Contents

Chapter

1.

2.

3.

4.

5.

6.

7.

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ... . $....”...

The Policy Dilemma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......”””.

Transported Air Pollutants: The Risks of Damage and the Risks of Control.

The Pollutants of concern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The Regional Distribution of Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... $.. ....”

Legislating Emissions Reductions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Appendix

A. Emissions and the Costs of Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B. Effects of Transported Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C. Atmospheric Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - . ’ ’ . . ..-’’”.-. .’.

D. Existing Domestic and International Approaches . . . . . . . . . . . . . . . . . . . . . . . . .

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .”.

Page

3

27

41

57

79

103

121

Page

149

207

265

300

321
Photo credit: MESOMET, Inc.

A hazy, polluted air mass is outlined on this July 1978 enhanced satellite photo. High levels of airborne sulfate and

ozone, along with low visibility, persisted for about a week over much of the Eastern United States and Canada. The

polluted air mass extends far offshore— at least 500 miles from manmade emissions sources—visible evidence of longdistance transport of air pollution.
Chapter 1

Summary
Contents

Page

The Pollutants of Concern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

The Risks From Transported Air Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

The Risks of Controlling Transported Air Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

FIGURES

Figure No. Page

I. Transported Air Pollutants: Emissions to Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2. Precipitation Acidity—Annual Average pH for 1980 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3. Ozone Concentration—Daytime Average for Summer 1978 . . . . . . . . . . . . . . . . . . . . . . . . . 7

4. Sulfur Dioxide and Nitrogen Oxides Emissions—State Totals for 1980 . . . . . . . . . . . . . . . 7

5. Sulfur Dioxide and Nitrogen Oxides Emissions Trends—National Totals, 1900-2030 . . . 8

6. Average Sulfur Transport Distances Across Eastern North America . . . . . . . . . . . . . . . . . . 9

7. Regions of the Eastern United States With Surface Waters Sensitive

to Acid Deposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

8. Recent Forest Productivity Declines Throughout the Eastern United States. . . . . . . . . . . . 11

9. Cost of Reducing Sulfur Dioxide Emissions by 10 Million Tons per Year,

Nationwide Increases in Annual-Average Electricity Bills for

a Typical Residential Consumer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Chapter 1

Summary

Until recently, air pollution was considered a

local problem. Now it is known that winds can carry

air pollutants hundreds of miles from their points

of origin. These transported air pollutants can damage aquatic ecosystems, crops, and manmade materials, and pose risks to forests and even to human

health. Throughout this report we discuss three of

these pollutants: acid deposition (commonly called

acid rain), atmospheric ozone, and airborne fine

particles.

The Clean Air Act—the major piece of Federal

legislation governing air quality in the United

States—addresses local air pollution problems but

does not directly apply to pollutants that travel

many miles from their sources. However, reports

of natural resource damage in this country, Canada, Scandinavia, and West Germany have made

transported air pollutants—particularly acid rain—

a focus of scientific and political controversy. Many

individuals and groups, pointing to the risk of irreversible damage to resources, are calling for more

stringent Federal pollution controls. Others, emphasizing scientific uncertainties about transported

air pollutants and drawing different conclusions

about how to balance risks against costs, contend

that further pollution controls are premature, may

waste money, and would impose unreasonable burdens on industry and the public.

OTA’s analysis of acid deposition and other

transported air pollutants concludes that these

substances pose substantial risks to American

resources. Thousands of lakes and tens of thousands of stream miles in the Eastern United States

and Canada are vulnerable to the effects of acid

deposition. Some of these have already been

harmed. Elevated levels of atmospheric ozone have

reduced crop yields on American farms by hundreds of millions of bushels each year. Acid deposition may be adversely affecting a significant fraction of Eastern U.S. forests; it, along with such

other stresses as ozone and natural factors such as

drought, may account for declining forest productivity observed in parts of the East. Both sulfur

oxides and ozone can damage a wide range of manmade materials. Airborne fine particles such as

sulfate reduce visibility and have been linked to increased human mortality in regions with elevated

levels of air pollution.

The costs of reducing pollutant emissions are

likewise substantial. Most current legislative proposals to control acid deposition would cost about

$3 billion to $6 billion per year. Adding these new

emissions control proposals to our Nations current

environmental laws would increase the total costs

of environmental regulation by about 5 to 10 percent. Average electricity costs would rise by several percent— as high as 10 to 15 percent in a few

Midwestern States under the most stringent proposals. Additional emissions controls could also

have important indirect effects, such as job dislocations among coal miners and financial burdens on

some utilities and electricity-intensive industries.

Any program to reduce emissions significantly

would require about 7 to 10 years to implement.

If no further action is taken to control emissions,

30 to 45 years will elapse before most existing pollution sources are retired and replaced with facilities more stringently regulated by the Clean Air

Act. The effective time frame of most proposals

to control acid deposition, therefore, is the intervening period of about 20 to 40 years—long

enough to be significant to natural ecosystems.

If all the risks posed by transported air pollutants were realized over this time period, resulting

resource damage would outweigh control costs. The

risks discussed throughout this report, however, are

potential consequences, not necessarily the consequences that will, in fact, occur.

One of the most difficult questions facing Congress, therefore , is whether to act now to control acid deposition or wait for results from ongoing multimillion-dollar research programs. Both

involve risks. Delaying action for 5 or 10 years will

allow emissions to remain high for at least a decade

or two, with the risk of further ecological damage.

But predicting the magnitude and geographic extent of additional resource damage while waiting

is not possible. Acting now involves the risk that

the control program will be less cost effective or ef3
4 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

ficient than one designed 5 or 10 years from now. The policy decision to control

Significant advances in scientific understanding transported air pollutants must

over this time period, however, are by no means risks of resource damage, the

or not to control

be based on the

risks of unwarassured. -

The distributional aspects of transported air

pollutants further complicate the congressional

dilemma. Because these pollutants cross State and

even international boundaries, they can harm regions far downwind of those benefiting from the

activities that produce pollution. Moreover, different economic sectors bear the risks of waiting

ranted control expenditures, and the distribution of these risks among different groups and

regions of the country. This study describes the

tradeoffs implicit in this choice by characterizing

the extent of the risks, their regional distribution,

and the economic sectors that bear them. It concludes with a list of policy options available to Congress for addressing transported air pollutants.

or acting now to control.

THE POLLUTANTS OF CONCERN

The transported air pollutants considered in this sulfate and nitrate. Acid deposition results when

study result from the emission of three primary pol- sulfur and nitrogen oxides and their transformalutants: sulfur dioxide, nitrogen oxides, and tion products return from the atmosphere to the

hydrocarbons. As these pollutants are carried away Earth’s surface. Elevated levels of ozone are

from their sources, they can be transformed through produced through the chemical interaction of nicomplex chemical processes into secondary pollut- trogen oxides and hydrocarbons (see fig. 1). Nuants: ozone and airborne fine particles such as merous chemical reactions—not all of which are

Figure 1 .—Transported Air Pollutants: Emissions to Effects

The transported air pollutants considered in this study result from emissions of three pollutants: sulfur dioxide, nitrogen oxides,

and hydrocarbons. As these pollutants are carried away from their sources, they form a complex “pollutant mix” leading to

acid deposition, ozone, and airborne fine particles. These transported air pollutants pose risks to surface waters, forests, crops,

materials, visibility, and human health.
Ch. l—Summary ● 5

completely understood—and prevailing weather

patterns affect the overall distribution of acid deposition and ozone concentrations.

Current levels of precipitation acidity and ozone

concentrations are shown in figures 2 and 3, respectively. Peak levels of acid deposition—as measured by precipitation acidity, or pH*—center

around Ohio, West Virginia, and western Pennsylvania. High levels of acid deposition are found

throughout the United States and southeastern

Canada. Peak values for ozone are found further

south than for acid deposition, centering around

the Carolinas. A band of elevated ozone concentrations extends from the mid-Great Plains States

to the east coast.

During 1980 some 27 million tons of sulfur

dioxide and 21 million tons of nitrogen oxides

were emitted in the United States. Figure 4

displays the regional pattern of emissions. About

80 percent of the sulfur dioxide and 65 percent of

the nitrogen oxides came from within the 31 States

bordering or east of the Mississippi River. Figure

5 shows how these emissions have varied since 1900.

Since 1940, sulfur dioxide emissions increased by

about 50 percent and nitrogen oxides emissions

about tripled. Throughout the same period, taller

emission stacks became common, allowing pollutants to travel farther.

Figure 5 also shows a range of projected future

emissions of these pollutants, assuming that current air pollution laws and regulations remain unchanged. Actual future emissions will depend on

such factors as the demand for energy, the type of

energy used, and the rate at which existing sources

of pollution are replaced by newer, cleaner facilities. By 2030—the end of the projection period—

most existing facilities will have been retired. Despite relatively strict pollution controls mandated

for new sources by the Clean Air Act, emissions

of both sulfur and nitrogen oxides are likely to

remain high for at least the next half century.

The pollutants responsible for acid deposition can

return to Earth in rain, snow, fog, or dew—col-

*Acidity is measured in pH units, Decreasing pH corresponds to

increasing acicidity, but in a nonlinear (logarithmic) way. Across the

United States, average annual rainfall pH varies between about 4 and

6. Compared to a pH of 6, pH 5 is 10 times more acidic; pH 4 is

100 times more acidic; and so on. Referring to the shading in figure

2, pH 4.2 is twice as acidic as pH 4.5; about 6 times more acidic than

pH 5; and about 20 times more acidic than pH 5.5.

lectively known as acid precipitation—or as dry

particles and gases. Averaged over the Eastern

United States, about equal amounts of sulfur

compounds are deposited in wet and dry forms.

However, in areas remote from pollution sources,

such as the Adirondacks, wet deposition may account for up to 80 percent of the sulfur deposited;

in urban areas near many sources of pollution the

situation is reversed. 1

Pollutants emitted into the atmosphere can return to Earth almost immediately or remain aloft

for longer than a week, depending on weather patterns and the pollutants’ chemical interactions.

During this time they move with prevailing winds,

which in the Eastern United States tend to move

from west to east and from south to north.

Preliminary analyses suggest that about onethird of the total amount of sulfur compounds

deposited over the Eastern United States as a

whole originates from sources over 500 kilometers (km) (300 miles) away from the region in

which they are deposited. Another one-third

comes from sources between 200 and 500 km ( 120

to 300 miles) away, and the remaining one-third

comes from sources within 200 km ( 120 miles).2

Because pollution sources are unevenly distributed across the Eastern United States and Canada,

the relative contribution of emissions from local,

midrange, and distant sources varies by region. As

shown in figure 6, sulfur deposition in the Midwest— a region with high emissions—is dominated

by emissions from sources within 300 km (180

miles). The sulfur compounds that reach the lessindustrialized New England region typically have

traveled farther. The ‘ ‘average’ distance—considering the contribution from both local and distant

sources—is about 500 to 1,000 km (300 to 600 miles).

] E. Altwicker and A. Johann es, ‘ ‘Wet and Dry Deposition in

Adirondack Watersheds, The Integrated Lake- ~1’atershcd Acidification Study: Proceedings of the IL WAS Annual Rc’ticw Conference,

Electric Power Research Institute, EPRI EA-2827, 1983: and

D. Fowler, ‘‘ Removal of Sulfur and Nitrogen C;ornpounds From the

Atmosphere, Ecolo<qi(al Irnpar-t of’ Acid Precipitation, SNSF Project, Norwa>, 1980.

‘J. Shannon, ‘ ‘Estimation of North American Anthropogenic Sulfur

Deposition as a Function of Source-Receptor Separation, paper presr.-nteci at the NA TO 14th In ternationaf Technical AfeetinLg on ,4ir

~~o]][ltlon ,$f(~clinq amf Its Application, Copenhagen, 19~:~.
6 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

/“

Figure 2.–Precipitation Acidity–Annual Average for 1980

Legend:
Ch. l—Summary ● 7

Figure 3.–Ozone Concentration–Daytime Average for Summer 1978

Figure 4.—Sulfur Dioxide and Nitrogen Oxides Emissions—State Totals for 1980
8 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

34
Ch. 1—Summary 9

Figure 6.-Average Sulfur Transport Distances Across Eastern North America

THE RISKS FROM TRANSPORTED AIR POLLUTANTS

The best documented and best understood effects of acid deposition are those on aquatic ecosystems. The sensitivity of a lake or stream to acid

deposition depends largely on the ability of the soil

and bedrock in the surrounding watershed to neutralize acid. Where the soil is very thin or has little

neutralizing capacity, or where the terrain is so

steep or rocky that rainfall runs right over it, the

bodies of water within a watershed are at risk.

When the waters of a lake or stream become more

acidic than about pH 5, many species of fish die

and the ecosystem changes dramatically. This may

be due to the acidity, to the metals (especially aluminum) released under acidic conditions, or to a

combination of both.

By categorizing the predominant soil and geological characteristics in each county of the Eastern United States, this study estimates the potential number of lakes and streams at risk from acid
10 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

deposition. Because of the uncertainties involved,

these numbers should be viewed as qualitative estimates only. In the 31 States bordering and east

of the Mississippi River, roughly 25 percent of the

Figure 7.—Regions of the Eastern

land area contains soils and bedrock that allow acidity to travel through a watershed to lakes and

streams (see fig. 7). About 17,000 lakes and 112,000

miles of streams lie within these sensitive areas. As

United States With Surface Waters

Sensitive to Acid Deposition

The regions shaded light grey contain soils and bedrock that allow acidity to travel through

a watershed to lakes and streams. Due to local variations, however, not all water bodies within

these areas are sensitive to acid deposition. Likewise, some sensitive water bodies may be

located outside the light grey areas. The dark areas contain lakes and streams that currently

have such limited ability to neutralize acida (as measured by water quality surveys) that they

are now extremely vulnerable to further acid deposition or are already acidic.

aRegions with surface waters that have mean annual alkalinity less than 100 microequivalents per liter.

SOURCES: Off Ice of Technology Assessment. Composite map from the Institute of Ecology, “Regional Assessment of Aquatic

Resources at Risk From Acid Deposition,” OTA contractor report, 1982; and J. Omernik, “Total Alkalinity of Surface Water,” draft map prepared for the U.S. Environmental Protection Agency, 1983.
Ch. 1—Summary ● 11

a “best guess, ” about half of these lakes and

streams have such limited ability to neutralize acid

that they will acidify if enough acid-producing pollutants are deposited. We estimate that about

3,000 lakes and 23,000 miles of streams—or

about 20 percent of those in the sensitive areas—

are now extremely vulnerable to further acid

deposition or have already become acidic. New

England has the greatest percentage of lakes and

streams considered sensitive to acid deposition. The

Upper Midwest also has large numbers of sensitive

lakes, and many sensitive streams are found in the

Central Appalachian region.

In addition to the acidification of aquatic ecosystems, transported air pollutants have been linked

to harmful effects to terrestrial ecosystems. Broad

forested areas subjected to elevated levels of acid

deposition, ozone, or both have been marked by

declining productivity and dying trees, although

it is uncertain how much of this is due to airborne pollutants. Figure 8 documents significant

Figure 8.— Recent Forest Productivity Declines Throughout the Eastern United States

The photograph shows corings from three softwood tree species growing on six sites across the East from Vermont to Tennessee.

The corings show normal growth-widely spaced tree rings —until about 1960 (marked with a stripe). From about 1960 to the

present the tree rings have markedly narrowed, evidence of decreased growth. Concerns have been raised that elevated levels

of ozone and acid deposition in these regions may be involved in the observed declining productivity. As of now, the cause

is unexplained.

SOURCE Arthur Johnson, University of Pennsylvania Samuel McLaughlin, Oak Ridge National Laboratory
72 ● Acid Rain and Transported Air Pollutants: lmplications for Public Policy

growth declines in several tree species beginning

about 1960 throughout the East from Vermont to

Tennessee. Acid deposition, ozone, heavy-metal

deposition, drought, severe winters, or a combination of these stresses are possible causes under investigation.

Acid deposition might be harming trees in two

ways: either directly (e. g., by removing nutrients

from leaves), or indirectly, by altering the soils on

which trees grow. If acid deposition harms trees

directly, much of the forested area of the Eastern

United States is at risk, with the greatest risk in

high elevation areas where deposition is often greatest. If acid deposition affects forest soils, forests

growing on nutrient-poor, naturally acidic soils are

of greatest concern. This study estimates that such

soils cover about 15 to 20 percent of the land area

of the Eastern United States, primarily parts of New

England, the Upper Midwest, and the South. Acid

deposition might be stripping such essential nutrients as calcium and magnesium from these soils,

or releasing metals, such as aluminum, that are

toxic to plants. Whether this nutrient loss or release of metals from the soil is large enough to affect forest productivity at current levels of acid

deposition is unknown.

A large area of U.S. forests is also exposed to

elevated ozone concentrations. Ozone has been

shown to damage tree foliage and reduce the growth

rates of certain sensitive tree species. But its

cumulative effect on forest productivity over the

lifetime of trees—half a century or more—is difficult to predict.

Transported air pollutants adversely affect agricultural productivity. Up to 90 percent of the damage to crops from air pollutants may be due to

ozone. Large areas of the United States, including

much of the Midwestern Corn and Soybean Belts,

are exposed to high levels of ozone. This study estimates that if ozone levels were reduced to their natural background levels, corn yields would have been

2 percent higher, wheat yields 5 percent higher, soybean yields 13 percent higher, and peanut yields

24 percent higher. Based on the value of these

crops, ozone causes about a 6- to 7-percent loss

of U.S. agricultural productivity.

Many areas of abundant agricultural production,

such as Illinois, Indiana, and Ohio, also receive

high levels of acid deposition. Some experiments

using simulated acid rain have demonstrated reduced yields of agricultural crops, but others have

found no effect.

Airborne pollutants accelerate the deterioration of many economically important materials.

Sulfur oxides damage iron and steel, zinc, paint,

and stone; certain types of rubber are susceptible

to ozone. Pollution-induced damage is difficult to

quantify because it cannot be distinguished readily

from the weathering effects of the natural environment. The bulk of materials damage is thought to

be caused by pollutants emitted locally. Regions

at greatest risk are urban areas (especially those in

industrial regions) and areas with historically

significant buildings and monuments. One recent

study estimated that reducing sulfur dioxide emissions in selected urban areas to achieve concentrations 25 to 30 percent below the current air quality

standard could yield materials-related benefits of

hundreds of millions of dollars annually.3 Pollutant effects on unique or historic structures may be

irreparable, and thus cannot be evaluated solely in

monetary terms.

Air pollutants—along with natural causes such

as humidity, fog, and dust—can significantly impair visibility. They reduce contrast, discolor the

atmosphere, and obscure distant objects. In the

Eastern United States, airborne sulfates appear

to be the single greatest contributor to reduced

visibility, causing about 50 percent of visibility impairment annually, and about 70 percent

during the summer.4 In the West, windblown dust

and nitrogen oxides can also impair visibility significantly.

Air concentrations of sulfur dioxide, nitrogen oxides, and ozone are currently regulated to protect

human health. No standards exist for airborne

sulfates, which may also pose a threat to human

health. At high exposure levels, sulfates can ag3E. H. Manuel, Jr., et al., “Benefits Analysis of Alternative Secondary National Ambient Air Quality Standards for Sulfur Dioxide

and Total Suspended Particulate, Mathtech, Inc., report submitted

to the U.S. Environmental Protection Agency, OAQPS, 1982.

‘For example, see M. Ferman, et al., ‘ ‘The Nature and Source of

Haze in the Shenandoah Valley/Blue Ridge Mountain Area, ‘J. Air

Pollution Control Assoc. 31: 1074-1082, 1981; and U.S. Environmental

Protection Agency, Protecting Visibility, An EPA Report to Congress,

EPA 450/5-79-008, 1979.
Ch. l—Summary 13

gravate existing heart and lung conditions such as

asthma. Several statistical studies comparing historical air pollution data and health records found

a correlation between airborne sulfate levels and

mortality, but whether there is a causal link between

the two is not clear. For instance, elevated sulfate

levels often occur with other airborne fine particles,

one or more of which might be causing harm.

Disagreement exists within the scientific community over the significance of airborne sulfates to

human health. Some researchers conclude that

there is a negligible effect at prevailing concentrations; others have found a significant association—several percent of annual mortality,

primarily among people with preexisting cardiac

or respiratory problems. By combining the various estimates, this study concludes that a reasonable estimate of the magnitude of health risk posed

by current levels of sulfates and other particulate

is about 50,000 premature deaths (2 percent of total

deaths) per year in the United States and Canada.

This estimated health risk from transported air pollutants is a measure of possible harm. It can neither be confirmed nor disproven until further research is conducted.

Acidified waters can dissolve metals and toxic

substances from soils, rocks, conduits, and pipes,

and subsequently transport them into drinking water systems. Municipal water supplies can be

monitored and corrected quite easily; potential

problems with well water in rural areas are more

difficult to detect and mitigate. Although acid deposition has not been proven to be the cause, water

samples from a few areas in the Adirondacks and

New England receiving high levels of acidity have

contained lead concentrations exceeding the healthbased standards.

THE RISKS OF CONTROLLING

TRANSPORTED AIR POLLUTANTS

The above discussion of the risks from transported air pollutants relies heavily on such words

as ‘ ‘could’ and ‘ ‘might’ because at present, we

can only make educated guesses about the scope

and severity of the problem. For example, scientists are certain that acid deposition damages lakes

and streams, and that ozone damages crops. But

they cannot say with certainty how many lakes and

streams and what quantity of crops have been

damaged. Nor can they forecast with confidence

what these damages will be in the future. Part of

the difficulty is the uncertainty about the extent to

which resource damage is cumulative—some types

of resource damage might worsen even if levels of

acid deposition remain about the same.

These uncertainties are compounded by imprecise knowledge of the transport and transformation

of pollutants emitted throughout the Eastern United

States and Canada. Scientists have devised atmospheric transport models to simulate the movement

of sulfur emissions. But even with these sophisticated tools, scientists can only estimate the amount

of sulfur pollution transported from one large region to another, over seasonal to annual time scales.

Similarly, scientists cannot confidently predict the

degree to which emissions reductions in one region

would reduce deposition in another.

Intertwined with the scientific uncertainties about

the benefits of a control program are disagreements

over values. Few would deny that there are significant environmental risks associated with transported air pollutants. But there are also risks associated with controlling these pollutants—the

risks that the benefits from reducing emissions

do not justify the economic and social costs.

Various groups and individuals differ sharply on

where the balance should be struck between protecting the environment and protecting other areas

of economic well-being. There is little agreement

on the intrinsic worth of resources or the equitable

distribution of costs to protect those resources. Unfortunately, more accurate atmospheric transport

models or a better understanding of the level of

emissions required to protect sensitive resources will

do little to solve such questions of values.
74 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

To put the risks and uncertainties of controlling

transported air pollutants into context, this study

examines a range of programs to reduce emissions,

focusing on the direct and indirect costs for specific regions of the United States and the country

as a whole.

Most of the proposals introduced during recent

sessions of Congress would control sulfur dioxide

emissions, since sulfur compounds contribute twice

as much acidity to rainfall in the Eastern United

States as nitrogen compounds and are more

strongly implicated with a variety of adverse effects.

This study estimates that the annual costs to reduce sulfur dioxide emissions in the 31 States

bordering and east of the Mississippi River could

range from about $1 billion (or less) for about a

10- to 20-percent reduction, to about $3 billion to

$6 billion for a 35- to 45-percent reduction below

1980 emissions levels by 1995.

The larger control programs could have several significant consequences. The average cost of

electricity will increase by several percent. Certain utilities and electricity-intensive industries

might be financially strained. And, if utilities

achieve emissions reductions in part by switching to low-sulfur coal, jobs would be displaced

from areas where coal high in sulfur content is

mined to areas producing low-sulfur coal.

Because electric utilities account for about threefourths of the sulfur dioxide emitted in the Eastern United States, most current legislative proposals

would require significant reductions in utility emissions. In particular, utilities in the Midwestern

States, which tend to burn high-sulfur coal, would

bear the greatest impact of an emissions control program. Ultimately, these costs would be passed on

to consumers in the form of higher utility bills. For

example, this study estimates that 10 million tons

of sulfur dioxide emissions could be eliminated

from existing sources nationwide for about $3

billion to $4 billion per year, increasing average electricity rates by 2 to 3 percent. These rate

increases would vary by State, as shown in figure

9. Consumers in some States would see no increases, while others would pay increases over three

times the national average. If the projected future

growth in emissions must also be offset through

reductions from current emitters (an additional

1 million to 3 million tons per year by 2000),

average residential electricity costs could rise by

about 4 to 5 percent, with increases of 10 to 15

percent in several States.

An emissions control program could strain the

financial resources of a number of electric utilities,

particularly if State regulatory policies prohibit

them from quickly passing on control costs to consumers. Based on selected economic ratings and the

range of current State policies, utility sectors in several States might be relatively vulnerable to the additional capital requirements for pollution control

equipment. Few of the States with the highest

percentages of economically vulnerable utilities,

however, are allocated extensive emissions reductions under current acid rain proposals.

Some firms and industries that rely heavily on

electricity could become less competitive if their

electricity rates were to increase substantially above

rates in other parts of the country. Of greatest concern are those that produce electrometallurgical

products, zinc and aluminum, alkali- and chlorinebased chemicals, and industrial gases.

If a control program is enacted that allows each

utility to freely choose its own method of achieving emissions reductions, some utilities will choose

to switch from burning high-sulfur coal to lowsulfur coal. Under such a ‘freedom-of-choice’

program to eliminate 10 million tons of emissions per year, future levels of high-sulfur coal

production could fall 10 to 20 percent below

1980 levels. Employment in regions that mine

high-sulfur coal could be 20,000 to 30,000 jobs

below projected levels. An equivalent number of

jobs would open up in Eastern and Western States

that mine low-sulfur coal. Legislation that mandates the use of high-removal control technology

could minimize such dislocations, but could increase total program costs by about $1.5 billion

per year.
Ch. l—Summary ● 1 5

Figure 9.—Cost of Reducing Sulfur Dioxide Emissions by 10 Million Tons per Year,

Nationwide Increases in Annual-Average Electricity Bills for a Typical Residential Consumer

A n

I

‘Average annual cost increase (1982 dollars) for a typical residence consuming 750 kWh/month electricity Percentage rate Increases in each State are calculated ‘rem

State. average 1982 electricity costs (ranging from about $200 to $900/yr, United States average about $600/yr)

SOURCE’ Office of Technology Assessment, based on analyses by E. H. Pechan & Associates, Inc.

POLICY OPTIONS

Four approaches for congressional action on acid

deposition and other transported air pollutants are

discussed below:

A. Mandating emissions reductions to further

control the sources of transported pollutants.

B. Liming lakes and streams to mitigate some

of the effects of acid deposition.

c.

D.

Modifying the Federal acid deposition research program to provide more timely guidance for congressional decisions.

Modifying existing sections of the Clean Air

Act to enable the Environmental Protection

Agency, States, and countries to more effectively address transported air pollutants other

than acid deposition.
16 ● Acid Rain and Transported Air Pollutants: Implication for Public Policy

Congress could choose to adopt some or all of these

approaches in its consideration of clean air legislation. A comprehensive strategy to address transported air pollutants might well include options

from all four of the approaches discussed below.

Approach A:

Discussion

Mandating Emissions Reductions

To Further Control the Sources of

Transported Pollutants.

Legislated emissions reductions could range from

modest reductions to keep emissions at—or somewhat below—current levels, to large-scale control

programs. In choosing an appropriate program,

Congress will need to weigh the risks of potential

resource damage, the risks of inefficient control expenditures, and the distribution of these risks

among different groups and regions of the country.

Mandating further emissions reductions would

require Congress to make a number of interrelated

choices. These include decisions about which pollutant emissions to reduce, from what regions, by

how much, and over what time period. Congress

would also need to choose specific policy mechanisms to implement the reductions, allocate their

costs, and address undesired secondary consequences of emissions reductions.

This study has divided these decisions into eight

distinct questions, which can be answered in different ways to produce different control programs.

Three representative control programs are presented at the end of the discussion of this approach.

● Which Pollutants Should Be Further

Controlled?

In the East, sulfur compounds currently contribute about twice as much acidity to precipitation as

nitrogen compounds. Moreover, throughout the

growing season, plants use much of the deposited

nitrogen as a nutrient, making sulfur compounds

responsible for a still larger share of acidity reaching

lakes and streams. Sulfur compounds damage materials and in the particulate form (sulfate) reduce

visibility and pose risks to human health. Both this

study and a recent report from the National Academy of Science conclude that decreasing sulfur dioxide emissions would reduce sulfur deposition by

roughly the same proportion. For these reasons,

. 3“

Photo credit: Roger Chen

A sulfate particle transformed from sulfur dioxide gas

in a water droplet. The black soot (fly ash) speeds the

conversion. Sulfate particles, when airborne, are part

of a “pollutant mix” that degrades visibility and poses

risks to human health. These small particles can be

suspended for several days, gradually settling to Earth

during dry periods, or rapidly washed from the air if

it rains. In either form—wet or dry-sulfur compounds

are major contributors to acid deposition.

sulfur dioxide is the logical focus for a program

to control acid deposition in the Eastern United

States.

Adding nitrogen oxides controls to the program is a reasonable next step if additional resource protection is desired. Nitrogen oxides

emissions are expected to increase more rapidly
Ch. 1—Summary ● 1 7

over the next few decades than sulfur dioxide emissions. During the spring—a vulnerable period for

aquatic life—both nitrogen and sulfur compounds

found in melting snow travel freely through watersheds to bodies of water and contribute to acidification. Reducing nitrogen oxides emissions would

also help lower regional ozone levels,

In the West, nitrogen compounds may contribute as much or more to precipitation acidity as

sulfur and, thus, should be considered if a nationwide control program is desired.

● How Widespread Should a Control

Program Be?

Both pollutant sources and resources sensitive

to the effects of transported air pollutants are

scattered across the Eastern United States. Because pollutants can travel hundreds of miles,

programs to protect sensitive resources must encompass much of this area. Four regions are potential candidates:

1.

2.

3.

4.

The 21 States east of the Mississippi River and

north of (and including) Tennessee and North

Carolina, which receive the greatest levels of

acidity. This region excludes several contiguous States that are large emitters.

The 31 States bordering and east of the

Mississippi River, which emit 83 percent of

the Nation’s sulfur dioxide and 66 percent of

its nitrogen oxides. This region has been the

focus of most legislative proposals to date.

The 37 States east of the Rocky Mountains,

which emit 89 percent of the Nation’s sulfur

dioxide and 85 percent of its nitrogen oxides,

The 48 contiguous States.

● What Level of Pollution Control Should

Be Required?

Possible choices for further emissions control programs range from modest control (which would

hold overall emissions at current levels) to largescale emissions reductions. The decision of how

much to reduce emissions involves two important

components: the scientific question of the

relationship between emissions reductions and resource protection, and the policy question of the

socially desirable level of protection.

Most of the control programs proposed in recent

sessions of Congress have aimed at reducing emissions by 8 million to 10 million tons per year below

1980 levels. Although the effects of such reductions

are hard to predict, this study estimates that reductions of 8 million to 10 million tons per year

below 1980 levels are likely to protect all but the

most sensitive aquatic resources in many areas

receiving high levels of acid deposition. Those

areas now receiving the highest levels of deposition— western Pennsylvania, for instance—

would also benefit from reductions of this magnitude, though some risk of damage would still

be present. Risks of damage to forests, agriculture,

materials, and health would likewise be reduced,

and visibility would improve. A control program

of this magnitude would cost about $3 billion to

$6 billion per year. Costs would rise steeply if

greater resource protection were desired.

More modest reductions, eliminating 2 million

to 5 million tons of sulfur dioxide per year from

existing sources, could be achieved for about $1 billion per year. Such a program would, at a minimum, offset expected emissions increases from utility and industrial growth, and might decrease

emissions by 2 million to 3 million tons per year

by the year 2000. Some resource improvement

might result, or degradation might be slowed, but

it is impossible at present to gauge by how much.

● By What Time Should Reductions Be

Required?

Significant emissions reductions from existing

sources would take at least 6 or 7—and possibly

10 or more—years to implement, given the planning, contracting, construction, and other steps

that would be necessary. Waiting 4 to 6 years

for the results of the Federal research program

could increase the time required to reduce deposition to 10 to 16 years or more. Although resource damage will continue, it is impossible to predict how much damage might occur to resources

during this additional delay, or how much more

efficient a control program designed at the end of

the decade might be. Because of the time needed

for planning, a control program initiated in the

near future would not involve major expenditures for at least 5 years. Control legislation could
18 ● Acid Rain and Transported Air Pollutants: lmplications for Public Policy

be modified with relatively modest cost penalties

until 2 to 3 years before the compliance date, at

which point major construction expenditures would

have to begin.

● What Approach to Control Should Be

Adopted?

Two general approaches are currently used for

environmental regulation: ‘‘source-based’ regulations and ‘ ‘environmental quality’ standards.

Source-based programs directly regulate the quantity of pollution allowed from emission sources. Programs based on environmental quality standards

set goals or standards for resource exposure to pollutants; steps are then taken to meet these goals.

Such a program requires a well-developed understanding of the transport, transformation, and

effects of pollutants. The knowledge needed to implement an environmental quality standard for

acid deposition is not yet available and may not

be for at least a decade. This study therefore concludes that a source-based program, which regulates emissions directly, is the only approach

available now for controlling acid deposition.

Such a program could specify, for example, maximum allowable emission rates (in pounds of pollutants per quantity of fuel burned) or maximum

allowable statewide emissions (in tons of pollutants

per year). A source-based approach could also limit

emissions by mandating the use of specific technologies such as scrubbers or coal washing.

● How Should Emissions Reductions Be

Allocated?

If Congress decides to mandate emissions reductions directly, it can either set a reduction formula

that applies to all or some of the sources within a

State, or it can set an overall reduction level for

each State and allow the State to allocate emissions

reductions within its borders. Congress could also

set specific environmental protection goals, including economic considerations, and direct the Environmental Protection Agency (EPA) to develop an

allocation plan to meet those goals.

Allocation formulas can take many different

forms. For example, emissions could be reduced

by an equal percentage in each State regardless of

whether the State is a relatively high or low emitter. Alternatively, allowable emission rates could

be set, requiring the greatest reductions from

sources that emit the greatest amounts of pollution

per unit of fuel burned or similar measure. Most

legislative proposals to date have followed the latter approach. A formula could be based on utility

emissions alone or statewide total emissions. Allocation formulas differ in their resulting geographic

patterns of emissions reductions and administrative

complexity.

● Who Pays the Costs of Emissions

Reductions?

The full costs of pollution control could be borne

by those sources required to reduce emissions. This

“polluter pays” philosophy is the traditional approach to environmental regulation; in the case

of transported air pollutants, however, the culpability of particular sources for specific resource

damage is difficult to assess. Thus, some advocate spreading the costs of a control program to

a larger group through such mechanisms as a tax

on electricity or emissions. Revenues would go

to a trust fund, to be used to help finance control

technology. Such cost-sharing mechanisms, however, can impose costs on areas that have taken

action in the past to control emissions or that

already have low emissions.

● What Can Be Done To Mitigate

Employment and Economic Effects of a

Control Policy?

To reduce employment dislocations resulting

from increased demand for low-sulfur coal, Congress could require the use of control technologies

designed for high-sulfur coal or require plants to

use locally mined coal. Mandating the use of scrubber technologies could increase the costs of emissions reductions by about 25 to 50 percent for a

large-scale program. Alternatively, if utilities are

allowed to switch from high- to low-sulfur coal,

workers or communities affected by the switch could

be compensated.
Ch. 1—Summary ● 1 9

To reduce the financial strain on specific utilities

or their customers, Congress could establish a trust

fund (as described under the previous question) to

help pay for pollution control equipment.

Options

Congress could design a control program by

selecting alternatives from each of the eight decision areas summarized above. Obviously, many

combinations are possible; three representative options are presented below.

Option A-1: Mandate small-scale emission

reductions.

A small-scale program would logically focus on

further controlling sulfur dioxide emissions—the

major manmade acidifying pollutant in the Eastern United States—within a 20- to 30-State region

producing and receiving the greatest acid deposition. Two million to three million tons of sulfur dioxide emissions could be eliminated from existing

sources for under $1 billion annually; 5 million tons

per year could be eliminated for about $1 billion

to $1.5 billion annually.

Control programs of this size would offset expected emissions increases of 2 million to 3 million

tons per year by the year 2000, holding levels of

acid deposition about constant or reducing them

slightly below current levels. Such a program could

be enacted alone, or as the first phase of larger programs discussed below, making the latter phase contingent on results of ongoing research.

Option A-2: Mandate large-scale emissions

reductions.

A large-scale program similar to those proposed

during recent sessions of Congress would reduce

sulfur dioxide emissions by 8 million to 12 million

tons per year. It could be confined to the Eastern

United States or applied nationwide and could also

include reductions in nitrogen oxides emissions.

We estimate that such a program would protect

all but the most sensitive lakes and streams in many

areas receiving high levels of acid deposition, Areas

receiving the greatest levels of acidity, however, still

might not be completely protected. Risks of damage to forests, crops, materials, and health would

also be reduced and visibility would improve.

The costs of such a program could range from

$2 billion to $3 billion per year to $6 billion to $8

billion per year, depending on its size and design.

Congress might choose to spread some portion of

control costs across a larger group than just those

sources required to reduce. A trust fund generated

by a tax on electricity or pollutant emissions could

be established for this purpose. Congress could also

mandate or subsidize the use of control technology

to minimize job dislocations associated with switching from high- to low-sulfur coal.

Option A-3: Specify environmental quality

goals or standards.

Rather than mandating specific emissions reductions, Congress could set environmental protection

goals (including economic considerations, if desired)

and direct EPA to establish a plan to achieve them.

Because the tools needed to establish such a program are not yet available, this approach would not

be feasible in the near future. It could, however,

be preceded by small-scale, mandated reductions

described earlier if Congress desired some emissions

reductions within a decade. The compliance date

for the remainder of the program might be set for

early in the next century, which might allow enough

time to develop the necessary modeling techniques,

establish the standard, and achieve the required reductions.

Approach B: Liming Lakes and Streams To

Mitigate Some of the Effects of

Acid Deposition.

Discussion

Several chemicals can be used to temporarily

treat acidified aquatic ecosystems. Mitigating the

effects of acid deposition on other sensitive resources

(e. g., forest soils) is not yet technically or economically feasible.

Adding large quantities of lime to water bodies

has been effective in counteracting surface water

acidification in parts of Scandinavia, Canada, and

the United States. These programs have significantly improved water quality at a number of lakes
20 Acid Rain and Transported Air Pollutants: Implications for Public Policy

Photo credit: Ted Spiegel

Sulfur dioxide being emitted from the Kingston powerplant in Tennessee. Sulfur dioxide gas is invisible to the naked

eye, but can be seen in the inset (upper right) with the aid of a special camera filter. The two 1,000-ft smokestacks were

built in 1976, replacing the nine smaller stacks built with the plant during the mid-1950’s. The tall stacks help the plant

comply with local air-quality regulations, but disperse pollutants more widely.
and ponds, permitting fisheries to be maintained,

Once begun, liming must be repeated every few

years to prevent reacidification and buildup of toxic

metal concentrations. Not all lakes and streams,

however, respond sufficiently to liming to reestablish aquatic life, and little is known about the ecological consequences of continued liming.

Federal funding over the last several years permitted only a few research projects on the effects

of liming to be undertaken each year. Several bills

introduced during recent sessions of Congress proposed additional Federal support for mitigation programs. The Administration recently proposed

about $5 million for liming research for fiscal year

1985. Funding at this level would provide more information on the feasibility of liming as a way to

counteract the effects of acid deposition on sensitive

lakes and streams. Such information would be extremely useful regardless of whether an emissions

control program is adopted. Specific options available to Congress for promoting mitigation research

are listed below.

Options

Option B-1: Expand current Federal mitigation

research efforts under the National

Acid Precipitation Assessment

Program (NAPAP).

Federal funding through NAPAP for research on

mitigation techniques—primarily liming—has been

very modest. Congress could make more research

funds available to expand this program so that it

would include lakes and streams of varying geological, geographic, and biological conditions.

Long-term monitoring of biological and chemical

changes in limed water bodies should be an integral

part of the program to determine frequency and

effectiveness of liming, as well as secondary effects

of this chemical alteration. Such a program could

aid the Fish and Wildlife Service in developing

guidelines that States, local communities, and private interests could use to mitigate the effects of

acidification.

Option B-2: Expand Federal-State cooperative

efforts for treating acidified surface

waters and assessing results.

Funds to assess the effectiveness of water treatments are available under the existing DingellJohnson Act, which imposes a 10-percent tax on

the wholesale cost of fishing tackle for projects to

benefit recreational fishing. However, States currently do little mitigation-related work with these

funds. Congress could direct additional resources

towards mitigation activities by placing requirements on the use of these funds, by making

more funds available, or by establishing new

Federal-State cooperative programs.

Option B-3: Establish demonstration projects

for acidified water bodies on

Federal lands.

Congress could direct the Fish and Wildlife Service or the Forest Service to establish programs to

treat selected lakes and streams on Federal lands

and monitor their chemical and biological responses.

Approach C: Modifying the Current

Research Program (NAPAP) To

Provide More Timely Guidance

to Congress.

Discussion

Under the Acid Precipitation Act of 1980 (Title

VII of the Energy Security Act of 1980, Public Law

96-294), Congress created an interagency task force

to carry out a comprehensive 10-year research and

assessment program on acid deposition. After 2

years of planning, the task force presented Congress with the National Acid Precipitation Assessment Plan. According to this plan, an integrated,

policy-related assessment is to be completed by 1987

and updated by 1989—a schedule that many members of Congress and public interest groups feel is

too slow.

Several bills have proposed accelerating the plan.

Such action has several disadvantages and is un-
22 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Photo credit: Ted Spiegel

This researcher is measuring the acidity of a lake in the Adirondack Mountains, N.Y. Research sponsored by both the

Federal interagency research program and such private groups as the Electric Power Research Institute has helped

scientists understand some of the causes and consequences of acid deposition. A continuing, strong research program

is needed, regardless of the outcome of emissions control legislation. Two important areas include: 1) effective methods

to treat already damaged lakes and streams (options B-1 to B-3), and 2) research on combined

air pollution stresses

likely to provide guidance to policy makers in the

short term. Redesigning the research schedule

would consume a substantial amount of time and

effort; moreover, many of the currently planned

studies cannot be completed in the shorter times

suggested. Accelerating the program might limit

longer term studies, which are of great importance

for evaluating and implementing any control program eventually put in place.

A strong, continuing research program is a necessary part of any strategy Congress might choose

to address the problem of acid deposition. Current

Federal research efforts could be strengthened in

several ways. Option C-1 below is appropriate if

Congress decides to wait several years to reconsider

to forests (option C-3).

an emissions control program; option C-2 is appropriate if Congress acts now to control acid deposition. Option C-3 could be adopted in either event.

Options

Option C-1: Establish a two-track research

program.

In the absence of a legislated emissions control

program, Congress could establish a policy assessment effort to be completed at an earlier date. The

program could be assigned to either the existing

interagency task force, or to a separate group entirely. Such a “two-track’ program, leaving the

current program largely intact, could analyze a
Ch. 1—Summary ● 2 3

series of control options within 2 or 3 years. This

effort would need to begin almost immediately and

therefore rely primarily on currently available information. Though this assessment would, by necessity, be based on less complete information than

one begun several years from now, it could provide a common set of control costs estimates, deposit ion reductions, and similar information about

alternative scenarios for policymakers to consider.

The assessment could provide important information for considering the initiation of a control program; the present, longer term effort would be completd in time to reevaluate a control program, if

enacted, beforc major expenditures occurred.

Option C-2: Redirect the research program if a

control program is legislated.

Though the National Acid Precipitation Program

was established as a long-term (10-year) effort, the

enabling legislation does not explicitly address its

fate if control legislation is passed. Maintaining the

program in such a case, with some modifications,

would have several benefits. Continued long-term

monitoring and research will be necessary to

evaluate the effectiveness of a control program after

its passage, providing the opportunity to modify

the control strategy if necessary. Also, with some

redirect ion, the program would provide valuable

guidance on implementing the control plan through

the 1990’s.

Option C-3: Broaden the ongoing research to

include other transported air pollutants.

The Acid Precipitation Act of 1980 established

an innovative, interagency research program addressing acid deposition. However, the effects of

acid deposition on many resources— in particular,

forests, crops, and materials—are difficult to separate from other pollutant stresses. Similarly, reducing emissions provides benefits in addition to

those associated with reduced levels of acid deposit ion, for example, improved visibility. Congress

could use the existing interagency structure and

broaden NAPAP’s mandate (and funding) to include research on other air pollutants. For example, recent studies showing forest productivity y

declines in the Eastern United States have raised

concerns about the combined stress from acid deposition, ozone, and heavy-metal deposition. An integrated approach to studying such pollutant mixes

could both strengthen the current research effort,

and, perhaps more important, provide guidance to

Congress about the more general problem of transported air pollutants.

Approach D:

Discussion

Modifying Existing Provisions

of the Clean Air Act To Enable

EPA, States, and Countries To

More Effectively Address

Transported Air Pollutants

Other Than Acid Deposition.

The Clean Air Act was designed to control airborne concentrations of pollutants known to endanger public health and welfare. No provisions

in the act provide a direct means of controlling the

deposition of air pollutants or their transformation

products.

Provisions were added to the act during its 1977

reauthorization to prevent a States emissions from

causing violations of National Ambient Air Quality

Standards in other States or contributing to a pollution problem in other countries (sees. 110

and 115, respectively). These provisions are worded

very generally and contain no guidelines for determining the sources or effects of transported air

pollutants.

Several States have attempted to use these provisions, either through petitions to EPA or litigation in Federal courts, to force other States to curb

emissions. To date, few of these suits or petitions

have been settled. Recent decisions by Federal

courts suggest that they are not prepared to require

EPA to give broader consideration to interstate pollution than it does now.

To make the Clean Air Act a more effective

means of controlling interstate and international

pollution transport, Congress could modify the act

in several ways. The changes discussed below would

be helpful for addressing many transported air pollution disputes, but would probably be of limited

use for such geographically widespread problems

as acid deposition.

99-413 0 - 84 - 3 : QL . 3
24 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Options

Option D-1: Amend requirements for

considering interstate pollution

under the Clean Air Act.

Section 110 of the Clean Air Act is a very

general provision that offers little guidance on how

much interstate pollution is permissible, whether

the law applies to the individual sources or to the

cumulative sources throughout a State, and how

interstate effects are to be demonstrated. Congress

could amend the section to clarify EPA responsibilities for assessing and regulating interstate pollution. In addition, Congress could modify procedures for review of interstate pollution petitions

(contained in sec. 126 of the act) to allow States

to move on to the judicial appeals process if EPA

does not act on the petitions before it. Such action

would help eliminate the current bottleneck of

States’ petitions within EPA. Again, such changes

would probably not make the Clean Air Act more

effective in dealing with acid deposition, as the section applies only to pollutants for which National

Ambient Air Quality Standards exist, Such changes

might, however, assist States seeking relief from

transported air pollutants currently regulated under

the Clean Air Act.

Option D-2: Amend the international

provisions of the Clean Air Act.

Section 115 of the Clean Air Act was designed

to address local pollution effects occurring across

an international boundary. As with section 1 IO(a)

(2)(E), its lack of specificity makes it an unwieldy

tool for controlling air pollutants transported over

long distances. Congress could amend this section

to make it a more effective means of controlling

these pollutants, for example, by identifying an

appropriate international agency (e. g., the International Joint Commission) or providing a mechanism to establish bilateral commissions to address

such problems. Such mechanisms might assist efforts to settle future international air pollution

disputes.
Chapter 2

The Policy Dilemma
Contents

Page

The Pollutants Addressed in This Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Why Transported Air Pollutants Are an Issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Public Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Why Transported Pollutants Are a Federal Concern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Characteristics of the Policy Debate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Disagreements Over Facts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Distributional Issues. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Disagreements Over Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Risk and Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Key Scientific Uncertainties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Uncertainty About the Extent and Location occurrent Damages . . . . . . . . . . . . . . . . . . 32

Uncertainty About Future Damages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Uncertainty About the Origin of Observed Levels of Transported Pollutants . . . . . . . . 34

Uncertainty About the Effectiveness of Emissions Reductions for Reducing Levels of

Transported Pollutants at Desired Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Uncertainty About Whether a Research Program Will Provide Significant New Information 36

FIGURE

Figure No. Page

10. Processes and Environmental Effects of Acid Deposition . . . . . . . . . . . . . . . . . . . . . . 28
Chapter 2

The Policy Dilemma

Fossil fuels are vital to the U.S. economy’s production of goods and services. However, burning

these fuels also produces large quantities of

pollutants— substances that, once released into the

atmosphere, can damage natural resources, health,

agricultural crops, manmade materials, and visibility. Consequently, our Nation’s laws and policies

must strike a balance between the economic benefits and the environmental risks of fossil fuel combustion and other pollution-producing activities.

This assessment focuses on one class of air pollutants: those that are transported over large regions, either in their original form or as chemically transformed products. Such pollutants include

acid deposition, ozone, and airborne sulfate. The

current Clean Air Actl was designed to ameliorate

‘Clean Air Act Amendment of 1977, Public Law 95-95 (Aug. 7,

1977), as amended,

local-scale pollution problems, and does not directly

control pollution transport across hundreds of miles.

Over the past several years, controlling pollutants

that contribute to acid rain has become a major policy issue. The House Committee on Energy and

Commerce and the Senate Committee on Environment and Public Works—the committees that oversee the Clean Air Act—requested OTA to assess

what is known about transported air pollutants, including the benefits and costs of controlling them.

OTA’s assessment primarily addresses potential effects in the eastern half of the United States, focusing on the risks of damage to sensitive resources,

the economic risks that arise from further controlling pollution emissions, and how these risks are

distributed among different groups and regions of

the country. Policy alternatives available to Congress are also presented.

THE POLLUTANTS ADDRESSED IN THIS STUDY

Acid deposition, ozone, and airborne sulfate are

produced from three air pollutants: sulfur dioxide,

nitrogen oxides, and hydrocarbons. Acid deposition, commonly referred to as ‘‘acid rain, involves

a variety of pollutants deposited in both wet and

dry forms; it results from sulfur and nitrogen oxide gases, sulfates and nitrates (transformation

products of these gases), and from interactions with

other chemicals in the atmosphere. Figure 10 illustrates the pathways these pollutants travel through

the environment. Both directly emitted or ‘ ‘primary pollutants and transformed or ‘‘secondary

pollutants contribute to acid deposition. Both can

be of concern on the local scale as well as on a regional scale. A pollutant can be returned to the

Earth’s surface within an hour or travel in the atmosphere for longer than a week, depending on its

chemical properties, and factors such as weather

patterns and other pollutants present in the atmosphere.

Besides contributing to acid deposition, the

secondary pollutants addressed in this study —sulfates, nitrates, and ozone—are of concern for other

reasons. Regional visibility degradation is closely

correlated with concentrations of airborne sulfate

particles. Sulfate particles in the atmosphere are also

small enough to be deeply inhaled, and are thus

of concern for their effects on human health.

Ozone—formed in the atmosphere from nitrogen

oxides and hydrocarbons—is injurious to plant life

and of concern to human health.

Secondary air pollutants have several factors in

common:

1. they can form over periods ranging from

hours to days and travel hundreds to possibly

thousands of kilometers;

2. they cannot be controlled directly, but only

by controlling the pollutants from which they

27
28 ● Acid Rain and Transported Air pollutants: Implications for Public Policy

10.—Processes and Environmental

SOURCE: Adapted from The Acid Precipitatlon Problem (Corvallis, Oreg.: U.S. Environmental Protection Agency, Environmental Research Laboratory, 1976).

3.

are formed (and possibly other pollutants that 4. they manifest themselves in several ways—

determine their rates of transformation); e. g,, sulfate contributes both to acid deposidifferent secondary pollutants result from the tion and to reductions in visibility.

same primary pollutants—e. g., nitrogen oxides can react to form both nitrates and ozone;

and

WHY TRANSPORTED AIR POLLUTANTS

ARE AN ISSUE

Public Concerns

Current evidence indicates that acid deposition

has significant adverse effects on lakes and streams.

Additionally, scientific concerns have been voiced

over potentially significant effects on forests and

soils, agricultural crops, manmade and natural

materials, visibility, and human health. Recognizing this risk of damage, some individuals and

groups have called on the Federal Government to

control pollutant emissions more stringently than

current laws require. They cite large numbers of

acidified lakes and streams, observed forest declines

in polluted areas of Western Europe and Eastern

North America, experiments showing crop damage, and deterioration of historic structures as

evidence that air pollutants are causing widespread

damage to important natural, economic, and cultural resources. Recommendations for additional

emissions control have come, for example, from the

National Commission on Air Quality, the National

Governors’ Association, the State and Territorial
Ch. 2—The Policy Dilemma * 29

Air Program Administrators, study groups of the

National Academy of Sciences, and the 1982 Stockholm Conference on the Acidification of the Environment.

Others, pointing to uncertainties about the causes

and consequences of transported pollutants, are

concerned that further emissions controls may be

mandated prematurely. They suggest that pollution transport processes, potential effects, and alternative mitigation strategies are poorly understood;

thus, further controlling emissions now may waste

money and impose unreasonable costs on industry

and the public. Over the past several years, such

concerns have been voiced by the U.S. Environmental Protection Agency (EPA), the Department

of Energy, the Business Roundtable, and the U.S.

Chamber of Commerce. Reducing total sulfur dioxide emissions by more than about 25 percent in the

Eastern United States is estimated to cost in the

billions of dollars annually. Efforts to control

transported air pollutants through stringent sulfur

dioxide emissions controls could increase electricity rates as well as displace mining jobs by reducing demand for high-sulfur coal.

Transported air pollutants also raise significant

equity issues. Those served by the activities generating acid rain and ozone can be different from

those who incur resource damage. Similarly, particular groups and regions might bear an unequal

share of the costs of controlling transported air

pollutants.

Why Transported Pollutants Are

a Federal Concern

Transported air pollutants have become an issue

for potential Federal action because they cross

political boundaries. The current Federal system

of pollution control relies on State-level abatement

programs to limit pollution levels within individual

States. * However, no effective means of controlling extensive pollution transport across State lines

currently exists. Transported pollutants also cross

the international boundary both into and from

Canada. Article 1, Section 10 of the Constitution

prohibits States from entering into agreements with

foreign nations without the consent of Congress;

thus, any pollution control agreements with Canada

would require Federal action. * *

Existing Federal air pollution control mechanisms are governed primarily by the Clean Air Act,

which Congress is now considering for reauthorization. To date, control strategies developed under

the Act have focused on controlling local ambient

air concentrations. However, many observers have

questioned the effectiveness of this approach for

controlling transported air pollutants.

● ● The United States and Canada signed a Memorandum of Intent

in August 1980, establishing a bilateral research plan to investigate

transboundary air pollution and pledging work toward a bilateral accord on transboundary air pollution. Negotiations began on June 23,

1981, and are still in progress.

● National emissions limits for new sources of pollution (New Source

Performance Standards) are in place to control future pollution

emissions.
30 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

CHARACTERISTICS OF THE POLICY DEBATE

Several aspects of transported air pollutants have

shaped the public policy debate over whether or not

to further control pollutant emissions at this time.

First, scientific uncertainty exists over the current

severity and geographic extent of the damages attributable to transported air pollutants, as well as

over the timeframe in which further damage might

occur. Second, and of great political importance,

transported air pollutants pose a distributional

problem, having intersectoral, interregional, international, and intergenerational equity aspects.

Third, significant disagreements in values exist over

how to balance the costs of controlling pollutants

and the environmental risks posed by pollution.

Disagreements Over Facts

Debate over scientific understanding of transported air pollutants is perhaps the most visible

aspect of the policy controversy. Many assert that

the causes and consequences of acid deposition are

both sufficiently understood and significant to warrant immediate action to control it. Others emphasize the complexity of the phenomena involved, and

argue that no regulatory strategy can be justified

on the basis of existing scientific knowledge.

Scientific uncertainty is not new to air pollution

policy. The continuing controversy over the nature

and magnitude of health risks—the critical measure

for setting local air quality standards—illustrates

the difficulty of unambiguously documenting the

scientific basis for regulation. Similarly, the extent

to which transported air pollutants affect health,

crops, visibility, materials, forests and soils, and

lakes and streams is uncertain. Current inability

to quantify these relationships precludes agreement

as to whether the benefits of reducing pollutant

levels would justify the costs involved in further controlling emissions.

Because some types of air pollutants can be transformed, dispersed, and transported over long distances, identifying the specific emission sources

responsible for resource damage in a particular area

is extremely difficult. Consequently, designing

emission control policies for transported pollutants

becomes difficult both analytically and politically:

analytically, because the sources that can most efficiently reduce deposition in the affected areas may

not be readily identifiable; politically, because placing the burden of control on certain regions may

appear to be arbitrary or inequitable,

Distributional Issues

The distributional aspects of transported air

pollutants further complicate the policy dilemma.

Pollution control, by affecting the relative prices

of various products, benefits economic activities that

are inherently less polluting, or that can reduce pollution less expensively, at the expense of more pollution-intensive goods and services. But the geographical scope of transported air pollutants creates

several distributional issues not present in conventional, local air pollutant problems.

Within the United States, winds carry pollutants

over long distances, so that activities in one region

of the Nation may contribute to resource damage

in other regions. Many of these activities primarily benefit the source region, while some of their

costs, in terms of resource damage caused by their

waste products, fall elsewhere. Long-range pollution transport thus redistributes benefits and costs

among regions. Programs to control transported

air pollutants would also have interregional

distribution aspects. The costs of controlling emissions might be imposed primarily on source regions

(depending on the scheme for allocating costs),

while the major benefits of reducing emissions

might accrue primarily to downwind, receptor regions.

Winds also carry pollutants over national borders, posing an international as well as an interregional distribution problem. About three to five

times more pollution is transported from the United

States to Canada than reaches this country from

Canada.2 The Canadian Government asserts that

fossil fuel combustion in the United States is damag2United States-Canada Memorandum of Intent on Transboundary

Air Pollution, Executive Summary, Work Group Reports, February

1983.
Ch. 2—The Policy Dilemma ● 3 1

ing lakes and streams, and might damage forests,

in Eastern Canada; consequently, Canada is paying some of the costs of U.S. economic activities.

Federal and provincial Ministers of the Environment have pledged to reduce sulfur dioxide emissions by 50 percent in Eastern Canada by 1994 and

urged the United States to undertake parallel emissions reductions. Distributional equity questions

would still exist if the two nations undertake further control programs, in that the United States and

Canada might benefit differentially from reduced

transboundary pollution.

The intergenerational aspects of transported air

pollutants raise yet another equity issue. Both the

appearance of harmful effects and the recovery of

damaged resources may lag behind changes in pollution levels. For instance, lake and stream acidification and forest damage may take on the order

of decades to occur. Because acid deposition may

diminish a watershed’s ability to neutralize future

acid inputs, future resource damages may depend

on the total amount of deposition an area has already received. In addition, resources may require

a relatively long period of time to recover following a reduction in the level of acidic inputs. If both

the onset and amelioration of adverse effects involve

extensive delays, the amount of acid deposition produced by one generation could affect the quality

of ecological and other societal resources available

to future generations.

Disagreements Over Values

Even if a scientific consensus existed on the

magnitude of the problem of transported pollutants,

policy choices would still be complicated by lack

of agreement over how to promote economic development while protecting the environment. Although the concept of a tradeoff between these two

values is widely accepted, various individuals and

groups differ sharply on where the balance should

be struck.

Disagreements over facts and values are intertwined. Differing value structures lead various individuals and groups to draw quite different conclusions from the same body of scientific information. Widespread recognition of scientific uncertainties has focused the policy debate on whether

both the magnitude of damage involved and the

effectiveness of control efforts are sufficiently known

to pursue emissions reductions. This dispute involves both relatively objective issues of science,

e.g., how reducing sulfur emissions might affect sulfur deposition in certain areas, and subjective issues

of values, e. g., what level of scientific certainty

and/or what degree of damage is required to justify

undertaking a control program.

RISK AND UNCERTAINTY

Scientists can describe potential resource damage control expenditures, and the distribution of

and regions of the United States most susceptible these risks among different groups and regions

to damage from transported pollutants, but they of the country.

cannot precisely quantify what levels of damage

have already occurred or could occur in the future. Risk, in the sense used in this report, refers to

Similarly, analysts can estimate the costs of alter- some possible, harmful outcome—either resource

native control strategies, and who might bear these damage or excessive control costs. Three concepts

costs, but how effective these control strategies are important:

would be for avoiding resource damage cannot be

calculated with confidence. Given the difficulty of 1.

quantifying the relationship between reducing emis- 2.

sions and preventing resource damage, Congress

must base near-term policy decisions on the risks 3.

of resource damage, the risks of unwarranted

a potential for harm exists;

there is some uncertainty about whether the

harm will actually come to pass; and

if it does, there is uncertainty about how extensive it will be.
32 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Throughout this report, OTA describes the risks

of controlling or not controlling transported air

pollutants, emphasizing those risks with potentially

significant consequences for society. To put this information in perspective, wherever possible, we

have tried to describe the uncertainty in estimates

of the magnitude and extent of the potential harm,

as well as how likely such harm is to occur.

Assessments of risk such as those presented in

chapter 3, and the regional descriptions presented

in chapter 5, focus on potential consequences, not

necessarily the consequences that will, in fact, occur. Uncertainty—stemming from limitations in

data and understanding—precludes drawing definitive scientific conclusions. Nonetheless, uncertainty does not remove the risks to which society

is actually subjected, although it makes these

risks substantially more difficult to describe.

Five key uncertainties, chosen for their relevance

to the policy debate, are presented below.

KEY SCIENTIFIC UNCERTAINTIES

Later chapters of this report will describe what

is at stake in decisions to control or not to control

transported air pollutants. This chapter outlines key

uncertainties to provide an overview of current debates within the technical and scientific community. Each of these uncertainties will also be discussed

throughout the report as appropriate to the issue

being addressed.

Five key uncertainties are especially relevant to

congressional decisions about transported air pollutants. These include controversies about:

1.

2.

3.

4.

5.

the extent and location of current damages,

future damages (whether they are cumulative

and/or irreversible),

the geographic origins of observed levels of

pollution,

the effectiveness of emissions reductions for

reducing current levels of transported pollutants, and

whether a research program will provide significant new results.

These scientific uncertainties affect several policy

concerns, including:

●

●

●

making air pollution control policy as fair as

possible, i.e., providing some legal recourse

to those bearing the risks of damage, and (if

a control program is adopted) distributing costs

of control fairly;

minimizing cumulative and irreversible damage, and their intergenerational implications;

weighing the risk of damage against gains that

might be achieved by waiting for better information or improved technology; and

. assuring that the societal benefits of a control

program justify the cost.

Uncertainty About the Extent and

Location of Current Damages

Scientists are certain that transported air pollutants have caused some damages. At issue is

the severity of the damage, whether it is fairly

localized or widespread, and which resources are

affected. For example, there is little question that

acid deposition damages lakes, and ozone harms

crops. The uncertainties revolve around how many

lakes and streams and what quantity of crops. For

these and other resources, the risks of extensive

damage over large parts of the United States are

substantial. Chapter 3 summarizes the aggregate

risks in the Eastern United States for a number of

affected resources; chapter 5 describes the regional

patterns of these risks using an extensive series of

maps. Appendixes discuss each resource of concern

in greater detail.

For certain concerns, such as the extent of damage to forests from acid deposition, the uncertainties are so large that it is difficult to describe the

patterns or magnitude of the risk. Damage to forests

from ozone, and the effects of toxic metals released

into drinking water due to acid deposition, also fall

into this category. The report also discusses these
Ch. 2—The Policy Dilemma 33

types of risks, presenting geographical patterns

where possible.

Uncertainty About Future Damages

Growing scientific recognition that transported pollutants are linked to observed damages

intensifies concern over the potential for future

damage, even if current damages are not extensive. Of particular importance is the extent to

which damages are cumulative and/or irreversible.

The Extent to Which Damages Are Cumulative

For some resources, pollution-related damages

might worsen over time if pollution remains at

about current levels. For short-lived species, such

as crops harvested annually, this is not a relevant

concern. Damage to this year’s crops from ozone—

and potentially from acid deposition—is caused

only by current levels of pollution. However, for

longer lived species such as trees, cumulative damage is of concern. Ozone injury and potential acid

deposition-related damage to forests maybe sma11

in any one year, but continued stress over many

years could ultimately reduce productivity.

The portion of current aquatic resource damage

attributable to the cumulative effects of deposition

over many years is also uncertain. One major unknown is the degree to which years of exposure to

acid deposition deplete the neutralizing capability

of soils in the surrounding watersheds.

The extent to which damages accumulate—and

over what time scale-has played a major role in

the policy debate over the risks of delaying control

action. If damages are not significantly cumulative,

delaying control action while awaiting further information would not increase the level of damage

Photo credit: New England Interstate Water Pollution Control Commission

Much of the acid deposition that eventually enters a lake or stream first reaches the ground in the surrounding

watershed, and travels with runoff water over soils and bedrock
34 Acid Rain and Transported Air Pollutants: Implications for Public Policy

from year to year (assuming that the level of pollution remains fairly constant). However, for those

effects of transported pollutants that are cumulative,

the longer control actions are delayed, the greater

the severity of the damage.

The Extent to Which Damages Are Irreversible

A closely coupled concern is whether damage can

easily be reversed, and if so, over what time period?

Again, once ozone concentrations are reduced below damaging levels, direct crop damage is easily

eliminated the following year. At the other extreme,

damage to monuments or other unique art objects

from air pollution would be irreversible.

If acid deposition is reduced, fish populations

may be restored either by restocking or by natural

means. However, if surrounding soils have lost their

Photo credit: New England Interstate Water Pollution control Commission

Acid deposition might harm trees directly or alter

the soils in which they grow. However, more research

is necessary to determine to what extent current levels of

acid deposition and other transported pollutants are

involved in observed declines in Eastern U.S.

forest productivity

acid-neutralizing capability, even moderate inputs

of acid may prevent fish from returning for decades

unless the water body is periodically treated with

lime. Similarly, if acid deposition causes nutrients

to be lost from a forest floor, forest productivity may

be impaired for many decades. The effects of a severe series of ozone episodes, or the potential cumulative effects of acid deposition, will persist in

the forest community until a new forest grows.

The potential irreversibility of resource damage

makes delaying control action until better information is obtained highly controversial. For those

damages that are reversible, it is important to know

how alternative levels of pollution reduction would

affect the extent of resource improvement. Chapters

3 and 5 present estimates of the benefit to crops

and aquatic resources of reducing ozone and acid

deposition levels, although considerable uncertainty

surrounds these preliminary estimates. However,

to the extent that damages are both significantly

cumulative and irreversible, waiting for better information would irreparably harm resources for this

generation and the next several to follow.

Uncertainty About the Origin

of Observed Levels of

Transported Pollutants

Pollutants Leading to Acid Deposition

The previous sections have outlined uncertainties concerning the potential benefits of reducing

current levels of transported pollutants. If policymakers wish to reduce current levels of pollutants,

the next logical question is, ‘‘Where are they coming from?” Three questions are important: 1)

whether the precursor pollutants are of natural or

manmade origin; 2) whether they come from local

sources or from distances exceeding hundreds of

kilometers; and 3) whether it is possible to define

the geographic origin of pollutants deposited in a

particular region. These questions are addressed

briefly in chapter 4, and in greater detail in appendix C.

The first two questions are not key uncertainties. Though pollutants of natural origin cause

some acid deposition, deposition over large areas

of the Eastern United States far exceeds the level
Ch. 2—The Policy Dilemma . 35

attributable to natural sources of pollutants. In

addition, while local sources (i. e., within 30

miles) do contribute to acid deposition, most

analyses indicate that a large share of the

deposition— in some cases, over half-originates

from both medium-range and distant sources

(i.e., greater than 300 miles away) as well.

The key uncertainty is whether scientists can

reliably determine how much of the deposition in

any one region originates from emissions in any

other. Computer models of varying sophistication

are available to perform such analyses, but their

accuracy in portraying this relationship is uncertain. The inherent variability of weather patterns and the complexity of atmospheric chemistry make it unlikely that models will ever be

able to predict how much one individual source

of emissions contributes to deposition in a small

area. However, these models can be used to assess

current annual average patterns of pollutant

transport over large geographic regions—on this

scale, models reproduce observed patterns of annual sulfur deposition in rainfall reasonably well.

Their capacity to synthesize extensive meteorological data makes these models the best available tools

for describing the current relationship between

emissions in one area and deposition in another.

Model-based estimates of the extent of interregional

transport for sulfur pollution are presented in

chapter 4.

Model adequacy is a critical element in several

suits and petitions by States to control transported

air pollutants under the interstate provisions of the

current Clean Air Act. EPA considers available

models inadequate to reliably analyze long-range

pollution transport; consequently, the Agency does

not assess the effects of pollution that travels beyond

50 kilometers (30 miles). However, the petitioning States assert that available ‘ ‘long-range transport’ models reflect the state of the art and should

therefore be used by EPA.

In addition, policy-level attempts to reduce pollutant deposition in identified, sensitive regions

would rely to a large extent on model-based abilities

to determine the sources of such deposition. However, no amount of accurate, detailed modeling information would be sufficient to eliminate policy

disputes over which region’s resources should be

protected, or which region’s emissions should be

controlled.

Photo credit: Ted Spiegel

Tracking this weather balloon by radar helps to determine

how air masses travel and mix under a variety of

atmospheric conditions. Such data are important for

understanding how pollutants are transported and

transformed when they are aloft

Because many regions have sensitive resources,

and all of them receive some deposition from each

of many emitting regions, a variety of possible

strategies could be used to reduce deposition on sensitive resources. For example, decisionmakers, in

response to equity concerns, could develop control

programs under which multi-state regions responsible for “large” shares of deposition in ‘‘several’

sensitive areas bear the ‘‘greatest share’ of emissions reductions. Whether the broad regional patterns of transport described by the models are accurate enough for this purpose is as much a policy

question as a scientific one.

Pollutants Leading to Ozone Formation

The same three questions apply to ozone:

whether the precursor pollutants are of natural or
36 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

manmade origin, whether they are of local or distant origin, and whether it is possible to pinpoint

the geographic source of deposition in a specified

region. As with acid deposition, ozone levels over

broad regions of the United States exceed natural

background levels. Though locally produced ozone

is a problem in many of the Nation’s urban areas,

ozone’s chemical precursors can travel long distances, and elevated ozone levels are found in rural

areas downwind from emission sources. However,

models of long-range ozone transport are in a rudimentary stage of development. Because the chemistry of ozone formation is very complex, major

uncertainties exist over the geographic origin of

elevated ozone concentrations in rural areas.

Uncertainty About the Effectiveness

of Emissions Reductions for Reducing

Levels of Transported Pollutants

at Desired Locations

Uncertainty about the effectiveness of reducing

emissions as a means of controlling transported pollutants stems from two factors. The first-uncertainty about how well current models describe the

relative contribution of one area’s emissions to another’s pollution—has been explained in the previous section. While this ‘‘source-receptor’ relationship cannot be defined precisely, existing models can synthesize extensive meteorological information to provide broad regional descriptions. Still,

the remaining uncertainty raises questions about

the extent to which emissions reductions in any

specific area would reduce pollution in another

area.

The second unknown concerns the chemical

processes that transform pollutants in the atmosphere. It is known that numerous complex

chemical reactions are involved in forming ozone,

airborne sulfates, and acid deposition. Uncertainties exist about how effective reducing emissions

of each precursor pollutant will be in controlling

the transformed products.

For example, sulfur dioxide emissions are transformed to sulfate, a major constituent of acid deposition, Reducing the total amount of sulfur dioxide emitted will undoubtedly reduce the overall

amount of deposited sulfate, but it is difficult to

quantify the reduction in deposition that a specific

emissions cutback will produce in a specific area.

Most analyses indicate that reducing sulfur dioxide emissions within a broad control region will

significantly, but not quite equally, reduce the

amount of sulfur deposited in various forms in

that region. However, some scientists are uncertain that reducing sulfur dioxide emissions alone

is the most efficient way to control acid deposition.

Because other pollutants (e. g., hydrocarbons and

nitrogen oxides) can enhance or impede chemical

transformations of sulfur dioxide, these other pollutants might also be controlled simultaneously to

reduce acid deposition in specific geographic

regions. Chapter 4 and appendix C discuss this in

greater detail.

Uncertainties about which pollutants to control,

as well as the uncertain relationship between emissions reductions and deposition reductions, complicate the policy objective of reaping the greatest

possible benefit from the costs of controlling emissions. Scientists are unable to confidently project

the precise pattern of deposition reductions that

would result from a specified emissions control plan.

Under these circumstances, a control program designed and implemented today might not produce

the maximum benefits achievable for a given cost.

Uncertainty About Whether a

Research Program Will Provide

Significant New Information

One of the most difficult decisions facing Congress is whether to act during this reauthorization

of the Clean Air Act, or to await results from ongoing, multimillion dollar Federal and private research efforts on acid deposition. While the research

efforts are intended to reduce the uncertainty discussed above, how much new insight 4 to 6 years

of further research will provide is unknown.

For example, years to decades are required to

observe changes in many ecological processes. Patterns of crop yield and forest productivity typically vary from year to year; separating the effect of

acid deposition from normally expected year-toyear fluctuations requires many years of data. The

processes of soil formation and depletion proceed

on the time scale of decades. These mechanisms
Ch. 2—The Policy Dilemma ● 3 7

Photo credit: Ted Spiegel

Collecting and testing water droplets from clouds high

above the ground in southern Ohio. Researchers also use

this airborne Iaboratory to analyze gaseous and

particulate pollutants in the atmosphere

can be artificially accelerated and studied in laboratories, but the extent to which such experiments

reflect real-world conditions is uncertain.

While scientists understand the basic mechanisms

of acid formation and deposition, detailed knowledge of the complex chemistry and meteorology involved will require many more years of research.

Ongoing efforts to evaluate the current generation

of computer models that simulate atmospheric processes have already taken several years, Efforts to

develop new transport and transformation models

are underway; the number of years needed to significantly improve existing models is unknown.

Uncertainties about the progress of research programs are important in considering the timetable

for policy decisions. Given the planning and construction efforts required to significantly reduce

pollutant emissions, a decision to control emissions

now may still require 6 to 10 or more years to implement. Waiting another 4 to 6 years for the

results of a research program before making control decisions increases the time required to reduce deposition to 10 to 16 years. Delaying control action increases the risk of resource damage

but reduces the risk of inefficient control expenditures. Congress could avoid this delay by

mandating controls now, while retaining the option

to change the law if new research results point to

alternative courses of action. To achieve compliance

within a decade, however, expenditures would have

to begin within 6 to 8 years. If results suggesting

an alternative control strategy appear much after

this time, major expenditures may be irrevocable.
Chapter 3

Transported Air Pollutants:

The Risks of Damage and

the Risks of Control
Contents

Page

No Congressional Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Resources at Risk..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Risks of Health Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Potential for the Courts or EPA To Rule in the Absence of Congressional Direction . 48

Risk of Strained International Relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

If Further Emissions Reductions Are Mandated . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Utility Control Costso . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Effects on the U.S. Coal Market . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Effects of Utility and Industrial Financial Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Risk That Control May Not Be As Effective or Efficient As Desired . . . . . . . . . . . 52

Effectiveness of Emissions Reductions for Achieving Desired Deposition Reductions . . 53

Efficiency Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Chapter 3

Transported Air Pollutants: The Risks of

Damage and the Risks of Control

As discussed previously, the risks of transported

air pollutants are amenable only to qualitative descriptions. Certain aspects can be described numerically—for example, the numbers of lakes and

streams currently altered by acid deposition, or people exposed to health risks from airborne sulfates

and other small particles. Wherever possible, this

report also presents numerical estimates of the risks

to a region’s resources, industry, jobs, and consumer pocketbooks, However, the substantial uncertainties associated with available data and theory

mean that these numerical descriptions should be

viewed as qualitative estimates, rather than exact,

quantitative answers. One should not be misled by

the apparent precision of the numbers. The information presented is intended to convey approximate outcomes—in some cases with unknown margins of error—and broad regional patterns.

This chapter summarizes the OTA estimates of

risk to the Eastern United States as a whole.

OTA-sponsored or in-house work provides the basis

for most of these estimates. Chapter 5 will examine

who bears these risks, by State and by economic

sector. These chapters use the somewhat artificial

dichotomy of mandating further emissions reductions vs. maintaining the status quo as a framework

for describing potential consequences. Chapters 6

and 7 of this report present congressional options,

including interim decisions, in greater detail.

NO CONGRESSIONAL ACTION

Resources at Risk

Two factors determine the potential for resource

damage from transported air pollutants: 1) the

amount of pollution to which the resource is exposed, and 2) the sensitivity of resources to acid

deposition and ozone. Resource sensitivity varies

from resource to resource—and among the specific

plants, animals, soils, and materials within each

resource category. Some resources are directly affected by the pollution received. For example, crops

are affected by exposure to ozone, and some building materials are affected by acid-producing substances deposited on their surfaces.

For other resources, sensitivity also depends on

characteristics of the local environment. For example, lakes and streams are affected primarily by the

amount of acid-producing substances that eventually travels through the watersheds to lakes and

streams, as well as by the acid deposition that falls

directly onto the surface of the water. The acid-neutralizing capabilities of the soil and bedrock in the

surrounding watershed help determine the susceptibility of water bodies to acid deposition. Acid

deposition may affect forests through subtle soil

chemical changes—here again, the sensitivity of the

forest resource could largely depend on soil characteristics.

Aquatic Ecosystems

More is known about how acid deposition affects

aquatic ecosystems—and the current extent of these

effects—than for any other resource. Substantial

evidence indicates that acid deposition alters water

chemistry in sensitive lakes and streams. Most vulnerable are small lakes and streams in watersheds

that have little capability to neutralize acid, due

either to the chemical composition and/or thinness

of the soils, or to terrain that is so steep or rocky

‘This section is based primarily on material from: The Institute of

Ecology, “Regional Assessment of Aquatic Resources at Risk From

Acid Deposition, contractor report submitted to the Office of Technology Assessment, 1982.

41
42 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

\

Photo credit: Lars Overrein

Highly acidified waters, and water chemistry changes caused by acidity, may prevent fish from developing. In the

experiment illustrated above. Brown trout eggs were placed simultaneously in waters of differing acidity. The embryos

shown at left failed to develop in acidic water (pH 4.6). The fry at right

were raised in less acid water (pH 5.5) and appear normal

that rainfall runs over it before acid can be neutralized.

Fish are sensitive both to the acidity of water,

and to toxic metals-primarily aluminum-that are

released from the watershed under acid conditions.

When waters become more acid than pH 5, many

fish species are eliminated and major changes in

lake ecosystem processes frequently occur. High

acidity, toxic concentrations of metals such as

aluminum, or some combination of the two appear

to cause these changes.

Based on the predominant soil and geological

characteristics in each county, OTA classifies about

25 percent of the land area of the Eastern 31-State

region as ‘‘sensitive, i.e. , allowing the transport

of acidity through a watershed to lakes and streams.

Within these identified sensitive regions are approximately 17,000 lakes and 112,000 miles of streams

—these figures provide an upper bound of the

aquatic resources at risk. Only a portion of the total

number of lakes and streams in the sensitive regions

should currently be considered vulnerable to acid

inputs. Small lakes and stream segments are, in

general, most susceptible to change. While some

areas have geologic characteristics that make them

sensitive to acidification, they may not receive

enough acid deposition to alter the water quality

of lakes and streams. In addition, local variations

in geology, soil conditions, and topography affect

the land’s ability to prevent acidification of water

bodies.

OTA used available water quality data from

about 800 lakes and 400 streams throughout eight

States in the Eastern half of the United States to

estimate the number of lakes and streams currently vulnerable to acid deposition. OTA estimates

that about 9,500 lakes and 60,000 miles of streams

currently have limited acid neutralizing capabilities

such that, given sufficient acid deposition, they

might acidify—a ‘‘best guess’ encompassing about

half the upper-bound estimate presented earlier.

OTA also used available water quality data, correcting for a percentage of lakes and streams that

may be naturally acidic, to estimate that about
Ch. 3—Transported Air Pollutants: The Risks of Damage and the Risks of Control . 43

3,000 lakes and 23,000 miles of streams have already become acidified, or have so little acid-neutralizing capability left that they are extremely vulnerable to further acid deposition. This corresponds

to about 20 percent of the lakes and streams found

in identified sensitive areas.

Of the approximately 50,000 lakes in Eastern

Canada, the Ontario Ministry of the Environment

estimates that about 20 percent, or 10,000, are currently acid-altered. *

Scientists cannot yet estimate how many more

lakes and streams could become acidified if current

levels of acid deposition continue into the future.

Two cumulative processes are important: 1) the potential loss of the soil’s ability to neutralize acid inputs, and 2) for lakes, the accumulation of acidifying substances over years to decades, until lake

waters come into equilibrium with the level of deposition received from the watershed. The latter

process delays lake response to acid deposition, with

greater time delays in larger lakes and lakes with

slow rates of water replacement.

Many smaller acid-altered lakes and streams in

the Northeast are probably in equilibrium with

present deposition levels. By assuming that continued acid deposition will not further degrade the

soil’s neutralizing capability-the ‘ ‘best-case’ situation— one can estimate improvements in water

quality that reduced levels of acid deposition might

produce. OTA used a simple, theoretical model to

project how future changes in acid deposition levels

might change the numbers of acid-altered lakes and

streams in the Eastern United States. If sulfate

deposition were decreased by 20 percent, OTA estimates that 10 to 25 percent of these water bodies

might show improvement. If sulfate deposition were

reduced by 30 percent, about 15 to 40 percent might

show improvement. If sulfate deposition were increased by 10 percent, OTA estimates that acid-alteration of lakes and streams might intensify by

about 5 to 15 percent.

Again, these are best-case estimates, assuming

that the effects of acid deposition are not cumulative. However, in those areas that are not in

● LI .S. -Canada Memorandum of Intent on Transboundary Air P[J -

lution, Impact Assessment, Work Group 1, February 1983.

equilibrium with above-normal deposition levels,

some lakes and streams might still continue to acidify slowly despite the reduction levels discussed

above. Such effects might be most pronounced in

the Southeast and upper Midwest.

Terrestrial Ecosystems

A variety of transported air pollutants affects both

croplands and forested ecosystems. Ozone, a gaseous pollutant toxic to plants, may account for up

to 90 percent of air pollution-related damage to

crops. How much crop damage is due to transported rather than locally produced ozone is uncertain. Observed effects include both damage to the

quality of crops (e. g., leaf spotting) and reductions

in crop yield.

Damage to crops from acid deposition under natural conditions has not yet been observed, although

experiments using simulated acid rain have shown

reduced yields and altered crop quality. Since the

chemistry of agricultural soils is already highly controlled with fertilizers and other chemicals, the primary effects of acid deposition would likely be on

the above-ground portions of plants. The role of

pollutant mixes may also be significant, since acid

deposition seldom occurs in the absence of other

pollutants. In some cases, it appears that the presence of sulfur or nitrogen oxides in the atmosphere

makes crops more susceptible to ozone damage.

To assess the risks to crops from transported air

pollutants, OTA has estimated the benefits that

might result from reducing ozone concentrations

to natural “background’ levels. Similar estimates

of the effects of acid deposition on crops, or of the

effects of pollutant mixes, are not yet possible.

Data from field experiments were used to estimate ozone effects on crop productivity for peanuts

(a sensitive crop), soybeans (sensitive/intermediate),

wheat (intermediate), and corn (tolerant). These

‘‘dose-response’ relationships were then combined

with 1978 ozone monitoring data and 1978 agricultural statistics. Results suggest that if ozone conzThis section is based primarily on material from: Oak R idgc N ational Laboratory, Environmental Sciences 13i\”ision, ‘ ‘An Anal?’sls

of Potential Agriculture and Forest Impacts of Long-Range Transport .Air Pollutants, contractor report submitted to the Offlce of Technology Assessment, 1982.
centrations had been reduced to natural, background levels in 1978, corn yields would have

increased by 2 percent, wheat by 5 percent, soybeans by 13 percent, and peanuts by 24 percent.

As measured by 1978 crop prices, ozone caused

about a 6- to 7-percent loss of agricultural productivity, of which almost two-thirds stemmed from

soybean losses.

In forest ecosystems, transported pollutants may

directly damage trees, as well as affect the soils in

which trees grow. Because trees are long-lived

species, they are vulnerable to long-term chronic

effects. Scientists have documented ozone damage

to the foliage of many tree species, but the concentrations of ozone necessary to cause damage is not

well known. About one-quarter to one-third of the

forested land area in the Eastern United States is

exposed to ozone concentrations about twice the

natural background levels.

Concern over the effects of acid deposition and

ozone on forests stems from observed productivity

declines and tree death in areas with elevated pollution levels. Pests or disease—common causes of

forest declines—do not appear to be responsible for

damage in such areas as the Adirondack Mountains in New York, the White Mountains in Vermont, the Pine Barrens in New Jersey, the Shenandoah Mountains in Virginia, the Smoky Mountains

in Tennessee, and forested areas of West Germany.

Acid deposition, ozone, heavy-metal deposition,

severe winters, drought, or a combination of these

are possible causes under investigation. Acid deposition might be a factor either by affecting trees

directly or by altering the soils on which trees grow.

Acid deposition can remove essential nutrients

such as calcium and magnesium directly from tree

foliage. If the rate of nutrient loss is greater than

can be replaced through the roots, nutrient defi-
Ch. 3—Transported Air Pollutants: The Risks of Damage and the Risks of Control ● 4 5

Photo credit: Arthur Johnson

Dead and dying red spruce at Camel’s Hump in the

Green Mountains of Vermont. Tree death and growth

decline of red spruce in Northeastern forests have

led some researchers to speculate about potential

links between forest damage and acid deposition.

Scientific investigations cannot yet confirm or rule

out acid deposition as a contributor

to the observed damages

ciency will result. Scientists do not know which tree

species are most susceptible to foliar nutrient loss,

or the level of acid deposition at which such loss

becomes harmful.

Forest soils may be altered by acid deposition

with either beneficial or harmful results. The

nitrates and sulfates from acid deposition can supply

essential plant nutrients. In many areas, nitrogen

in the soil is in short supply; on these soils nitrates

in acid rain might improve forest productivity. Sulfur-deficient soils, however, are quite rare.

Nonacidic or weakly acidic soils typically contain such large quantities of neutralizing substances

(e. g., calcium) that harmful changes to these soils

seem unlikely. Of greatest concern are forest ecosystems with naturally acidic soils. The major soilmediated risks from acid deposition include:

1. mobilization of metals such as aluminum that

are toxic to plants in sufficient quantity, and

2. the potential stripping of calcium, magnesium, and other nutrients essential for plant

growth from the soil.

Naturally acidic soils occur fairly extensively, being the predominant soil type in about half the

counties east of the Rocky Mountains covered by

forest or rangeland. In about one-third of these

acidic soils, the strong, freely moving acids from

acid deposition can release aluminum and other

toxic metals from the soil. However, whether toxic metals are released in sufficient quantities to affect forest productivity is unknown. The remaining two-thirds of Eastern acidic soils are underlain

with surface layers that can trap sulfate, possibly

preventing the release of aluminum in these areas.

Acid deposition can remove essential nutrients

such as calcium and magnesium from the soil, but

the rate of removal-and the importance relative

to other factors—is difficult to determine. Moderately acid soils are thought to lose nutrients at a

faster rate than more acid soils, but the more acid

soils typically have less nutrients. On nutrient-poor

acid soils, especially those where sulfate can travel

freely through the soil, further nutrient loss—even

at a slow rate—from the soil, forest canopy, and

decomposing plant material might be significant.

About 15 to 20 percent of the Eastern counties meet

these criteria, but whether nutrient loss is significant enough to affect near-term forest productivity is unknown.

Though relatively rare in the Eastern United

States, some moderately acid soils might further

acidify from nutrient loss over decades of exposure

to acid deposition. About 1 to 5 percent of the

Eastern counties (depending on the soil criteria

used) are dominated by soils of this type.

Data and knowledge limitations prevent a more

detailed description of the risks of transported air

pollutants to forests than given above. Of concern
46 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

are forested lands exposed to: 1) high ozone concentrations, 2) high levels of acid deposition, or

3) underlain with soils that maybe sensitive to acid

deposition.

Other Resources

Air pollution damages a broad range of materials-including building stone, rubber, zinc, steel,

and paint. Ozone is the pollutant that most affects

rubber, while many other materials are chiefly affected by sulfur oxides. Humidity plays a key role

in materials damage—dry-deposited sulfur dioxide

and sulfate that dissolve on moist surfaces (forming concentrated sulfuric acid) may cause greater

damage than relatively less acidic rain. Since air

pollution is only one of many environmental factors (e. g., temperature fluctuations, sunlight, salt,

micro-organisms) that cause materials damage, it

is difficult to determine what proportion of damage

it accounts for. Moreover, it is difficult to determine the proportion of materials damage caused

by transported pollutants as opposed to local pollution sources.

Analyses of the monetary costs of materials damage frequently make assumptions about the quantity of sensitive materials exposed to elevated pollution levels and the effects of damage on replacement or repair rates. A recent EPA-funded study

employed an alternative approach, using data on

expenditures in 24 metropolitan areas and 6 manufacturing sectors to estimate the extra materialsrelated costs attributable to sulfur pollution.3 It concluded that reducing sulfur dioxide emissions in urban areas to meet concentrations about 25 to 30

percent below the national primary standard would

create benefits of approximately $300 million annually for about one-half the households and about

5 to 10 percent of the producing sector in the United

States. These results cannot be extrapolated to provide estimates of benefits to the Nation overall, as

the lack of necessary data precludes analyzing the

rest of the economy in this manner.

Photo credit: Ted Spiegel

Statues in a Kentucky cemetery illustrate one of the

difficulties in assessing pollution-related damages to

materials. Acidic pollutants and natural weathering

have helped erode both the covered and uncovered

marble statues shown above. However, rainfall also

washes away some of the dry-deposited pollutants

from the uncovered statue at right

Yet another resource at risk from transported air

pollutants is visibility.4 Visibility levels depend on

a number of factors, including humidity, manmade

pollutant emissions, and such other factors as fog,

dust, sea spray, volcanic emissions, and forest fires.

Pollutants impair visibility by scattering and absorbing light. Concentrations of fine particles-primarily sulfates and nitrates—can sufficiently inter3E. H. Manuel, Jr., et al., “Benefits Analysis of Alternative Secondary National Ambient Air Quality Standards for Sulfur Dioxide

and Total Suspended Particulate, Mathtech, Inc., report submitted to the U.S. EnvironmentaJ Protection Agency, OAQPS, 1982.

‘This subsection is based primarily on: B. L. Niemann, ‘‘Review

of the Long-Range Transport of Sulfate Contribution to Regional

Visibility Impairment, contractor report submitted to the Office of

Technolog y Assessment, 1983.
Ch. 3—Transported Air Pollutants: The Risks of Damage and the Risks of Control 47

fere with the transmission of light to reduce visibility

levels significantly. Elevated levels of these and

other particles in the atmosphere periodically create

regional haze conditions, reducing contrast, distorting nearby objects and causing distant ones to disappear, discoloring the atmosphere, and decreasing the number of stars visible in the night sky. Examination of airport data, pollution measurements,

and satellite photography also indicates that regional-scale hazy air masses move across large geographic areas, and cause significant visibility reduction in areas with little or no air pollutant emissions. Episodic haze conditions during summer currently make it the worst season for visibility.

Sulfate concentrations correlate well with visibility impairment over large regions of the United

States; in the East, sulfate appears to be the single

most important contributor to visibility degradation. Recent studies suggest that sulfates account

for 70 percent of visibility impairment during the

summer, and 50 percent annually, in the Eastern

United States. Nitrates rarely contribute substantially to visibility degradation in the East. However,

in the Western United States, windblown dust and

nitrogen oxides can also reduce visibility significantly.

Risks of Health Effects5

Extremely small particles, including airborne sulfates, are the component of transported air pollutants of greatest concern for human health. These

small particles can travel long distances through the

atmosphere and penetrate deeply into the lung if

inhaled. Statistical (cross-sectional) studies of death

rates throughout the United States have found some

correlation between elevated mortality levels and

elevated ambient sulfate levels. Whether sulfate is

actually linked to premature mortality, or merely

indicates other harmful agents (e. g., other particulate) associated with sulfates, is unknown.

To estimate damages caused by transported air

pollution quantitatively, OTA used sulfate concentrations as an index of this ‘‘sulfate/particulate

mix . The analysis projected a range of mortality

5Thls section is based primarily on: Brookhaven National

I.aboratory, Biomedical and Environmental Assessment Division,

‘‘ I.onq-Range Transport Air Pollution Health Effects, contractor

report subm ]tted to the Office of Technology Assessment, 1982.

●

Photo credit: John Skelly

View of the Peaks of Otter in the Shenandoah National

Park under different visibility conditions. The picture at

top was taken on a relatively pollution-free day; the

picture on the bottom shows the same scene when a

regional-scale hazy air mass obscures the view

estimates for a given population exposure level, in

order to incorporate disagreements within the scientific community over the significance of sulfates to

human health. While some researchers conclude

there is a negligible effect, others have found a significant association, ranging up to 5 percent of the

deaths per year in the United States and Canada

attributed to current airborne sulfate/particulate

pollution. Though further research and data are

needed to resolve this controversy, this pollutant

mix could be responsible for about 50,000 premature deaths per year (about 2 percent of annual

mortality), particularly among people with preexisting respiratory or cardiac problems. If pollutant

emissions remained the same through the year

2000, increases in population might cause slightly

higher numbers of premature deaths; a 30-percent

decrease in emission levels by 2000 might reduce

the percentage of deaths annually attributable to

air pollution to 1.6 percent (40,000 persons). In

each of these cases, ranges of mortality are estimated to extend from zero deaths to about three

times the number reported above.
48 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Researchers have not found consistent associations between health effects and outdoor concentrations of nitrogen oxides. High localized concentrations of nitrogen dioxide are considered greater

cause for concern than ambient levels of transformed and transported nitrogen oxide pollutants.

However, quantitative estimates of health-related

damages due to nitrogen oxides, or of the populations at risk from these pollutants, cannot yet be

developed.

Acidified waters can dissolve such metals as

aluminum, copper, lead, and mercury, and release

such toxic substances as asbestos, from pipes and

conduits in drinking water distribution systems as

well as from soils and rocks in watersheds. Water

samples from some areas receiving high levels of

acid deposition show elevated metal concentrations,

raising concern about a possible connection between

acid deposition and degradation of drinking water

quality. Drinking water samples in the Adirondacks

have shown lead concentrations of up to 100 times

health-based water quality standards. Mercury concentrations above public health standards have been

found in fish from acidified lakes in Minnesota,

Wisconsin, and New York. Elevated levels of aluminum and copper, two metals not considered toxic

to the general public, have also been found both

in Adirondack well water and in surface water samples throughout New England. Acidified municipal water supplies can be monitored and corrected

quite easily. However, acidified well water in rural areas is more difficult to detect and mitigate.

Potential health effects due to acidification of these

water supplies and subsequent leaching of toxic

substances remain of concern.

Potential for the Courts or EPA

To Rule in the Absence of

Congressional Direction6

The existing Clean Air Act does not directly address long-range pollution transport; however, provisions added to the Act during a previous reauthorization (1977) require States and EPA to ensure

that stationary sources of pollution in any given

State do not prevent attainment of air quality stand-

‘This section is based primarily on material from: ‘ ‘Avenues for

Controlling Interstate Pollution Under the Current Clean Air Act,

the Office of Technology Assessment staff paper, 1982.

ards in another State. These provisions are worded

very generally; the act contains no procedures or

guidelines for determining how interstate pollution

effects are to be measured, or what levels of interstate transport are impermissible.

A number of States have sought to use these interstate pollution provisions as a vehicle for compelling other States to curb emissions of transported

pollutants. These States have challenged EPAapproved pollution control plans in court, and have

petitioned EPA to require reductions in cumulative

emissions from upwind States in order to abate

present levels of interstate pollution. EPA has made

no determinations on petitions requesting relief

from long-range pollution effects; however, in legal

proceedings the Agency has taken the position that

no reliable analytic tools are currently available to

assess long-range pollution transport. Affected parties are likely to challenge any future EPA determination on these petitions in court; thus, in the

absence of further congressional action, the judicial

branch could ultimately be required to arbitrate the

long-range transport controversy.

Risk of Strained

International Relations7

Present Federal policies on transported pollutants

have also strained relations between the United

States and Canada. Bilateral efforts are proceeding

under a Memorandum of Intent (MOI) to develop

an accord on the acid deposition issue. However,

the Canadian Government has not been pleased by

the progress of these negotiations. A dissatisfied

Canada could choose to link the acid rain issue to

other important areas of bilateral concern. The

Clean Air Act currently provides Canada no explicit means of legal recourse for abating long-range

transported air pollution from the United States.

However, the previous administration took actions

under the international provision of the Clean Air

Act that may have created a legal obligation for this

country to reduce emissions.

7This section is based primarily on material from: Environmental

Law Institute, “Long-Range Air Pollution Across National Boundaries: Recourses in Law and Policy, contractor report submitted to

the Office of Technology Assessment, 1981.
Ch. 3—Transported Air Pollutants: The Risks of Damage and the Risks of Control ● 4 9

IF FURTHER EMISSIONS

REDUCTIONS ARE MANDATED

Of the major transported pollutants, congressional attention has focused on controlling acid

deposition. Acid deposition results from both sulfur

and nitrogen oxides; however, in the Eastern

United States, sulfur oxides currently contribute

about twice as much acidity as nitrogen oxides.

Several bills proposed during the 97th and 98th

Congresses would mandate reducing sulfur dioxide emissions by about one-third to one-half either

throughout the continental United States or in the

31 States bordering and east of the Mississippi

River.

Of the 26 to 27 million tons of sulfur dioxide

emitted in the United States during 1980, about

22 million tons were emitted in the Eastern 31

States. Electric utilities emitted about 70 to 75 percent of the total eastern, approximately 16 million

tons. Non-utility combustion (primarily industrial

boilers) accounted for about 10 to 15 percent of the

total, with the remainder coming from industrial

processes and other sources. Each of three States—

Ohio, Pennsylvania, and Indiana—emitted in excess of 2 million tons of sulfur dioxide per year,

totaling 30 percent of the region’s emissions. Six

additional States—Illinois, Missouri, Kentucky,

Florida, West Virginia, and Tennessee—emitted

in excess of 1 million tons each, together producing an additional 30 percent of the 3 1-State total.

Most current legislative proposals would place

the greatest burden of emissions reductions on the

utility sector and the Midwestern States. The costs

likely to result from a control program include:

1.

2.

3.

increased electricity costs to consumers,

loss of coal production and subsequent unemployment in regions where high-sulfur coal is

mined, and

financial strain to certain vulnerable utilities

and industrial corporations.

The risk imposed by a control program is that

some of these costs might be unnecessary. A control program designed 10 years hence might achieve

the same level of protection at lower cost than one

designed today; similarly, the level of required protection might be more accurately identified. This

section first presents the potential costs of control,

and then discusses the risk that the control program

might not be as efficient or cost effective as desired.

Utility Control Costs

Both the total tonnage of sulfur dioxide to be

eliminated, and control costs per ton, determine

the cost of controlling utility sulfur dioxide emissions. Costs rise as greater removal is sought, both

because more emissions are being controlled and

because the cost of eliminating each additional ton

of sulfur dioxide increases. OTA estimates the costs

of reducing sulfur dioxide emissions in the 31 Eastern States, in 1982 dollars, to be about:

●

●

●

●

●

●

$0.5 to $1 billion/year to eliminate about 4 to

5 million tons/year

$1 to $2 billion/year to eliminate about 6 to

7 million tons/year

$2 to $2.5 billion/year to eliminate about 8 million tons/year

$2.5 to $3.5 billion/year to eliminate about 9

million tons/year

$3 to $4 billion/year to eliminate about 10 million tons/year

$4 to $5 billion/year to eliminate about 11 million tons/year

The estimates above are based on the costs of

controlling utility emissions, and do not include

costs to offset any future emissions increases from

utilities and industry. These costs can also be presented as percent increases in average residential

rates for electricity, on both a regional and State

basis. For example, a 50-percent reduction in utility

sulfur dioxide emissions (8 million tons per year,

about 35 percent below total regional emissions)

would increase average residential rates by about

2 to 3 percent. Rate increases would vary by State,

of course—consumers in some States would pay no

increases, while others would pay over twice the

regional average. For specific utilities, costs may

be somewhat higher—several utilities have asserted
50 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

that their residential rates might increase by 25 percent or more. 8

These cost estimates are for control strategies that

limit rates of emissions— sulfur dioxide emitted per

quantity of fuel burned—similar to provisions in

several bills proposed during the 97th and 98th

Congresses. The range of cost estimates for each

reduction level presented above reflects alternative

methods of allocating emissions reductions within

a State. In addition, the estimates assume that each

utility chooses the most cost-effective method applicable to plant conditions. This results in a mix

of scrubber use and fuel switching throughout the

region.

The cost of removing a ton of sulfur dioxide is

generally lower when a plant’s emission rate is high.

Consequently, total regional control costs are lower

when emissions cutbacks are allocated to States on

the basis of their emissions rates than when equal

percentage reductions are required for all States.

As discussed in chapters 6 and 7, this method of

allocating reductions concentrates a higher proportion of reductions on Midwestern States whose utilities burn high-sulfur coal. However, many areas

that currently have lower sulfur dioxide emissions

rates already pay higher electricity costs than prevail

in the Midwest.

Effects on the U.S. Coal Market

Switching from high- to low-sulfur coal is one

of the major available options for achieving substantial emissions reductions. Consequently, mandating

further emissions reductions creates the risk of

significant coal-market disruptions by increasing

the demand for low-sulfur coals at the expense of

high-sulfur coals. Risks of production and employment losses occur almost exclusively in the Eastern

United States, where coal reserves are primarily

of high-sulfur content. The Western coal-producing

States, and parts of Kentucky and West Virginia,

contain low-sulfur coal reserves and might therefore

benefit from acid deposition controls. For the nation as a whole, regulations designed to control acid

8’ ‘A Report on the Results From the Edison Electric Institute Study

of the Impact of the Senate Committee on Environment and Public

Works Bill on Acid Rain Legislation (S. 768), ” National Economic

Research Associates, Inc., report submitted to Edison Electric Institute,

1983.

deposition would probably not affect total coal production.

The extent to which utility and industrial users

would shift to low-sulfur coal depends on the

relative cost advantage of fuel switching as opposed

to removing sulfur dioxide by technological means

(e.g., scrubbers). Each method has clear advantages

for some situations, but for many plants, the cost

difference is modest enough to make predictions

of future preferences highly uncertain. The following projections of future coal production and employment shifts are based on current costs, and

might change significantly if new control technologies become available or coal prices change.

OTA estimated the extent to which coal production and employment would be affected by an emissions reduction program of 10 million tons or more

that neither mandates nor provides financial incentives for using particular control technologies.

Under such a program, 1990 levels of production

in the high-sulfur coal areas of the Midwest (Illinois,

Indiana, and western Kentucky) and Northern Appalachia (Pennsylvania, Ohio, and northern West

Virginia) might decline to about 10 to 20 percent

below 1979 levels. Estimates of production declines

are averaged over these regions, and thus may be

greater or less in some States and counties than

others.

For the low-sulfur coal areas of Central Appalachia (eastern Kentucky, southern West Virginia,

Tennessee, and Virginia) and the Western United

States, acid rain control measures are projected to

expand coal production beyond currently projected

1990 levels. This effect is more pronounced in Central Appalachia than in the West, due to its proximity to Eastern markets.

In general, employment changes would follow

changes in production. A 10-million-ton emissions

cutback is projected to reduce employment in highsulfur coal-producing areas by between 20,000 and

30,000 jobs from projected 1990 levels. About

15,000 to 22,000 additional jobs would open up in

Eastern low-sulfur coal-producing areas, and an additional 5,000 to 7,000 jobs in the West. The risk

of unemployment is most severe in Illinois, Ohio,

northern West Virginia, and western Kentucky—

for these areas, coal-mining employment is projected to decline more than 10 percent below current levels.
Ch. 3—Transported Air Pollutants: The Risks of Damage and the Risks of Control ● 5 1

Photo credit: Douglas Yarrow

Last shift comes out at Eccles #5 before the 1977 contract strike

These employment shifts would cause proportional changes in direct miner income. At the national level, benefits to low-sulfur regions are projected to balance out losses to high-sulfur regions.

This level of aggregation, however, obscures the

regional distribution of coal-related economic costs.

Direct income effects for a 10-million-ton emissions

reduction are estimated below:

● Northern Appalachia: $250 to $350 million per

year loss;

● Central Appalachia: $400 to $550 million per

year gain;

● Midwest: $250 to $400 million per year loss;

● West: $100 to $200 million per year gain.

The total economic impacts of coal-market shifts—

reflecting, in addition, indirect employment and

income effects on other economic activities—may

be two to three times greater.

Effects on Utility and

Industrial Financial Health

While the costs of further controlling utility sulfur

emissions are ultimately passed on to electricity consumers, they can strain the resources of financially troubled utilities that must initially pay them.

Additionally, reducing industrial process and boiler

emissions imposes the risk of rendering sulfur dioxide-emitting industries in controlled regions less
52 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

competitive than their less or uncontrolled counterparts in other geographic areas.

On the basis of average 1980 utility bond ratings

and stock indicators, utility sectors in eight States

appeared to be relatively vulnerable to the additional capital requirements that could result from

further sulfur dioxide control: Arkansas, Connecticut, Florida, Maine, Michigan, Pennsylvania,

Vermont, and Virginia. * If cutbacks are allocated

on the basis of emissions rates, three of these

States—Pennsylvania, Florida, and Michigan—

are likely to be required to reduce emissions significantly. Greatest reductions would be required

in Pennsylvania, where present State regulatory

policies also cause substantial delays before utilities

can pass increased fuel costs and/or construction

costs on to consumers.

Several other States have regulatory policies considered unfavorable to utility pollution control expenditures, although their utilities showed better

average financial health in 1980. The regulatory

policies set by public utility commissions in each

State can significantly affect the financial burden

of raising additional capital to further control sulfur

dioxide emissions. Such policies vary substantially from State to State. Moreover, these policies are

subject to change, and might themselves be affected

by the passage of new pollution control legislation.

Major increases in electricity costs due to increased controls might also hurt utilities by reduc-

‘Individual utilities in relatively weak financial conditions were also

found in Massachusetts, Indiana, Ohio, Georgia, New Jersey, and

West Virginia.

ing demand for electricity. However, OTA-projected increases in average electricity rates resulting

from stricter sulfur dioxide emissions controls are

not high enough to affect demand for electrical

power appreciably.

OTA also identified industries in which electricity

is a major component of production costs. For

about 15 industries, concentrated primarily in the

areas of primary metals, chemicals and allied products, and stone, clay, and glass products, electricity costs exceed 10 percent of the value added* by

the manufacturer—nearly four times the national

average. Electricity costs are equal to about 40 percent or more of the value added in industries that

produce electrometallurgical products, primary

zinc, primary aluminum, alkali- and chlorine-based

chemicals, and industrial gases—these five industries alone use about 16 percent of the electricity

consumed by industry in this country. Within these

energy-intensive industries, manufacturers served

by utilities with high control costs might be rendered less competitive than those in regions that

are either uncontrolled or incur lower control costs.

Preliminary analyses of industrial process emissions also suggest some potential for economic dislocation in the iron and steel and cement industries

if their emissions were to be strictly controlled.

Stricter sulfur dioxide emissions controls, if imposed

in the Southwestern United States, could also create

hardships for the region’s currently depressed copper smelting industry.

● ’ ‘Value added” is the difference between the selling price of the

product and the cost of energy and materials to manufacture it.

RISK THAT CONTROL MAY NOT BE AS

EFFECTIVE OR EFFICIENT AS DESIRED

Proposals for controlling sulfur dioxide emissions

aim to reduce sulfur deposition—a major contribution to acidification—in areas sensitive to its effects.

However, as discussed previously, incomplete understanding of pollutant transport and transformation creates the risk that any control strategy designed at this time: 1) will not reduce deposition

to the extent, and in the specific locations, desired;

and 2) may not be as cost-effective as possible.

This section reviews estimates of the reduction

in acid deposition needed to minimize further damage to sensitive resources—and the likelihood of

reaching these “deposition targets” under alternative control strategies. In addition, the section

discusses the potential for designing a more costeffective strategy to reduce acid deposition by controlling nonsulfur pollutants in addition to sulfur

dioxide.
Ch. 3—Transported Air Pollutants: The Risks of Damage and the Risks of Control ● 53

Effectiveness of Emissions

Reductions for Achieving Desired

Deposition Reductions

While any major reduction in acid deposition

levels would likely benefit some sensitive resources,

scientists have attempted to define ‘ ‘target’ deposition levels—the maximum level of deposition for

avoiding further damage to all but the most sensitive resources. * Target deposition values have been

presented in reports by the National Academy of

Sciences (NAS), the Impact Assessment Work

Group established by the United States-Canada

Memorandum of Intent on Transboundary Air

Pollution, * * a working group at the 1982 Stockholm Conference on the Acidification of the Environment, and others. These have been expressed

as levels of acidity, levels of sulfate in rainfall, or

total deposited sulfur.

OTA estimated the reductions in ‘ ‘wet sulfur

deposition’ —the sulfur deposited in rain and

snow—necessary to reach these target deposition

levels. As outlined in chapter 5 and appendix C,

the estimates range from eliminating about 50 to

80 percent of deposition in those areas receiving

highest levels, to eliminating about 20 to 50 percent of deposition over large regions of Eastern

North America identified as having sensitive

aquatic resources.

Several bills introduced during the 97th and 98th

Congresses proposed cutting sulfur dioxide emissions back by about 8 to 10 million tons per year—

about a 35 to 45 percent reduction in Eastern U.S.

emissions. Using two different types of computer

models, OTA estimated the sulfur deposition reductions that might result if these legislative proposals were enacted. The more optimistic model

estimate suggests that both wet and dry sulfur deposition would be reduced by as much as 45 to 60

percent in the areas of greatest deposition. Both wet

and dry sulfur deposition would be reduced by

about 30 to 50 percent annually over large regions

● Maximum deposition targets are based on protecting aquatic

resources, as too little is known about the sensitivity of other resources

to allow similar levels of protection to be defined. In addition, most

targets are based on amounts of wet deposition, since current data

are insufficient for considering dry deposition.

● ● Only the Canadian members of the Work Group recommended

a target deposition value.

of Eastern North America. The second model projection—based on conditions that prevail during extreme pollution episodes—suggests that emissions

reductions of 35 to 45 percent would comparably

reduce dry sulfur deposition. However, the model

predicts that wet sulfur deposition would respond

less directly, decreasing by about 25 to 35 percent

in areas of greatest deposition, and by 20 to 30 percent over much of Eastern North America, during

high pollution episodes. g

These estimates provide a plausible range of deposition reductions that might result from reducing

emissions by 35 to 45 percent. The reductions in

total sulfur deposition estimated above are difficult

to compare to target deposition levels, because these

targets have been expressed in a variety of ways.

However, the following preliminary conclusions can

be drawn, subject to a large degree of uncertainty:

In areas of greatest deposition, for example, western Pennsylvania, reducing Eastern United States

sulfur dioxide emissions by 8 to 10 million tons per

year might not be sufficient to bring deposition

levels within the targeted maximum for protecting

all but the most sensitive resources. In areas receiving less deposition, such as northern New England,

the southern Appalachians, and the upper Midwest,

sulfur dioxide emissions reductions of this magnitude are likely to achieve the target deposition

levels.

Efficiency Concerns

Because large-scale cutbacks in sulfur dioxide

emissions will cost billions of dollars annually, some

have suggested that even if the deposition reduction goals could be achieved now, a more costeffective program might be designed when atmospheric processes are better understood, Such concerns raise the following questions:

1, Can specific sources or source areas affecting

sensitive resource areas be identified for emissions control?

‘A recent NRC study for the National Academy of Sciences used

slightly modified model assumptions to reexamine the OTA analysis.

The NRC committee concluded that reductions in wet sulfur deposition would more closely approximate the reductions in sulfur dioxide

emissions than OTA had estimated. Acid Deposition: Atmospheric

Processes in Eastern North America, Committee on Atmospheric

Transport and Chemical Transformation in Acid Deposition, National

Research Council, National Academy Press, Washington, DC., 1983.
54 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

2. Can cutbacks in other acidifying pollutants,

such as nitrogen oxides, eliminate acid deposition for lower cost?

3. Can sulfur deposition be controlled more cost

effectively by controlling co-pollutants such as

reactive hydrocarbons concurrently with sulfur dioxide emissions?

Atmospheric transport models for linking source

regions and receptor regions have been available

for several years, but their accuracy is subject to

debate, Current understanding suggests that, given

the widespread distribution of sensitive resources,

a program to bring deposition within the previously mentioned target rates in all sensitive areas would

have to encompass most of the Eastern United

States. Within some bounds, emissions reductions

from one area can be substituted for reductions

from another without jeopardizing the desired pattern of deposition, but the goal of minimizing total

costs is likely to conflict with cost distribution goals.

The dual problems of defining the value of one resource area relative to others, and equitably distributing costs, are difficult political questions that

could not be solved through more accurate modeling capabilities.

Controlling nitrogen oxides may be less expensive for some sources than controlling sulfur oxides, but whether it is as efficient for preventing

resource damage is subject to question. Currently, twice as much rainfall acidity comes from sulfur

oxides as from nitrogen oxides. In addition, plants

often take up nitrogen oxides as nutrients, further

increasing the proportion of lake and stream acidity

produced by sulfur oxides. Though future research

may reveal that intermittent events—such as spring

snow melts containing high levels of both deposited

nitrogen oxides and sulfur oxides—are responsible

for the greatest share of damage, current understanding suggests that sulfur oxides are the first

choice for control.

Future research may reveal more cost-effective

opportunities for reducing sulfur deposition by controlling co-pollutants concurrently with sulfur dioxide emissions. Preliminary modeling results indicate

that the ratio of reactive hydrocarbons to nitrogen

oxides is an important determinant of the atmospheric transformation of sulfur oxides. Though

broad regional sulfur oxide deposition overall might

remain relatively constant, reducing emissions of

these co-pollutants along with sulfur dioxide might

achieve more desirable patterns of deposition than

would result from reducing sulfur dioxide emissions

alone.
Chapter 4

The Pollutants of Concern
Contents

Page

Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Current and Historical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Future Emissions Under Current Laws and Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Patterns of Pollutant Emissions, Air Concentrations, and Deposition . . . . . . . . . . . . . . 63

Geographical Emissions Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Geographical Patterns of Deposition and Air Concentrations for

Transformed Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

The Regional Patterns of Sulfur Oxides Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

TABLES

Table No. Page

1. 1980 Total Emissions of Sulfur Dioxide, Nitrogen Oxides, and

Hydrocarbons in the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

2. Historical Trends in Sulfur Dioxide, Nitrogen Oxides, and Hydrocarbon Emissions . . . . 58

3. Projected Sulfur Dioxide Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

4. Projected Nitrogen Dioxide Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

FIGURES

Figure No. Page

11. Forecasts of Utility Sulfur Dioxide Emissions for the Eastern 31-State Region

of the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

12. Sulfur Dioxide Emissions Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

13. Nitrogen Oxide Emissions Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

14. Hydrocarbon Emissions Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

15. Precipitation Acidity—Annual Average pH for 1980,

Weighted by Precipitation Amount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

16. Annual Sulfate Ion Deposition in Precipitation for 1980,

Weighted by Precipitation Amount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

17. Airborne Sulfate—Annual Average Concentration for 1977-78. . . . . . . . . . . . . . . . . . . . . . 68

18. Ozone Concentration-Daytime, Growing Season Average for 1978. . . . . . . . . . . . . . . . . 69

19. The Effects of Time and Distance on Conversion and Deposition of Sulfur Pollution . . 70

20. 1979 Sulfur Dioxide Emissions and Estimated Sulfur Deposition—

Percent Contributed and Received in Four Subregions Covering the Eastern Half

of the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

21. Percent of Sulfur Deposition Estimated To Originate From Within Each Region and

From Other Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

22. Estimated Percentage of Sulfur Deposition From Emissions Over 500 km Away . . . . . . 74
Chapter 4

The Pollutants of Concern

This chapter: 1) provides estimates of pollutant

emissions, 2) describes current geographic patterns

of emitted pollutants, and concentrations and

deposition of transformed pollutants, and 3)

analyzes the patterns and processes of pollutant

transport and transformation. The pollutants of

concern and their transformation products are:

●

●

●

sulfur dioxide—both as sulfur dioxide gas and

as the transformation product, sulfate;

nitrogen oxides—as a gas, as the transformation product, nitrate, and as a precursor of

ozone; and

reactive hydrocarbons—as precursors of

ozone.

OTA has assembled estimates of current emissions and historical and projected emissions trends

for these three pollutants. Projections of sulfur dioxide and nitrogen oxides emissions are provided

for the United States overall, for the Eastern 31-

State region, and by major producing sector. The

chapter examines future utility emissions of sulfur

dioxide in greater detail.

To show where these emissions originate, current emissions levels are described in a series of

maps. The chapter then presents maps of measured

deposition levels for acidity and sulfate, and air concentrations for ozone and airborne sulfate. These

maps can be used to compare the origins of the

three emitted pollutants to the eventual destinations

of the transformed pollutants on which the assessment focuses.

Finally, the chapter presents model-based estimates of the regional transport of sulfur oxides—

the most abundant acid-producing pollutant, and

the pollutant for which the greatest amount of information about transport, transformation, and

deposition patterns is available. In addition, the section briefly describes the chemical processes that

transform the three emitted pollutants, to aid in understanding how changes in emissions levels might

affect resulting levels of transported pollutants.

EMISSIONS

Current and Historical

In the United States during 1980 approximately

26 million tons of sulfur dioxide, 21 million tons

of nitrogen oxides, and about 24 to 28 million tons

of hydrocarbons (volatile organic carbon) were

emitted by manmade sources. Of this total, about

22 million tons of sulfur dioxide, 14 million tons

of nitrogen oxides, and about 19 to 20 million tons

of hydrocarbons were emitted in the 31 States east

of or bordering the Mississippi River. For the Nation overall, the major sources of sulfur dioxide

emissions—about 90 to 95 percent of the total—

are electric-generating utilities, industrial boilers,

and industrial processes. Similarly, three sectors—

utilities, mobile sources, and industry-produce

more than 95 percent of the country’s manmade

nitrogen oxides emissions. Mobile sources and industrial processes produce about 80 to 85 percent

of U.S. hydrocarbon emissions, while the remainder comes from a wide variety of sources.

Table 1 presents current (1980) estimated emissions of sulfur dioxide, nitrogen oxides, and hydrocarbons for each of the 50 States. 1 To place the current level of emissions into historical perspective,

table 2 shows estimated total U.S. and Eastern

3 l-State emissions of sulfur dioxide and nitrogen

oxides, and estimated total U.S. hydrocarbon emissions, for selected years between 1940 and 1980.

Between 1940 and 1970, nationwide sulfur dioxide emissions increased by roughly 50 percent, from

about 19 million to 30 million tons per year. From

‘Estimates are from Emissions, Costs, and Enq”neering Assessment,

Work Group 3B, United States-Canada Memorandum of Intent on

Transboundary Air Pollution, June 15, 1982. Tables 3 and 4 compare the 50-State and Eastern 31 -State region totals, by utility and

industrial sector, with other estimates of sulfur dioxide and nitrogen

oxides emissions.

57
58 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table 1 .—1980 Total Emissions of Sulfur Dioxide, Nitrogen Oxides, and Hydrocarbons in the United States

(1,000 tons/year)

State S0 2 NO x HC State S0 2 NO X HC

Alabama . . . . . . . . . . . . . . . . . . . . . .

Alaska. . . . . . . . . . . . . . . . . . . . . . . .

Arizona . . . . . . . . . . . . . . . . . . . . . . .

Arkansas . . . . . . . . . . . . . . . . . . . . .

California . . . . . . . . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . . . . . . . .

Connecticut . . . . . . . . . . . . . . . . . . .

Delaware . . . . . . . . . . . . . . . . . . . . .

District of Columbia. . . . . . . . . . . .

Florida . . . . . . . . . . . . . . . . . . . . . . .

Georgia. . . . . . . . . . . . . . . . . . . . . . .

Hawaii . . . . . . . . . . . . . . . . . . . . . . .

Idaho . . . . . . . . . . . . . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . . . . . . . . . .

Iowa . . . . . . . . . . . . . . . . . . . . . . . . .

Kansas . . . . . . . . . . . . . . . . . . . . . . .

Kentucky . . . . . . . . . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . . . . . . . . . .

Maine . . . . . . . . . . . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . . . . . . . . .

Massachusetts . . . . . . . . . . . . . . . .

Michigan . . . . . . . . . . . . . . . . . . . . .

Minnesota . . . . . . . . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . . . . . . . .

Missouri . . . . . . . . . . . . . . . . . . . . . .

760

20

100

445

130

70

110

15

1,100

840

60

50

1,470

2,000

330

220

1,120

300

100

340

340

900

260

280

1,300

450

55

260

220

1,220

275

135

50

20

650

490

45

80

1,000

770

320

440

530

930

60

250

250

690

370

280

570

530

50

250

270

2,550

360

370

70

35

880

580

75

170

1,200

700

300

350

430

790

120

370

600

1,100

500

330

690

Montana . . . . . . . . . . . . . . . . . . . . . . 160

Nebraska . . . . . . . . . . . . . . . . . . . . . 75

Nevada . . . . . . . . . . . . . . . . . . . . . . . 240

New Hampshire . . . . . . . . . . . . . . . 90

New Jersey . . . . . . . . . . . . . . . . . . . 280

New Mexico . . . . . . . . . . . . . . . . . . 270

New York . . . . . . . . . . . . . . . . . . . . . 950

North Carolina . . . . . . . . . . . . . . . . 600

North Dakota . . . . . . . . . . . . . . . . . . 100

Ohio . . . . . . . . . . . . . . . . . . . . . . . . . 2,650

Oklahoma . . . . . . . . . . . . . . . . . . . . . 120

Oregon . . . . . . . . . . . . . . . . . . . . . . . 60

Pennsylvania ...,.... . . . . . . . . . . 2,020

Rhode Island . . . . . . . . . . . . . . . . . . 15

South Carolina . . . . . . . . . . . . . . . . 330

South Dakota . . . . . . . . . . . . . . . . . 40

Tennessee . . . . . . . . . . . . . . . . . . . . 1,100

Texas . . . . . . . . . . . . . . . . . . . . . . . . 1,270

Utah . . . . . . . . . . . . . . . . . . . . . . . . . 70

Vermont . . . . . . . . . . . . . . . . . . . . . . 7

Virginia . . . . . . . . . . . . . . . . . . . . . . . 360

Washington . . . . . . . . . . . . . . . . . . . 270

West Virginia . . . . . . . . . . . . . . . . . . 1,100

Wisconsin . . . . . . . . . . . . . . . . . . . . 640

Wyoming . . . . . . . . . . . . . . . . . . . . . 180

U.S. total . . . . . . . . . . . . . . . . . . . 26,500

120

190

80

60

400

290

680

540

120

1,140

520

200

1,040

40

200

90

520

2,540

190

25

400

290

450

420

260

21,220

160

200

70

100

810

195

1,250

680

70

1,280

460

330

1,360

120

550

110

580

3,400

160

45

530

500

150

530

110

28,350

SOURCE: Emissions,Costs and Engineering Assessment, Work Group 3B, United States–Canada Memorandum of lntent on Transboundary Air Pollution, June 15, 1982

Table 2.—Historical Trends in Sulfur Dioxide, Nitrogen Oxides, and

Hydrocarbon Emissions (millions of tons)

Sulfur dioxide Nitrogen oxides Hydrocarbons

Easter n Eastern

Year National

ab 31 Statesb National a

’

h

31 Statesb National a

1940 . . . . . . . . . 19.1 — 7.2 — 15.3

1950 . . . . . . . . . 18.1-21.6 14.6 7.4-10.3 5.4 19.3

1955 . . . . . . . . . 17.7 14.3 8.5 6.4 –

1960 . . . . . . . . . 21.2-22.2 18.9 11.5-14.0 8.5 23.8

1965 . . . . . . . . . 26.7 22.8 14.2 10.4 —

1970 . . . . . . . . . 28.7-30.8 24.0 17,7-20.4 12.4 29.8

1975 . . . . . . . . . 27.3-28.2 23.4 19.3-21.6 13.3 25.1

1980 . . . . . . . . . 25.2-26.1 21.2 21.0-22.8 13.9 24.0-28.3C

SOURCES:National Air Pollution Emission Estimates, 1940-1980, U.S. Environmental Protection Agency, January 1982,

EPA-450M-82-001.

“’Historic Emissions of Sulfur and Nitrogen Oxides in the United States from 1900 to 1980,” G. Gschwandtner,

et al., 1980. Draft reports to EPA from Pacific Environmental Services, Inc.

cEmissions Costs and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of Intent

on Transboundary Air Pollution, June 15, 1982
Ch. 4—The Pollutants of Concern ● 5 9

1970 to 1980 emissions totals show a decline from

about 30 million to 26 million tons per year, and

from about 24 million to 21 to 22 million tons for

the Eastern 31 -State region. Estimates are availble for pre- 1940 emissions levels, but these are

based on incomplete data. These data suggest that

throughout the period 19’20-40, nationwide sulfur

dioxide emissions averaged roughly 17 million tons

per year.2 A ppendix A presents historical emissions

estimates in greater detail.

Over the period 1940-80, nitrogen oxides emissions grew much more rapidly than sulfur dioxide—virtually tripling—but have declined slightly

from 1978 to 1980. Hydrocarbon emissions are estimated to have doubled, from about 15 million tons

in 1940 to about 30 million tons per year in 1970.

From 1970 to 1980, hydrocarbon emissions declined—according to various estimates, to about 24

to 28 million tons per year.3

Future Emissions Under Current

Laws and Regulations

Assuming that current air pollution laws and regulations remain unchanged, future emissions of

both sulfur dioxide and nitrogen oxides will depend

primarily on three factors:

● future demand for energy, including energy

for electricity generation, industrial fuel use,

and automobiles;

● the type of energy used to meet future demand, for example, the extent of such nonfossil energy use as nuclear and hydropower,

and less polluting fuels such as natural gas; and

● the rate at which existing pollution sources—

both stationary sources and highway vehicles—are replaced with newer sources more

tightly controlled under the Clean Air Act.

2“ Historic Emissions of Sulfur and Nitrogen Oxides in the United

States From 1900 to 1980, ” G. Gschwandtner, et al., 1983. Draft

report to EPA from Pacific Envi ronmcntal Services, Inc.

‘ H ~drxx arbon cm isslons are d iff]( ult to est imatc, In part because

d major w)urc c of th(. ir product ion is the e~aporat ion of chemical

solt ents As shown in tables I And !2, the 24-m ll]ion - ton est imatc is

de ri~~d from U S F:nv ircrrrmentd Pt-otc( t ion Agen( y, .\’ariona/ ,4ir

P(dlu[an( Emiss]orr Estimates, 1940-1980, while the 28-mllllon-ton

frgure is from the U. S -Canada NI(II, Work Group 3B, Emissions,

Costs and Enginet-rin<q .4ssevsmcnt.

Each of these factors is, of course, uncertain, but

analysts can estimate pollutant emissions that would

result from plausible future trends. The first three

parts of this section will present several projections

of future sulfur dioxide, nitrogen oxides, and hydrocarbon emissions over the next two to three decades. The fourth part will discuss how these factors, as well as further emission controls, affect

future sulfur dioxide emissions from the utility

sector.

Sulfur Dioxide Emissions

Table 3 presents various projections of sulfur dioxide emissions through the year 2010. For the

United States as a whole, sulfur dioxide emissions

are projected to increase over 1980 levels by 10 to

25 percent by 2000, and by 20 to 30 percent by

2010. The greatest projected rate of increase is in

the industrial sector—25 to 40 percent by 2000.

Within the 31 Eastern States, the industrial sector is again projected to account for the fastest

growth in emissions. By 2000, total sulfur dioxide

emissions are projected to increase by 10 to 30 percent, while emissions from the industrial sector

alone increase between 50 to 90 percent. By 2010,

total emissions are projected to increase by about

15 to 25 percent over 1980 levels. These projections assume that rising oil and natural gas prices

will cause many current users of these cleaner fuels

to switch to coal. Utility emissions are forecast to

increase slightly through about 2000 and then to

begin declining slightly. Because of the growth increase projected for the industrial sector, utility

emissions will drop from about 75 percent of the

total in 1980 to about 60 to 65 percent of the total

by 2010.

Nitrogen Oxides Emissions

While mobile sources are currently the single

largest nitrogen oxides-producing sector, by 2010

rapid growth in emissions from the utility sector

is expected to make utilities the single largest source

of nitrogen oxides. Table 4 presents various projections of nitrogen oxides emissions for utilities,

mobile sources, and industry.

For the United States, nitrogen oxides emissions

by 2000 are expected to increase over 1980 levels

by about 25 percent; by 2010, emissions are forecast
60 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table 3.—Projected Sulfur Dioxide Emissions (million tons/year)

United States Eastern 31 States

1980 1985 1990 1995 2000 2005 2010 1980 1985 1990 1995 2000 2005 2010

Total: Total

MOI 1 . . . . . . . 26.5 – 25.3 – 29.3 – – MOI 1 . . . . . . . 21.8 – 21.4 – 24.3 – –

EE1 2a 

. . . . . . . 27.3 26.9 27.2 29.4 31.1 – 33.4 EE12a 

. . . . . . . 21.7 21.2 21.6 23.5 23.9 – 24.6

EE12b . . . . . . . 27.3 28.7 29.4 32.0 34.6 – 35.0 EE12b 

. . . . . . . 21.7 23.5 24.2 26.6 27.9 — 26.7

Utility: utility:

MOI 1 . . . . . 17.3 – 17.5 — 17.9 — — MOI 1 . . . . . 16.0 – 15.9 — 16.1 — —

EE1 2a 

. . . . . 17.5 17.6 17.9 18.6 18.2 — 18.2 EE12a 

. . . . . 16.2 1505 15.7 15.9 15.1 — 14.5

EE1 2b . . . . . 17.5 19.3 20.1 21.2 21.6 – 19.8 EE12b 16.2 17.8 18.3 19.0 19.1 — 16.6

EPA 3 . . . . . 17.4 18.8 20.0 20.2 19.6 — 18.7 EPA3 : : : : : 16.2 17,1 17.9 18.0 17.1 — 15.8

NWF 4 . . . . . – – 19.6 — 21.0 – – NWF 4 

. . . . – – 17.8 — 18.1 — —

EEI 5

. . . . . . — — 18.3 – – — –

lndustry:?’:

Industry:

MOI 1 . . . . 7.4 – 5.9 – 9.3 – – ? ’

:

MOI 1 . . . . . 4.4 – 4.1 – 6.7 – –

EEI 2C . . . . . 7.5 7.4 7.2 8.6 10.5 – 12.2 EEI 2C . . . . . 3.8 4.2 4.4 6.3 7.2 — 8.2

EEI 5

. . . . . . — — 4.4 — — — —

Sources of estimates:

1. MOI—Emissions, Costs and Engineering Assessrnent, Work Group 3B, United States-Canada Memorandum of Intent on Transboundary Air Pollution, June 15, 1982.

2. EEI—”Summary of Forecasted Emissions of Sulfur Dioxide and Nitrogen Oxides in the United States Over the 1980 to 2010 Period,” prepared by ICF Inc. and National

Economic Research Associates for the Edison Electric Institute and Utility Air Regulatory Group, April 1982.

2a—National Economic Research Associates (NERA) estimate.

2b—lCF Inc. estimate.

2c—Joint NERA/ICF estimate.

3. EPA—Personal communication from J. Austin, EPA. Projections prepared for EPA by ICF Inc., using assumptions stated in “Analysis of a 10 Million Ton Reduction

In Emissions From Existing Utility Powerplants,” ICF Inc., June 1982.

4. NWF—’’Cost and Coal Production Effects of Reducing Utility Sulfur Dioxide Emissions,” prepared for National Wildlife Federation and National Clean Air Coalition

by ICF Inc., Nov. 14, 1981.

5. EEI—’’January 25, 1982 Preliminary ICF Analysis of the Mitchell Bill Prepared for the Edison Electric Institute, ” Edison Electric Institute letter, Feb. 8, 1982.

Table 4.—Projected Nitrogen Oxides Emissions (million tons/year)

United States Eastern 31 States

1980 1985 1990 1995 2000 2005 2010 1980 1985 1990 1995 2000 2005 2010

Total:

MOI 1 . . . . . . . 21.2 – 21.2 – 26.6 –

EEI2a 

. . . . . . . 21.0 22.2 22.3 23.9 26.2 –

EEI2b 

. . . . . . . 21.0 21.7 22.3 24.0 26.5 –

Utility:

MOI 1 

. . . . . 6.4 – 7.5 – 9.6 –

EEI 2a . . . . . 7.2 8.8 9.3 10.2 11.1 –

EEI 2b . . . . . 7.2 8.3 9.3 10.3 11.4 –

Industry:

? ’

:

MOI 1 . . . 4.6 – 4.2 – 5.6 –

EEI 2C . . . . . 3.5 3.7 4.2 4.7 5.3 –

Mobile:

MOI 1 . . . . . 9.4 – 8.6 – 10.7 –

EEI 2C . . . . . 9.4 8.9 8.2 8.4 9.2 –

—

32.8

31.8

—

14.8

13.8

—

6.0

—

11.5

Total:

MOI 1 . . . . . . . 14.0 — 15,0 — 18.5

EEI 2a . . . . . . . 14.9 15.6 15.6 16.4 17.7

EEI 2b 

. . . . . . . 14.9 15.5 15.8 16.8 18.4

Utility:

MOI 1 . . . . . 4.8 — 5.7 — 6.9

EEI 2a 

. . . . . 5.4 6.5 6.8 7.2 7.6

EEI2b 5.4 6.4 7.0 7.6 8.3

EEI 3

. : : : : : – – 6.2 – –

Industry: 1 :

MOI . . . . . 2.4 – 3.0 – 3.7

EEI 2C . . . . . 2.3 2.5 2.8 3.2 3.7

EEI 3

. . . . . . – – 2.6 – –

Mobile:

MOl 1 

., . . . 6.2 — 5.8 — 7.3

EEI 2C . . . . . 6.5 6.0 5.5 5.5 6.0

—

—

—

—

—

—

—

—

—

—

—

—

—

21.8

21.3

9.9

9.4

—

—

4.1

—

—

7.4

Sources of estimates:

1. MO1—Ern/ss/ems, Costs and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of Intent on Transboundary Air Pollution, June 15, 1982.

2. EEI—’’Summary of Forecasted Emissions of Sulfur Dioxide and Nitrogen Oxides in the United States Over the 1980 to 2010 Period,” prepared by ICF Inc. and National

Economic Research Associates for the Edison Electric Institute and Utility Air Regulatory Group, April 1982.

2a—National Economic Research Associates (NERA) estimate.

2b—lCF Inc. estimate.

2c—Joint NERA/lCF estimate.

3. EEI—’’January 25, 1982 Preliminary ICF Analysis of the Mitchell Bill Prepared for the Edison Electric Institute, ” Edison Electric Institute letter, Feb. 8, 1982.
Ch. 4—The Pollutants of Concern ● 6 1

to increase by about 50 to 55 percent, The utility

sector is projected to account for most of this increase (about 60 to 75 percent). For the 31 Eastern

States, nitrogen oxides emissions are projected to

increase by about 20 to 30 percent by 2000, and

by about 45 percent by 2010.

Hydrocarbon Emissions

Reliable quantitative estimates of future hydrocarbon emissions are not available at this time.

However, in general, hydrocarbon emissions are

projected to decline somewhat from 1980 levels, and

then to remain relatively constant. Petroleum refining and storage is the only major source of hydrocarbons projected to significantly increase emissions

through 2000; expected improvements in abatement practices and potential shifts away from liquid hydrocarbon fuels toward coal use might partially or completely offset such increases.4 Emissions

from industrial processes—a major source of hydrocarbons—depend heavily on the specific process in use, making these emissions very difficult to

estimate.

Utility Sulfur Dioxide Emissions

in the 31 Eastern States

As demonstrated by the variations among the

projections presented in tables 3 and 4, forecasting

pollutant emissions is not an exact science. Emissions scenarios depend on numerous assumptions

about future economic conditions. For example,

projections of rapid growth of sulfur dioxide emissions from the industrial sector assume increased

industrial output, along with a change from oil use

to coal. The range of the projections reflects different plausible assumptions about future rates of

industrial growth and the relative future price of

oil and coal.

OTA used a simple projection model to examine

how various factors affect forecasts of utility sulfur

dioxide emissions in the Eastern half of the country. The major factors affecting utility emissions

are: 1 ) demand for electricity (for this analysis,

OTA assumes growth to be 2.5 percent per year,

with a range of 2.0 to 3.0 percent per year); and

2) retirement age of existing plants (for this analysis,

‘En \ironmenta/ Outlook f 980, L’. S. Environmental Protection

Agency, July 1980, EPA-60018-80-003.

OTA assumes the useful life of a plant to be 50

years, with a range of 40 to 60 years). Other factors include reliance on nonfossil energy sources

(assumed to provide the same proportion of electricity generation as in 1980), emission rates from

new sources regulated under the New Source Performance Standards (NSPS) (assumed to average

0.6 lb sulfur dioxide per million Btu), and reductions required to comply with State Implementation Plans (SIPS) (assumed to be about 1 million

tons of sulfur dioxide; possible SIP relaxations

might reduce this amount).

Figure 11 shows how these factors affect emissions

forecasts, using a 60-year forecast period to allow

for replacement of all utility plants operating in

1980. Figure 11A illustrates the sensitivity of emissions forecasts to demand for electricity. The lowest

curve shows emissions in the unlikely event that

no growth in demand occurs. Under such a scenario, emissions would decline to 20 percent of the current 16 million tons of utility sulfur dioxide emissions when all existing sources are replaced by new

sources regulated under NSPS.

Existing facilities are assumed to retire after 50

years of service. Assuming an increase in demand

for electricity ranging from 2 to 3 percent per year,

emissions will increase to 7 to 11 percent above current levels by 2000, decline to about 50 to 75 percent of current levels by 2025 to 2030, and then begin to climb again. However, as figure 11 B shows,

these trends are extremely sensitive to the average

life of existing sources, assumed to be 50 years for

the estimates presented above. Figure 11 B illustrates

emissions trends assuming 2.5 percent growth per

year, but varying the average retirement age of existing utility plants. A 40-year retirement age would

cause emissions to decline steadily to about 50 percent of current levels by 2015 to 2020, and subsequently rise. If the useful life of existing plants is

extended to 60 years, emissions might rise to about

20 percent above current levels by 2010, decline

to about 80 percent of current amounts by 2030,

and then begin to rise again.

Figure 11 C shows the effect of limiting allowable

emission rates now, as opposed to waiting for

NSPS-regulated new sources to replace existing

utilities. The distance between the ‘‘base case’

curve (no change in current laws and regulations)

and the ‘ ‘emissions rate limitation curves repre-
62 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 11.— Forecasts of Utility Sulfur Dioxide Emissions for the Eastern 31-State Region of the United States

SOURCE: Office of Technology Assessment
Ch. 4—The Pollutants of Concern . 63 —

sents the difference in emissions at any point in

time. A 1.5 lb sulfur dioxide per million Btu ‘ ‘emissions cap’ on all Eastern utility sources by 1990

would reduce emissions to about 50 percent of current levels. Emissions would then increase to about

60 percent of current levels by 2025 and (after all

existing sources retired) follow the same growth

trend as the base case by 2030. Under a 1.2 lb per

million Btu cap by 1990, emissions would decrease

to 40 percent of current emissions by 1990, and then

rise to about 60 percent of current levels by 2025.

Assuming a shorter retirement age would, of

course, decrease the length of time during which

the base case and the emissions cap scenarios substantially differed, and a longer retirement age

would increase that time.

The range of projections from the simple model

discussed above agrees reasonably well with the

more sophisticated projections presented earlier in

this section. Projections beyond 2000 to 2010 are

presented to illustrate how emissions levels might

respond to plausible changes in electricity demand

and utility operating procedures, but should not be

considered accurate forecasts, as many other factors may change over so long a time.

PATTERNS OF POLLUTANT EMISSIONS,

AIR CONCENTRATIONS, AND DEPOSITION

Geographical Emissions Patterns

Figures 12, 13, and 14 display maps of emissions

densities (in tons per square mile per year) for sulfur

dioxide, nitrogen oxides, and reactive hydrocarbons, respectively. For all three pollutants, emissions densities are generally greater in the East than

in the West.

Geographical Patterns of Deposition

and Air Concentrations for

Transformed Pollutants

Figures 15 through 18 display maps of deposition

levels for acidity and sulfate in precipitation, and

air concentrations for airborne sulfate and ozone—

each of which is a major determinant of potential

damage from transported air pollutants. Patterns

of rainfall acidity and sulfate deposition, and airborne sulfate concentrations, are similar over the

Eastern United States. The regional distribution

of ozone differs substantially from the other three.

The best information available on patterns of

acidic deposition comes from monitoring networks

that collect rainfall samples. Though only about half

of all acid deposition over the Eastern United States

comes from precipitation, dry deposition of gaseous

and particulate pollutants is not extensively monitored. Figure 15 shows average annual precipation

acidity (measured as ph*) throughout North America during 1980. Figure 16 shows the geographical

patterns of of wet-deposited sulfate. The highest

deposition rates center around eastern Ohio, western Pennsylvania, and northern West Virginia. A

band surrounding this area—from the Atlantic

Ocean west to the Mississippi River, and from

southern Ontario to northern Mississippi, Alabama, and Georgia—receives from 50 to 80 percent of these peak deposition rates. The data used

to construct this map are from 1980; deposition will

vary from year to year at any given location, but

the broad pattern will probably remain quite similar.

Figure 17 displays airborne sulfate concentrations

in rural and remote areas, illustrating large-scale,

regional patterns. The highest concentrations occur

in a broad band covering the Midwest and Middle Atlantic States.

*Acidity is measured in pH units. Decreasing pH corresponds to

increasing acidity. The pH scale is not linear; compared to a pH of

6, pH 5 is 10 times more acid, pH 4 is 100 times more acid, and

so on.
64 Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 12.—Sulfur Dioxide Emissions Density (tons/mile2, 1980)

SOURCE Environmental Protection Agency, based on data from National Emission Data System

Patterns of ozone concentration are also available osition, centering on North and South Carolina.

from monitoring data, Figure 18 displays growing- A band of elevated ozone extends from the Midseason average ozone concentrations, after elimi- Great Plains States to the east coast, as far north

nating local-scale variations due to urban influ- as central Indiana and south to the central Gulf

ences. In the Eastern United States, peak values Coast States.

for ozone are found further south than for acid depTHE REGIONAL PATTERNS OF

SULFUR OXIDES TRANSPORT

How pollutant emissions from a particular region Figure 19 schematically illustrates the gradual

(or group of regions) affect ambient air quality and transformation and deposition of sulfur pollution

pollutant deposition at some other location is a ma- as an air mass travels downwind over several days.

jor controversy in the long-range transport debate. Sulfur pollution can be deposited in both its emitted

Emitted pollutants are transformed, transported, form, sulfur dioxide (lighter shading), and as sulfate

and deposited through a complex chain of chemical (darker shading), after being chemically transand physical processes. formed in the atmosphere. Both forms can be de-
Ch. 4—The Pollutants of Concern . 65

Figure 13.— Nitrogen Oxide Emissions Density (tons/mile2)

SOURCE Environmental Protect Ion Agency, based on data from National Emission Data System

Figure 14.—Hydrocarbon Emissions Density (tons/mile2)

SOURCE Environmental Protection Agency, based on data from National Emission Data System
66 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 15.— Precipitation Acidity—Annual Average pH for 1980, Weighted by Precipitation Amount

/“

/“

/“ ● 6.80

/

/“

/“

/“

/“

● 5.44

Legend:

“/v\

u(

Data compiled from Canadian 5.0 and American monitoring 5.5

networks.

SOURCE: Impact Assessment, Work Group 1, United States-Canada Memorandum of Intent on Transboundary Air Pollution, final report, January 1983
Ch. 4—The Pollutants of Concern . 67

Figure 16.—Sulfate in Precipitation, 1980 (annual deposition in milliequivalents/meter2)

●

● 2.8

● 6.6

1

20

Legend:
68 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 17.—Airborne Sulfate—Annual Average Concentration for 1977-78 (micrograms/meter3)

NOTE: Contours are baaed on data collected during selected months to represent seasonal averages between August 1977 and June 1978 at SURE II stations.

SOURCE: B. L. Neimann, “Data Bases for Regional Air Pollution Modeling,” presented at the EPA Regional Air Pollution Modeling Workshop, Port Deposit, Md., October 1979.
Ch. 4—The Pollutants of Concern . 69

Figure 18.–Ozone Concentration–Daytime, Growing Season Average for 1978

(parts per billion, June to September daily 7-hr average)

SOURCE: J. Reagan, personal communication, Environmental Protection Agency, 1983.

posited ‘ ‘wet’ (i.e., by removal from the air during periodic precipitation events) and ‘ ‘dry’ (by

the slow, continuous removal of gaseous and particulate sulfur oxides).

As distance from the emission source increases,

the relative amount of sulfur deposited in each of

these forms changes. Dry deposition predominates

close to the emission source; wet deposition predominates in distant areas. Most scientists estimate

that these two processes deposit about equal

amounts of sulfur when averaged annually over the

Eastern United States. Both wet and dry deposition contribute to the total acidity received by

ecosystems.

Computer models of pollution transport attempt

to describe this process mathematically. Transport

models are currently the only practical procedure

available to estimate the relationship between areas

of origin and areas of deposition. * Transport models for sulfur oxides have been available for several

years, though their accuracy is still a subject of scientific debate. Appendix C discusses the strengths

and weaknesses of these models. Preliminary models of nitrogen oxides transport are just now being

developed.

The model results are best used to estimate one

region’s relative contribution to deposition in

another, rather than for projecting the magnitude

of deposition quantitatively. The discussion that fol-

“Newly developed tracer techniques may provide additional information on pollution transport. The U.S. and Canadian Governments

are jointly conducting the ‘‘cross-Appalachian tracer experiment’

(CAPTEX), using a chemical called to trace the flow

of acidic pollutants from sources in Ohio and Ontario.
70 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 19.—The Effects of Time and Distance on Conversion and Deposition of Sulfur Pollution

Sulfur can be deposited in both its emitted form, sulfur dioxide (lighter shading), and as sulfate (darker shading), after being

chemically transformed in the atmosphere. Both compounds can be deposited in either dry or wet form. The relative amount

of sulfur deposited in these forms varies with distance from emission sources. Dry deposition predominates in areas close

to emission sources. Wet deposition is responsible for a larger percentage of pollutant load in areas distant from source regions.

SOURCE Office of Technology Assessment

lows characterizes current patterns of sulfur oxide

transport, but should not be considered a quantitative description.

The results of transport models suggest that pollutants travel from one region to another, in all

directions, with greater movements of pollutants

from west to east and from south to north than in

other directions. In addition, while pollutants can

travel long distances, emissions within a region contribute a large share to total deposition in that

region.

To illustrate these points, Eastern North America

can be divided into four regions as shown in figure

20. These regions were chosen to intersect at the

area of peak wet sulfur deposition in 1980, to minimize deposition biases for any one region. Figure

20 also displays the percentage of sulfur dioxide

emitted in each region, and model-based estimates

of the percentage of total (wet plus dry) sulfur

deposited. Sulfur dioxide emissions are roughly

comparable in the northeastern region (I), southeastern region (II), and southwestern region (III).

Emissions in the northwestern region (IV) are over

twice the amount of any of the other regions. Total

sulfur deposition is lowest in the southern regions

(II and 111) and highest in the northern regions (I

and IV).

Figure 21 presents model-based estimates of how

much deposition in each region originates from

within its borders, and from each of the other

regions. For example, the pie chart in the upper

right shows that, of the total sulfur deposited in
Ch. 4—The Pollutants of Concern ● 7 1

Figure 20.— 1979 Sulfur Dioxide Emissions and Estimated Sulfur Deposition—Percent Contributed

and Received in Four Subregions Covering the Eastern Half of the United States

Emissions

Percentage of Eastern 

sulfur dioxide emissions

or sulfur deposition.

35-400/0

m 25-350/o

*

 10-15 ”/0

Deposition

I

SOURCE: J. Shannon, personal communication, Argonne National Laboratory and E. H. & Associates, Inc., 1982.

99-413 0 - 84 - 6 : QL . 3
72 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 21.— Percent of Sulfur Deposition Estimated To Originate From Within Each Region

and From Other Regions (winter and summer 1979) —

From 

--27$/0 / 

 I I III

570/0 \
Ch. 4—The Pollutants of Concern ● 7 3

region I (northeastern), approximately 40 percent

originates within its own borders, about 40 percent

comes from region IV (northwestern), and about

’20 percent from the other two regions combined.

When regions as large as these are analyzed, each

contributes as much or more to its own deposition

as any other single region contributes to it. However, because all regions contribute to deposition

in all other regions, a large percentage of deposition in any given region (in some cases over 50 percent) comes from outside. The greatest amounts

of interregional transport follow the direction of

prevailing winds—generally west to east and south

to north.

While the analysis above indicates the magnitude

and direction of interregional transport, it does not

show the average distances sulfur pollutants can

travel. Figure 22 displays model-based estimates

of the percentage of deposition due to long-distance

transport, arbitrarily defined as greater than 500

km (300 miles). A 500-km radius circle is shown

to illustrate the scale of transport being discussed.

Because wet deposition predominates in remote

areas and dry deposition predominates close to

emission sources, the two processes are illustrated

separately.

In general, long-distance transport accounts for

a greater percentage of wet deposition than of dry

deposition. Throughout the Midwest and Central

Atlantic States, about 30 to 50 percent of the wet

deposition originates from emissions greater than

500 km away, as compared to 10 to 30 percent for

dry deposition. Throughout New York and New

England, long-distance pollutant transport contributes 50 to 80 percent of the wet deposition and

30 to 60 percent of the dry deposition. Over much

of the South, most of the deposition originates from

sources within 500 km—about 10 to 30 percent of

both wet and dry deposition is due to long-distance

transport.

These results are model-based simulations of the

1980 summer season. The percentages will vary for

other seasons and years, but the broad patterns

should be similar.

The accuracy of pollution transport models,

which use detailed emissions data and sophisticated

meteorology, is a subject of scientific debate.

Measured levels of wet sulfur deposition for 1980

agree fairly closely with OTA’s model-based calculations, averaging over large regions on an annual basis, Dry deposition is not monitored routinely enough to compare with model estimates. The

model does not include nitrogen oxides, the other

major contributor to acid deposition, nor does it

portray the complex chemistry involving other atmospheric pollutants.

The chemical reactions that produce acid deposition involve a mix of pollutants present in gas form,

dissolved in liquids (e. g., in clouds), and adhering

to particles. Sulfur dioxide, nitrogen oxides, and

hydrocarbons undergo transformations that may

follow many complex chemical pathways. The sequence actually followed depends on concentrations

of other chemicals that may inhibit, compete with,

or enhance production and deposition of acidity.

The same chemicals that transform or ‘ ‘oxidize’

sulfur dioxide and nitrogen oxides to acid are also

essential for forming ozone. In addition, the physical characteristics of the atmosphere—windspeed,

sunlight intensity, and rainfall frequency—affect

these transformations.

Predicting quantities of deposition at a specific

time and place is not yet possible, and may not be

for many years. Making such predictions would require detailed information on the current concentrations of sulfur dioxide, nitrogen oxides, and

hydrocarbons, as well as on the history of the air

mass, including the frequency and amounts of fresh

pollutant inputs, the frequency and duration of recent rainfall events, and other specific chemical and

physical information.

However, current understanding of the various

chemical and physical processes involved permits

scientists to characterize very generally-over large

spatial scales, and seasonal time scales-the effects

of reducing emitted quantities of various pollutants.

The deposition changes that would result from reducing emissions of sulfur dioxide, nitrogen oxides,

and hydrocarbons are discussed in appendix C, and

are summarized briefly below:

Reducing sulfur dioxide emissions will reduce

the total amount of acid formed in the atmosphere, if levels of nitrogen oxides and

hydrocarbons remain constant, and chemical

reactions are not limited by a shortage of ox-
74 . Acid Rain and Transported Air Pollutants: implications for Public Policy

Figure 22.— Estimated Percentage of Sulfur

Over 500 km (300 miles) Away

Wet deposition

Deposition From Emissions

(summer 1980)

Dry deposition

Percent contribution

from greater than 500 km away

>70%

50-700/0

30-50%0

10-30 ”/0

SOURCE: J. Shannon, personal communication, Argonne National Laboratory, 1982.
Ch. 4—The Pollutants of Concern 75

●

●

idizing agents. Furthermore, given these conditions, a decrease in sulfur dioxide emissions

should decrease total sulfur deposition by an

approximately equal proportion. Where deposition will decrease can only be estimated on

a regional scale.

Decreasing nitrogen oxides emissions—while

holding hydrocarbon emissions constant—

would decrease the amount of ozone produced

over a large region, as well as the amount of

nitric acid ultimately deposited. The total

amount of sulfur deposited would probably not

be affected, although the conversion of sulfur

dioxide to sulfate might accelerate somewhat,

affecting the regional distribution of deposition.

Reducing hydrocarbon emissions can decrease

the production of ozone, and of some key

chemicals responsible for transforming sulfur

dioxide and nitrogen oxides to acids. This

would slow the production of sulfuric and nitric

acids, again altering the patterns of deposition,

but probably would not affect total amounts

of deposition.

If current regulations remain unchanged, sulfur

dioxide emissions are projected to remain about

constant or increase slightly, hydrocarbon emissions

to remain about constant, and nitrogen oxides emissions to increase. Local acid deposition due to nitric

acid would probably increase. The amount of total

sulfur deposited might remain about constant, but

reactions involving increased nitrogen oxides emissions might cause the geographic patterns of sulfur

deposition to change.

Given the complexities of atmospheric chemistry,

and inherent meteorological variability, as well as

the need to develop detailed emissions inventories

(especially for nitrogen oxides and hydrocarbons),

it is unlikely that a definitive model linking particular sources to specific receptors will be developed

in the next decade. Policy decisions to control or

not to control precursor emissions will have to be

made without the benefit of such precise information.
Chapter 5

The Regional Distribution of Risks
Contents

Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

No Congressional Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Aquatic Ecosystems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Terrestrial Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Other Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Visibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Risk of Health Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

If Further Emissions Reductions Are Mandated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Rates of Pollutant Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Utility Control Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Risk to the Utility Industry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Risks of Shifts in Coal Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

FIGURES

Figure No , Page

23. Estimated Percentages of Lakes Vulnerable to Acid Deposition in Sensitive Regions

of the Eastern United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

24. Estimated Percentages of Streams Vulnerable to Acid Deposition in Sensitivc Regions

of the Eastern United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

25. Freshwater Recreational Fishing— Relative Economic Importance . . . . . . . . . . . . . . . . . . . 83

26. Production of Corn and Soybeans in 1978 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

27. Percent of Land Area Capable of Commercial Timbcr Production . . . . . . . . . . . . . . . . . . 85

28. Estimated Gains in 1978 Corn and Soybean Yields From Reducing Ozone

Concentrations to “Natural” Levels, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

29. Soil Sensitivity to Acid Deposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

30. Agriculture— Relative Economic Importance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

31. Forestry—Relative Economic Importance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

32. Median Yearly Visual Range for Suburban and Nonurban Areas . . . . . . . . . . . . . . . . . . . 90

33. Population Exposure to Airborne Sulfate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

34. Average 1980 Emission Rates for Sulfur Dioxide From Utility and Industrial Sources . 93

35. Average 1980 Emission Rates for Nitrogen Oxides From Utility and

Industrial Sources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

36. Cost of Reducing Sulfur Dioxide Emissions 10 Million Tons per Year, Nationwide

Increases in Annual-Average Electricity Bills for a Typical Residential Consumer . . . . . 96

37. Cost of Reducing Sulfur Dioxide Emissions 6 Million Tons per Year,

Eastern 31 States Increases in Annual-Average Electricity Bills for a

Typical Residential Consumer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

38. Expenditures for Residential Electricity—Relative Economic Importance . . . . . . . . . . . . . 98

39. Electric Utilities-Selected Financial Indicators of Sensitivity to Control Expenditures . 99

40. Quantities and Sulfur Content of Coals Produced for Electric Utilities,

by State—1980 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

41. Coal—Relative Economic Importance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Chapter 5

The Regional Distribution of Risks

INTRODUCTION

Chapter 3 presented the risks of controlling and

not controlling transported air pollutants for the

Eastern 3 l-State region overall. However, the ways

in which these risks are distributed throughout the

region arc of prime significance to the policy debate.

Most importantly, considerable variation is found

in:

s

●

●

the distribution of pollution sources, and

hence, the distribution of potential control

costs ;

the distribution and extent of resources at risk,

their levels of exposure, and their inherent sensitivity to transported pollutants; and

the relative importance of the economic sector at risk to each State’s economy.

Scientific uncertainties complicate the task of

describing the distribution of risk. However, even

if scientists attained ‘ ‘perfect knowledge’ of the

causes and consequences of transported air pollutants, different groups and regions of the country

would bear these risks. Thus, while it is impossible to precisely specify these groups and regions at

present, the distributional aspects of transported

pollutants are inherently part of the policy problem.

This chapter describes how the risks associated

with three pollutants—acid deposition, ozone, and

airborne sulfate— are distributed. The order of discussion closely follows the presentation in chapter

3 of the aggregate risks to the Eastern 31 -State region. This chapter, however, focuses on the regional distribution of these risks, and is extensively

illustrated with maps.

Two situations are described: 1) the risk of resource damage and adverse health effects if Congress maintains the status quo for pollutant emissions, and 2) the costs and economic effects of

additional pollution-control measures that might be

adopted.

Some of the risks of controlling or not controlling transported air pollutants can be thought of

as ‘ ‘localized’ risks. For example, fewer than half

the States contain deposits of high sulfur-content

coal; only in these States could current coal production be lost due to additional pollution-control

requirements. Similarly, only parts of the Eastern

United States contain lakes and streams considered

potentially sensitive to acid deposition. Other risks

can be characterized as ‘ ‘distributed’ ‘—risks that

are present in Virtually all States in the Eastern region, For example, crops are grown in all States.

Three factors determine the relative importance of

ozone-caused crop damage: 1 ) the concentration

of ozone in a State, 2) the sensitivities of a States

crops to ozone, and 3) the importance of agriculture to the State economy. Likewise, the effects of

utility pollution-control costs depend both on the

amount of the State income spent on electricity and

on a State pollutant emissions.

In addition to describing the geographic patterns

of risk from transported air pollutants, this chapter

assesses the relative importance of five economic

sectors of concern: agriculture, forestry and forest

product-related industries, freshwater recreational

fishing, coal mining, and electricity generation. The

first four sectors vary considerably in economic importance from State to State—from a small percentage of the regional average to several times that

average. The last sector, electricity generation, is

much more uniformly distributed.

79
80 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

NO CONGRESSIONAL ACTION

Aquatic Ecosystems

As discussed in chapter 3, lakes and streams are

affected not only by the acid deposition falling

directly on them, but also by the amount of acidproducing substances entering them from surrounding watersheds. Regions with soils and bedrock that neutralize acidic deposition are not likely to be affected. The areas outlined in figures 23

and 24 are thought to allow acidity to travel through

watersheds to lake and streams. These areas contain soils that either cannot neutralize acidity, or

are so steep and rocky that rainfall has little contact with soils and runs directly into lakes or

streams. The size of the circles on each map illustrates the extent of lake and stream resources in

each region. The greatest number of lakes is found

in the upper Midwest, followed by New England.

The greatest mileage of small streams is found in

New England, followed by the mountain region of

Figure 23.-Estimated Percentages of Lakes Vulnerable to Acid Deposition

in Sensitive Regions of the Eastern United States

n

SOURCE: The Institute of Ecology, “Regional Assessment of Aquatic Resources at Risk From Acid Deposition,” OTA contractor report, 1982
Ch. 5—The Regional Distribution of Risks . 81

Figure 24.—Estimated Percentages of Streams Vulnerable to Acid Deposition

in Sensitive Regions of the Eastern United States

D

o

SOURCE: The Institute of Ecology, “Regional Assessment of Aquatic Resources at Risk From Acid Deposition, ” OTA contractor report, 1982.

West Virginia, Kentucky, western Virginia, North numbers of moderately vulnerable lakes are found

Carolina, and eastern Tennessee.

However, because of local variation in soil and

watershed characteristics, not all the lakes and

streams within these regions will be vulnerable to

acidic deposition. The intensity of shading within

each outlined area indicates the percentage of lakes

and streams estimated to be vulnerable to acid deposition, based on water quality characteristics. The

northeastern regions have the greatest percentages

of ‘extremely’ vulnerable lakes and streams—we

estimate about 30 to 40 percent of the over 5,000

lakes and 10 to 20 percent of the 65,000 stream

miles in the area. These regions also receive high

levels of acidic deposition. In addition, large

in the upper Midwest, and extensive mileages of

moderately vulnerable streams are found in the central Appalachian/Blue Ridge regions.

Directly comparing current conditions to historical data, only a small number of surface waters

in North America are known to have acidified. Data

from several decades ago are sparse; in addition,

differences in sampling and measurement techniques make comparisons with current data difficult. A review of the available evidence for

acidification found significant changes in water

body chemistry in studies of: 250 lakes in Maine,

94 lakes in New England, 40 lakes in the Adirondacks, and two streams in the New Jersey Pine Bar-
82 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

rens, as well as in 16 lakes near Halifax, Nova

Scotia, 22 lakes in the LaCloche Mountains, Ontario, and Clear Lake, Ontario. Changes in water

chemistry over time have also been reported for 38

North Carolina streams, 6 Nova Scotia rivers, and

314 surface waters in Pennsylvania; however, firm

conclusions cannot be drawn from these studies. 1

In the Adirondack Mountains, the only U.S. location in which scientists have documented fish

population declines, the New York State Department of Environmental Conservation has reported

the disappearance of fish populations in about 180

lakes. Researchers have found correlations between

acidity levels and survival of fish in Adirondack

lakes and streams. Four other areas are known to

have experienced losses of fish populations

associated with surface water acidification: 1 ) the

LaCloche Mountain region of Ontario, 2) Nova

Scotia, 3) Southern Norway, and 4) Southern

Sweden.

Acid deposition may not be the sole cause of the

changes discussed above. Other man-induced

stresses and natural processes can also alter surface

water chemistry. However, the largest numbers of

acidified and extremely sensitive lakes and streams

are located in regions currently receiving the highest

levels of acid deposition.

Though the economic value of these particular

sensitive resources cannot yet be estimated, the Fish

and Wildlife Service has estimated that about 21

million people spent $6.3 billion on all recreational

freshwater fishing activities in the Eastern United

States during 1980. Figure 25 illustrates how these

expenditures vary by State, displaying the importance of recreational fishing to each State’s economy

relative to the 3 1-State regional average.

‘R. A. 1,inthurst, J P. Ilakt, r, and A. M 13art uska, 4‘ F; f’fccts of

.Acidic Deposition A Ilricf’ Review, ” Proct’eding-s of the .4PCA Special-

(}’ (~onfi’rencc on Atnmspheri( Dt’posltiorr, Air Pollution Control Asso-

( iat ion, Ncr\cmber 1982, rei.lew ing I ntcrnat ional Electric Research

F,xchange, Efk-ts of S02 ,and 1[s Deri\ati\e.s (m Hea/th and EC (]]o,~,

(kmtral Electricity Generatin~ Board, Leathcrhead, England; National

Research Counci] of’ Canada, Acidification in the Canadian Aquatic

f~n~ironment: .%lentilic Criteri,i ftir .4ssessing the IW&ts of .4cidlc

I)cposirion on AquarJc Ecos)sfcms, Associated Committee on Scientific Criteria for En\’ironmentat Quality, National Research Council

[Jf’Canada, NRC(; ISO. 18475, 1981 ; and J Baker, ‘ ‘Effects on Aquatic

Biology, Drafi Critical Asst’ssn]ent Lhcunlcnt: 7Yle rlcidlc Lkposition Phenomenon and 1[s Ef]it(.s, Ch,ipter E-5, 5.6 Fisht.s (Octobcr

1982)

Because there are few data to determine whether lakes and streams sensitive to acid deposition are

those preferred for recreational fishing, OTA cannot estimate potential regional economic losses

resulting from the elimination of fish populations.

One local-scale study, however, has estimated losses

to New York resident anglers of approximately $1.7

(1982 dollars) million annually from lost fishing opportunities in about 200 acidified Adirondack lakes

and ponds. 2 Potential losses to individuals whose

livelihoods depend on the recreational fishing industry were not estimated. On a regional scale, the

States at greatest economic risk are those with: 1)

the greatest numbers of sensitive lakes, 2) the

highest levels of acid deposition, and 3) the highest

relative expenditures for recreational fishing.

Among these are the New England States of Maine,

Vermont, and New Hampshire; the Appalachian

region of West Virginia and eastern Kentucky; and

parts of the Midwestern States of Wisconsin and

Minnesota.

Terrestrial Ecosystems

Figure 26 shows major agricultural production

areas for two major crops, corn and soybeans.

Figure 27 presents the location of forests.

Figure 28 illustrates the crop yield gains that

might occur if ozone concentrations were lowered

to estimated natural background levels. The regions

of highest crop production—an area slightly north

of the peak ozone concentrations—show the greatest

improvement. Here, in the corn and soybean belt

of the Midwest, even moderate levels of ozone can

cause substantial crop damage. For Iowa, Indiana,

and Illinois, reducing ozone concentrations to

background levels might cause both soybean and

corn yields to increase by about 20 to 40 million

bushels per year in each State. (See app. B for

potential productivity gains in wheat and peanuts

with decreased ozone concentrations. )

Comparing figures 15 (patterns of acidity) and 26

(current corn and soybean yields) indicates that

elevated levels of acid deposition occur within

several major crop-producing States, including

Illinois, Indiana, and Ohio. Reductions in both soy- —. .—

‘F. (;, hlenz and J. K. hlullen, ‘ ‘Ac edification Impact on Fisheries: Substitution and the t’aluatlon of Re( reat ional Resources, Econ(mji[ Pcrspt’cti\w on Acid Deposition, ‘1’.11. Cro(ker (cd ) (Ann Artmr: Butter-worth Press, 1984).
Ch. 5—The Regional Distribution of Risks ● 8 3 - .

Figure 25.—Freshwater Recreational Fishing— Relative Economic Importance

1980 recreational fishing expenditures by State (expenditures on freshwater recreational fishing, scaled

by State income, compared to regional average)

SOURCE: Office of Technology Assessment, from U.S. Census Bureau and U.S. Fish and Wildlife Service data

bean and corn productivity have been observed in

field experiments with simulated acid rain, but

other experiments have yielded contradictory

results.

Scientists have recently discovered productivity

declines in several tree species throughout the Eastern Unitcd States from New England to Georgia.

Acid deposition, ozone, heat)-metal deposition,

drought, severe winters or a combination of these

are possible causes under investigation.

By coring trees and measuring the thickness of’

annual growth rings, scientists have observed marked

reductions in productivity beginning about 1960

in red spruce, shortleaf pine and pitch pine, Corings from about 30 other species at 70 sites throughout the East are currently being analyzed to deter-

Ch. 5—The Regional Distribution of Risks 85

Figure 27.— Percent of Land Area Capable of Commercial Timber Production

a

The U S Forest Service defines commercial timberland as lands capable of producing greater than 20 cubic feet of industrial roundwood per acre per year, in natural stands

SOURCE Oak Ridge National Laboratory, 1981, U S Forest Service State forest Inventory

mine the geographic extent and severity of the problem. Routine measurements of tree growth by the

U.S. Forest Service have shown productivity declines in loblolly pine and shortleaf pine during the

1970s in the Piedmont region of South Carolina

and Georgia.

Although ozone is known to harm trees, quantitative estimates of forest productivity losses due

to ozone are lacking because of the difficulty of performing experiments on long-lived species. By comparing figures 18 and 27, one can observe that elevated ozone concentrations coincide with forested

regions in the southern Appalachian Mountains,

the Ozark Mountains, and parts of the southern

softwood area of the Southeastern and South Central States.

Much of the forested area of New England, the

Appalachian Mountains, and parts of the southern

soft wood forests of Alabama and Georgia receive

elevated levels of acid deposition, as can be seen

in figures 15 and 27. However, the relationships between forest health and levels of deposition are not

well known. The nitrogen deposited is a beneficial

nutrient, but the acidity might damage leaf surfaces, remove nutrients from foliage, alter susceptibility to pests (either beneficially or detrimentally), or alter forest soil chemistry.

Forest soils are at risk from acid deposition due

to: 1 ) release (mobilization) of soil-bound metals,

such as aluminum, that are toxic to plants if present in sufficient quantity, 2) potential leaching of

calcium, magnesium, and other nutrients essential

for plant growth from the soil, and 3) further acidification of soils. Figure 29 displays the geographic

distribution of these risks. Available information

allowed OTA to identify’ those counties in which

soils susceptible to these effects predominate; other locations where they occur to a lesser extent could

not be determined.
86 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 28.—Estimated Gains in 1978 Corn and Soybean Yields From Reducing

Ozone Concentrations to “Natural" Levels

Corn yield gains (bushels/acre) with ozone reductions

based on 1978 agriculture census and 1978 EPA ozone data.

SOURCE Oak Ridge National Laboratory, “An Analysis of Potential Agriculture and Forest Impacts of Long-Range Transport Air Pollutants, ” OTA contractor report

1983
Ch. 5—The Regional Distribution of Risks ● 8 7

Figure 29.-Soil Sensitivity to Acid Deposition (nonagricultural)

Forested and range areas with soils thought to be susceptible to the effects of acid deposition. Shaded areas represent counties

in which a susceptible soil type predominates. The three levels of shading correspond to different soil types, and potential

effects, rather than to degrees of susceptibility.

Legend

SOURCE: Oak Ridge National Laboratory, “An Analysis of Potential Agriculture and Forest Impacts of Long-Range Transport Air Pollutants,” OTA contractor report, 1983.

99-413 0 - 84 - 7 : QL . 3
88 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 30.-Agriculture— Relative Economic Importance

elative importance of agriculture-related income to State income, 1978-80

SOURCE: Office of Technology Assessment, from U.S. Census Bureau data.

Soils must already be acidic—about pH 5 or

lower—to release aluminum in the presence of the

strong acids in acid deposition. Regions where naturally acid soils predominate are shown as the

medium and light gray areas in figure 29. However,

the soils in the light gray areas trap sulfate in their

lower layers, which somewhat reduces the amount

of this strong acid available for releasing aluminum.

Soils that are both acidic and do not impede the

flow of sulfate (shaded a medium gray in fig. 29)

predominate in New England and northern New

York State, and parts of the upper Midwest and

Florida. These regions are considered most susceptible to the toxic effects of aluminum; however,

whether resulting aluminum concentrations will be

high enough to significantly alter forest productivity

is not yet known.

Figure 29 also displays regions of the Eastern

United States where nutrient loss is of concern. The

dark patches are areas with moderately acid soils.
Ch. 5—The Regional Distribution of Risks . 89

Figure 31.— Forestry -Relative Economic importance

Relative importance of forestry-related income to State income, 1978-80

Key:

SOURCE: Office of Technology Assessment, from U.S. Census Bureau data.

Loss of calcium, magnesium, and other nutrients

from these relatively uncommon soils through

decades of exposure to acid deposition might cause

these soils to further acidify. Nutrients can also be

lost from more acidic soils—typically already nutrient poor—but probably at a slower rate. Most

susceptible are those regions (shaded medium gray)

with nutrient-poor acid soils that allow sulfate to

move freely, potentially carrying away nutrients

from the soil, plant canopy, and decaying plant

material. However, whether the rate of nutrient loss

from these soils is more rapid than replacement by

weathering is unknown.

Both agriculture and forestry are important to

the overall economy of the Eastern United States,

each providing about 3.7 percent of the total regional income. Agriculture and related services are

responsible for about $22 billion of the region’s income; forestry, wood, lumber, paper, and allied
90l Acid Rain and Transported Air Pollutants: Implications for Public Policy ———

Figure 32.—Median Yearly Visual Range (miles) for Suburban and Nonurban Areas

Data from 1974-76, estimated from visual observations and other methods

SOURCE. Trijonis, J., and Shapland, R., 1979: Existing Visibility Levels in the U. S.: Isopleth Maps of Visibility in Suburban/Nonurban Areas During 1974-76, EPA

450/5-79-010, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina.

industries generate about $21 billion in personal

income.

Figures 30 and 31 display those States’ economies

that depend most on these sectors. When considering potential crop damage, States subject to the

greatest monetary risk are those that are both:

1) exposed to elevated ozone (fig. 18), acid deposition (fig. 15), or both; and 2) generate the largest

share of State income from agriculture (fig. 30).

Iowa, Illinois, Indiana, Missouri, Arkansas, Mississippi, Alabama, and North Carolina are at

greatest economic risk from ozone damage. If acid

deposition affects crops, the above States plus VerWhen considering potential forestry-related

effects, States at greatest economic risk are those

that: 1) generate the largest share of income from

forestry (fig. 31); 2) are exposed to elevated ozone

(fig. 18), acid deposition (fig. 15), or both; and 3)

contain soils susceptible to change (fig. 29). States

at greatest economic risk from ozone include the

southern softwood region extending from Arkansas to North Carolina. Many of these States receive

high levels of acid deposition and have soils considered susceptible to mobilization of toxic aluminum or nutrient loss, as do the New England States

of Vermont, New Hampshire, and Maine.

mont would be at greatest risk.
Ch. 5—The Regional Distribution of Risks ● 9 1

Figure 33.—population Exposure to Airborne Sulfate (an indicator of potential health effects from sulfates

and other airborne particulate in each State)

concentration in micrograms per cubic

meter). Model estimates based on

1978 data.

SOURCE Brookhaven National Laboratory, Biomedical and Environmental Assessment Division, “Long Range Transport Air Pollution Health Effects, ” OTA contractor

report, May 1982

OTHER RISKS

Materials

Materials at greatest risk from exposure to acidic

deposition include metals, such as steel and zinc,

and stone masonry. Regions at greatest risk correspond to those with the greatest population densities and areas with historically significant buildings

and monuments, Scientists estimate that the bulk

of materials damage is caused by local-scale pollutants, and that sulfur dioxide emissions are responsible for a major share of pollutant-induced

damages to a broad range of materials, Elevated

ozone concentrations are harmful to such materials

as paint on home exteriors and rubber. The distribution of materials sensitive to air pollutants is

not well known, since inventories have been taken

in very few areas.

●

Visibility

For the Eastern United States, sulfate is the single

most important contributor to visibility degrada-
92 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

tion; patterns of impairment in the region correlate

fairly well to airborne sulfate concentrations (presented earlier as fig. 17). Sulfate is currently

estimated to account for 50 percent of visibility

degradation annually, and 70 percent of summer

visibility degradation in the East. In the West,

nitrates may play a larger role than sulfates in

visibility impairment. Figure 32 shows annual average risibilities throughout the Nation for the mid1970’s, the most recent information available to

OTA. Visibility in the Eastern United States has

improved slightly over the past decade, but is still

less than pre-1960 levels.

Current Eastern visibility levels are generally far

lower than those in the West. However, it should

be noted that unimpaired Eastern visibility levels

would be significantly lower than in the West, due

to higher Eastern humidity levels. In addition,

where visibility is already low, an increment of additional sulfate may not reduce visibility much further; in more pristine areas, the same increment

of additional sulfate may significantly decrease

visibility.

Risk of Health Effects

The health risk to any individual is thought to

be correlated to sulfate concentrations in the atmosphere. However, whether premature mortality observed in statistical studies actually results from

sulfate in air pollution, from different components

of the sulfate-particulate mix, or from other factors not considered, is unknown. This risk varies

from increases of less than 1 percent in excess mortality in the West to about 4 percent (a range from

about O to 10 percent) in the regions of highest sulfate concentration. The health risk to a State is determined both by the potential increase in mortality

and by the State’s population. Some of the Northeastern States with the highest population densities

(e.g., New York, Pennsylvania, and Ohio) are also

exposed to the highest airborne sulfate concentrations, and are therefore at greatest risk. Figure 33

displays the total exposure of each State’s population to airborne sulfate, an indicator of the relative

risk of premature mortality in each State.

IF FURTHER EMISSIONS REDUCTIONS

ARE MANDATED

Rates of Pollutant Emissions

The regional patterns of pollutant emissions are

perhaps the best indicator of how costs to control

transported air pollution might be distributed. Figures 12 and 13 in chapter 4 display maps of emissions densities (in tons per square mile) for sulfur

dioxide and nitrogen oxides. This section discusses

another measure of pollutant emissions more directly related to potential control costs—emission rates,

expressed as pounds of pollutants per quantity of

fuel burned.

To date, the major legislative proposals to control acid deposition have focused primarily on sulfur

dioxide emissions. Though emissions reductions

can be allocated to States in many ways, most of

these bills propose reductions based on emission

rates. This approach avoids penalizing areas emitting large quantities of sulfur dioxide because of

high electrical or industrial productivity; instead,

reductions are concentrated in areas that emit

greater-than-average amounts of sulfur dioxide for

a given amount of production.

Sulfur dioxide emission rates vary widely among

States. Emission rates can be decreased either by

using: 1) a lower sulfur fuel, or 2) technological

means, such as capturing the sulfur dioxide gas with

‘‘scrubbers’ after the fuel is burned.

Figure 34 displays estimates of statewide average

sulfur dioxide emission rates from utilities and industrial boilers. Within the Eastern 31-State region,

utilities account for about 70 to 75 percent of sulfur

dioxide emissions, and industrial boilers for about

10 to 15 percent.

The Midwestern States have the highest utility

emission rates, and are therefore at greatest risk

from additional pollution control regulations. In-
Ch. 5—The Regional Distribution of Risks 93

Figure 34.—Average 1980 Emission Rates for Sulfur Dioxide From Utility and Industrial Sources (lb SO2/MMBtu)

SOURCE: E. H. Pechan & Associates, from Energy Information Administration data (EIA forms 4 and 423), and EPA National Emissions Data System (NEDS).
94 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 35.—Average 1980 Emission Rates for Nitrogen Oxides From Utility and Industrial Sources (lb NO2/MMBtu)

I

SOURCE: E. H. Pechan & Associates, from Energy Information Administration data (EIA forms 4 and 423), and EPA National Emissions Data System (NEDS)
Ch. 5—The Regional Distribution of Risks ● 9 5

dustrial boiler emission rates are more evenly distributed, with highest average rates occurring in

the Midwestern and Central Atlantic States.

Nitrogen oxides are both a component of acid

deposition and a precursor to ozone. Reducing

nitrogen oxides emissions from existing sources has

not been proposed to date, although some bills have

prohibited further increases in nitrogen oxides emissions or allowed reductions to substitute for sulfur

dioxide reductions.

The three major sources of nitrogen oxides in

the 31 -State region are mobile sources (45 percent),

utilities (35 percent), and industrial boilers (15 to

20 percent). Highway vehicles account for about

75 percent of the emissions from mobile sources,

or about one-third of total Eastern U.S. nitrogen

oxides emissions.

Figure 35 displays State-average nitrogen oxides

emission rates from utilities and industrial boilers,

respectively. As with sulfur dioxide emissions, proposals for controlling nitrogen oxides might allocate

reductions on the basis of emission rates. Emission

rates are more evenly distributed for nitrogen oxides than for sulfur dioxide. Additional mobilesource controls would regionally distribute costs according to patterns of new vehicle purchases.

Utility Control Costs

Figure 36 displays the effects of further pollution

control on the cost of electricity. Annual increases

in a typical residential consumer’s electricity bills

are estimated for a 10-million-ton reduction in sulfur dioxide emissions from existing utility sources.

Total costs of such a program would be about $3

to $4 billion per year (1982 dollars), assuming each

utility chooses the most cost-effective method of reducing emissions. Emissions reductions are allocated to States on the basis of 1980 utility emission rates. (Similar to several legislative proposals,

reductions are based on each State’s share of sulfur

dioxide emitted in excess of 1.2 lb per million Btu

of fuel burned. ) For this hypothetical pollutioncontrol plan, the reduction formula applies to the

contiguous 48 States; however, reductions, in the

Eastern 31 States would be quite similar if the formula applied only to these Eastern States. * The

“W’estern sulfur dioxide cm]ssions in excess of 1.2 lb per million

Btu are less than 5 percent of the allocated reductions.

highest rate increases occur in the Midwestern

States and a few Southeastern and New England

States.

Figure 37 displays the cost of a smaller pollution

control program. About 6 million tons of sulfur dioxide could be eliminated annually in the Eastern

31 States by limiting utility emission rates to 2 lb

per million Btu, at a cost of about $1 to $1.5 billion per year. If the control program was confined

to the 22-State region receiving the highest levels

of acid deposition, about 4.8 million tons per year

could be eliminated for annual costs of $1 billion

or less.

These cost estimates assume that all required

emissions reductions would come from utilities, and

that additional emissions coming from new utility

plants or increased use of existing plants are not

offset by further reducing existing plant emissions.

In addition, these cost estimates assume that the

use of control technology (e. g., scrubbers) is not

required.

Similar to the maps presented earlier depicting

the relative economic importance of recreational

fishing, agriculture, and forestry, figure 38 displays

the relative share of State income spent on residential electricity. For the region as a whole, about 2.3

percent of personal income, or $26 billion, is spent

on electricity. The distribution of these expenditures

by State is much more uniform than for the sectors discussed above, but is somewhat higher

throughout the South.

Risk to the Utility Industry

Additional expenditures to control emissions

could potentially affect the financial health of individual utilities. Three major factors determine the

extent to which utility companies could be affected:

1) the extent of emissions reductions required under

a given control program, 2) the utility’s financial

position, and 3) State-level regulatory policies that

affect a utility’s short- and medium-term ability to

pass on the costs of pollution control to consumers.

OTA did not attempt to analyze how these factors

would affect the financial health of the more than

100 major publicly owned utilities in the 31 Eastern

States, but drew on available information to assess

the relative sensitivity of each State utility sector

to further emissions control.
96. Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 36.-Cost of Reducing Sulfur Dioxide Emissions 10 Million Tons per Year, Nationwide Increases in Annual”

Average Electricity Bills for a Typical Residential Consumer

Figure 39 displays patterns of utility earnings and

bond ratings for 1980 in each State, two indicators

of the financial health of a State’s utility sector. Figure 34 shows statewide average 1980 utility emission rates for sulfur dioxide—the best indicator of

the extent of utility-sector reductions likely to be

required under most of the control proposals introduced in the 97th and 98th Congresses.

Comparing figures 34 and 39 shows that few

States both: 1) had high emission rates, and 2) fell

into the least favorable financial category, in 1980.

However, several Midwestern States with high

emission rates (and, therefore, potentially subject

to extensive control requirements) fell into the moderately favorable financial categories.

Policies established by State public utility commissions can affect an individual utility’s near-term

ability to pass on the costs of pollution control to

consumers. For example, for coal-burning utilities

that might choose to use scrubbers, the State’s pol-
Ch. 5—The Regional Distribution of Risks ● 9 7

Figure 37.—Cost of Reducing Sulfur Dioxide Emissions 6 Million Tons per Year, Eastern 31 States Increases

in Annual-Average Electricity Bills for a Typical Residential Consumer

Key:

SOURCE Office of Technology Assessment, based on analyses by E. H. Pechan & Associates, Inc.

icies regarding capital investment, in combination

with the utilities’ current financial ratings, determine the burden of raising capital for constructing

scrubbers. Results of a survey of current State regulatory policies, and a discussion of their relative

importance, are presented in appendix A. However, these policies might change considerably if

a major Federal program to further limit pollution

emissions is enacted.

Risks of Shifts in Coal Production

Because switching to lower sulfur fuel is often

a cost-effective way to reduce sulfur dioxide emissions, emission-reduction schemes could cause coal

production to shift from high-sulfur coal regions

to low-sulfur coal regions.

Figure 40 displays coal production by State for

both high- and low-sulfur coal. The size of each
98 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 38.—Expenditures for Residential Electricity—Relative Economic Importance

Relative share of State income spent for residential electricity, 1980

ffice of Technology Assessment, from U.S. Census Bureau and Edison Electric Institute data.

circle indicates the magnitude of State coal production. The shading indicates the average sulfur content of the coals mined, using the darkest shadings

for the highest sulfur coal. Midwestern and northern Appalachian high-sulfur coal States incur the

greatest risk of production losses, However, total

coal production is projected to be unaffected; production gains of similar magnitudes would occur

in the low-sulfur coal regions of Central Appalachia

and the West.

Of all the economic sectors at risk, coal mining

is the least evenly distributed across the Eastern region. The approximately $7 billion of regional income from coal mining in the Eastern 31 States is

concentrated in 9 States, as shown in figure 41.

States at greatest economic risk are those in which:

1) a large share of State income comes from coal

mining (fig. 41), and 2) most of the coal produced

is of relatively high-sulfur content (fig. 40). States

meeting these criteria include West Virginia, Kentucky, Pennsylvania, Alabama, and Virginia. For

these States, the income from coal mining is more

than twice the regional average, and more than 80

percent of the coal produced emits greater than 1.2

lb sulfur dioxide per million Btu when burned.
Ch. 5—The Regional Distribution of Risks . 99

Figure 39.— Electric Utilities-Selected Financial Indicators of Sensitivity to Control Expenditures

Key for financial indicators

Sensitive to additional air pollution control requirements: relatively poor bond ratings and below-average

return on common equity in 1980.

Moderately sensitive to additional air pollution control requirements: poor bond ratings or below-average

return on common equity in 1980.

I I Insensitive to additional air pollution control requirements: relatively good bond ratings and above-average

return on common equity in 1980.

SOURCE K. Cole, et. al., “Financial and Regulatory Factors Affecting the State and Regional Economic Impact of Sulfur Oxide Emissions Control, ” OTA contractor

report, 1982
100 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure 40.–Quantities and Sulfur Content of Coals Produced for Electric Utilities, by State–1980
Ch. 5—The Regional Distribution of Risks 101 — —

Figure 41 .—Coal—Relative Economic Importance

Relative importance of coal-related income to State income, 1978-80

SOURCE: Office of Technology Assessment, from U.S. Census Bureau data.
Chapter 6

Policy Options
Contents

Page

Current Law and Recent Legislative Proposals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Approaches and Options . . . . . . ..***.* .*.*.... . . . . . . . . ....**.* ● ..*.*** . . . . . . . 106

Approach A: Mandating Emissions Reductions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Approach B: Liming Lakes and Streams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Approach C: Modifying the Federal Acid Deposition Research Program . . . . . . . . . . . . . . . . 115

Approach D: Modifying Existing International and Interstate Sections of the Clean Air Act 118

TABLE

Table No. Page

5. Organization of the National Acid Precipitation Assessment Program . . . . . . . . . . . . . . . . . 115
Chapter 6

Policy Options

This chapter presents options for congressional

action on acid deposition and other transported air

pollutants. As background, it first describes existing

CURRENT LAW

LEGISLATIVE

The present Clean Air Act is designed to control airborne concentrations of pollutants that endanger public health and welfare. The act requires

EPA to set National Ambient Air Quality Standards (NAAQS), and makes each State responsible

for bringing its air pollutant concentrations down

to or below the NAAQS. * Despite these limitations

on allowable concentrations, large quantities of

pollutants are still emitted and eventually deposited. Provisions were added to the act in 1977 to

prohibit a State’s emissions from contributing to

violations of NAAQS in other States, or to any pollution problem in other countries. These provisions,

however, appear to be ineffective for dealing with

problems of the geographic scope of acid deposition.

The act further restricts future emissions by placing stringent emission limits on new sources of pollution, such as electric utilities and motor vehicles.

These New Source Performance Standards (NSPS)

are expected to achieve reductions in total emissions within 30 to 50 years. Continuing emissions

from both old and new sources, however, will maintain or increase pollution levels during the next few

decades unless additional controls are mandated.

To date, congressional action on acid deposition

has been limited to funding research. The Acid Precipitation Act of 1980—Title VII of the Energy

Security Act, Public Law 96-294—created an Interagency Task Force to conduct a comprehensive 10-

year assessment of the causes and consequences of,

and means and costs of controlling, transported

acidic pollutants, The Task Force presented an

——

“National Ambient Air Quality Standards currently exist for six

pollutants: sulfur dioxide, nitrogen dioxide, ozone, total suspended

particulate, carbon monoxide, and lead.

Federal statutes relating to transported air pollutants, and summarizes the legislative proposals

introduced during the 97th and 98th Congresses.

AND RECENT

PROPOSALS

Assessment Plan to Congress in June 1982. Under

the plan, Congress would receive policy-related “integrated assessments’ between 1987 and 1989.

Several bills were introduced during the 97th and

98th Congresses to accelerate the research program

from 10 to 5 years; another bill would direct the

Task Force to report to Congress on the progress

of research, and provide recommendations for action, once every 2 years. Options for making the

research plan more responsive to congressional (and

potentially, regulatory) needs are presented later

in this chapter under “Approach C: Modifying the

Federal Acid Deposition Research Program.

Legislators have also introduced a variety of proposals to control acid deposition directly. Many

would establish a 31-State control region, and mandate reductions of annual sulfur dioxide emissions

in the region by 8 to 12 million tons below actual

1980 emission levels by the early 1990’s. Individual

States would be allocated reductions through formulas based primarily on utility sulfur dioxide

emission rates. Variations on this approach include

designating a smaller, 22-State control region, designating a 48-State control region, establishing a

trust fund to pay some or all of the costs of emissions reductions, allocating reductions by considering both utility and industrial emissions, and allowing 2 tons of nitrogen oxides emissions to be

substituted for each required ton of sulfur dioxide

emissions reductions.

The bills vary in their treatment of new sources

of emissions; some allow emissions from post-1980

sources to increase total emissions in the region,

while others require further reductions to offset new

emissions. Options for controlling the sources of

105
106 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

transported air pollutants are discussed under ‘ ‘Approach A: Mandating Emissions Reductions. ”

Bills addressing other aspects of transported pollutants have also been introduced during the 97th

and 98th Congresses. For example, several bills

would tighten nitrogen oxide emission standards

for utility and mobile sources, accelerate development of innovative pollution control technologies,

and provide Federal funding to lime acid-altered

bodies of water that have ceased to support some

fish species. Alternatives for implementing the last

of these proposals are presented under ‘‘Approach

B: Liming Lakes and Streams. ”

Bills have also been introduced to amend the interstate and international provisions of the Clean

Air Act. Clarifying the scope of these provisions

could aid States, EPA, and affected foreign countries in dealing with transboundary pollution problems other than acid deposition—in particular, middistance transport of air pollution currently regulated under the act. Options for amending these

sections of the current law are presented under

“Approach D: Modifying the Existing International and Interstate Sections of the Clean Air Act.

APPROACHES AND OPTIONS

This section presents congressional options for

addressing acid deposition and other transported

air pollutants, grouped according to four major approaches:

●

●

●

●

Approach A: Mandating emissions reductions to

further control the sources of transported

pollutants;

Approach B: Liming lakes and streams to mitigate some of the effects of acid deposition;

Approach C: Modifying the Federal acid deposition research program to provide more timely

guidance for congressional decisions; and

Approach D: Modifying existing sections of the

Clean Air Act to enable-EPA, States, and countries to more effectively address transported pollutants other than acid deposition.

Congress could choose to adopt some or all of these

approaches in considering clean-air legislation. A

comprehensive strategy for addressing transported

air pollutants might well include options from all

four approaches. The four are described below,

along with their respective options.

APPROACH A:

Mandating Emissions Reductions

Discussion:

Additional legislated emissions reductions could

range from modest, possibly interim, reductions to

offset expected future emissions growth, to largescale control programs. In choosing an appropriate program, Congress will need to weigh the risks

of potential resource damage against those of inefficient control expenditures. These decisions are

complicated by the scientific uncertainties, disagreement over values, and distributional issues discussed throughout this report.

Mandating further emissions reductions would

require Congress to make a number of interrelated

choices. These include decisions about which pollutant emissions to reduce, from what source regions, by how much, and over what time period.

Congress would also need to choose specific policy

mechanisms to implement the reductions, allocate

their costs, and address undesired secondary consequences of emissions reductions.

OTA has outlined a series of eight control-policy

decisions that must be made in order to design acid

deposition control legislation. These are summarized below, to provide the framework for considering three representative emissions control options

presented at the end of this section. Chapter 7 discusses the eight control-policy decisions in greater

detail, and presents options available to Congress

under each decision area.

● Which Pollutants Should Be Further Controlled?

Three pollutants are potential candidates: sulfur

dioxide, nitrogen oxides, and hydrocarbons. Sulfur

dioxide and nitrogen oxides (and their transforma-
Ch. 6—Policy Options . 107

tion products) are major sources of acidity to the

environment. In the Eastern United States, sulfur

compounds annually contribute about twice as

much acidity to precipitation as nitrogen compounds. Moreover, during most times of the year,

plants use much of the deposited nitrogen as a nutrient, making sulfur compounds responsible for a

still larger share of acidity reaching water bodies.

For these reasons, any control program for the Eastern United States would have to include provisions

for reducing sulfur dioxide emissions.

If desired, additional resource protection can be

achieved by also mandating reductions of nitrogen

oxides emissions. Nitrogen oxides emissions are expected to increase more rapidly over the next few

decades than sulfur dioxide emissions. During

springtime snow melt, both sulfur and nitrogen

compounds accumulated in the snow over the winter can reach water bodies unimpeded. In the West,

nitrogen compounds may contribute as much as or

more acidity to precipitation than do sulfur compounds, and thus should be considered if a nationwide control program is enacted.

Hydrocarbons can affect the geographic distribution of acid deposition. The atmospheric chemistry involved, however, is not sufficiently understood to ‘‘fine-tune’ a sulfur dioxide or combined

sulfur dioxide and nitrogen oxides control program

with hydrocarbon emissions control.

c How Widespread Should a Control Program

Be ?

Four regions are potential candidates for emissions reductions, starting with the Northeastern

United States and expanding southward and westward: 1 ) the approximately 2 l-State Northeastern

region receiving the greatest levels of acid deposition; 2) a 31-State region (all States east of and

bordering on the Mississippi River), incorporating

a band of States around the region of greatest deposition; 3) a 37-State region, including all States east

of the Rocky Mountains; and 4) the contiguous 48

States.

About 65 percent of the Nation’s sulfur oxides

and 45 percent of its nitrogen oxides are emitted

in the 2 l-State region east of the Mississippi and

north of and including Tennessee and North Carolina. About 85 percent of the Nation’s sulfur oxides and 65 percent of nitrogen oxides are emitted

in the 31-State region.

● What Level of Pollution Control Should Be

Required?

The congressional choice of how much pollution

to eliminate must, of necessity, be based on incomplete information. Expected resource-protection

benefits, control costs, and other potential risks and

benefits are concerns that must be balanced to determine the socially desirable level of emissions reductions. The costs of various levels of control are

relatively well-known, but only a few reference

points are available for assessing the potential benefits of further emissions control.

An acid deposition control program could range

in size from one that would prevent future increases

in emissions—eliminating about 2 to 3 million tons

of the 22 million tons of sulfur dioxide emitted annually in the Eastern 31-State region to offset expected growth through the year 2000—to one that

would achieve large-scale reductions below current

levels. Eliminating about 11 to 12.5 million tons

of sulfur dioxide per year might be considered the

upper end of this range; mandating even larger

emissions reductions would require most existing

utilities to adopt more stringent emissions controls

than those governing emissions sources subject to

NSPS.

Reducing sulfur dioxide emissions in the eastern United States by 8 to 10 million tons per year

below current levels would probably protect all but

the most sensitive aquatic resources in many areas

receiving high levels of acid deposition, but not in

those areas receiving the greatest amounts. Risks

of damage to sensitive forests, materials, and crops

would also be reduced. In addition, airborne fineparticle levels would be lower, improving visibility

and reducing risks to human health. Such reductions— near the upper end of the feasible range—

would cost about $3 to $6 billion per year, depending on the design of the control program. Costs

would rise steeply if greater resource protection

were desired; both control costs and the amount

of resource protection would be less with lower

emissions reductions.

About 2 to 5 million tons of sulfur dioxide emissions per year could probably be eliminated for
108 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

about $1 billion per year or less. This would certainly be enough to prevent emissions from increasing through 2000 (i. e., offset expected industrial

and utility growth), and could potentially decrease

emissions 2 to 3 million tons below current levels

by 2000. Risks of damage to sensitive aquatic resources, forests, agriculture, materials, and health

would be reduced, but at present it is impossible

to gauge by how much.

Congress could either specify the level of emissions reductions directly or state the policy goals

to be met and instruct the Administrator of EPA

to set the level of reductions.

● By What Time Should Reductions Be Required?

A congressional decision to require further controls is likely to take at least 6 or 7—possibly 10

or more—years to implement. Extensive Federal,

State, and source-level planning will be required

even before the contract and construction stages

begin. Smaller levels of emissions reductions, if

achieved primarily through fuel switching, might

be implemented somewhat more quickly.

Alternatively, Congress might decide to wait for

guidance from the National Acid Precipitation Assessment Program, thereby delaying controls an additional 4 to 6 or more years. Additional risks of

resource damage would result from such a delay,

but current understanding does not allow their

quantification.

Congress could also direct Federal and State officials to begin control planning now, but make the

contract and construction phase conditional on the

results of further research. Control programs could

be modified or specific implementation plans

changed as late as about 2 years before the compliance date, at which point major construction expenditures would have to begin.

● What Approach to Control Should Be

Adopted?

Existing environmental regulations focus on

either: 1 ) pollution sources, i.e., directly regulating total emissions or emission rates from sources

or regions; or 2) pollutant exposure, i.e., setting

goals or standards to limit human or environmental

exposure to pollutants.

The first approach, a source-oriented control program, could be implemented now, either by directly

limiting emissions or emission rates or by requiring the use of control technologies.

Controlling acid deposition through the second

approach would require a well-developed understanding of the transport, transformation, fate, and

effects of pollutants. Such knowledge—accurate

enough for a receptor-based regulatory program—

does not yet exist for acid deposition. By the mid1990’s, however, models and similar tools might

have accuracy sufficient for designing a receptorbased approach on a regional scale (i.e., with emissions reductions allocated to State-size or larger

areas).

. How Should Emissions Reductions Be Allocated?

Congress could limit emissions directly by:

1) mandating a reduction formula that applies to

all or a subset of individual sources within a control region; or 2) allocating emissions reductions

to States, allowing the States to allocate source-level

cutbacks within their borders. Alternatively, Congress could direct EPA to allocate emissions reductions to meet specified congressional goals.

Policy considerations pertinent to designing an

allocation formula include: “Who is to gain the

benefit of resource protection and who is to bear

the burden of reductions?” and ‘‘How administratively and economically efficient is the plan?’

Most legislative proposals to date have been based

on: 1 ) emission rates (i. e., sulfur dioxide emitted

per quantity of fuel burned) in order to reduce emissions most cost effectively, and 2) utility emissions

only, to reduce the administrative complexity of

determining each State’s share. While fairly accurate data are available on the 70 percent of Eastern sulfur dioxide emissions from utilities, emissions from other sectors are difficult to estimate

accurately.

Chapter VII and appendix A review a number

of allocation approaches, some based on total State

emissions, some on a State’s utility emissions alone.

Each allocation formula varies in the resulting geographic pattern of emissions reductions, total costs

for equivalent regionwide reductions, and administrative complexity.
Ch. 6—Policy Options ● 109

● Who Pays the Costs of Emissions Reductions?

Allocating reductions and allocating their costs

are two distinct issues. Congress could: 1) require

affected sources to pay the full costs of control, or

2) create a fee or tax to spread control costs over

a larger group than those required to reduce emissions. While the former approach is consistent with

the current Clean Air Act, the latter recognizes the

difficulty of linking emissions from any given source

to damage in areas far removed.

● What Can Be Done to Mitigate Employment

and Economic Effects of a Control Policy?

Cutting back sulfur dioxide emissions could significantly affect two industries: coal mining and

electric utilities. If utilities and other emitters are

allowed to switch to lower sulfur fuels= often a costeffective means of reducing emissions—some production will shift from regions producing highsulfur coal to those producing low-sulfur coal, with

associated employment and economic effects. Employment shifts might be reduced by requiring emitters to install control technologies designed for use

with high-sulfur coals, or by restricting coal purchases according to location of coal supply. Such

a program might increase total control costs considerably, however. For reductions in the range of

8 to 10 million tons per year, costs might rise by

25 to 50 percent, depending on the specifics of the

plan. Special compensation to workers or communities affected by the new law would also be possible.

Those utilities that choose (or are required) to

use control technologies for meeting major emissions reduction requirements would need to raise

additional capital to build such equipment. Congress could reduce financial pressures on utilities

by establishing a tax to help pay for the costs of

control, or by funding research and demonstration

projects to develop potentially cheaper control technologies.

Options:

Congress could design a control program by selecting alternatives from each of the eight decision

areas summarized above. Obviously, many combinations are possible; the three options presented

below represent portions of the decisionmaking

spectrum ranging from modest reductions to largescale control programs. Each strikes a different balance between the risks of future resource damage

and the risks of inefficient pollution control.

Option A-1: Mandate Small-Scale Emissions Reductions.

A small-scale program would logically focus on

controlling sulfur dioxide emissions—the major

manmade acidic pollutant in the Eastern United

States—within the broad region receiving greatest

levels of acid deposition. Eliminating about 2 to 5

million tons of sulfur dioxide emissions per year

would be feasible within about 5 to 7 years from

the date of passage. Reductions of this magnitude

would probably hold acid deposition levels about

constant, or result in modest declines, through the

end of the century.

The control region might encompass either the

Northeastern 21 States or the 31 Eastern States.

All States could be required to eliminate an equal

percentage of emissions (e. g., 10 to 20 percent),

or be allocated reductions based on emission rates

(e.g., an emission rate limitation of between 2.5

and 4.0 lb of sulfur dioxide per million Btu of fuel

burned). Each State might be responsible for determining which sources to control and how much pollution to eliminate from each source. Alternatively,

Congress could mandate emission rate limitations

for all sources emitting in excess of a specified rate.

Other possibilities for modest emissions reductions include mandatory coal washing for certain

types of coal, or requiring selected sources to use

emissions control technology. The former might

eliminate up to about 2 million tons of sulfur dioxide per year, while the latter approach could be

designed to achieve cutbacks of any desired magnitude in the range of 2 to 5 million tons per year.

Either of these last two approaches would minimize

losses of high-sulfur coal production and related

employment, but would increase the cost of control.

A small-scale program could be accomplished for

under $1 billion per year (1982 dollars) for a cutback of 2 to 3 million tons per year of sulfur dioxide, and for about $1 to $1.5 billion per year for

about a 5-million-ton reduction, Costs could range,

however, as high as $2.5 billion per year for a 5-

million-ton program requiring the use of emissions

control technology. Congress could require the
110 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

sources allocated emissions reductions, and their

customers, to pay the cost of reductions directly,

or spread the costs more widely by establishing a

fee on electricity or pollutant emissions.

Option A-2: Mandate Large-Scale Emissions Reductions.

Many of the acid deposition control proposals

introduced during the 97th and 98th Congresses

would reduce sulfur dioxide emissions by 8 to 12

million tons annually. Several include reductions

in nitrogen oxide emissions as part of the control

program as well.

As discussed in chapter 5, large-scale sulfur dioxide emissions reductions (8 to 10 million tons annually below 1980 levels) would probably protect

all but the most sensitive lakes and streams in many

areas receiving high levels of acid deposition. Areas

currently receiving the highest levels of acid deposition (e. g., Western Pennsylvania) would also benefit, but to a lesser extent—a larger proportion of

their aquatic resources might still be at risk.

The control region for a program of this scale

might include the 31 Eastern States, all States east

of the Rocky Mountains, or the 48 contiguous

States. If the desired control region extends to the

West, nitrogen oxides emissions become increasingly important, as nitrogen oxides contribute relatively larger shares of precipitation acidity in the

West than in the East.

A large-scale program would require about 8 to

12 years to implement. By choosing a longer compliance time (e. g., 12 years), Congress could allow

greater opportunity for modifying control plans to

incorporate future research results or newly developed control technologies. The program could be

altered or implementation plans changed until

about 2 to 4 years before the scheduled compliance

date. Although Federal, State, and source-level personnel would have spent considerable time and effort planning the program, few contracts would

have been let before that time, and major capital

expenditures would not have occurred. The program could either have a single compliance date

or be implemented in phases, beginning with a first

phase similar to option A-1.

Emissions reductions can be allocated to States

in many ways. Major alternatives are discussed in

detail in chapter 7 and appendix A. Each formula

has distributional implications—for both who reduces and who receives the benefits of the reductions. In addition, the formulas vary in administrative complexity. For example, many recent acid

rain control proposals have been based on utility

emissions in excess of a specified rate— 1.2 or 1.5

lb of sulfur dioxide per million Btu of fuel burned.

This is perhaps the least expensive approach for reducing regional emissions, but it concentrates much

of the required reduction in the Midwest. Such a

program would cost from $2 to $5 billion per year,

depending on the stringency and design. Offsetting future emissions growth, if required, might cost

an additional $1 to $2 billion per year.

Because such an approach would be costly for

electricity consumers in some States, Congress

might want to create a trust fund to finance part

of the program. A trust fund to pay for capital costs

associated with emissions control technology would

also assist an already capital-short utility industry.

The trust fund could be based either on pollutant

emissions or on a surrogate, such as electricity generated or fuel deliveries.

Paying part of the costs of pollution control technology through a trust fund (but not reimbursing

fuel-switching costs) would also help to prevent

losses in high-sulfur coal production and employment. However, encouraging the use of control

technology through a trust fund, or mandating its

use, would increase total control costs and reduce

potential gains in Western coal production.

Option A-3: Mandate an “Environmental Quality” Standard.

Rather than mandating specific emissions reductions, Congress could direct the Administrator of

EPA to develop a control plan to achieve congressionally specified environmental quality goals (including cost considerations, if desired). Though at

present scientists cannot accurately predict the

benefits of various levels and regional patterns of

emissions reductions, such capability might be possible by 1995 or 2000. A control program could then

be based in part on a better understanding of the

relationship between emissions and deposition

among State or multi-State regions. It is unlikely,

however, that scientists will be able to relate emis-
Ch. 6—Policy Options . 111

Photo credit: Ted Spiegel

The coal from this Ohio mine is about to be

“washed’ ’-physically cleaned—to remove sulfur, ash,

and other impurities. About one-third of the coal burned

by Eastern and Midwestern utilities is washed, thereby

preventing about 2 million tons of sulfur dioxide

emissions each year. An additional 2 million tons could

be eliminated by more extensive use of this technique

#

sions from single sources to small receptor areas

for the foreseeable future.

A concerted 10- to 15-year effort might produce

a control program either less expensive or more effective than that outlined in option A-2. However,

the longer time required to achieve compliance—

it would be about 2005 to 2010 before the plan could

be implemented—would also permit additional resource damage.

Congress might choose to precede such a program with mandated, small-scale emissions reductions, such as presented in option A-1. The reductions required under option A-1 are unlikely to

Photo credit Ted Spiegel

At the Bruce Mansfield powerplant in Pennsylvania,

lime is destined for use in the plant’s flue-gas

“scrub ber.” The lime is mixed with water and sprayed

over the exhaust gas, removing over 90 percent of the

sulfur dioxide that otherwise would have been emitted.

The sulfur-laden lime slurry is discharged as a wet

sludge that must be disposed with care to prevent

water contamination. Newer technologies promise

easier waste disposal or the possibility of

reclaiming a usable product

exceed those eventually required under the environmental quality standard; at a minimum, they

would prevent acid deposition levels from increasing before the remainder of the plan is implemented.

APPROACH B:

Liming Lakes and Streams.

Discussion:

OTA estimates that about 3,000 lakes and 23,000

miles of streams in the Eastern 31 States are ex-
112 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

tremely sensitive to acid deposition or are already

acid-altered. Damage to or elimination of fisheries

has been documented in several regions of eastern

North America. Any congressional decision to reduce emissions that contribute to acid deposition

would take at least a decade to implement, so it

might be many years before lakes could be seen to

improve. Moreover, while a significant portion of

these lakes and streams would benefit from substantial emissions reductions, some might still not

improve sufficiently to ensure support of selfsustaining fish populations.

Several forms of chemical treatment have been

used for reducing acid-related damages to sensitive

aquatic ecosystems. Most involve neutralizing

acidic waters and sediments with large quantities

of alkaline substances. One technique-temporarily

restoring the buffering capacity of a lake or stream

with lime-often improves water quality sufficiently

to maintain reproducing fisheries. Treating terrestrial ecosystems has also been proposed; however,

while alkaline materials are commonly added to

acidic agricultural soils, little experimentation has

occurred on forested ecosystems. Counteracting

surface-water acidity cannot substitute for controlling transported pollutants at their source. Such

measures can, however, provide short-term protection to some currently altered resources, by treating

one of the symptoms of acid deposition.

Not all lakes and streams respond sufficiently to

liming to maintain reproducing fisheries. In particular, lakes with short water-retention times (i. e.,

where water remains in the lake for less than a

year), and streams with great variations in flow,

are very difficult to lime effectively. Historically,

such additional factors as demonstrated ability to

support a significant, viable fishery, recreational

potential and public access to waters, and degree

of acidification have been used to guide the choice

of liming targets. For those lakes where liming is

effective, a single application of lime will restore

buffering capacity for a period of 3 to 5 years; to

prevent reacidification, lime must be reapplied

every few years.

While liming has enhanced fish survival in a

number of lakes and streams, its long-term implications for the food chain on which fish depend is

uncertain. Scientists do not know how periodic

changes in water body chemistry through liming

will affect aquatic ecosystems over the long term.

Little research has been done on alternative measures or on minimizing adverse impacts of liming.

Increased Federal and State efforts to develop and

test aquatic treatment methods could help to increase availability of fishing recreation in highly

sensitive areas over the next few decades.

Liming has been effective in counteracting surface-water acidification in parts of Scandinavia,

Canada, and in the United States in New York and

Massachusetts. The most extensive U.S. program

was begun by the New York State Department of

Environmental Conservation in 1959. It initially

targeted small, naturally acidic ponds in heavily

used recreational areas, and expanded to treating

selected acidified lakes with significant potential to

support recreational fishing during the mid-1970’s.

The program is quite small-only about 60 lakes

in total (covering about 1,000 acres) have been

treated since its inception. Following liming, water quality has improved at a number of lakes and

ponds, and self-propagating sport fishing populations have been reintroduced and maintained.

Costs for liming ponds and lakes under the New

York State program have ranged from approximately $30 to $300 per acre for each application,

depending on the size and accessibility of the water body. A recent study of liming requirements

in the Adirondack Mountain region of New York

State estimated that a 5-year program for liming

several hundred acidified lakes in the region could

be implemented for between $2 and $4 million per

year, depending on the desired buffering level.1

This does not include the costs of restocking fish

or continuing monitoring of lake water chemistry

and biology, which would increase the cost considerably.

Federal funds have been available since 1950

under the Dingell-Johnson Act to aid States in carrying out “projects having as their purpose the

restoration, conservation, management, and enhancement of sport fish and the provision for public

use and benefits from these resources. A IO-percent excise tax on the wholesale cost of fishing tackle

‘Frederic C. Menz and Charles T. Driscoll, ‘‘An Estimate of the

Costs of Liming To Neutralize Acidic Adirondack Surface Waters,

Contribution #13 of the Upstate Freshwater Institute, June 1983.
Ch. 6—Policy Options ● 113

Photo credit: New England Interstate Water Pollution Control Commission

Adding lime to a lake can temporarily restore its ability to neutralize incoming acids, thereby preventing harm to aquatic

life. Lakes near roads can often be limed by boat (shown above); for others, large quantities of lime must be transported

by aircraft. Not all lakes and streams can be effectively limed

provides revenues under the act. States are reimbursed for 75 percent of their expenditures on projects approved by the U.S. Fish and Wildlife Service (FWS). About 60 percent of total Dingell-Johnson funds are currently used by States for survey,

management, and research activities.

Dingell-Johnson funds have been used in the past

to support individual liming projects; they provided

startup money to the New York State Department

of Environmental Conservation’s liming program

from 1959 to 1965. FWS program staff suggest that

States able to demonstrate the potential cost-effectiveness of liming to meet a specific acidification

problem could presently receive Federal funds for

liming and follow-up monitoring.

A proposal to expand the coverage of the DingellJohnson excise tax to include additional recreational

fishing equipment is currently before the Congress

(H.R. 2163); if passed, the proposal would approximately double receipts collected under the act. Expanding the fund has been advocated as a means

of allowing States to keep up with the costs of sport

fish management in an era of rising costs and declining State resources. Such a move might also encourage States to include mitigation efforts among

their project proposals for Federal funding.

Lack of funding for liming projects, however,

may not be the most important impediment to expanding mitigation activities. Improving our current ability to restore or protect acid-altered waters
114 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

will require extensive monitoring of the chemical

and biological changes that follow liming applications. Until considerably greater resources are allocated to studying the ways in which liming affects various types of water bodies, the results of

each application will remain uncertain.

Federal research on aquatic treatment methods,

as specified in the Acid Precipitation Act of 1980,

began in 1982 under the direction of the FWS. To

date, the Federal research effort has produced a

technical report on liming, and an agenda of further research needs determined by participants in

an international mitigation conference. Total Federal funding for these efforts in fiscal year 1983

amounted to $225,000.

The administration recently proposed about $5

million dollars for liming research for fiscal year

1985. Such funding increases would permit researchers to study the effects of liming on water

bodies with differing geological, chemical, and

biological characteristics throughout the Eastern

United States, and to investigate the effectiveness

of alternative mitigation measures.

Options:

Specific options available to Congress for Federal support of research and implementation of

techniques to mitigate some of the effects of acid

deposition are described below.

Option B-1: Expand Federal Research on Aquatic

(and Other) Treatment Methods.

Although researchers at the FWS have begun to

investigate the effects of a few mitigation techniques—primarily liming—on aquatic life in acidified lakes, levels of funding are low and permit only

a few research projects to be undertaken each year.

Additional funding—for example, at the $5 million per year level proposed by the administration— would allow the FWS program to expand its

coverage to a variety of lakes and streams being

treated under differing geological, geographic, and

biological conditions. Such expansion would aid the

FWS in developing guidelines on liming and other

mitigation techniques for use by States, local communities, and private interests.

Further research on treatment methods for terrestrial ecosystems and watersheds could also be undertaken through either the Forest Service or FWS.

Congress could provide additional funding specifically for mitigation research, or direct the Interagency Task Force (responsible for directing Federal acid deposition research under the Acid

Precipitation Act of 1980) to allocate a greater portion of its existing budget to such activities.

Option B-2. Expand Federal-State Cooperative Efforts for Treating Acidified Surface Waters and

Assessing Results.

While costs for liming acidified surface waters

are relatively modest, assessing the effectiveness of

these treatments can be much more expensive than

liming itself, and requires substantial technical expertise. Federal funds to support liming and followup monitoring are potentially available under the

existing Dingell-Johnson Act, although States currently carry out very little mitigation-related work

with these funds.

Congress could instruct the FWS to provide

guidelines to States on requirements for qualifying for Dingell-Johnson funds to treat acidified surface waters. Congress could also broaden the act’s

excise tax base to provide States with additional

funds as an indirect means of encouraging Statelevel mitigation efforts. Alternatively, Congress

could establish a new Federal-State cooperative program specifically to support surface-water treatment

and subsequent monitoring activities.

Option B-3: Establish Demonstration Projects for

Acidified Water Bodies on Federal Lands.

The Federal Government has extensive land

holdings in areas of the Eastern United States that

are considered sensitive to the effects of acid

precipitation, including the White Mountain National Forest in New Hampshire, the Green Mountain National Forest in Vermont, and the Allegheny

National Forest in northwestern Pennsylvania.

Congress could direct the Forest Service and the

FWS to establish cooperative demonstration programs to treat selected lakes and streams on Federal lands with significant recreational fishing

potential or heritage fish populations, and subsequently monitor their chemical and biological responses. Funding could be provided through the

existing interagency acid deposition research program to fund FWS monitoring activities, or be allocated to the Forest Service specifically for surfacewater mitigation.
Ch. 6—Policy Options ● 115

APPROACH C:

Modifying the Federal Acid

Deposition Research Program

Discussion:

Under the Acid Precipitation Act of 1980 (Title

VII of the Energy Security Act of 1980—Public

Law 96-294), Congress created an Interagency

Task Force* to conduct a comprehensive 10-year

national assessment program on acid deposition.

The goals of the research program are:

● to identify the causes and sources of acid precipitation,

● to evaluate the environmental, social, and economic effects of acid precipitation, and

● to determine the effectiveness of actions available to control the emissions responsible for

acid deposition, and mitigate harmful effects

of acid deposition on receptor systems.

The act requires the Task Force to submit annual reports to the President and Congress, describing the progress of the research program and recommending actions that Congress and appropriate

Federal agencies might take to alleviate acid deposition and its effects.

The Task Force presented a detailed research

program—the National Acid Precipitation Assessment Program (NAPAP)—to Congress in June

1982. NAPAP outlines the general strategy for

organizing the research effort, using 10 working

groups organized by scientific discipline. These

working groups are composed of program managers

and experts from the Federal agencies participating

in the research effort. Areas of responsibility for

each of the 10 working groups are outlined in table

5.

The plan specifies an ambitious research program requiring extensive coordination among

groups. If the research continues on schedule, the

Task Force expects to develop by 1985 preliminary

estimates of current and potential resource damage due to acid deposition. It plans to use this information, along with models developed by the task

● The Interagency Task Force is composed of heads and representatives of various agencies and national laboratories and four members

appointed by the President.

Table 5.—Organization of the National Acid

Precipitation Assessment Program

Task Group A: Natural Sources

Coordinating agency—NOAA. Responsibility—assess the

effect of natural emissions on acid deposition.

Task Group B: Man-Made Sources

Coordinating agency—DOE. Responsibilities-refine existing sulfur dioxide and nitrogen oxides emissions estimates,

and develop improved models to estimate future sulfur and

nitrogen emissions from major polluting sectors.

Task Group C: Atmospheric Recesses

Coordinating agency—/VOAA. Responsibilities—examine

the link between emission of pollutants and acid deposition.

Task Group D: Deposition Monitoring

Coordinating agency—DO/, Responsibilities—develop a

long-term national program to monitor the chemical composition of acid deposition (both wet and dry), and improve the

reliability and accuracy of sampling techniques.

Work Group E: Aquatic Effects

Coordinating agency—EPA. Responsibilities—1) assess

the resources at risk in the United States from acid deposition, 2) study the mechanisms by which biological damage

can occur, 3) evaluate the risk of acidifying drinking water

supplies through acid deposition, and 4) analyze strategies

to mitigate the harmful effects of acid deposition.

Task Group F: Terrestrial Effects

Coordinating agency—DOA. Responsibilities—assess the

nature and extent of the effects of acid deposition on crops,

forests, and noncommercial terrestrial ecosystems.

Task Group G: Effects on Materials

Coordinating agency—DOI. Responsibilities—assess the

effect of air pollution— in particular, acid deposition—on a

range of economically important materials and historic monuments and structures.

Task Group H: Control Technologies

Coordinating agency—EPA. Although this group was referred to in the National Plan of June 1982, the latest draft

operating plan does not contain a work statement for the control technology group, nor does it specify deliverable reports.

Task Group 1: Assessments and Policy Analysis

Coordinating agency—EPA. Responsibilities—integrate

the research results of the other work groups, and carry out

cost-benefit analyses to assist the Task Force in formulating guidance for policy makers.

Task Group J: International Activities

Coordinating agency–DOS. Responsibility–ensure that

the National Program is coordinated with ongoing U. S.-

Canadian and other international activities related to acid

deposition.

SOURCE: Office of Technology Assessment, based on information from the National Acid Precipitation Assessment Program, June 1982; and the interagency Task Force on Acid Precipitation, January 1982.

groups, to produce integrated, policy-related assessments in 1987 and 1989. The 1985 damage estimates are expected to be used primarily for redirecting or fine-tuning the further research efforts. Since

the planned assessment activity calls for extensive

methods development and data collection before
116 Acid Rain and Transported Air Pollutants: Implications for Public Policy

policy analysis begins, NAPAP does not anticipate

‘ ‘useful guidance to policy makers’ until 1987 to

1989.

Many members of Congress and public interest

groups have expressed concern about the length of

time projected for NAPAP to produce a useful policy assessment. While such a research plan might

produce more accurate analyses than those resulting

from a shorter effort, many consider waiting until

1989 for this level of refinement unacceptable. Several bills introduced in the 97th and 98th Congresses proposed to accelerate the originally planned

10-year program to a 5-year effort.

Such a legislated acceleration could seriously

compromise the scientific credibility of the results.

Substantial time and effort would be needed to redesign the research schedule. (The present program

required 2 years to plan. ) Many currently planned

research efforts are designed to build on results from

work presently under way; these projects would

have to be significantly redesigned so that they

could begin more quickly. Moreover, many of the

currently planned efforts simply could not be accelerated, even if additional funding were provided.

For many field experiments on lakes, forests, and

soils, doubling the number of experiments in one

year usually cannot substitute for 2 consecutive

years of research. It is doubtful that a new generation of atmospheric transport models could be developed within a few years. Such modeling efforts

involve years of trial and error—and require several more years of monitoring data to validate the

results over a range of climatological conditions,

A strong, continuing research program is a necessary part of any strategy Congress might choose

to address the problem of acid deposition. Several

modifications, however, might make the current

program more responsive to congressional information needs.

If a decision on an emissions control program

is delayed for several years, Congress could estab-
Ch. 6—Policy Options ● 117

lish a new, separate assessment activity investigating a range of legislative options. Findings from

ongoing Federal research could then be incorporated into policy guidance more quickly than is

planned under the present timetable, without disturbing the longer term Federal plan.

If Congress acts to control acid deposition, the

program could be redirected to support implementation and evaluation of the legislation. Concerns

have been raised within the scientific community

that if control legislation is enacted, important research efforts might not be adequately funded over

the long term. At least 5 years would elapse between

the time legislation is passed and emissions reductions are achieved. Continued research in a number

of fields would be important for further evaluation

of the control strategy throughout this period, and

for designing and implementing the chosen control program into the 1990’s.

Many within the scientific community are also

concerned over the breadth of the research program, regardless of whether a control program is

adopted. NAPAP’s enabling legislation focuses on

acid deposition. However, researchers have found

this emphasis to be restrictive in two ways. Several resources—notably forests, crops, and materials-are exposed to multiple air pollutants; understanding the effect of any single pollutant requires

research on all. Similarly, the potential benefits of

emissions reductions are not limited to those associated with lowered levels of acid deposition.

For example, reductions of sulfur dioxide emissions will improve visibility and lower concentrations of airborne fine particles. It is difficult, however, to coordinate the various existing Federal airpollution research programs addressing these problems with the NAPAP effort. The innovative research management framework established by the

Acid Precipitation Act of 1980 could serve as the

basis for a more encompassing Federal air-pollution

research effort.

Options:

Specific options available to Congress for modifying the current acid deposition research program

are described below.

Option C-1: Establish a “Two-Track” Research

Program.

Concurrent with the existing research program,

Congress could mandate a separate policy assessment—with separate funding—to be completed by

a specified date. The current Plan could remain intact, although some modifications might be necessary to provide needed information to the policy

assessment effort. Such a ‘‘two-track’ program

could provide Congress with timely policy guidance, without jeopardizing the longer term research

currently under way.

Congress could require the assessment to evaluate a series of control alternatives within 2 or 3

years. Though the evaluation would have to be

based on incomplete information (as might the currently planned integrated assessment), a common

set of alternative scenarios would be available for

policymakers to consider. This option would establish a research effort similar to this OTA assessment—a description of plausible outcomes from

various policy alternatives-but with the benefit of

a few more years of data and greater resources.

Such a research effort would use a consistent set

of assumptions and models to evaluate:

●

●

●

●

●

the costs of each control program,

secondary effects of control (e. g., shifts in coalmining related employment),

expected deposition reductions (using several

currently available atmospheric transport

models),

other air quality benefits (e. g., improvements

in visibility and air concentrations for fine particulate), and

resource benefits (e. g., percent of land area

receiving deposition at or below levels thought

to be safe for sensitive aquatic resources).

EPA (which currently coordinates the Assessments and Policy Analysis Task Group), might be

designated to conduct the short-term evaluation,

or another organization (e. g., the Council on Environmental Quality) might be chosen if two separate assessments are desired. One (or a consortium)

of the national laboratories or the National Academy of Sciences are possible candidates from outside the Federal agencies.
118 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Option C-2: Redirect the Research Program If a

Control Program Is Legislated.

The Acid Precipitation Act of 1980 does not provide for modifying the research program if a control program were enacted. Continued research—

with some redirection—would serve several purposes if control legislation were passed. Research

results could be used in designing and implementing the details of the chosen control strategy through

the 1990’s. Because it might take about a decade

to implement, the control program would require

vigorous research support to reflect the most current, rather than 10-year-old, scientific information. In addition, the research program could provide data to evaluate the effectiveness of the

legislation after passage.

The Interagency Task Force is already examining necessary changes to the research plan to be

responsive to potential control legislation. Congress

could direct the Task Force to modify the program

to provide information appropriate for regulatory

decisionmaking.

Option C-3: Broaden the Research Program To

Address Other Transported Air Pollutants.

The Acid Precipitation Act of 1980 established

an innovative, interagency research program to

evaluate the effects of acid deposition and the effectiveness of means available to control it. The effects on many resources, however, are difficult to

determine without active research on other pollutants. Similarly, the benefits of reducing pollutant

emissions are not confined to those associated with

reduced levels of acid deposition.

Congress could use the existing interagency

structure and broaden its mandate to include research on other air pollutants. For example, research showing forest productivity declines in the

United States and West Germany has led scientists

to become concerned about the combined stress

from acid deposition, ozone, and heavy-metal deposition. Broadening the research program could provide useful information to Congress for evaluating

both current proposals to control acid deposition

and, perhaps more importantly, future modifications to the Clean Air Act that might be desirable

for addressing the more general problem of transported air pollutants.

APPROACH D: Modifying

Existing International and Interstate

Sections of the Clean Air Act

Discussion:

The 1977 Amendments to the Clean Air Act

added provisions to regulate interstate and international air pollutant effects through the existing

control mechanism of state implementation plans

(SIPS). Section lo requires SIPS to prevent a State’s emissions from causing violations of

air quality standards in other States. * The section

further prohibits EPA from approving a SIP or a

SIP revision that causes violations of National Ambient Air Quality Standards (NAAQS) in another

State. Currently, however, this section applies only

to air concentrations of pollutants for which

NAAQS exist and therefore does not directly address acid deposition.

EPA has not issued regulations interpreting section 110(a)(2)(E) since it was enacted in 1977; however, agency reviews of potential interstate pollution violations to date have been limited to the

portion of the SIP undergoing revision. When proposed SIP revisions would relax an individual

source’s emissions limitations, EPA assesses only

how the source’s proposed emissions increase would

affect interstate air quality. EPA also takes the position that there are no adequate modeling tools to

assess the long-range effects of either individual or

multiple sources.

Several States and other petitioners have filed suit

in the U.S. Circuit Courts to challenge EPA’s approval of SIP relaxations, claiming that the resulting

pollution increases would violate this interstate pollution provision. Few of these legal suits, however,

have been settled. While some uncertainty remains

over how the courts will interpret interstate pollu2Sec. 110 states that the SIP must contain: Adequate provisions (i) prohibiting any stationary source within the State from emitting any air pollution in amounts which will (a) prevent attainment

or maintenance by any other State of any such national primary or

secondary ~bient air quality standard, or (b) interfere with measures

required to be included in the applicable implementation plan for any

other State under Part C to prevent significant deterioration of air

quality or to protect visibility and, (ii) insuring compliance with requirements of sec. 126, relating to interstate pollution abatement. (sec.

1 lo) .
Ch. 6—Policy Options . 119

tion control requirements, recent decisions suggest

that the Federal courts are not prepared to interpret section 110 to require broader consideration of interstate pollution effects than occurs

under current EPA practices.

Section 126 allows any State or political subdivision to petition the Administrator of EPA to remedy

interstate pollution. The language of section 126

is relatively vague, and to date EPA has not issued

interpretive regulations. The section relies on provisions of section 110 for determining the

prohibited quantity of interstate pollution. A number of States seeking relief from long-range interstate pollution have filed section 126 petitions. EPA

has consolidated the petitions of the States of New

York, Pennsylvania, and Maine into a single proceeding. These States have requested far-reaching

relief from alleged interstate pollution problems,

including revision of EPA policies and broad-scale

reductions in emissions throughout the Eastern

United States.

EPA has not yet ruled on these petitions; despite

the statutorily mandated deadline (60 days) for ruling on a State’s petition, a number have been outstanding for years. States have the right to challenge an EPA determination on a section 126

petition in court, but no such challenge is possible

until EPA acts on the petitions. In March 1984,

six Northeastern States sued EPA to rule on the

outstanding petitions but no court action has yet

been taken.

Section 115 of the Clean Air Act provides an administrative mechanism for controlling pollution

that crosses international boundaries. It is activated

either by the Administrator of EPA or at the request of the Secretary of State. If the Administrator

determines that the United States is causing or contributing to ‘‘air pollution which may reasonably

be anticipated to endanger public health or welfare

in a foreign country, EPA must require revisions

to SIPS in the States in which the emissions originate. Section 115 allows control of any air pollutant— unlike the interstate pollution provisions,

which can be used only to control air concentrations of pollutants for which NAAQS have been

issued. Thus, the section may be interpreted to permit direct control of acid deposition caused by transboundary pollution. *

Acid deposition resulting from long-range pollution transport has become a major issue between

the United States and Canada. At present, no

agreement between the two nations directly addresses transboundary air pollution; however, the

two countries have begun negotiations to reach a

bilateral accord under a Memorandum of Intent

signed Aug. 5, 1980.

Options:

Specific options to clarify Clean Air Act provisions controlling long-range pollution transport

(sections lo, 126, and 115) are described

below.

Option D-1: Amend the Interstate Pollution Provisions of the Clean Air Act.

Section 110 of the Clean Air Act is the

major existing interstate pollution provision. It was

designed to address local-scale interstate pollution

problems. The section applies to air concentrations

of pollutants for which NAAQS exist (e. g., airborne

particulate); it does not directly address acid deposition. * *

Currently, EPA reviews only the effects of SIP

revisions on interstate pollution levels. States are

also concerned, however, with the cumulative emissions from sources outside their border leading to

potential air quality degradation within their State.

Several States have protested to both EPA and the

courts about EPA’s interpretation of this and other

aspects of the section.

● On Jan. 13, 1981, then EPA Administrator Douglas M. Costle

announced a finding of endangerment with respect to acid deposition in Canada, and moved to activate this international provision.

To date, however, EPA has sent no formal notification requiring revision of any State implementation plan.

* ● Amendments to sec. 11 O(a)(2)(E). if combined with, for example, a new deposition standard, or ncw NAAQS for sulfates and

nitrates, could in theory be used to control acid deposition. However,

such mechanisms would offer, at best, an indirect and uncertain means

of doing so, They would leave to administrative discretion a wide range

of political issues, including the size of the control region, the required

amount of emission reductions, and the distribution of reductions

among States or other regions. They would also require a lengthy

standard-setting and allocation process, and could engender substantial legal and procedural battles among EPA, the States, and the Federal

court system.

99-413 0 - 84 - 9 : QL. 3
120 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Clarification of EPA’s responsibilities for restricting interstate pollution requires congressional guidance on several aspects of section 110.

These include: 1) whether the section restricts interstate pollution from individual sources only, or

from the cumulative emissions of sources throughout the State, 2) how much interstate pollution is

permissible, 3) what constitutes proof of causation

of interstate pollution effects, 4) whether EPA is

required to review the entire SIP for compliance

with section 11 O(a)(2)(E) when States revise a portion of their SIPS, and 5) whether EPA is required

to review SIPS approved before the section went

into effect.

Closely related to clarification of section 1 IO(a)

(2)(E), Congress could require EPA to develop

guidelines for reviewing interstate pollution petitions (currently contained in section 126 of the

Clean Air Act). Section 126 could also be modified

to require EPA to resolve petitions within a specified amount of time. For example, Congress could

retain the 60-day requirement for holding hearings

on a section 126 petition, but allow EPA additional

time from the close of the hearing to reach a determination. By further specifying de facto denial of

the petition if the agency fails to make a determination within, for example, 6 months to a year, Congress could make it possible for States to receive

judicial review of section 126 petitions in the

absence of administrative review by EPA.

Such changes could be effective in ending the current bottleneck of States’ petitions within EPA, permitting States to bypass stalled or inactive agency

decisionmaking procedures and move on to the judicial-appeals process for section 126 petitions,

Option D-2: Amend the International Provisions

of the Clean Air Act.

Section 115 of the Clean Air Act was designed

to address local pollution effects occurring near an

international border. However, an EPA administrator who chooses to implement section 115 can

require further control of any air pollutant from

any number of States that may contribute to an international pollution problem. The section provides

no guidance on what levels or kinds of transboundary pollution are impermissible, how to allocate

control responsibilities among States, or how to

revise SIPS to require control of pollutants for which

NAAQS do not exist. At present, the open-endedness of the authority delegated by section 115 makes

it an unwieldy and potentially a politically volatile

tool for controlling such long-range transported air

pollutants as acid deposition and ozone.

The section could be amended to provide more

specific instructions and guidelines to the EPA Administrator. For example, Congress could direct the

Administrator to consult with the Department of

State to designate an appropriate international

agency or establish a bilateral commission to determine the magnitude of the problem and the levels

of control to be required. For addressing air pollution transport to and from Canada, Congress

might direct the Administrator to refer the problem to the International Joint Commission, established by Canada and the United States in 1909

to monitor transboundary pollution problems.

Activating section 115, however, could conflict

with other bilateral mechanisms for dealing with

transboundary pollution problems. In the case of

U.S.-Canadian acid deposition problems, initiating

action under section 115 might interfere with ongoing talks with Canada under the 1980 Memorandum of Intent on Transboundary Air Pollution.
Chapter 7

Legislating Emissions Reductions
Contents

Page

Decision 1: Which Pollutants Should Be Further Controlled? . . . . . . . . . . . . . . . . . . . . . 123

Decision 2: How Widespread Should a Control Program Be? . . . . . . . . . . . . . . . . . . . . . 125

Decision 3: What Level of Pollution Control Should Be Required? . . . . . . . . . . . . . . . . 126

Decision 4: By What Time Should Reductions Be Required? . . . . . . . . . . . . . . . . . . . . . 130

Decision 5: What Approach to Control Should Be Adopted? . . . . . . . . . . . . . . . . . . . . . . 131

Decision 6: How Should Emissions Reductions Be Allocated? . . . . . . . . . . . . . . . . . . . . . 133

Decision 7: Who Should Pay the Costs of Emissions Reductions? . . . . . . . . . . . . . . . . . . 138

Decision 8: What Can Be Done To Mitigate Employment and Economic Effects

of a Control Policy? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

TABLES

Table No. Page

6. Summary of Control-Policy Decisions and Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7. Sulfur and Nitrogen Oxide Emissions by Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

8. Costs of Reducing Sulfur Dioxide Emissions in the Eastern 31 States . . . . . . . . . . . . . . . . 129

9. Sulfur Dioxide Emissions Reductions With Emission Rate Limitations—

31 Eastern States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

10. Sulfur Dioxide Emissions Reductions With Emission Rate Limitations—

Entire United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

11. Emissions Reductions Required by Alternative Allocation Approaches . . . . . . . . . . . . . . . 137

12. 50-State Taxes Raising $5 Billion per Year During the Early 1980’s . . . . . . . . . . . . . . . . 140

13. Interstate Coal Shipments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Chapter 7

Legislating Emissions Reductions

Chapter 6 presented four approaches available

to Congress for addressing transported air pollutants. Under the first approach—further controlling

the sources of pollutant emissions—three options

were discussed. These correspond to broad strategies for further emissions control: mandating a

small-scale emissions reduction program; mandating a large-scale program; and establishing a control program based on an environmental quality

standard.

If Congress decides to enact an emissions control program at this time, the choice of one of these

three broad strategies is only the first step in designing legislation. Policy makers would also have to

make a number of complex, interrelated decisions

to specify the details of the chosen strategy. For example, more than 10 bills before the 98th Congress

propose large-scale emissions reductions, but the

differences among them are substantial.

Accordingly, this chapter is intended to serve as

a guide for turning the broad emissions control

strategies presented in chapter 6 into a legislative

proposal. It also provides a framework for evaluating specific provisions of the many acid deposition control bills introduced to date. The chapter

expands on the brief discussion of the eight controlpolicy decisions presented in the previous chapter.

Table 6 summarizes the eight decisions, along with

their corresponding options.

Other transported air pollutants, such as ozone

and airborne sulfates, will be mentioned where

appropriate, but detailed options for controlling

them, either separately or in combination with acid

deposition, are not presented. Where possible, each

discussion will assess the current state of knowledge,

the possibility of acquiring further relevant information in the near future, and the societal value

choices involved.

Decision 1: Which Pollutants Should

Be Further Controlled?

Discussion:

Most acid rain control proposals to date have

focused on reducing emissions of sulfur dioxide.

There are several reasons for this.

Table 6.—Summary of Control-Policy Decisions

and Options

Decision 1: Which Pollutants Should Be Further Controlled?

Option la: Sulfur Dioxide Alone

Option lb: Both Oxides of Sulfur and Nitrogen

Option 1c: Sulfur Dioxide, Nitrogen Oxides, and

Hydrocarbons

Decision 2: How Widespread Should a Control Program Be?

Option 2a: 21 Northeastern States

Option 2b: 31 Eastern States

Option 2c: 36 Eastern States

Option 2d: 48 Contiguous States

Option 2e: Allow EPA to Define Appropriate Control

Region

Decision 3: What Level of Pollution Control Should Be

Required?

Option 3a:

Option 3b:

Option 3c:

Decision 4:

Option 4a:

Option 4b:

Option 4c:

Option 4d:

Decision 5:

Option 5a:

Option 5b:

Option 5c:

Mandate Emissions Reductions

Mandate Reductions, Including Offsets for

Future Emissions Growth

Require EPA To Specify Reductions

By What T/me Should Reduction Be Required?

6 to 10 years

10 to 16 years, Allowing a Delay for Research

8 to 12 Years, With a “Mid-Course”

Reevaluation

Stagger Compliance Schedules

What Approach to Control Should Be Adopted?

Directly Specify Emissions Reductions or

Emission Rate Limitations

Specify Use of Control Technologies

Establish an “Environmental Quality”

Standard

Decision 6: How Should Emissions Raductions Be Allocated?

Option 6a: Directly to Sources

Option 6b: To States

Option 6c: Responsibility of Governors in Control

Region

Option 6d: Responsibility of EPA

Option 6e: Allow Trading of Emissions Reductions

Requirements

Option 6f: Allow Substitution of Nitrogen Oxides

Emissions Reductions

Decision 7: Who Will Pay the Coats of Emissions Reductions?

Option 7a: Sources Allocated Emissions Reductions

Option 7b: Establish a Trust Fund To Pay Part of Costs

Decision 8: What Can Be Done To Mitigate Employment and

Economic Effects of a Control Policy?

Option 8a: Require Reductions by Technological Means

Option 8b: Strengthen Clean Air Act, Section 125

Option 8c: Establish Worker Assistance Program

Option 8d: Utility Tax Breaks

Option 8e: Pollution Control Technology R&D

SOURCE: Off Ice of Technology Assessment.

Substantially greater amounts of sulfur dioxide

are released into the atmosphere in the Eastern half

of the United States than nitrogen oxides. Eastern

U.S. sulfur dioxide emissions in 1980 were about

123.
124 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

22 million tons, whereas nitrogen oxides emissions

were about 14 to 15 million tons. Sulfur dioxide

and its transformation products currently contribute

about twice as much to precipitation acidity in the

Northeast as do nitrogen oxides.

Once deposited, sulfur compounds are more likely to threaten natural ecosystems than nitrogen

compounds. While sulfur and nitrogen are both essential nutrients in soil ecosystems, most Eastern

forests require and retain far greater amounts of

nitrogen than of sulfur. Consequently, sulfur compounds are more likely to travel through watersheds

and increase the acidity of water bodies, while

nitrogen compounds are more frequently taken up

by plants before they reach lakes and streams. *

Finally, approaches to controlling sulfur dioxide are

more developed than for nitrogen oxides.

Nitrogen oxides emissions, however, are expected to contribute an increasing share to Eastern acid deposition, as nitrogen oxides emissions

are projected to rise at a faster rate than sulfur dioxide emissions. In the Western United States, nitrogen compounds currently contribute as much to

precipitation acidity as sulfur compounds do, and

in many regions a greater amount. Nitrogen oxides are also involved in the production of ozone,

a transported air pollutant known to damage crops

and forests.

Air concentrations of both nitrogen oxides and

hydrocarbons influence the rate at which sulfur dioxide is transformed to sulfates. Model-based studies indicate that altering nitrogen oxides and hydrocarbon concentrations does not affect total sulfur

deposition nearly as much as does directly reducing sulfur dioxide concentrations. The presence of

these “co-pollutants’ can alter wet sulfur deposition, but does not significantly affect dry sulfur

deposition. The limited understanding of atmospheric chemistry, however, provides little guidance

for designing a control program involving these

pollutants along with sulfur dioxide. Appendix C

discusses how these other pollutants may potentially

affect the amount of sulfur deposited within the

Eastern United States.

● Nitrogen compounds deposited in snowfall are of greatest concern

to aquatic ecosystems when they are released during spring snow melt.

The “acid shock” caused by the acidity released from snow melt occurs during spawning periods, when fish populations are most susceptible to damage.

Conclusions and Options:

Three pollutants are possible candidates for acid

deposition control: sulfur dioxide, nitrogen oxides,

and hydrocarbons. Any program to control Eastern levels of acid deposition should include reductions in sulfur dioxide emissions. Depending on the

desired degree of resource protection and geographic extent and scheduling of the control program,

other pollutants might be included as well.

Options available to the Congress are described

below.

Option la: Reduce Emissions of Sulfur Dioxide

Over the Eastern United States, deposition of sulfur oxides is generally greater than deposition of

nitrogen oxides. In addition, sulfur oxides appear

to have greater potential for damaging ecosystems

and degrading visibility, and are of concern because

of possible health effects from airborne sulfates.

While co-pollutants may affect the degree to which

cutting back sulfur dioxide reduces deposition, reducing sulfur dioxide emissions is the most plausible means of reducing acid deposition in the Eastern United States.

Option lb: Reduce Emissions of Both Oxides

of Sulfur and Nitrogen

While cutting back sulfur dioxide emissions alone

may substantially reduce Eastern acid deposition,

controlling nitrogen oxides emissions in addition

to sulfur oxides would provide further protection

to sensitive natural resources. Currently, nitrogen

oxides are the second greatest manmade source of

acidity. Nitrogen oxides emissions, however, have

increased much more rapidly than sulfur dioxide

emissions during the past few decades, and are projected to increase an additional 25 percent by 2010.

Thus, they will contribute an increasing share of

acid deposition. Reductions of nitrogen oxides

emissions would also help lower regional ozone

levels.

Congressional action to reduce acid deposition

in the Western United States, if desired, must also

address nitrogen oxides emissions. A nationwide

acid deposition control program might therefore involve both pollutants.
Ch. 7—Legislating Emissions Reductions ● 125

Option 1c: Reduce Emissions of Sulfur Dioxide, Nitrogen Oxides, and Hydrocarbons

Sophisticated models of both the chemistry and

meteorology of the atmosphere may eventually

make it possible to design more cost-effective

strategies relying on control of all three pollutants

involved in acid deposition. The modeling capability to design such a strategy for a near-term control program, however, does not yet exist; and it

is uncertain whether this capability will be available within the next decade. Such multiple-pollutant control might best be considered for future

refinements to an ongoing acid deposition control

program.

Decision 2: How Widespread Should

a Control Program Be?

Discussion:

Most of Eastern North America—from southern Ontario and Quebec to northern Mississippi,

Alabama, and Georgia, and from the Atlantic

Coast as far west as the Mississippi River—receives

precipitation more acidic than pH 4.5. This area

includes large regions with lakes and streams considered sensitive to the effects of acid deposition at

this level.

While a substantial fraction of pollutant emissions is deposited locally, the remainder travels with

air masses moving over a region, and is deposited

at distances and directions determined by prevailing chemical and meteorological conditions. Pollutants contributing to acid deposition may travel

well over 500 miles. A large share of sulfur deposition—in some regions, over half-originates from

sources over 300 miles away. For example, model

analyses suggest that 50 to 70 percent of the sulfur

deposited in northern New York State, New England, and parts of southeastern Canada is emitted

from sources more distant than 300 miles. * Consequently, acid deposition is regional in scope: emissions sources in a multi-State region contribute to

deposition in many other regions, depending on

complex and variable atmospheric conditions.

● These model-based analyses are discussed more thoroughly in ch.

3 and app. C,

Many legislative proposals to date have focused

on a 31-State region encompassing the States east

of, and the first tier of States west of, the Mississippi River. Of the 26 to 27 million tons of sulfur

dioxide emitted in the continental United States in

1980, about 22 million tons, or 80 to 85 percent,

came from this 31-State region. In addition, sulfur

dioxide control proposals have focused on electric

utilities, which emit about three-quarters of Eastern sulfur dioxide. In the West, utilities emit about

30 percent, while industrial sources emit about 60

percent (half of which comes from smelters). The

prevailing use of low-sulfur coal in the West results

in significantly lower sulfur dioxide emissions rates.

Of the 21 to 22 million tons of nitrogen oxides

emitted in the continental United States in 1980,

about two-thirds, or 14 million tons, came from the

31-State region. In the East, about 35 percent came

from utility combustion and about 15 percent from

nonutility combustion. In the West, utilities contribute about 20 percent and nonutility combustion about 30 percent of the total. Mobile sources

emit about 45 percent of nitrogen oxides in both

regions.

As discussed in Decision 1, either sulfur oxides,

nitrogen oxides, or some combination of the two

could be controlled uniformly across the chosen region, or separately for subregions within it. Table

7 shows emissions data for the United States as a

whole and for several regional breakdowns.

Conclusions and Options:

All of the legislative proposals to control acid

deposition to date have included emissions reductions in, at least, the 21 Northeastern States. We

present four possible emissions control regions—

all of which include this region, but extend south

and west depending on the geographic extent of resource protection desired. Congress could specify

the size of the control region directly in legislation,

or require EPA to establish a control region that

best meets congressional goals.

Congressional options are described below.

Option 2a: Require Emissions Reductions

From 21 Northeastern States

Given the geographic extent of sensitive resources

exposed to high levels of acid deposition and the
126 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table 7.-Sulfur and Nitrogen Oxide Emissions by Region

S O2 emissions Percent of N Ox emissions Percent of

(thousand tons) U.S. total (thousand tons) U.S. total

48 States. . . . . . . . . . . . . . 26,420 100 ”/0 21,120 100 ”/0

37 States. . . . . . . . . . . . . . 23,640 89 17,910 85

31 States. . . . . . . . . . . . . . 21,810 83 14,000 66

21 States. . . . . . . . . . . . . . 16,540 63 9,720 46

Rockies, west. . . . . . . . . . 2,780 11 3,210 15

17 Western States . . . . . . 4,620 17 7,120 34

SOURCE: Costs. and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of Intent on Transboundary Air Pollution, June 15, 1982.

average distance of pollutant transport, we feel the

smallest effective control region would consist of

the States east of the Mississippi River and north

of (and including) Tennessee and North Carolina.

This region roughly covers the portion of the United

States receiving the most acidic precipitation—in

1980 averaging lower than pH 4.5, a level thought

to harm sensitive lakes and streams. About 65 percent of the Nation’s sulfur oxides and 45 percent

of its nitrogen oxides are emitted in this region.

The region excludes, however, several major

emission-producing contiguous States—i. e., Missouri, the fifth largest sulfur dioxide-emitting State,

and the southern States of Georgia, Alabama, and

Florida. Major nitrogen oxide-emitting States that

border the region are Louisiana, Missouri, and the

above-mentioned Southern States.

Option 2b: Require Emissions Reductions

From 31 Eastern States

This region consists of those States east of and

bordering on the Mississippi River, and has been

the focus of most legislative proposals and control

strategies to date. It emits about 80 to 85 percent

of the Nation’s sulfur oxides and 65 percent of its

nitrogen oxides, One large emitter, Texas, borders

this region, ranking sixth-highest in sulfur dioxide

and first in nitrogen oxide emissions among the 50

States. Texas utilities generally emit sulfur dioxide

at relatively low rates, however, averaging 0.3 lb

per million Btu fuel burned.

Option 2c: Require Emissions Reductions

From the 37 Eastern States

This region encompasses all States east of the

Mississippi, plus two tiers of Western States, i.e.,

the States east of the Rocky Mountains. This region emits about 90 percent of the Nation’s sulfur

oxides and 85 percent of its nitrogen oxides. Because emissions rates in the six additional States

are relatively low, applying most of the current acid

rain control proposals to this region would not appreciably change reductions required from the 31

Eastern States.

Option 2d: Require Emissions Reductions

From the Entire 48 Contiguous

States

This option treats acidic deposition as a national

problem and requires all regions to further control

emissions. While effects from acid deposition are

currently of greatest concern in the East, highly

acidic precipitation events have been observed in

parts of the Western States. As discussed previously, different pollutants might be controlled in the

East (where sulfur dioxide is the major pollutant)

and the West (where nitrogen oxide emissions are

greater).

Option 2e: Allow EPA To Define the

Appropriate Control Region

Rather than legislating a specific control region,

Congress could define the goals of a control program and require EPA to establish the control region by a specified date. EPA could then use information available at that time (e. g., pollution

transport models, maps of sensitive regions, control cost estimates) to demarcate a region consistent with congressional guidelines.

Decision 3: What Level of Pollution

Control Should Be Required?

Discussion:

The decision on how much to reduce emissions

must take into account two important components:
Ch. 7—Legislating Emissions Reductions . 127

1) the scientific question of the relationship between

emissions reductions and resource protection, and

2) the policy question of what is the socially

desirable level of resource protection. The latter involves such policy concerns as balancing the costs

of reductions with the expected resource-protection

benefits, and distributing the risks and costs equitably among different groups and geographic areas.

No unique ‘ ‘formula” exists for comparing the

risks of resource damage with the costs of further

emissions controls. Neither scientific nor economic

methods can presently analyze the various policy

concerns precisely. Moreover, differing priorities

among regions and interest groups will lead each

to weigh these concerns differently. Several reference points are available, however, for comparing

both the benefits and costs of various levels of reduction.

Several groups1 have estimated maximum levels

of acid deposition that most sensitive lakes and

streams could receive without undergoing further

damage. Specifying deposition limits to protect

against damage to such other resources as crops,

forests, or materials is not yet possible.

OTA’s analysis of how emissions reductions

would affect deposition levels concludes that in areas

of highest deposition—e. g., western Pennsylvania

and northern West Virginia—reducing sulfur dioxide emissions 8 to 10 million tons per year below

current levels might not be sufficient to bring deposition levels within these recommended targets for

protecting all but the most sensitive aquatic

resources. In areas of lower deposition, such as

northern New England, the southern Appalachians,

and the upper Midwest, the recommended deposition limits might be achievable through sulfur dioxide emissions cutbacks of this magnitude. Thus,

reductions of this magnitude would probably not

overshoot a possible congressional goal of protecting all but the most sensitive aquatic resources.

1 Work Group 1, Impact Assessment, U.S.-Canada Memorandum

of Intent on Transboundary Air Pollution, Phase IZ Summary Report, October 1981; National Research Council, Acid Deposition,

Atmospheric Processes in Eastern North America, Committee on

Atmospheric Transport and Chemical Transformation in Acid Precipitation (Washington, D. C.: National Academy Press, 1983); ~.

S. Evans, et al., “Acidic Deposition: Considerations for an Air Quality

Standard, ” Water, Air and Soil Pollution 16:469-509, 1981.

Risks of damage to sensitive forests, materials,

and crops would also be reduced. In addition, airborne fine-particulate levels would be lower, improving visibility and reducing risks to human

health.

Whether this is the desired level of protection

must be addressed, however. Reducing emissions

by about 8 to 10 million tons of sulfur dioxide per

year below current levels (including offsets for expected new growth) would cost about $3 to $6 billion per year (1982 dollars), depending on the design of the program. Smaller, less expensive

cutbacks will provide less protection for sensitive

resources, but how much less is unknown. Larger

emissions reductions might protect more resources,

but the costs would rise steeply.

In addition to preventing potential future damages, reductions might improve water quality in

currently acidified lakes and streams. Projections

from a simple computer model have been used to

estimate how reductions in sulfate deposition might

improve water quality. * If sulfur dioxide emissions

were reduced to 8 to 10 million tons below 1980

levels, about 15 to 40 percent of the aquatic resources already acidified or extremely sensitive to

further acid deposition might experience some

recovery.

With emissions about 4 to 5 million tons below

1980 levels, we estimate that water quality will improve in a maximum of 10 to 25 percent of these

aquatic resources. Reductions of this magnitude,

including offsets for emissions growth, might be

achievable for $1 to $3 billion per year (1982

dollars).

Congress, however, might decide that the uncertain magnitude of benefits to be gained does not

justify such multibillion-dollar expenditures. Holding emissions levels constant, or possibly decreasing them slightly below current levels, might be considered more appropriate until more is known about

the extent of the risks to sensitive aquatic resources,

forests, agriculture, materials, and human health.

For expenditures of about $1 billion per year or less,

about 2 to 5 million tons of sulfur dioxide can be

● This model assumes that the effects of acid deposition are not cumulative and are reversible in a short time period. If these conservative

assumptions are incorrect, the level of recovery will be slower.
128 ● Acid Rain and Transposed Air Pollutants: Implications for Public Policy

eliminated annually—certainly enough to offset

projected emissions growth through 2000, and possibly to decrease emissions levels 2 to 3 million tons

below 1980 levels by that time. This is likely to provide some benefit to sensitive resources but, again,

such benefits cannot be quantified accurately.

Given the uncertainty that reducing emissions

will decrease resource damage to the extent, and

in the locations expected, and the resulting difficulty in estimating the benefits, policymakers may

have to determine the level of emissions reductions

qualitatively. Even if both the benefits and costs

of emissions reductions could be rigorously quantified--e.g., by the multiyear research program currently under way in EPA and other agencies—several other factors would enter into the decision.

Many of the resources at risk from continued acid

deposition, such as lakes and forests, provide benefits that cannot be calculated solely in economic

terms. While these resources do generate income—

e.g., freshwater fishing and forestry are multibillion-dollar industries—they are valued for noneconomic reasons as well. Similarly, losses in

employment in the high-sulfur coal industry from

emissions reductions may cause greater hardships

than estimates of lost income indicate.

Finally, benefits and costs of controlling transported pollutants differ substantially among various economic sectors and geographic areas within

a control region. Calculating aggregate benefits and

costs for the entire affected region ignores these

distributional effects.

Conclusions and Options:

Congress could specify emissions reductions to

reach a socially desired level of resource protection,

considering the costs of further emissions control,

the potential resource protection benefits, and other

policy concerns, The level of reduction chosen,

however, must of necessity be a ‘‘best guess” based

on incomplete information.

For expenditures of $1 billion per year or less,

enough sulfur dioxide emissions could be eliminated

to hold emissions constant (i. e., offset expected industrial and utility growth), or to reduce emissions

levels 2 to 3 million tons below current levels by

the year 2000. This would reduce future risks to

sensitive aquatic resources, forests, agriculture, materials, and health, but by how much is uncertain.

Eliminating 8 to 10 million tons of sulfur dioxide

annually from existing utilities by this date would

cost $2 to $5 billion per year.

Reductions of this magnitude might protect all

but the most sensitive aquatic resources in many

areas, but might not afford this level of protection

in areas currently receiving the highest levels of

acidic deposition. The level of emissions reductions

necessary to protect against potential damage to

such other resources as crops, forests, or materials

is not yet known.

Once the aggregate regional level of emissions

reductions is chosen, Congress must further decide

whether the control program should be designed

to accomplish: 1) a ‘ ‘one-time’ emissions reduction (i. e., eliminating a specified emissions tonnage

from existing sources, but not restricting future

emissions growth), or 2) an absolute ‘ ‘ceiling’ on

regional emissions, thus requiring further reductions as new sources are built.

An increase of about 1 to 3 million tons of sulfur

dioxide emissions per year is projected by 1995. The

highest rates of emissions growth are expected in

the South and the West. Thus, an absolute ceiling

on emissions would be difficult to achieve in these

regions, as well as in those States that currently have

low emissions rates.

Alternatively, Congress could give EPA responsibility for setting reduction levels.

Options available to Congress are described

below.

Option 3a: Mandate Specific Levels of

Emissions Reductions

A congressionally mandated emissions control

program could range from preventing projected increases in emissions to large-scale reductions below

current levels. In the Eastern 31-State region, a

pragmatic estimate of about 11 to 12.5 million tons

of sulfur dioxide per year constitutes the upper limit

of feasible emissions reductions, given current technology and costs. Larger reductions would require

stricter emission rate limitations for all existing utility plants than those currently applicable to new

plants under New Source Performance Standards.
Ch. 7—Legislating Emissions Reductions ● 129

Table 8 presents estimates of the costs of controlling utility sulfur dioxide emissions in the Eastern 31 States. Cost estimates are for control strategies based on specified maximum allowable

emission rates, assuming 1980 emissions and emission rates. The costs of other programs will vary,

depending on how emissions reductions are allocated and implemented. However, both the amount

of sulfur dioxide emissions eliminated from existing

facilities and the extent of future emissions growth

determine the net reductions at any future date.

Future emissions growth in the region might shrink

the reductions presented in table 8 by about 1 to

3 million tons per year by 2000.

Option 3b: Mandate Reductions, Including

Offsets for Future Emissions

Growth

If Congress specifies emissions reductions, it

must also determine how to treat future growth in

emissions. For example, added emissions from new

sources would shrink an 8-million-ton cutback in

sulfur dioxide emissions from existing sources to

an overall reduction of 5.5 to 6.5 million tons below

current levels by 1995. This might be considered

adequate through about 2000, when the effectiveness of the program can be reevaluated.

However, to reduce overall emissions by, for example, 8 million tons below current levels by 1995,

existing sources would have to reduce emissions by

9.5 to 10.5 million tons. To offset emissions from

sources not yet built—already subject to tight control under current New Source Performance Standards—State plans would have to eliminate enough

‘‘extra’ current emissions to accommodate potential future emission levels, or face the risk of

discouraging new industrial or utility growth.

For the more stringent emissions control programs listed in table 8, offsetting future emissions

growth as well might cost an additional $1 to $2

billion per year.

Option 3c: Require EPA To Specify Emissions

Reductions To Meet Congressional

Goals

Congress could give EPA responsibility for setting reduction levels by a given date, according to

specified congressional goals for resource protection and economic considerations. EPA could then

incorporate emerging research findings into its technical judgment of what level of reductions are consistent with congressional goals. The choice could

be left completely to EPA discretion, or be bounded

by the Congress (e. g., eliminating 2-to-5 million,

or 5-to-10 million tons of sulfur dioxide emissions).

Scientists might soon be able to estimate the extent of aquatic resource protection afforded by various levels of emissions reductions, but might require many years to develop similar estimates for

other resources. Nonetheless, such estimates, even

for aquatic resources, are likely to remain controversial for many years, due to uncertainties over

how reductions in emissions would affect deposition levels, and how reductions in deposition levels

would affect aquatic resources. If Congress required

EPA to weigh the benefits and costs of emissions

reductions, it would also need to specify the economic goals to be met, the kinds of benefits to be

included in calculations, and the treatment of regional differences in costs and benefits.

Table 8.—Costs of Reducing Sulfur Dioxide Emissions in the Eastern 31 States

(Excludes costs to offset future emissions growth; all costs in 1982 dollars)

Emission rate Emissions Average cost Marginal cost

limitation reductions Total costa

of reductions of reductions

(Ibs. SO2

/million Btu) (million tons SO2) ($ billions) ($/ton) ($/ton)

2.5 4.6 0,6-0.9 170-240 320

2.0 6.2 1.1-1.5 200-280 440

1.5 8.0 1.8-2.3 260-330 700

1.2 9.3 2.6-3.4 310-400 740

10.3 3.2-4.1 350-440 830

0.8 11.4 4.2-5.0 400-480 1,320

aExcludes costs to meet current SIPs

bCost (in dollars per ton) to achieve the next increment of reductions.

SOURCE: Office of Technology Assessment, based on analyses by E. H. Pechan & Associates, Inc., 1983.
130 Acid Rain and Transported Air Pollutants: Implications for Public Policy

Decision 4: By What Time Should

Reductions Be Required?

Discussion:

This decision focuses on the tradeoff between the

risk of resource damage from continued levels of

acid deposition, and the risk of inefficient or unnecessary control expenditures by acting on limited

knowledge of many of the atmospheric and ecological processes involved. Throughout the discussion,

it is necessary to keep in mind that further emissions controls would take at a minimum about 6

to 10 years to implement, given the planning, contracts, construction, and other steps necessary to

significantly reduce pollutant emissions.

A “fast-track’ program—one requiring emissions reductions in 6 to 10 years—could probably

be met only if Congress directly specified the

amount of reductions. Such a program would require individual control decisions to be made

quickly; even then, if large-scale reductions were

mandated, it might not be possible to install scrubbers and expand low-sulfur coal supplies rapidly

enough to meet the deadline.

Waiting 4 to 6 years for further research results

would increase the time required to reduce deposition to 10 to 16 years, but might lead to a better

control program. During the waiting period, knowledge of acid deposition and its effects will advance,

and more cost-effective control technologies might

be developed. However, it is not possible to count

on significant scientific breakthroughs in this relatively short time.

An intermediate schedule could mandate reductions now, but allow more time for implementation than the ‘ ‘fast-track’ program. The program

could be designed to incorporate results from the

Federal acid deposition research program in about

3 to 5 years, to determine whether the control program should remain intact, be modified, or be discontinued. Federal and State planning processes

could proceed without delay—recognizing that the

research program might not substantially alter current understanding-but such a program would not

require additional pollution control expenditures

until after the reevaluation point.

Innovative approaches to pollution control—e.g.,

technologies such as LIMB (limestone injection

multistage burners) or regenerable processes, discussed in appendix A—raise additional schedulingrelated issues, as they may take longer to plan and

install than more traditional approaches. Congress

could provide incentives to try these potentially

more cost-effective technologies by extending compliance deadlines when they are used.

Conclusions and Options:

A major emissions control program would require, at minimum, about 6 to 10 years to implement. A longer compliance period might be desired

to allow policy makers the opportunity to consider

the results of the Federal acid deposition research

plan. The additional delay, however, might result

in more extensive resource damage.

Options available to the Congress with regard

to scheduling emissions reductions are described

below.

Option 4a: Require Reductions in 6 to 10

Years

Achieving significant reductions within 6 to 10

years would probably require Congress to specify

emissions reductions or emission rate limitations.

State-level planning and source-level implementation of reductions would have to proceed rapidly.

Federal and private-sector acid precipitation research findings might occur too late to be used for

modifying the program.

Option 4b: Require Reductions in 10 to 16

Years, Allowing a Delay for Research

Delivery of Federal research results in 4 to 6 years

could serve as the starting date for planning specified reductions or an environmental quality standard. Compliance with the program would then require an additional 6 to 10 years.

Option 4c: Require Reductions in 8 to 12

Years, With a “Mid-course’

Reevaluation

Federal and State planning could begin immediately, but the compliance date could be set so that
Ch. 7—Legislating Emissions Reductions . 131

individual sources would not have to begin planning construction and contracts until after a reevaluation period in about 3 to 5 years. New research

results, if any appeared, could be used to determine

whether the control program should remain intact,

be modified, or be eliminated.

Option 4d: Stagger Compliance Schedules

To promote potentially more cost-effective technologies, sources using innovative emissions control approaches could be given extra time to comply with any of the schedules outlined in options

4a through 4c.

If interim reductions are desired in conjunction

with longer compliance schedules (e. g., options 4b

and 4c), earlier reductions could be required from

sources switching to low-sulfur fuels or from those

sources emitting at the highest rates. Mandatory

coal washing, though more expensive than approaches that allow each source to choose its leastexpensive alternative, is another method for achieving interim reductions. This alternative has the

advantage of being potentially less disruptive to the

coal industry.

Decision 5: What Approach to

Control Should Be Adopted?

Discussion:

Several regulatory frameworks are available to

the Congress for controlling transported air pollutants. These fall into two broad categories:

1. “Environmental quality” approaches—setting goals or standards for resource exposure

to pollutants—including:

● Establishing environmental quality goals or

standards based on air concentrations of

pollutants.

● Establishing environmental quality goals or

standards based on pollutant deposition

rates.

2. “Source-based” approaches—directly regulating emissions from sources or regions—

including:

● Specifying total emissions reductions (in

tons of pollutants per year), or allowable

pollutant emission rates (most commonly

expressed as pounds of pollutant per unit

of fuel burned for stationary sources, and

grams of pollutant per mile for automobiles).

Requiring either specific types of control

technologies (e. g., scrubbers), or technology-based performance standards.

Air quality goals are currently implemented

through both approaches. For example, National

Ambient Air Quality Standards (NAAQS) are environmental quality standards, Allowable air concentrations of pollutants are set to protect the public

health and welfare. New Source Performance

Standards (NSPS) are source-based standards.

They seek to minimize future pollutant emissions

by regulating emission rates, even for cases in which

NAAQS would be met without their use. NSPS for

coal-fired utilities both set a maximum allowable

emissions rate and require the removal of 70 to 90

percent of potential sulfur dioxide emissions by

technological means.

NAAQS might be used as a framework for controlling transported pollutants. Welfare-based secondary standards for these pollutants could be made

more stringent and enforced more rigorously. Such

an approach might be effective for controlling resource damage from ozone. To address acid deposition, Congress could require EPA to establish

NAAQS for sulfate and nitrate particulate, the

principal transformation products of sulfur dioxide

and nitrogen oxides. To make the NAAQS approach effective, EPA would have to broaden its

consideration of long-range pollution transport.

The NAAQS are air concentration standards,

however, designed to minimize human health effects from breathing pollutants, crop and forest

damage from exposure to pollutant gases, or materials damage from exposure to gases or particles.

A different type of environmental quality standard—a deposition standard-would be more consistent with our understanding of the environmental

effects of acid deposition. Though conceptually attractive, a deposition standard would be quite difficult to implement. Natural variations in precipitation and wind patterns can cause an area’s

deposition to vary considerably from year to year.

Due to the many source regions and sensitive receptor regions involved, designing measures to

comply with the standards, either at the Federal

or State level, would be a difficult and time-con-
132 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

suming administrative and political process. Moreover, while existing models can link large source

regions to large receptor regions, identifying specific sources responsible for deposition in specific

areas far downwind is beyond their current capabilities.

A source-based approach—the one embodied in

most of the acid rain control proposals to date—

would require emissions reductions throughout a

broad region believed to contribute to acidification

in sensitive areas. Unlike deposition standards, the

implementation of source-based approaches is not

restricted by the major uncertainties and inherent

characteristics of the acid deposition problem. Two

types of source-based regulatory approaches are

possible: 1) directly specifying emissions reductions

or allowable emissions rates, and 2) limiting emissions by requiring the use of specific technologies

or technology-based performance standards.

The first approach can be used either to directly

control sources or to assign reductions to regions,

leaving the choice of which sources to control to

another decisionmaking body. The advantages and

disadvantages of these alternatives are discussed in

Decision 6: How Should Emissions Reductions Be

Allocated?

Specified emissions or emissions rates give each

emitter the option of choosing the least expensive

control method, according to individual plant conditions. The second approach—technology-based

standards—reduces or eliminates a plant’s options.

Technology-based standards, however, avoid some

of the adverse effects of ‘nontechnological’ methods of pollution control—i. e., switching to cleaner

fuels. Technological standards would minimize production and employment losses in many Eastern

U.S. coal regions. As discussed in detail in Decision 8, there is a tradeoff between minimizing these

adverse, indirect effects of control, and allowing

emitters to choose the least expensive control

method.

Conclusions and Options:

If Congress decides that an acid deposition control program should be implemented in the near

future—within about 10 to 15 years-several

‘‘source-based’ approaches to control are feasible.

A control program based on an “environmental

quality” standard (similar to the ambient air quality

standards of the Clean Air Act) might be possible

in the future, but the scientific tools needed to support such an approach are not yet available.

Options available to Congress are discussed

below.

Option 5a: Directly Specify Emissions Reductions or Emissions Rate Limitations

Emissions limitations may be specified for either

a class of sources or by region. Decision 6 discusses

the distributional implications of various kinds of

reduction programs. The approach presumes that

the effects of acid deposition are significant enough

to warrant emissions reductions, but that scientific

uncertainties permit no more resolution in a control approach than to reduce aggregate, regional

emissions. Limiting emissions by region or source

category may involve inefficiencies in that it does

not specifically seek to connect the location and

amount of emissions to the location and sensitivity

of areas of deposition. This approach, however, best

reflects current knowledge about the relationship

between emissions and acid deposition.

Option 5b: Specify the Use of Control Technologies

Emissions could also be reduced by specifying

technology performance standards (e. g., 50-percent

reduction, “best available, ” and so on) or mandating the use of specific technologies (e. g., coal washing). Like option 5a, the approach does not depend

on linking source regions to receptor regions.

Technology-based standards are potentially more

expensive than a control program that allows each

emitter to meet the required reductions through the

least-expensive (or otherwise advantageous) method

of control. Technology standards are administratively simple, however, and would minimize coal

market disruptions that might result from other approaches to control. (Potential effects on coal production are discussed in detail in Decision 8.)

Option 5c: Specify an “Environmental Quality

Standard” Approach

Acid deposition control strategies could be pursued by: 1 ) establishing and enforcing more stringent secondary NAAQS for sulfur dioxide and ni-
Ch. 7—Legislating Emissions Reductions ● 133

trogen oxides, or 2) developing NAAQS for air

concentrations of sulfates and nitrates. Secondary

NAAQS for ozone are currently identical to the

health-based primary standard—a l-hour maximum allowable concentration. A secondary standard based on a longer averaging time might better

reflect potential terrestrial resource damages from

chronic ozone exposure.

Alternatively, to control acid deposition, standards could be developed to limit the rate of deposition of acidity or sulfur and nitrogen compounds

over a given surface area, These standards could

vary regionally, depending on the sensitivity of

resources to acid deposition.

Because transported air pollutants routinely cross

State boundaries, implementing an environmental

quality standard to control transported pollutants

would require Federal or regional mechanisms for

revising State Implementation Plans to meet the

new standards. This strategy is constrained by the

problem of linking well-defined source areas to welldefined receptor areas—a scientific question that

may not be resolved for many years. Even if transport models were improved, the inherent variability

of the atmosphere would require limiting the total

amount of pollutants emitted from a State or similar-size region, rather than setting emissions limits

for individual sources. Moreover, this approach

would involve a long and detailed standard-setting

and implementation process. *

Decision 6: How Should Emissions

Reductions Be Allocated?

Discussion:

Strategies for controlling transported air pollutants must address the following issues:

●

●

Who is to allocate emissions reductions to

sources or States?

If Congress chooses to allocate reductions directly, what method should be used?

*For purposes of comparison, although Clean Air Act revisions in

1977 directed EPA to review and revise the existing NAAQS for five

pollutants by 1980, as of 1983 only the standard for ozone had been

revised. A revision had been proposed for carbon monoxide; the standards review of the remaining three pollutants will probably be completed by the end of 1984.

The question of who is to pay the control costs—a

matter distinct from who is to reduce emissions—is

discussed in Decision 7.

Two approaches are available to Congress for directly specifying emissions reductions: 1 ) mandating

a reduction formula for all or a subset of individual

sources within the region, or 2) allocating reductions to States or other subregions, allowing another

decisionmaking group, such as a State or EPA, to

allocate emissions reductions to individual sources.

Congress could also allocate emissions reductions

indirectly by assigning responsibility for designing

allocation schemes, either with or without accompanying guidelines. Congress might set a goal of

reducing deposition within a specified region, recognizing that a wide variety of allocation formulas

could achieve that goal. Reductions from one subregion could be substituted for those in a different

subregion, within certain bounds, while still maintaining the same average pattern of deposition reductions.

Congress might provide additional guidelines—

for example, that the eventual formula allocate reductions on the basis of the current best estimates

of how much sources contribute to deposition in

given areas. Other guidelines might include minimizing costs to the control region as a whole, limiting the percentage of emissions to be eliminated

in any given region, or considering past pollution

control efforts.

Four broad policy considerations are pertinent

to designing an allocation formula for reducing

emissions, or providing guidelines for others to

follow:

● Who is to gain the benefit of resource protection,

● Who is to bear the burden of reductions,

● The plan’s administrative efficiency, and

● The plan’s economic efficiency.

In planning an allocation formula, tradeoffs

among these various interrelated concerns must be

considered. For example, a plan that attempts to

maximize economic efficiency may be difficult to

administer, or might concentrate reductions in one

or more regions.

Political consideration of “Who is to gain the

benefit of resource protection” is intertwined with
134 ● Acid Rain and Transported Air pollutants: Implications for Public Policy

several of the issues discussed previously. Congress

could either attempt to reduce deposition in selected

high-deposition areas with large concentrations of

sensitive resources, or attempt broader-scale protection. A uniform deposition standard, for example, implies the goal of protecting all areas equally,

regardless of their concentrations of sensitive resources. Targeting specific areas for deposition reductions, however, favors one State’s resources over

another’s.

The decision on who reduces emissions must consider the scope of desired resource protection, as

well as other aspects of any allocation scheme. A

plan that provides uniform protection might disperse the required reductions over a larger area than

one focusing on sensitive regions. In addition, each

specific formula affects the relative share allocated

to utilities as opposed to industries; regions whose

local coals are higher or lower in sulfur content;

and so on.

Allocating reductions on the basis of emissions

per area differs in costs and distributional implications from a plan based on an allowable pollutant emission rate per amount of fuel burned. The

first approach concentrates reductions in areas with

a high density of sources, even if these sources are

relatively pollution-free. The second approach focuses on sources with high rates of pollution, even

though the sources might be few and far between.

Neither approach directly addresses such factors as

past emissions reductions or patterns of pollution

deposition.

Appendix A presents eight alternative allocation

formulas for reducing sulfur dioxide emissions, and

the implicit rationales and distributional consequences of each. Three are based on total emissions,

five on utility emissions alone. Variants include formulas based on: emissions per area; emissions per

capita; equal percentage reductions per State; Stateaverage utility emissions rates; emissions above a

specified emissions rate; and emissions per quantity of electricity generated (including nonfossil

energy).

Another aspect of choosing an allocation formula

is administrative feasibility. For example, many

control proposals have allocated emissions reductions based on utility emissions not only because

they emit about three-quarters of the sulfur dioxide

in the 31 Eastern States, but also because the remaining emissions are difficult to characterize. Accurate estimates of emissions rates for many small

industrial boilers are unavailable. Industrial process emissions would have to be regulated according

to emissions per product, rather than per quantity

of fuel burned, and separate standards would have

to be set for each industry.

Finally, for a given overall reduction, each allocation formula results in a different distribution of

costs, as well as different total costs. Controlling

plants that emit at high rates is usually cheaper per

ton of pollutant removed than controlling lower

emitting plants. However, the potential cost to the

particular source—or to the State with a large proportion of plants emitting at high rates—increases

as the required reductions increase. Allocation formulas that minimize total program costs tend to

concentrate reduction requirements on States with

the highest average emissions rates.

Conclusions and Options:

If Congress decides to directly assign emissions

reduction responsibilities to either sources or States,

many reduction formulas are possible. Several policy considerations pertinent to designing an allocation formula include: 1) the resulting distribution

of reductions (which determines both the distribution of costs and deposition reductions; 2) the plan’s

total costs, and 3) the plan’s economic efficiency.

Tradeoffs among these various interrelated concerns must be considered.

In addition to options for congressional allocation of emissions reductions, we also present options for: 1 ) assigning allocation responsibilities to

either EPA or the governors of States in the control region, and 2) adding flexibility to the chosen

formula by allowing trading of emissions reductions

requirements.

Options available to Congress for allocating emissions reductions are described below.

Option 6a: Allocate Emissions Reductions

Directly to Sources

Emissions reductions could be allocated directly

to sources by two means:

1. Legislating maximum allowable emissions

rates. Congress could set maximum allowable emis-
Ch. 7—Legislating Emissions Reductions . 135

sions rates for electric utilities, industrial boilers,

and industrial process emissions. Reductions

achievable by specifying alternative maximum

emissions rates for utilities, industrial and commercial boilers, and all large boilers are presented for

the 3 l-State Eastern region in table 9 and for the

contiguous 48 States in table 10.

2. “Targeting” emissions reductions to specific

sources. Reductions could also be allocated to only

the largest sources. Of the 16 million tons of sulfur

dioxide emitted by utilities in the 31-State Eastern

region during 1980, close to 60 percent came from

the top 50 sources, about 70 percent from the top

75 sources, and close to 80 percent from the top

100 sources. Alternatively, Congress could target

those plants emitting at the highest rates. About

75 percent of 1980 utility sulfur dioxide emissions

came from plants emitting in excess of 2.5 lb of

sulfur dioxide per million Btu, and 60 percent came

from plants emitting in excess of 3.0 lb of sulfur

dioxide per million Btu.

These relatively few sources could substantially

reduce regional emissions by using scrubbers under

procedures similar to the existing New Source Performance Standards. Each of these ‘‘targeted reduction’ schemes, however, draws an arbitrary

cutoff line—those just above it would be required

to reduce emissions substantially (e. g., 90 percent

Table 9.—Sulfur Dioxide Emissions Reductions With

Emission Rate Limitations—31 Eastern States

Ibs. SO2/10 6 Btu . . . . . . . . . . . . . . . . . 1.0 1.2 1.5 2.0 2.5 3.0 4.0

All boilers (1980 emissions = 19,200 thousand tons/year)

Thousand tons/year. . . . . . . . . . . . . . 11,600 10,400 8,900 6,800 5,100 3,700 2,000

Percent reduction in class. . . . . . . . 60 54 46 35 26 19 10

Percent reduction below total a . . . . 53 48 41 31 23 17 9

Utility boilers (1980 emissions = 16,070 thousand tons/year)

Thousand tons/year. . . . . . . . . . . . . . 10,300 9,320 8,020 6,170 4,620 3,370 1,730

Percent reduction in class. . . . . . . . 64 58 50 38 29 21 11

Percent reduction below total a . . . . 47 43 37 28 21 15 8

Nonutility boilers (1980 emissions = 3,200 thousand tons/year)

Thousand tons/year. . . . . . . . . . . . . . 1,300 1,100 900 640 460 360 220

Percent reduction in class. . . . . . . . 40 35 28 20 15 11 7

Percent reduction below totala . . . . 6 5 4 3 2 2 1

a1980 total sulfur dioxide emissions = 21,800 thousand tons/year.

SOURCE: E. H. Pechan & Associates, from Energy Information Administration data (EIA forms 4 and 423), and EPA National

Emissions Data System (NEDS).

Table 10.—Sulfur Dioxide Emissions Reductions With

Emission Rate Limitations—Entire United States

Ibs. SO2/10 6 Btu . . . . . . . . . . . . . . . . . 1.0 1.2 1.5 2.0 2.5 3.0 4.0

All boilers (1980 emissions = 21,000 thousand tons/year)

Thousand tons/year. . . . . . . . . . . . . . 11,900 10,600 9,000 6,900 5,100 3,700 2,000

Percent reduction in class. . . . . . . . 57 48 43 33 24 18 9

Percent reduction below total a . . . . 45 40 34 26 19 14 7

Utility boilers (1980 emissions = 17,380 thousand tons/year)

Thousand tons/year. . . . . . . . . . . . . . 10,530 9,470 8,100 6,200 4,630 3,370 1,730

Percent reduction in class. . . . . . . . 61 55 47 36 27 19 10

Percent reduction below total a . . . . 40 36 31 23 17 13 7

Nonutility boilers (1980 emissions = 3,600 thousand tons/year)

Thousand tons/year, . . . . . . . . . . . . . 1,300

. ,

1,100 930 660 480 370 230

Percent reduction in class. . . . . . . . 37 32 26 18 13 10 6

Percent reduction below totala . . . . 5 4 4 2 2 1 1

a1980 total sulfur dioxide emissions = 26,400 thousand tons/year

SOURCE: E. H. Pechan & Associates, from Energy Information Administration data (EIA forms 4 and 423), and EPA National

Emissions Data System (NEDS).

99-413 0 - 84 - 10 : QL. 3
136 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

reduction by technological means), while those just

below the cutoff would be exempt.

Option 6b: Allocate Emissions Reductions to

States (or Other Jurisdictional

Entities

Congress could allow States to achieve specified

emissions reductions in any way they choose. Other

appropriate jurisdictional units include Air Quality

Control Regions (AQCRs) or even operating utilities (which often own several individual sources).

While this approach would add another layer of

administrative complexity, allowing each State or

other jurisdiction to allocate reductions offers potentially significant cost savings over uniform

emissions rate requirements. For example, OTA

estimates that for cutbacks of about 8 to 10 million

tons per year, allowing States to design “least-cost”

allocation plans could reduce costs by about 20 to

25 percent from those that impose uniform limits

on emission rates.

Congress could allocate emissions reductions to

States in many ways. The allocation formula could

be based on: 1) utility emissions alone (the sector

for which the most accurate emissions data exist,

2) emissions from both utility and nonutility combustion, or 3) total emissions (including industrial

process emissions).

Reductions based on each State’s utility emissions or combined utility, industrial, and commercial boiler emissions could be calculated from:

. emissions in excess of a specified rate (sulfur

dioxide emitted per quantity of fuel burned),

or

. average emission rates (giving credit to States

for less polluting sources).

Reductions based on total emissions could be calculated from:

●

●

●

●

emissions per unit area,

emissions per capita,

equal percentage reductions for each State, or

a series of allowable emission rates set separately for each major sector (i. e., utilities,

industrial boilers, and major industrial

processes).

Other factors that could be incorporated into

State-level allocation formulas include:

● extent of use of nonfossil or low-emitting

energy sources, or

● upper limits on the extent of reductions required.

Table 11 compares the State-by-State emissions

reductions required under several of these alternatives to achieve a total regional reduction of about

8 million tons of sulfur dioxide per year.

Option 6c: Direct the Governors of the States

in the Control Region To Allocate

Emissions Reductions

Rather than assigning specific reductions to

States, Congress could require the governors of the

States within the control region to design an allocation formula. Congress could either provide guidelines or allow the governors complete freedom to

develop a plan. Congress would have to determine

the number of governors necessary to reach agreement (e. g., either a simple or a two-thirds majority)

and alternative mechanisms in the event that agreement is not reached.

Option 6d: Provide Control Program Guidelines and Direct the Administrator

of EPA To Develop the Allocation

Formula

This option must be used if Congress adopts an

environmental quality standard approach, but

could also be used for developing an allocation formula following more general principles. For example, Congress could legislate resource protection

goals (specifying equal protection from pollutants

for all regions or greater protection in areas with

high concentrations of sensitive resources), upper

and lower limits on any State’s emissions reductions requirements, guidelines for considering past

reductions, and so on. The Administrator of EPA

would then translate these goals as closely as possible into regulatory language.

Option 6e: Allow Trading of Emissions Reductions Requirements

To reduce the cost of implementing emissions

reductions, Congress could allow sources or States
Ch. 7—Legislating Emissions Reductions ● 137

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138 Acid Rain and Transported Air pollutants: Implications for Public Policy

to purchase reductions, rather than requiring each

source or State to meet its own requirement directly, This type of flexibility would allow sources with

higher-than-average control costs—due, for example, to engineering design or poor availability of

alternative fuels—to purchase the rights to more

cost-effective reductions.

Congress could allow this type of trading

throughout the entire control region, or permit it

only within smaller areas (e. g., EPA Federal regions) to maintain a desired regional pattern of reductions. Such trading could be allowed freely on

the open market, or through a marketable permit

system to assist and monitor transactions.

If future emissions from sources not yet built

must be offset by reductions from existing sources,

allowing trading would be particularly helpful to

States with high rates of utility or industrial growth.

Option 6f: Allow Substitution of Nitrogen Oxides Emissions for Part of Required

Sulfur Dioxide Emissions Reductions

For some sources, reducing nitrogen oxide emissions costs less than reducing sulfur dioxide emissions. To lower the costs of implementing required

reductions, Congress could allow sources to choose

the mix of pollutant cutbacks that minimizes control costs, subject to a specified substitution formula. Substitution of nitrogen oxides could be allowed on a ton-for-ton basis, 1.4 to 1 (the ratio of

the acidifying potential of the two pollutants), or

be based on estimates of how the two pollutants affect natural ecosystems. Because much of the deposited nitrogen is used by plants, substitution

ratios ranging from 2 tons of nitrogen oxides for

each ton of sulfur dioxide, to ratios as high as 4

to 1, might be considered.

Because the current inventory of nitrogen oxide

emissions is not very accurate, however, a substitution program based on historical emissions (e. g.,

1980) would be difficult to administer. Given the

uncertainties in nitrogen oxide emissions and in

control cost data, OTA cannot estimate the extent

of use or potential cost savings of such a provision.

Decision 7: Who Should Pay the Costs

of Emissions Reductions?

Discussion:

Emissions control costs can be allocated according to two general approaches: 1 ) full costs of control could be paid by sources required to reduce

emissions, or 2) control costs could be funded from

a group larger than those required. For example,

a tax on pollutant emissions or electricity sales could

be used to generate a trust fund to pay for reductions.

Currently, sources of emissions incur lower costs

of production through their ability to dispose of pollutants in the atmosphere. These pollutants create

costs to people whose livelihoods depend on the

resources at risk from acid deposition. The situation, however, is not a simple case of ‘ ‘polluting

region’ versus ‘‘receptor region. The benefits of

lowered production costs are shared throughout the

Nation in the form of lower product prices, although the greatest benefit accrues in the locale of

the source, Likewise, people living outside regions

that have resources at risk benefit from using those

resources, but the people within these regions benefit most.

The first approach allocates the control costs to

those who would be responsible for reductions. Yet

since it is not possible to precisely link emissions

from any given source to damage in areas far removed, some assert that this would be unfair.

The alternative approach would distribute the

costs of reductions to a larger group. For example,

imposing a pollution tax implies that all emissions

contribute to the risk of resource damage, not just

those from sources emitting in excess of a specified rate. Because so few sources are actually monitored, however, such an approach would be administratively complex.

Other trust fund approaches, such as a tax on

electricity generation, are also possible. Because

electricity generation is carefully monitored, this

approach would be much easier to implement.

Though an electricity tax approach is not based on
Ch. 7—Legislating Emissions Reductions ● 139

the amount of pollution produced, it recognizes that

energy consumption creates much of the pollution.

This approach, however, spreads the burden of control costs to all energy consumers, even those in

regions with lower polluting sources such as natural gas or hydropower, and those already paying

for pollution control. Another alternative is an electricity tax that is graduated on the basis of a pollution emission rate, combining aspects of the two

previous approaches.

A trust-fund approach has some undesirable economic and administrative aspects, though it is difficult to estimate how severe these may be. A fund

that covered most or all of the costs of emissions

control could reduce incentives for sources to minimize control costs. In addition, substantial plantto-plant variations in scrubber costs and region-toregion variations in fuel-switching costs could create

considerable difficulties in establishing allowable

cost schedules.

OTA has compared the distributional implications of three tax approaches: 1) a tax on electricity generation; 2) a tax on sulfur dioxide emissions;

and 3) a tax on both sulfur dioxide and nitrogen

oxide emissions, set so that two-thirds of the revenues are generated from sulfur dioxide and onethird from nitrogen oxide emissions. This is roughly

the ratio of sulfur and nitrogen compounds deposited in precipitation in the Eastern United States.

All three tax approaches are assumed to apply to

all 50 States.

A tax on electricity generation would collect all

revenues from electricity consumers. A sulfur dioxide tax would collect about 70 percent of revenues

from the utility sector, and about 30 percent from

industry. Taxing both sulfur dioxide and nitrogen

oxide emissions would collect 55 to 60 percent of

the total revenues from utilities, 25 to 30 percent

from industry, and 10 to 15 percent from highway

vehicles. Emissions from residential and other miscellaneous sources were not included in either of

the pollution-tax approaches.

OTA analyzed how the alternative tax approaches

would affect costs for each State’s electricity consumers only. Since man y manufactured goods are

distributed nationwide, industrial costs are often

borne by consumers over a much larger area than

the State in which the industry is located. A tax

on highway vehicles (e. g., a sales or registration

tax) would be distributed on a roughly per-capita

basis.

Table 12 displays estimates of percentage increases in residential electricity rates from an electricity tax raising $5 billion annually. State-to-State

variations are due solely to differences in the average electricity rate currently paid by consumers in

each State. Table 12 also shows residential electricity rate increases under both pollution-tax alternatives.

These approaches result in lower nationwideaverage rate increases than an electricity tax because part of the costs is borne by other sectors.

Because of the large variation in pollution emission

rates among utility plants, however, costs would

be less evenly distributed, both within each State

and from State to State. Because utilities emit a

larger share of nationwide sulfur dioxide than nitrogen oxide emissions, rate increases are typically

somewhat lower for a tax on both sulfur dioxide

and nitrogen oxide emissions (column 2) than on

sulfur dioxide emissions alone (column 3).

Rate increases shown in table 12 illustrate the

relative distribution of costs under 1980 conditions.

Future changes in electricity demand and pollutant emissions could alter these estimates substantially. For example, reducing sulfur dioxide emissions by 10 million tons per year would reduce total

revenues collected under a pollution tax by about

15 to 30 percent, depending on the tax approach.

Further details can be found in appendix A.

Conclusions and Options:

Under the Clean Air Act, sources that are required to reduce pollutant emissions must pay the

entire costs of control. Several acid deposition control bills introduced to date would maintain this

policy. Others have proposed a cost-sharing mechanism, whereby a tax on electricity or pollutant

emissions would be used to help fund the costs of

control.

Options available to Congress are described

below.
140 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table 12.—5O-State Taxes Raising $5 Billion per Year

During the Early 1980’s (total in later years will

vary with changes in emissions and electricity generated)

Average residential electricity rate

increase (percent) from alternate

tax approaches

(Before control, 1980

Total emissions)

State electricity SO2 and NOx SO2 only

Alabama . . . . .

Alaska . . . . . . .

Arizona . . . . . .

Arkansas . . . . .

California . . . .

Colorado . . . . .

Connecticut . .

Delaware. . . . .

District of

Columbia . .

Florida.. . . . . .

Georgia . . . . . .

Hawaii . . . . . . .

Idaho . . . . . . . .

Illinois . . . . . . .

Indiana . . . . . .

Iowa. . . . . . . . .

Kansas . . . . . .

Kentucky. . . . .

Louisiana . . . .

Maine. . . . . . . .

Maryland . . . . .

Massachusetts

Michigan . . . . .

Minnesota. . . .

Mississippi . . .

Missouri . . . . .

Montana . . . . .

Nebraska. . . . .

Nevada . . . . . .

New

Hampshire . . .

New Jersey. . .

New Mexico . .

New York . . . .

North Carolina

North Dakota .

Ohio. . . . . . . . .

Oklahoma . . . .

Oregon . . . . . .

Pennsylvania .

Rhode Island .

South Carolina

South Dakota.

Tennessee . . .

Texas. . . . . . . .

Utah . . . . . . . . .

Vermont . . . . .

Virginia . . . . . .

Washington . .

West Virginia .

Wisconsin . . . .

Wyoming. . . . .

4.0

4.0

3.1

4.4

3.0

3.7

2.5

2.4

4.5

3.1

4.2

1.8

8.2

3.6

3.8

3.7

4.5

4.2

3.3

3.6

2.9

4.3

3.8

4.0

4.1

6.4

4.7

3.9

2.9

2.6

2.9

2.1

3.7

4.1

3.3

4.5

3.1

3.0

3.6

3.6

4.9

3.7

3.6

3.5

3.3

9.5

4.2

4.4

6.1

2.0

0.9

0.7

0.6

0.2

1.3

0.3

1.4

2.2

1.7

0.8

0.0

2.9

5.9

3.0

1.8

5.7

0.5

0.4

1.8

1.6

2.5

1.8

6.6

0.9

1.3

1.0

2.9

0.8

1.0

0.7

1.8

1.9

4.5

0.6

0.1

2.7

1.3

1.4

1.1

5.3

0.7

0.8

0.1

1.2

0.5

4.1

4.1

3.0

2.5

1.4

0.7

0.5

0.2

1.2

0.3

1.8

2.7

2.2

4.5

1.1

0.0

3.6

7.7

3.5

2.0

0.2

0.6

2.3

2.1

3.0

2.0

2.6

8.8

0.9

1.3

0.9

3.6

0.9

0.9

2.1

2.0

5.9

0.3

0.1

3.5

1.5

1.7

1.1

7.0

0.5

0.6

0.0

0.7

5.1

5.2

2.9

U.S. total . . . 3.3 1.9 2.3

SOURCE: Off Ice of Technology Assessment.

Option 7a: Require the Sources Allocated

Emissions Reductions, and Their

Customers, To Pay the Cost of

Those Reductions

This approach is simple to administer and provides the greatest incentives for each source to minimize control costs. Given the difficulty of precisely

linking emissions in one region with resource damage in another, however, many have questioned

the ‘ ‘fairness’ of the cost allocation.

Option 7b: Establish a Trust Fund To Provide

Some or All of the Necessary Funds

for Reducing Emissions

Funds could be drawn from a tax on emissions,

a tax on electricity production, or even from general

revenues, This approach is administratively complex and might reduce incentives for minimizing

control costs. Costs would be distributed more uniformly among States than under option A; still, this

distribution of the costs and benefits of emissions

reductions also raises regional equity concerns.

Decision 8: What Can Be Done To

Mitigate Employment and Economic

Effects of a Control Policy?

Discussion:

Two industries are likely to be most affected by

legislated reductions in sulfur dioxide emissions:

coal mining and electric utilities, In the absence of

restrictions imposed by Congress, emissions reductions would be achieved through a mix of switching

to lower sulfur fuels and installing flue-gas desulfurization units (“scrubbers”). Individual sources’

control decisions—unless specified by Congress—

will be determined by the relative cost effectiveness

of the two approaches for that source and location.

Both control options have undesirable consequences: fuel switching is projected to cause some

coal production to shift from high-sulfur to lowsulfur producing regions, affecting employment and

economic patterns. Scrubbing allows the continued

use of high-sulfur coal, but imposes high capital

costs on a utility industry already requiring additional capital for continued growth and health.
Ch. 7—Legislating Emissions Reductions ● 141

As discussed in chapters 3 and 5, a program to

reduce sulfur dioxide emissions by 10 million tons

per year might reduce mining employment in highsulfur coal regions by 20,000 to 30,000 jobs from

otherwise projected future levels, and to cause economic activity in the range of $600 to $800 million per year to shift from high- to low-sulfur producing regions. These chapters also discuss the

utility industry’s recent financial situation, showing that during 1980 utilities in a number of Eastern States were in relatively poor positions to raise

new capital either through bond-related borrowing

or by issuing additional stock. An acid rain control program could have some effect on the financial health of these utilities, but the magnitude of

the effect is unknown.

Two approaches are available to minimize the

effects of an acid rain control program on the coal

industry:

● The ‘‘technological approach, i.e, either directly or indirectly mandating the use of control technologies. For example, Congress could

require that a set percentage of the sulfur potentially emitted from coals be removed by

technological means, regardless of how much

sulfur the coal contains.

● The ‘‘local coal approach, which would restrict utility coal consumption on the basis of

the location of the coal supply, as in Section

125 of the Clean Air Act.

The technological approach could, in effect, require sources to achieve reductions via high-removal emissions control technologies, such as wet or

dry flue-gas “scrubbers. Such an approach is the

basis for current New Source Performance Standards, which require 70- to W-percent removal of

potential emissions by technological means. Because the use of scrubbers cannot be avoided by

switching to lower-sulfur fuels, locally available

higher sulfur coals—which tend to be cheaper because of lower transportation costs—would often

be preferred.

Such a policy is not without additional costs,

however. OTA analyzed the cost of installing scrubbers on 50 of the largest utility plants emitting sulfur

dioxide at a rate greater than 3 lb per million Btu.

These 50 plants emitted about 7.6 million tons of

sulfur dioxide in 1980 and consume about 60 percent of the high-sulfur coal produced for utilities.

Mandating the use of scrubbers on these plants

would cost about $1.5 billion per year more than

allowing each plant to use the most cost-effective

method of achieving the same reductions.

In a control program eliminating 10 million tons

of sulfur dioxide emissions per year, such a provision would increase total program costs by an additional one-third to one-half. Moreover, many

available technology-based emissions reduction

methods (e. g., wet scrubbing) produce large quantities of liquid or solid effluents. A typical 1,000

MW plant scrubbing high-sulfur coal produces

about 200,000 tons of sludge per year. This must

be disposed of—posing additional environmental

risks— if useful products cannot be recovered

economically.

If more modest sulfur dioxide emissions reductions are desired—less than 2.5 million tons per

year—Congress could require physical cleaning for

all coal above a specified sulfur content. This technology-based approach would also help prevent production and unemployment losses in high-sulfur

coal regions.

Additional coal-cleaning could eliminate moderate amounts of sulfur emissions at a relatively low

cost for existing boilers that use higher-sulfur coals.

Costs range from about $250 to $350 per ton of

sulfur dioxide removed for Midwestern high-sulfur

coals to $1,000 to over $3,000 per ton removed for

southern Appalachian low- and medium-sulfur

coals. The low range of coal-cleaning costs is competitive with or slightly higher than costs for fuelswitching.

Generally, the higher the sulfur content of the

coal, the more economical y the sulfur can be removed from it. Depending on the type of coal, 10

to 40 percent of its sulfur can be fairly easily

removed. If a greater percentage of the sulfur must

be removed, physical coal washing alone becomes

economically inefficient.

Coal washing is currently a widely used technique. One-third of the utility coal mined in the

Eastern high-sulfur coal producing States was

washed in 1979, removing about 10 percent of

potential sulfur dioxide emissions (about 1.8 million tons) from these coals.
142 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

In many instances, the benefits of coal cleaning

can partially offset the cost, because: 1 ) cleaning

reduces the ash content of coal, reducing both costs

of transportation to the powerplant and ash disposal

requirements at the powerplant; 2) removal of impurities increases the heating value (energy per unit

of weight) of coal; and 3) washing creates a more

uniform fuel that can increase boiler operation efficiency.

The second major approach to mitigating the

coal-market effects of proposed emissions reductions

is based on section 125 of the Clean Air Act, which

allows the States or EPA to restrict coal consumption to coals produced ‘‘locally or regionally, if

such an action would ‘‘prevent or minimize significant local or regional economic disruption or

unemployment. “ The potential effectiveness of the

current section 125 is difficult to judge because

neither the statute, nor EPA in its ongoing proceedings, has defined “locally or regionally’ available

coal or “significant’ economic disruption. No ruling has yet been made under section 125, although

EPA has proposed a ruling based on a petition filed

by the United Mine Workers and others in the State

of Ohio in 1978.

Table 13.—lnterstate

Appropriately defining “locally or regionally”

available coal is extremely important for designing a workable local-coal policy. If, for example,

“local or regional” was to be considered synonymous with State boundaries, invoking section 125

would leave interstate trade in high-sulfur coal

vulnerable to control-induced disruption. Table 13

presents interstate exports of medium- and highsulfur coal as a percentage of total utility coal production for each coal State. As much as 66 percent

of Illinois’ and 82 percent of Kentucky’s high-sulfur

coal would remain vulnerable under such a definition.

Protection can be increased only by expanding

the area considered local or regional, thereby incorporating larger percentages of a State’s highsulfur coal market. For example, if the Illinois ‘ ‘region” were expanded to include Missouri, Indiana,

and Michigan, the proportion of high-sulfur coal

exported outside the ‘‘region’ would fall from 66

percent (when considering only Illinois) to 21 percent (when considering all four States).

The variation in sulfur content of a “region’s’

coal reserves is another factor that must be conCoal Shipments

Major 1980 production Noncompliance a coal

coal-producing for utility market exported to other States Major destination States

States (millions of tons) (percent of State production) (shipments greater than 1 million tons)

Alabama . . . . . . . . . . 15.8 10

Arizona . . . . . . . . . . . 10.5 0

Colorado. . . . . . . . . . 13.6 3

Illinois. . . . . . . . . . . . 54.4 66 FL, GA, IN, 1A, MO, WI

Indiana . . . . . . . . . . . 27.3 22 GA, KY

Kentucky . . . . . . . . . 112.4 73 AL, FL, GA, IN, Ml, MS, NC, OH, SC,

TN, VA, WV, WI

(East). . . . . . . . . . . (73.9) (75)

(West) . . . . . . . . . . (38.5) (69)

Missouri . . . . . . . . . . 5.0 34 KS

Montana . . . . . . . . . . 27.9 52 MN, WI

New Mexico. . . . . . . 17.0 1

North Dakota . . . . . . 15.3 21 SD

Ohio . . . . . . . . . . . . . 34.3 27 AL, Ml, PA

Pennsylvania . . . . . . 50.9 30 MD, NY, OH, WI

Tennessee . . . . . . . . 35

Texas . . . . . . . . . . . . 27.0 o

Utah . . . . . . . . . . . . . 8.5 7

Virginia . . . . . . . . . . . 13.8 71

West Virginia. . . . . . 53.1 MI, NJ, NC, OH, PA

(North). . . . . . . . . . (30.8) (46)

(South) . . . . . . . . . (22.3) (30)

Wyoming . . . . . . . . . 89.7 10 IL, 1A

a“Noncompliance” coal is defined as coal that would not permit utilities to comply with a 1.2 lb SO2/million Btu emissions limit without applying control technology.

SOURCE: DOE/EIA Form 423, supplied to OTA by E. H. Pechan & Associates.
Ch. 7—Legislating Emissions Reductions ● 143

sidered when designing appropriate regional

boundaries. Including reserves of vastly different

sulfur content in the same region is unlikely to prevent disruption to the high-sulfur coal industry. For

instance, defining a region to include southern West

Virginia and Ohio would still permit dramatic shifts

from high- to low-sulfur coal under the statutory

constraints of section 125, since major quantities

of low-sulfur reserves lie in southern West Virginia.

Thus, section 125 could effectively mitigate control-induced coal-market shifts only if regions could

be designed to include a significant portion of a

State’s coal customers, while excluding large reserves of coal with differing sulfur content. In practice, a balance would have to be struck between

defining regions large enough to protect sufficient

amounts of coal, and small enough to exclude significantly different coal reserves.

The analysis above suggests that issues of definition may present significant problems for effective

implementation of section 125. Moreover, restricting competition among coal suppliers on the basis

that a given level of unemployment warrants Federal action could cause a great deal of political controversy. EPA concludes that its ‘‘experience with

Section 125 casts considerable doubt on the workability of this portion of the statute.

EPA suggested a third alternative, analogous to

programs providing adjustment assistance to workers, firms, and communities injured by foreign

competition resulting from free-trade laws. A program could be designed to provide special compensation to workers and communities seriously affected by environmental regulations.

As of 1980, Congress had established about 20

special worker-assistance laws that supplement regular Federal-State unemployment insurance programs. Most provide assistance to workers either

unemployed or underemployed as a result of a Federal action or policy. Several of these programs are

ongoing; for example, the Trade Act of 1974 provides assistance to workers adversely affected by

foreign competition. Others have been established

to help workers so affected by one-time Federal actions. These include temporary benefits for airline

employees under the Airline Deregulation Act of

2

46 Fed. Reg. 8109.

1978, for loggers affected by the expansion of the

Redwoods National Park, and for railroad employees affected by the establishment of Amtrak and

Conrail.

The largest special worker-assistance program,

the Trade Adjustment Assistance program to help

workers hurt by foreign competition, paid $1.6 billion to more than 500,000 workers during 1980.

Most of the others are much smaller.

Benefits provided by these programs range from

relocation, training, and job search benefits (but

no direct monetary payments) to monetary benefits

ranging from 60 to 100 percent of the worker’s salary. Some programs are funded through congressional appropriations, while others receive funds

from the public or private corporations involved

(e.g., the railroads absorbed by Amtrak). Most of

the programs provide benefits for between 1 and

6 years. Two programs provide benefits until age

65.

To assist coal miners adversely affected by acid

rain legislation, Congress could establish a special

worker-assistance program similar to those described above. The program could provide special

retraining to help workers find jobs in other industries in their communities and assist workers that

desire to move to other areas where greater employment opportunities may be available. It should be

noted, however, that during past fluctuations in coal

production, workers in the Appalachian area have

tended to remain in their home communities without jobs rather than relocate to areas where employment opportunities may be greater.

Congress could also provide for direct payments

to unemployed workers either for a set period (e. g.,

1 to 6 years) or until retirement age. Funds for the

program could come from congressional appropriations or through a trust fund established from a tax

on electricity generation, pollution emissions, or

coal sulfur content.

Measures for reducing economic incentives to

switch to lower sulfur fuels, or for prohibiting the

use of nonlocal fuel, would increase scrubber-related capital requirements for the utility industry.

One method available to Congress to minimize the

capital burden on utilities, and the subsequent cost

to consumers, was discussed under the previous policy question, ‘‘Who Should Pay the Cost of Emis-
144 ● Acid Rain and Transported Air Pollutants: implications for Public Policy

sions Reductions? A tax on electricity generation

or pollution emissions could be used to reimburse

utilities for all or part of the capital costs of pollution control technology. Annual operating and

maintenance costs—about half the total costs of

controls— might still be paid by each utility’s consumers, but the burden of raising construction capital would be reduced.

Modifications to the Federal tax code have been

proposed as another means of reducing the capital

costs of pollution control. The Economic Recovery

Tax Act of 1981 (Public Law 97-84) allows utilities

to use accelerated depreciation to recover investment costs. This provides tax benefits to utilities,

creating more favorable cash-flow conditions.3 The

availability of tax-exempt industrial development

bonds to finance pollution control hardware (thereby allowing utilities to raise capital at lower interest

rates) is another means by which the Federal Government currently offsets the additional capital costs

of pollution control.

Additional changes to the tax laws—e. g., increasing tax deductions for pollution control investment —would help some, but not all, utilities to finance pollution control technology. About 20

percent of major privately owned utilities paid no

Federal income tax in 1981. Over 50 percent paid

some tax, but took the maximum allowable investment tax credit (85 percent of a company’s tax

liability). 4

Another approach to reducing capital requirements for pollution control is to encourage development of potentially lower cost control technologies, such as LIMB (Limestone Injection

Multistage Burners) or regenerable processes. At

present, government and industry support for new

pollution control technologies tends to emphasize

technologies for sources yet unbuilt. Current law

does not require existing plants to use technology-based pollution control for meeting ambient

air quality standards.

Investments in research and development for pollution control technologies to retrofit existing

3For a discussion of how this law benefits utilties, see D. W. Kiefer,

“The Impact of the Economic Recovery Tax Act of 1981 on the Public

Utility Industry, ” Congressional Research Service, 1982.

‘D. W. Kiefer, “Tax Credits: Their Efficacy in Helping the Utility Industry Finance Retrofitting to Reduce Sulfur Dioxide Emissions, Congressional Research Service, 1983.

sources are subject to both: 1) the risks inherent

in any R&D program and, 2) the unpredictable demand for these technologies, given uncertainties

about future pollution control regulations. Federal

cost-sharing of R&D for retrofitting existing sources

would reduce investment risks and might encourage

research on innovative, and potentially new, costsaving technologies. The Federal Government

could also increase its own research activities in this

area.

Conclusions and Options

In addition to the direct costs of control, acid

deposition control legislation could have undesirable

secondary consequences. Three options are presented to minimize economic hardship to miners

of high-sulfur coal. Two options are presented to

help ease potential difficulties the utility industry

might face in raising capital to pay for pollution

control technology.

Options available to Congress to mitigate undesirable effects of a control policy are described

below,

Option 8a: Require Sources To Reduce Emissions by Technological Means

Congress could mandate emissions reductions by

technological means, to minimize potential production shifts within the U.S. coal industry and thereby

minimize adverse regional employment and economic changes. For large-scale reductions, Congress could mandate control requirements similar

to NSPS. Requiring emitters to remove a high percentage of potential sulfur dioxide emissions

through such control technologies as scrubbers

would minimize the economic advantage of switching to lower sulfur coal.

For smaller reductions—up to about 2.5 million

tons of sulfur dioxide per year—Congress could direct EPA to require washing for particular coals.

To minimize the costs of this option, Congress

could direct EPA to exempt those coals for which

washing is not cost effective.

Mandating emissions reductions through technological means would minimize unemployment

in high-sulfur coal areas and stimulate the pollution control and construction industries. This approach, however, would also increase overall con-
Ch. 7—Legislating Emissions Reductions ● 145

trol costs, limit the potential economic gains to areas

that produce low-sulk- coal, and increase electricity costs to consumers.

Option 8b: Strengthen and Clarify the Local

Coal Protection Provision of the

Clean Air Act, Section 125

Section 125 of the Clean Air Act allows States

or EPA to prohibit the use of coals that are not produced “locally or regionally, ” if such an action

would ‘ ‘prevent or minimize significant local or regional economic disruption or unemployment.

Congress provided no guidance, however, on the

meaning of these terms, and no ruling has been

made under the section to allow policymakers to

determine its effectiveness.

Congress could enhance the section’s effectiveness by defining ‘ ‘significant” economic disruption

or unemployment (e. g., a threshold of projected

increased unemployment of 10 percent, 20 percent,

etc.). In addition, Congress could provide guidance

on defining a region for use in implementing the

section.

Assuming that the provision could be implemented effectively, it would achieve the same goal

as option 8a—minimizing unemployment in highsulfur coal regions—but would increase overall control costs. EPA has stated, however, that its ‘ ‘experience with Section 125 casts considerable doubt

on the workability of this portion of the statute.

Option 8c: Establish a Special WorkerAssistance Program for Affected

Coal Miners

Congress has established many special workerassistance laws to help people that are either unemployed or underemployed as a result of a Federal action. A similar program could be established

to assist high-sulfur coal miners adversely affected

by acid rain legislation.

Such a program could provide direct monetary

benefits or relocation, training, and job-search

assistance, Funding for the program could come

from either general tax revenues or a tax on electricity, sulfur dioxide emissions, or coal sulfur

content.

Option 8d: Reduce Utility Capital-Raising Requirements for Pollution Control

Equipment

Additional pollution control regulations would

increase the capital requirements of the utility industry at a time when some utilities are in poor financial condition. Adopting either option 8a or 8b

as part of an emissions reduction program would

increase the use of control technology, thereby increasing capital requirements even further.

Several means are available to Congress to aid

utilities in raising the necessary capital. Two

measures already in use are industrial development

bonds to finance pollution control equipment and

tax breaks under the Economic Recovery Tax Act

of 1981 (Public Law 97-84). Ensuring the continued

availability of low-cost industrial development

bonds can lower the costs of pollution control equipment to both utilities and consumers. Additional

tax breaks, similar to the accelerated method of

depreciation permitted by the Economic Recovery

Tax Act of 1981, but specific to pollution control

equipment, could also be provided. Because many

utilities already pay little or no Federal income tax,

however, such a policy would assist some, but not

all, utilities that might choose technology-based

controls.

A more direct approach to reducing the capital

requirements of the utility industry was presented

under Decision 7. Congress could establish a tax

on electricity or pollutant emissions to pay for all

or part of the capital costs of pollution control

equipment.

Option 8e: Provide Federal Support for R&D

on Pollution Control Technologies

for Existing Sources

Congress could increase FederaI research and development activities or take measures to encourage

private-sector R&D. More specifically, Congress

could establish a cost-sharing program for research

on innovative methods of retrofitting existing

sources with pollution control technologies. Focusing the program on retrofit technologies would direct limited Federal funds to pollution control

methods for sources most affected by possible acid
146 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

rain control legislation-existing sources that do not nologies that could reduce utility capital recurrently use pollution control technologies. A pro- quirements and minimize production shifts within

gram to assume some or all of the risks of R&D the coal industry.

might encourage development of cost-saving tech-
Appendixes
Appendix A

Emissions and the Costs of Control

A.1

A.2

A.3

A.4

A.5

A.6

HISTORIC

CONTROL

EMISSIONS OF SULFUR AND NITROGEN OXIDES (p. 149)

TECHNOLOGIES FOR REDUCING SULFUR AND

NITROGEN OXIDE EMISSIONS (p. 153)

ALLOCATION OF SULFUR DIOXIDE EMISSIONS REDUCTIONS AND

THE COSTS OF CONTROL (p. 167)

ALTERNATIVE TAX STRATEGIES TO HELP FUND ACID RAIN

CONTROL (p. 180)

OTHER EMISSION SECTORS (p. 183)

POTENTIAL SECONDARY ECONOMIC EFFECTS OF EMISSIONS

CONTROL PROGRAMS (p. 190)

A.1 HISTORIC EMISSIONS OF SULFUR

AND NITROGEN OXIDES

During 1980, about 25 million to 27 million tons of

sulfur dioxide (S02) and about 21 million to 23 million

tons of nitrogen oxides (NOX

) were emitted nationwide

by electric utilities, industry, highway vehicles, and

other sources. S02 emissions peaked around 1970 at

about 29 million to 31 million tons per year; NOX

emissions peaked during the late 1970’s at about 21 million to 24 million tons per year.

Estimates such as these are calculated from data collected by the Environmental Protection Agency (EPA)

and the Department of Energy (DOE) on a large variety of emitting sources. Pertinent information includes,

for example, fossil fuel consumption, sulfur content of

fuels burned, and average NOX emissions rates from

various types of boilers and highway vehicles. Due to

the extensive data collection and monitoring activities

of both agencies, current emissions estimates are accurate to within 5 to 10 percent nationwide. However, the

uncertainty around emissions estimates is larger for

prior years. Reasonably complete data exist for the last

three decades; emissions between 1900 and 1950 must

be inferred using whatever historical records exist.

Assumed values are necessary to fill in missing data to

complete the calculations.

Tables A-1 and A-2 present estimates of 1980 SO2

and NOX emissions by State and sector. These estimates were calculated by EPA for the U.S.-Canada

Memorandum of Intent on Transboundary Air Pollution. 1 Nonutility combustion (table A-1, co1. 3, table

A-2, co1. 4) includes emissions from industrial, commercial, and residential combustion sources. Industrial

process emissions of SO2 (table A-1, co1. 4) include emissions from nonferrous smelters, petroleum refineries,

cement plants, natural gas plants, iron and steel mills,

and sulfuric acid plants. Transportation emissions of

NOX (table A-2, col. 2) include highway vehicles and

such off-highway mobile sources as aircraft, railroads,

vessels, and construction equipment.

Estimated historic emissions of SO2 and NOX from

1900 to 1980 are presented graphically below.2 These

estimates are from ongoing work by an EPA contractor, and are subject to further review and revision. (The

estimates for 1980 agree to within about 5 percent with

the emissions estimates presented in tables A-1 and A-2. )

Figure A-1 presents State-level S 02 and NOX

emissions estimates for the period 1950 to 1980. Most

of the data needed to calculate these estimates were

available by State from various government reports;

]‘ Emlswms, Cnsts and Enq-meerln~ .%scssment, \$’ork Group 3B, Lrnlted

.Statcs-Canadd ,Vfemor-andurn of [rrrt,rrr on Transbound~r;. Ar P(d/uri(In, ,J\Inc

1982.

‘The maps and graphs presented In ~his xc tlon are from the clraf[ rep[,r t

‘‘ Hlstorl( F,mlssinns of Sulfur and Nltrogcn oxIdcs In the L’nltrxi Statt.. F’rc}rl]

1900 [[l 1980, ‘ ‘ (; (;w hwan(ltner, K C ( A( hwandtner, and K El[irl(lqt, (A

t<)bcr 1983 ‘1’hc work was perfornlt.d t~} Pdc lfi( ~;n\ tronn~t, n[al Ser\,lc cs, I nc ,

undc r ( orrt r.i( t [(] EPA

149
150 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table A-1 .—Estimated 1980 S02 Emissions (thousands of tons)

Total 1980 Utility Nonutility Process Other

State SO2 emissions combustion combustion emissions SO2 emissions – L

Alabama. . . . . . . . . . . . . . . . .

Alaska . . . . . . . . . . . . . . . . . .

Arizona. . . . . . . . . . . . . . . . . .

Arkansas . . . . . . . . . . . . . . . .

California . . . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . . .

Connecticut. . . . . . . . . . . . . .

Delaware . . . . . . . . . . . . . . . .

District of Columbia . . . . . .

Florida . . . . . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . . . . . .

Hawaii . . . . . . . . . . . . . . . . . .

Idaho . . . . . . . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . . . . .

Iowa . . . . . . . . . . . . . . . . . . . .

Kansas . . . . . . . . . . . . . . . . . .

Kentucky . . . . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . . . . .

Maine . . . . . . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . . . .

Massachusetts . . . . . . . . . . .

Michigan . . . . . . . . . . . . . . . .

Minnesota . . . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . . .

Missouri . . . . . . . . . . . . . . . . .

Montana . . . . . . . . . . . . . . . . .

Nebraska . . . . . . . . . . . . . . . .

Nevada . . . . . . . . . . . . . . . . . .

New Hampshire . . . . . . . . . .

New Jersey . . . . . . . . . . . . . .

New Mexico . . . . . . . . . . . . .

New York..... . . . . . . . . . . .

North Carolina . . . . . . . . . . .

North Dakota . . . . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . . . . .

Oklahoma . . . . . . . . . . . . . . .

Oregon . . . . . . . . . . . . . . . . . .

Pennsylvania . . . . . . . . . . . . .

Rhode Island . . . . . . . . . . . . .

South Carolina . . . . . . . . . . .

South Dakota . . . . . . . . . . . .

Tennessee . . . . . . . . . . . . . . .

Texas . . . . . . . . . . . . . . . . . . .

Utah . . . . . . . . . . . . . . . . . . . .

Vermont . . . . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . . . . .

Washington . . . . . . . . . . . . . .

West Virginia . . . . . . . . . . . .

Wisconsin . . . . . . . . . . . . . . .

Wyoming . . . . . . . . . . . . . . . .

U.S. total . . . . . . . . . . . . . .

Percent of U.S. total . . . . . . 16 5

SOURCE: Emissions, Costs and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of lntent on Transboundary Air Pollution, June 1982.

759

19

900

102

446

132

72

109

15

1,095

840

58

47

1,471

2,008

329

223

1,121

304

95

338

344

907

260

285

1,301

164

75

243

93

279

269

944

602

107

2,647

121

60

2,022

15

326

39

1,077

1,277

72

7

361

272

1,088

637

184

543

12

88

27

78

77

32

52

5

726

737

42

0

1,126

1,540

231

150

1,008

25

16

223

275

565

177

129

1,141

23

49

34

80

110

85

480

435

86

2,172

38

3

1,466

5

213

29

934

303

22

1

164

69

944

486

118

86

3

9

32

56

24

35

26

8

97

44

8

11

188

290

57

11

66

76

65

56

58

154

44

48

55

25

4

2

10

75

2

335

116

13

311

15

25

254

8

84

83

106

16

5

142

41

84

107

30

95

1

787

29

197

17

0

25

0

159

14

6

30

119

151

27

39

29

153

4

42

1

152

18

75

81

104

5

203

0

42

166

71

23

4

118

52

8

239

0

13

3

27

719

27

0

14

132

43

5

29

35

2

17

14

116

13

5

6

2

113

45

3

5

38

27

13

22

18

50

10

17

11

35

22

32

25

11

17

5

2

52

16

59

28

5

46

16

24

63

2

16

4

33

148

6

1

41

29

16

40

8

26,557

100

17,373

65

3,504

13

4,296 ‘1,385
App. A—Emissions and the Costs of Control ● 151

Table A-2.—Estimated 1980 NOX Emissions (thousands of tons)

Total 1980 Utility Non utility Other

State N OX emissions Transportation combustion combustion NOx emissions

Alabama. . . . . . . . . . . . . . . . .

Alaska . . . . . . . . . . . . . . . . . .

Arizona. . . . . . . . . . . . . . . . . .

Arkansas . . . . . . . . . . . . . . . .

California. . . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . . .

Connecticut . . . . . . . . . . . . .

Delaware . . . . . . . . . . . . . . . .

District of Columbia . . . . . .

Florida . . . . . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . . . . . .

Hawaii . . . . . . . . . . . . . . . . . .

Idaho . . . . . . . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . . . . .

lowa . . . . . . . . . . . . . . . . . . . .

Kansas . . . . . . . . . . . . . . . . . .

Kentucky . . . . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . . . . .

Maine . . . . . . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . . . .

Massachusetts . . . . . . . . . . .

Michigan . . . . . . . . . . . . . . . .

Minnesota . . . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . . .

Missouri. . . . . . . . . . . . . . . . .

Montana . . . . . . . . . . . . . . . . .

Nebraska . . . . . . . . . . . . . . . .

Nevada . . . . . . . . . . . . . . . . . .

New Hampshire . . . . . . . . . .

New Jersey . . . . . . . . . . . . . .

New Mexico . . . . . . . . . . . . .

New York . . . . . . . . . . . . . . . .

North Carolina . . . . . . . . . . .

North Dakota . . . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . . . . .

Oklahoma . . . . . . . . . . . . . . .

Oregon . . . . . . . . . . . . . . . . . .

Pennsylvania. . . . . . . . . . . . .

Rhode Island . . . . . . . . . . . . .

South Carolina . . . . . . . . . . .

South Dakota . . . . . . . . . . . .

Tennessee. . . . . . . . . . . . . . .

Texas . . . . . . . . . . . . . . . . . . .

Utah . . . . . . . . . . . . . . . . . . . .

Vermont . . . . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . . . .

Washington . . . . . . . . . . . . . .

West Virginia . . . . . . . . . . . .

Wisconsin . . . . . . . . . . . . . . .

Wyoming . . . . . . . . . . . . . . . .

U.S. total . . . . . . . . . . . . . .

Percent of U.S. total . . . . . .

450

58

258

217

1,225

276

134

52

22

648

494

45

81

1,005

773

321

437

531

928

59

248

254

690

373

285

568

126

195

83

56

406

290

680

536

125

1,145

526

192

1,037

36

260

89

517

2,544

144

25

405

289

452

420

255

21,267

100

164

27

119

131

820

115

90

22

14

347

236

26

52

425

280

165

176

183

190

42

143

158

302

200

125

254

63

124

35

27

246

97

385

253

60

438

181

144

434

28

127

58

224

745

65

22

250

193

87

208

69

9,367

44

172

0

91

26

115

86

20

19

2

214

189

13

0

416

361

98

86

272

98

1

61

57

237

112

50

237

23

40

43

25

66

80

130

214

53

516

105

3

390

3

84

200

522

39

1

62

25

302

145

103

83

27

40

45

205

67

23

9

6

52

39

3

15

129

99

47

151

67

552

13

37

37

121

53

79

49

22

22

4

4

68

109

139

50

11

162

216

25

164

5

39

4

69

1,113

33

2

65

32

55

57

78

31

4

9

15

85

9

1

2

1

35

31

3

15

35

33

9

24

9

89

3

7

2

29

8

31

27

18

8

1

1

25

4

26

19

1

29

24

20

49

0

10

7

25

163

7

0

28

39

9

11

6

6,225

29

4,595

22

1,080

5

SOURCE. Emissions, Costs and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of lntent on Transboundary Air Pollution, June 1982.

99-413 0 - 84 - 11 : QL. 3
152 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure A.1.—SO2 and NOX Emissions From 1950 to 1980, By State

1950
App. A—Emissions and the Costs of Control ● 153

when data were missing, information from the nearest

year of record was used.

During 1950, between 18 million and 21 million tons

of SO2 were emitted nationwide. By 1970, annual SO2

emissions had increased by about 10 million tons over

1950 levels; between 1970 and 1980, emissions declined

by about 4 million tons per year.

Figure A-1 also illustrates the geographic pattern of

N OX emissions. During the 1950’s, nationwide NOX

emissions were about 8 million to 10 million tons per

year. By 1980, nationwide NOX emissions were over

twice 1950 levels.

Figure A-2 graphically illustrates SO2 and NOX

emissions from 1900 to 1980 by sector and geographic

(multi-State) region. For SO2, the sectors include: electric utilities; industry (including industrial boilers

and—for 1950 and later—copper smelters and cement

plants); commercial and residential boilers; and other

sources, including railroads, vessels, and off-highway

vehicles. The sectors for which NOX emissions are estimated include those listed above, plus highway vehicles and natural gas pipelines. The regions are single or

grouped EPA Federal regions, as shown on the accompanying map.

Emission trends for SO2 show a consistent pattern in

each of the regions. While pre-1950 trends are uncertain, SO2 emissions appear to have increased until about

1925, decreased during the Depression, increased once

again during World War II, and then declined until the

1950’s. After 1950, annual emissions increased through

about 1970, and then declined. In some regions, for example, New York and New England (regions 1 and 2),

this historic pattern of emissions increases and decreases

appears as variations around a fairly constant long-term

average. In other regions, for example, the Mid-Atlantic

and Southeastern regions (regions 3 and 4), short-term

variations accompany a longer term trend of increasing annual SO2 emissions.

Annual NOX emissions have increased throughout

the century in ail regions. New York and New England

(regions 1 and 2) show the lowest rates of increase, while

the Southeast and South Central regions (regions 4 and

6) show the most rapid increases.

A.2 CONTROL TECHNOLOGIES FOR REDUCING

SULFUR AND NITROGEN OXIDE EMISSIONS

Acid deposition and ozone result primarily from the

chemical transformation of three pollutants: oxides of

sulfur, oxides of nitrogen, and hydrocarbons. This section discusses the techniques available for controlling

emissions of oxides of sulfur and nitrogen. Where possible, for each emission control approach, the following

information will be presented:

● the processes involved in the technique;

. its stage of development, i.e. , whether the technology is currently commercially available or requires

further research and development (R&D);

● the effectiveness of the technique, i.e. , the degree

of reduction it can reliably achieve;

c costs; and

● secondary effects.

The major source of nitrogen oxides and sulfur dioxide is the combustion of fossil fuels. During the combustion process, sulfur contained in the fuel reacts with

oxygen to form sulfur oxides, primarily sulfur dioxide

gas (SO2) and, after sulfate. Nitrogen—contained in

both the air used for combustion as well as in the fuel—

reacts with oxygen to form gaseous nitrogen oxides

(NOX). There are three general approaches to controlling these emissions:

●

●

●

precombustion: the amount of sulfur or nitrogen

in the fuel being burned can be reduced, either by

using fuels naturally lower in sulfur or nitrogen

content, or by subjecting the fuels to some kind of

physical or chemical process to remove sulfur and

nitrogen;

during combustion: the combustion process can

be altered to reduce the amount of sulfur and nitrogen compounds released in the gas stream; and

postcombustion: the products of combustion can

be treated to remove pollutants before they are released into the atmosphere.

All three of these approaches have been successfully

used to reduce emissions from existing sources.

In addition to these differences among approaches to

control, the stage of development of the emissions control techniques discussed in this appendix varies considerably. Technologies may be characterized as:

In-use technologies. —Those with demonstrated

control capabilities currently sold on a commercial

scale in the United States.

Available technologies.—Those that have been

tested and proven but are not currently operational

in the United States on any significant scale.
154 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

0

o

C9

o “
App. A—Emissions and the Costs of Control ● 155
156 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

0

o

x

z
App. A—Emissions and the Costs of Control . 157

● Emerging technologies.--Those still primarily in

the R&D phase, but have undergone testing on at

least a pilot scale. *

Control approaches also differ widely in the amount

of emissions reductions they are capable of achieving

and in their cost effectiveness. Each technology is most

cost effective in a particular range of emissions reductions. For instance, the precombustion approach of

physical coal cleaning is technically feasible only for SO2

reductions of less than 40 percent. On the other hand,

the postcombustion approach of flue-gas desulfurization

is cost effective in the 50- to 95-percent SO2 removal

range. The control technique appropriate for a given

facility thus depends a great deal on the level of reduction desired.

Table A-3 presents summary information on the control technologies described in this appendix. Due to sitespecific conditions, the removal efficiency levels given

are intended for approximation only.

“’1’hl~ typolo$y IS used [u charactrrlm technnlw+cs In EmJ.ssIons, ~~osfs and

EnK,necr,rrg .4sscwnent, W’ork Group ‘}B, J ( (Jn,[cd st~[~s.(;ana(la hiernorandum of Intent on Trandmundarv .Alr Pollutmn, 1982 ‘‘

Table A-3.—Overview

Controlling Sulfur Dioxide Emissions

Precombustion Approaches

FUEL-SWITCHING

Sulfur dioxide is formed when sulfur, an element naturally present in coal and oil, is oxidized during the

combustion process. The greater the concentration of

sulfur in the fuel being burned, the greater the production of SO2 gas. One way to reduce SO2 emissions

is, therefore, to use fuels with lower concentrations of

sulfur.

The amount of emissions reductions attainable by

fuel-switching at a given plant depends on: 1) the

amount of sulfur in the fuel currently being used, and

2) the amount of sulfur in the fuel available for replacement. The sulfur content of coal currently being used

for electricity generation varies considerably, from about

0.2 to 5.5 percent sulfur by weight (from about 0.4 to

10 lb SO2 per million

of

3.5team Electric Plan? Factors

tmn, 1978)

Control Technologies

Btu of coal).3

(W’ashinyton, [) (: National ( :(MI ASSIX IaReduction Revenue

efficiencies Requirements Stage of

Control technology (percent) (mills/kWh) development

Sulfur dioxide

Fuel-switching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-90 ”/0 o-7 In use

Physical coal cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-40 1-5 In use

Chemical coal cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60-85 NA Emerging

Wet flue gas desulfurization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-95 10-17 In use

Dry flue gas desulfurization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40-90 9-15 In use

Regenerable flue gas desulfurization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-90 12-25 Available

Oil desulfurization:

Indirect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-40 4-6 In use

Direct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-90 NA In use

Nitrogen oxides:

Low-NO X burner—commercial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-50 0-3 In use

Low-NO X burner—developmental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-80 0-3 Emerging

Thermal DeNox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-65 NA In use

Flue gas treatment without catalyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35-40 NA Available

Flue gas treatment with catalyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80-90 NA Available

Combined sulfur dioxide/nitrogen oxides:

Limestone injection multistage burner:

Sulfur dioxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-90 3-5 Emerging

Nitrogen oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50-70 3-5 Emerging

Fluidized bed combustion:

Sulfur dioxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <90 NA Emerging

Nitrogen oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-30 NA Emerging

SOURCE’ Office of Technology Assessment, primarily from EPA estimates.
158 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

The two principal components of the costs of fuelswitching are: 1 ) the “fuel-price differential, ” i.e., the

difference in price between the high- and low-sulfur fuel;

and 2) the type of fuel-handling facilities, boilers, and

emissions control devices at the plant. Low-sulfur coal

is typically more expensive than high-sulfur coal, especially in the East and Midwest.

Figures A-3 and A-4 illustrate the cost differences between high- and low-sulfur coal. Figure A-3 shows the

costs of a high-sulfur, Illinois coal at various distances

away from the mine. Similar costs are presented for an

Appalachian low-sulfur coal in figure A-4. The costs of

the low-sulfur coal are shown to be 50 percent higher

than the high-sulfur coal even in the areas closest to the

mines. The cost differential confronting specific utility

plants will vary considerably, depending on site-specific

factors and market arrangements.4

Many Western low-sulfur coals contain more ash than

Eastern high-sulfur coals and can potentially emit

greater amounts of particulate. Therefore, particulate

emissions control devices (electrostatic precipitators or

baghouses) generally have to be upgraded if low-sulfur

fuels are used at existing plants. Fuel-handling facilities

may also have to be altered because Western coals are

often more difficult to pulverize than Eastern coals. In

addition, certain kinds of boilers are designed to burn

coal with very specific characteristics (e. g., energy yield,

ash, and moisture content). These boilers would have

to be modified to burn low-sulfur coal efficiently or

derated (i.e., produce less electricity). The capital costs

of upgrading particulate controls, fuel-handling facilities, and boilers are relatively minor compared to the

increased fuel costs involved in fuel-switching. One estimate of the cost of achieving a 6-million-ton SO2 emissions reduction by fuel-switching at the 50 largest

emitters is $1.4 billion per year (1982 dollars), or about

$250 per ton of SO2 removed. ’

There are 217 billion tons of ‘compliance” coal (i. e.,

capable of meeting an SO2 emissions rate limitation of

1.2 pounds per million Btu (lb/MMBtu) without the application of control technologies) in the demonstrated

reserve base. G This quantity of coal could support U.S.

production for a period of about 50 years (assuming 50

percent recoverability and 3 percent annual growth in

consumption). Therefore, achieving substantial emissions reductions through fuel-switching would not be

constrained by the resource base over the near future.

However, 85 percent of the Nation’s ‘‘compliance’

reserves are located West of the Mississippi, while 63

percent of coal consumption and 72 percent of coal pro-

‘E H, Pechan & Associates, information supplied to OTA, October 1981

5PEDC0 Environmental Inc , Acid Rain: Control Strategies for Coal-Fired

Utility Boilers—L’olume I, Summary Report, prepared for the Department of

Energy, May 1981, tables 3-1 and 3-2.

CE. H Pechan & Associates, information supplied to OTA, April 1982.

duction occurs East of the Mississippi.7 In order to be

viable, a large-scale emissions reduction program relying

primarily on fuel-switching would have to significantly

expand Western coal production and transportation

capacity. *

COAL CLEANING: PHYSICAL OR CHEMICAL

The second precombustion approach involves physically or chemically treating coal to remove some of the

sulfur it contains. Sulfur in coal exists in two major

forms: inorganic and organic. Inorganic or “pyritic”

sulfur can be removed relatively inexpensively by exploiting differences in the physical properties of pyrite

and coal particles. Organic sulfur is chemically bound

to the carbon molecules of coal, and can be removed

only by breaking the bonds through some chemical process. These chemical processes are less developed and

more expensive than the physical processes that remove

pyritic sulfur, but their sulfur removal potential is

higher. * *

Physical Coal Cleaning.—Physical coal cleaning

(often called coal washing) takes advantage of differences

in the sizes, densities, and surface properties of pyrite

and coal particles. The first step of the cleaning process

is to separate raw coal into different size ranges. Breakers and crushers are used to separate the softer coal from

the harder rock and other debris contained in the coal

entering the treatment plant. After breaking and crushing, the coal is typically filtered through screens to divide

it into coarse, intermediate, and fine size ranges.

The method used to extract the pyritic sulfur from

the coal depends on the size of particles. Coarse and intermediate size particles allow differences in the specific

gravity of pyritic sulfur and coal particles to be used (pyrite has a specific gravity of 5—i. e., is five times heavier

than water; coal is approximately 1.4). The coal mixture

is immersed in a fluid, where the heavier pyritic particles

sink and the lighter particles float. The coal product and

refuse material can then be removed separately.

Fine mineral particles cannot be effectively separated

by the specific gravity techniques. Physical coal cleaning

‘U.S. Department of Energy, Energy Information Administration, Coal t%-

cfucrion-1979, DOE/EIA-01 18(79), Apr. 30, 1981

*See Ollice of Technology Assessment, Direct Use of Coal, OTA-E-86, April

1979, O’I-A, An Assessment of Development and Production Potential of Federal Coal Leases, OTA-M- 150, December 1981, especially ch. 12. For an ac -

cuunt of the socioeconomic’ effects of the decline of coal production, see T. R

Ford (cd,), The Southern Appalacluan Region, A Sur\,ey (1.exmgton, Ky.

University of Kentucky Press, 1960)

● “FoI a survey of coal-cleaning techmques, see James D. Kilgroe, “Coal

Cleaning for Sulfur Cioxide Emission Control, ” paper submitted to the Acid

Rain Conference, Springfield, Va , Apr 8-9, 1980 The description of physical coal cleanutg in this section relles heawly on Kdgroe’s paper Otber surveys

of coal-cleaning techniques can be found m EPA-450/3-81 -004, Control Techniques fix Sulfur Oxicfe Emissions Fmm Stationary Sources, 2d ed , Aprd 1981,

and F, PA-600/7-78-002, Engineering/Economic Analyses of Cod Prepara[iun

With S02 Cleanup Processes, January 1978,
App. A—Emissions and the Costs of Control ● 159

7

x

Ez
160 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy
App. A—Emissions and the Costs of Control . 161

of fine particles relies on a process in which the raw coal

particles are treated with a chemical that, because of

differences in surface properties, adsorbs differently on

the surface of coal particles than other substances in the

mixture. Air bubbles introduced into the chamber attach

to the coal particles and carry the coal to the surface,

where they can be skimmed off. The pyrite and other

particles sink, and are removed separately.

Table A-4 shows the extent to which coal produced

for the utility market by eight Eastern and Midwestern

coal-producing States is physically cleaned. One-third

of the coal produced by these States for utility was

washed in 1979, resulting in an estimated 1.8-millionton reduction in the potential SO2 emissions (approximately equivalent to a 10-percent reduction in the potential SO2 emissions). 8

The emissions reduction potential of physical coal

cleaning depends primarily on: 1 ) the initial sulfur level

in the raw coal, 2) the ratio of pyritic to organic sulfur,

and 3) the coal-cleaning technique used. Pyritic sulfur

accounts for between 30 and 70 percent of the total sulfur

content of Coal. g Higher sulfur coals tend to have a larger

proportion of pyritic sulfur than lower sulfur coals. Consequently, the higher the sulfur content of coal, the

greater the percentage removal possible through this

process. Table A-5 shows the results of an analysis prepared for the Environmental Protection Agency (EPA)

on the potential for sulfur removal by coal cleaning in

eight Eastern and Midwestern States. 10 As the first

‘\’ersar, Inc , Coal Rrwources and Sulfir Err]l.won Rt-gularlorrs .4 Sur\c~

of El,qht Eastern and .\ fdwestern Srares, prepared for EP.4, PM 1-240319, May

1981

‘Jamm D Kllgroe, ‘ ‘Coal (;leaning for Sulfur Dloxlcic Emission Control,

pap-r suhmltted to the Acid Ram Conference, Sprm#ielci, \’a , Apr 8-9, 1980

1

“\rersdr, op c It

column of the table shows, reductions of between 8 and

33 percent are attainable. The second column lists the

SO2 emissions rate (in lb/MMBtu) achievable after coal

washing.

Table A-6 shows the costs and emissions reduction

potential of requiring all coal to be cleaned before its

use. An additional reduction in SO2 emissions of about

2.5 million tons could be achieved from the coals produced by these eight States (equivalent to a 17-percent

reduction of emissions from coal produced by these

States). As the table shows, coal cleaning is associated

with a wide range of costs—from a low of $224/ton of

SO2 removed in Indiana to a high of over $3,000/ton

removed in southern West Virginia (in 1982 dollars).

Cleaning high-sulfur coals-those with the largest emissions reduction potential—is in general more cost effective than cleaning lower sulfur coals. The regionwide

average cost (not including southern West Virginia and

Virginia) is about $505/ton of SO2 removed. Coal cleaning adds between $4 and $9/ton to the price of coal, and

between 2 and 4 mills/kWh in annual revenue requirements. 11 This compares with an average price of residential electricity of about 50 to 60 mills/kWh. 12

A Department of Energy contractor has assessed the

costs and emissions reduction potential of washing the

coal delivered to the 50 largest emitters in the United

States. SO2 removal efficiencies range from 3 to 34 percent. Costs range from $4 to $7/ton of coal cleaned, $170

to $4,900/ton of SO2 removed, and from 0.8 to 4.4 mills/

kWh (1980 dollars). Cleaning the coal used by these 50

11 Ibid

“U. S Department of Energy, Energy Information Admmlstratmn, 1980 Annual Report to Con,gre.ss, i’olume 11, DOE/EIA-01 73-80/2.

Table A-4.—Reductions in 1979 SO2 Emissions Achieved by Cleaning Utility Coal From Eight States

Sulfur content of coal Average SO2

Coal delivered Utility coal (expressed as 101 tons SO2) reduction by

to utilities cleaned in delivered coal cleaning

in 1979 1979 As mined in 1979

Region and State in which coal was mined (103 tons) (percent) (10s tons) (10s tons) (percent)

Northern Appalachia:

Pennsylvania. . . . . . . . . . . . . . . . . . . . . . . 47,400 30 2,100 1,860 12

Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38,300 11 2,750 2,670 3

Northern West Virginia . . . . . . . . . . . . . . 31,300 23 1,760 1,690 4

Southern Appalachia:

Southern West Virginia. . . . . . . . . . . . . . 17,500 9 300 290 1

Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . 13,400 7 280 270 1

Eastern Kentucky. . . . . . . . . . . . . . . . . . . 68,600 22 1,630 1,570 4

Eastern Midwest:

Western Kentucky . . . . . . . . . . . . . . . . . . 38,100 34 2,880 2,600 13

Indiana. , . . . ... , , ... , ... , ., . . . . . . ., 25,300 52 1,620 1,410 13

Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49,500 72 3,570 2,780 22

Alabama:

Alabama. . . . . . . . . . . . . . . . . . . . . . . . . . . 14,600 32 460 440 5

Eight-State total/average. . . . . . . . . . . 344,000 33 17,350 15,580 10

SOURCE: Versar, Inc., Coal Resources and Sulfur Emission Regulations: A Survey of Eight Eastern and Midwestern States, prepared for EPA, PB 81-240319, May 1981.
162 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table A-5.—Average SO2 Emission Reductions and Emission Rate Potentials for

Coal From Eight States (1979 data)

Average emission

reduction using Average Number of

physically cleaned coala

emission potential washability

Region and State (percent) (lb SO,/MMBtu) samples -

Northern Appalachia

Pennsylvania . . . . . . . . . . . . . . 33.2 4.0 170

Ohio . . . . . . . . . . . . . . . . . . . . . . 25.9 5.8 90

Northern West Virginia. . . . . . 28.9 4.9 30

Southern Appalachia:

Southern West Virginia . . . . . 10.1 1.4 16

Virginia . . . . . . . . . . . . . . . . . . . 7.6 1.1 8

Eastern Kentucky . . . . . . . . . . 15.9 2.3 13

Eastern Midwest:

Western Kentucky . . . . . . . . . . 31.5 6.6 37

Indiana. . . . . . . . . . . . . . . . . . . . 26.4 5.9 21

Illinois . . . . . . . . . . . . . . . . . . . . 29.3 6.6 40

Alabama . . . . . . . . . . . . . . . . . . . . 10.8 2.0 10

%Coal crushed to 1/12 inch top size and separated at 1.6 specific gravity.

SOURCE: Versar, Inc., Coal Resources and Sulfur Regulations: A Survey of Eight Eastern and Midwestern States, prepared

for EPA, PB 81-240319, May 1981.

Table A.6.—Typical Cost Effectiveness of Additional Coal Cleaning for Eight Eastern and Midwestern States

Additional annual Levelized cost Cost effectiveness

SO2 reduction of cleaning (1982 $/ton SO2 removed)

Region and State 1 0

3 ton Percent (1982 $/clean ton) Without benefits With benefits

Northern Appalachia:

Pennsylvania . . . . . . . . . . . . . . . . . . . . . 450 24 $6.90 $476 $301

Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . 720 27 8.36 369 233

Northern West Virginia . . . . . . . . . . . . 250 15 6.70 564 398

Eastern Midwest:

Western Kentucky . . . . . . . . . . . . . . . . 530 20 5.44 243 101

Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . 170 12 3.79 224 49

Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . 210 5 5.64 330 155

Southern Appalachia:

Southern West Virginia . . . . . . . . . . . . — O 6.70

Virginia. . . . . . . . . . . . . . . . . . . . . . , . . . — O

c c

7,09

Eastern Kentucky . . . . . . . . . . . . . . . . . 150 8.45 991 680

Alabama . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 1 5 6.51 845 437

Eight-State total/averaged . . . . . . . . . . 2,545 16 6.56 505 294

aOver current practice.

bOf raw coal.

cThese coals typically have a cost effectiveness exceeding $3,000/ton

dAverages do not include States where insufficient data are given.

SOURCE: U.S. Environmental Protection Agency, draft memorandum, Coal Cleaning Background Paper, May 19, 1963. (Note: this memo has not been formally released

by the U.S. Environmental Protection Agency and should not be construed to represent Agency policy.)

plants is estimated to yield a 1.5-million-ton reduction

in S02 emissions (about 7 percent of total SO2 emissions

in the Eastern United States) at an average annual cost

of $870 million, or $580/ton of SO2 removed. 13 This

study does not account for the emissions reductions or

costs of coal used by these utilities that is currently being

cleaned.

Coal cleaning has several benefits in addition to reduced SO2 emissions. First, cleaning reduces the ash

content of coal, reducing ash disposal requirements at

I JpE~~O, Op cit. , May 1981

the power facility. Second, the removal of impurities

(sulfur, ash, and others) increases the “heating value”

(energy per unit of weight) of coal, Increased heating

value reduces coal transportation costs and pulverization

requirements at the plant. Finally, because cleaning

creates a fuel with more uniform characteristics (e. g.;

ash, moisture, sulfur, and energy content), increased

efficiency of boiler operation is possible. 14 These benefits

1~Eng,~eeri~g/&Ono~iC An~yS~ of Coal Preparation with SOZ cleanup

Processes, U S. Environmental Protection Agency, EPA-600/7 -78-O02, January

1978; see also, Cost Benefits Associated With the Use of Physically Cleaned

CoaJ, prepared by PEDCO, EPA-600/7-80-105, May 1981,
.

App. A—Emissions and the Costs of Control ● 163

can in many instances offset a large portion of the costs

of coal cleaning.

Physical coal cleaning may produce a substantial

amount of solid waste. The cleaning process causes approximately one-fourth of the mined material to be

discarded as waste. 15 Moreover, some coal (approximately 5 to 10 percent of the energy value) is lost in

the process of removing impurities. 16

Chemical Coal Cleaning.—Chemical coal cleaning

can remove higher percentages of sulfur contained in

coal because it can in some cases remove organic as well

as pyritic sulfur. These processes, however, have only

been successfully operated at the laboratory scale, and

are estimated to be 5 to 10 years away from commercial

viability. Chemical coal-cleaning processes vary widely

from relatively simple methods that use chemical solutions to leach sulfur and other impurities out of coal,

to processes such as solvent-refined coal, which alters

the characteristics of coal so much that it is usually considered a coal-conversion process. 1

7

Two of the chemical coal-cleaning processes receiving

the greatest amounts of current research attention are

the Meyers process and microwave desuIfurization. The

Meyers process, developed by TRW, Inc., is a chemical leaching process that combines coal with a ferric

sulfate or sulfuric acid solution to remove sulfur. This

process can remove 80 to 99 percent of the pyritic sulfur

in coal (larger removal efficiencies than physical coal

cleaning), but cannot remove organic sulfur. 18

One of the several coal-cleaning processes that remove

organic as well as pyritic sulfur is microwave desulfurization. Developed by General Electric, this process

begins by wetting crushed coal with a sodium hydroxide

solution; the mixture is then briefly irradiated with

microwave energy. During irradiation, the sodium hydroxide reacts with pyritic and organic sulfur to form

sodium sulfide. The coal is immersed in water to remove

the sulfur-laden sodium sulfide, and the process is repeated again. Laboratory tests have achieved total sulfur

removals in excess of 90 percent. 19

Because chemical coal-cleaning techniques are in the

early stages of development, costs are difficult to estimate. It is not yet clear whether chemical coal cleaning

will be economically competitive with flue-gas desulfurization (described under “Postcombustion Approaches’ in the future. Chemical coal cleaning can

be expected to produce the same side effects-waste disposal requirements, removal of ash and other impurities,

increased heating value, and improved boiler efficiency— as physical coal cleaning.

OIL DESULFURIZATION

Oil desulfurization is a widely applied method for reducing SO2 emissions. The primary method is called

hydrodesulfurization; oil is treated with hydrogen, which

partially removes the sulfur by combining with it to form

hydrogen sulfide gas. Oil is first distilled to separate the

crude into various petroleum products. Most of the sulfur concentrates in the heavier residues. The lighter fractions, or distillate, are redistilled under a vacuum. In

one variant of hydrodesulfurization, referred to as the

indirect method, the second distillate is hydrotreated

(i.e., reacted with hydrogen) to remove the sulfur as hydrogen sulfide gas. The product is reblended with the

vacuum residue to yield low-sulfur fuel oil. This method

can reduce the sulfur content by 30 to 42 percent. 20

In another variation of hydrodesulfurization, referred

to as the direct method, the residue from distillation is

hydrotreated, and then reblended with the distillate to

form a lower sulfur fuel, or both the residue and distillate

from vacuum distillation are separately hydrotreated before relending. This technique can achieve a degree

of desulfurization as high as 70 to 90 percent, but is not

yet commercially available. Indirect hydrodesulfurization is presently the predominant method for producing low-sulfur (less than 1 percent sulfur) fuel oil from

high-sulfur crudes. Both the indirect and direct methods are similar to coal cleaning in that the higher the

degree of desulfurization, the higher the costs. Estimated

costs for desulfurizing oil containing 3-percent sulfur

content to 1 -percent sulfur content, range from $17 to

$40/ton in 1980 prices, depending on the choice of process.

21

Disadvantages of hydrodesulfurization are the high

investment and operating costs, and the high energy requirements. Since fuel oil combustion is not expected

to increase significantly in the United States, the present desulfurization capacity is expected to remain at

current levels for the near future.

Combustion Alteration Approaches

LIMESTONE INJECTION

MULTISTAGE BURNER (LIMB)

Many in the United States consider the LIMB to be

one of the most promising control technologies under

development today. The technique controls both SO2

‘{’N Elarn dnd “1’ri{ hcn C:{)n$ultan[s, I.td , Prt,*t,n( <iIl[i fi’ull)re I.(,\ (,1$ ()!

.Su//ur I)IuYIdr Enussions In N“or[bern Europe. Swedish Nfintstr), ,Junc 1‘)70

~ I Ron ]ont.~, ~mr( Ior, ~;nilronmt,r]l~ Aff’airs, knt.n( an ~~trol~’~~m 1r]st 1t[ltc’,

11’,ishln~t[)n, D C , personal t (~rnmunlc atlon
164 Acid Rain and Transported Air Pollutants: Implications for Public Policy

and NOX emissions. The LIMB is based on the use of

staged burner techniques for NOX control, in combination with sorbent (normally limestone) which is injected

through the burners for SO2 control. SO2 reacts with

the limestone to form solid calcium sulfate.

This technology is still under development; its removal efficiencies and costs are very uncertain at this time.

Planning goals established by EPA set objectives of 50

to 70 percent removal of SO2 and NOX

, at a capital

cost of $30 to $40/kW.22 If these goals are achieved, the

LIMB would offer substantial cost improvements over

existing technologies. It is very possible that the LIMB,

because it may be retrofitted into existing plants at a

competitive cost, may emerge as a particularly attractive control technology option. However, EPA plans to

limit the LIMB research program to basic bench- and

large pilot-scale R&D through 1985, since funding is

unavailable for Government sponsorship of a full-scale

demonstration at this time.23

FLUIDIZED BED COMBUSTION

Another technique that removes SO2 during the combustion process is fluidized bed combustion. For this

process, crushed coal is fed into a bed of inert ash mixed

with limestone or dolomite. The bed is held in suspension (’ ‘fluidized’ by the injection of air from the bottom of the bed. SO2, formed during combustion, reacts

with the limestone or dolomite to form solid calcium sulfate, which can be removed from the boiler without interrupting the combustion process.

Fluidized bed combustion can remove up to 90 percent of the SO2

. Available estimates, though preliminary, show the cost effectiveness of fluidized bed

combustion to be about equal to conventional boilers

using flue-gas desulfurization. 24 Further research is still

needed before large-scale use could be justified; however, for small facilities (up to 250 MW), fluidized bed

combustion is a feasible method today. Oil may also be

burned in a fluidized bed, but no such plant is yet in

operation.

Aside from lower emissions, fluidized bed boilers have

the advantages of greater energy efficiency, lower combustion temperatures keeping the formation of nitrogen

oxides down, and smaller boiler size. Fluidized bed boilers can burn both high- and low-sulfur coals.

“James Abbott and Blalr Martin, U S Fmwronmtmtd Prott-[twn Agenc},

Research Triangle Park, N C , personal communwatmn

“Julian Jones, U S En\ironmtmtal Protectwn Agency, Research “1’rianglc

Park, persona] c ommunic atmn

~~~~[)rk C,rc]up ~B. ~P. c ‘t

Postcombustion Approaches

FLUE-GAS DESULFURIZATION

Flue-gas desulfurization (FGD) technology removes

the SO2 produced during combustion by spraying the

exhaust gases in the stack with a chemical absorbent,

typically lime or limestone. This process is popularly

referred to as ‘‘scrubbing. Of the three types of FGD

systems—wet, dry, and regenerable—wet processes are

most widely used. Presently there are over 100 scrubbers using all three methods in operation in the United

States.

WET SCRUBBERS

The most common absorbents used for wet scrubbing

are lime and limestone. The absorbent is dissolved or

suspended in water to form a slurry that can then be

sprayed or forced into contact with escaping gases. The

slurry converts SO2 into calcium sulfite and calcium sulfate (gypsum) solids. Limestone scrubbing is the simplest, cheapest, and most developed SO2 wet-removal

process available.

Technology to wet-scrub the flue gas with a lime or

limestone slurry has been commercially available for

about 10 years. As of March 1981, 5.1 percent of installed generating capacity (and 14 percent of coal-fired

capacity) was controlled by wet scrubbers. By 1990, the

figure is projected to increase to 9.4 percent of installed

capacity .25

Wet lime or limestone scrubbers can remove between

70 to 90 percent of the SO2 formed during combustion.

With the addition of another chemical--adipic acid—removal efficiencies can be increased to 95 percent, while

limestone requirements can be reduced by up to 15 percent. 26 However, adipic acid additives may present additional sludge disposal problems.

A Tennessee Valley Authority (TVA) study conducted in 1980 estimated the capital costs of a wet limestone system using low-sulfur Western coal (O. 7 percent

sulfur, 9,700 Btu/lb) to be $168 to $176/kW. For highsulfur Eastern coal (3. 5 percent sulfur, 11,700 Btu/lb)

capital costs range from $236 to $244/kW. These estimates are based on costs for a new 500-MW plant, operating at a 63-percent lifetime capacity. The range in cost

estimates is due to variations in bids from different con-

)s~l s F.n,.lronrrlenta] Protrx tmn Agcncv.

‘‘ EPA Ullllty F(; D Survt.) (1 -

tokJcr-December 1980, EPA-600/7-81 -O12b, ,January 1981,

~f’~1 S En%lrc)nmcnta] prote( tlon Agency, Researx h .$urnrrldr)’ (:on(rO//lnLq

SO~, oflic c of Rewarch and Development, Augu\t 1980
App. A—Emissions and the Costs of Control ● 165

tractors and the specific considerations for each site.

Annual revenue requirements from the TVA study

range from 10.5 to 10.9 mills/kWh for low-sulfur coal

and 16.4 to 16.7 mills/kWh for high-sulfur coal. 27

The annual revenue requirements for FGD units

depend on several factors, including coal sulfur content,

size of the unit, age of the plant, and desired percentage reduction. The costs per ton of sulfur dioxide removed by scrubbers rise steeply as the uncontrolled

emission rate drops. For example, removing 90 percent

of the sulfur from a coal emitting 2 lb of sulfur dioxide

per million Btu is about 75 percent more expensive (on

a dollar/ton basis) than scrubbing a 4 lb/million Btu coal

for the same size unit. Likewise, scrubbing a 1 lb/million Btu coal is about 75 percent (or more) costlier than

scrubbing a 2 lb/million Btu coal in a similar unit.

Costs for retrofitting a scrubber onto an existing plant

depend on the lifespan of the plant; the shorter the remaining lifetime of the plant, the higher the annual revenue requirements to recover the capital costs of the

FGD. Also, because of economies of scale in construction, retrofitting a scrubber onto a larger unit is less expensive than onto smaller ones. Units smaller than about

100 MW are typically quite expensive to retrofit with

scrubbers.

Operating problems associated with wet systems are

corrosion/erosion of metal surfaces, scaling (where hard

sulfate and sulfite deposits form on equipment), and

plugging (where soft deposits form). Ways of minimizing these problems are currently being researched. In

addition, operation of wet scrubbers requires approximately 3 to 5 percent of a plant’s energy output. 28

The major environmental disadvantage of wet FGD

systems is that they produce large amounts of sludge.

Limestone scrubbing produces a compound (mainly calcium sulfite and sulfate) that has the consistency of

toothpaste, making it difficult to dewater, store, and

handle. The total amount of FGD waste produced in

a typical 1,000-MW plant burning 3.5 percent sulfur

coal is about 225,000 tons annually. A recent report concluded that in the future the United States will produce

more sludge from FGD scrubbing than from treating

municipal sewage. 29

Sludge may, however, be chemically treated to reduce its water content and improve its compressive

strength. Forced oxidation converts the waste calcium

sulfite to calcium sulfate, which precipitates as large

crystals with better settling characteristics. Other means

27”1’ A Burnett, et al , ‘ ‘Spray D~er FGD Technical Rewew and Economic

Asscssmen(, ‘‘ “1’ennessee i’alley Authorl[}, presen(ecf a( U S Envwunmental

Pmtertlon Agency Sixth FGD Symposlurn, Houston, ‘1’ex , [)ct 28-31, 1980

‘%’ Ne+lt, ‘‘Scrubhers The Technolog) Nobody W’anted, ” EPR[]o[lrnal, ~ol 7, No 8, October 1982

z9~T s ~nk,lromenta] ~ro[ect Ion Agenc), S’u]ft]r fhf SSIOfl S” ~On~HJl ~’~~ hnolo, q}, and W’astc ~Mana,gemen(, office of Research and Development, Nlav

1982

of improving the sludge’s properties, such as fixation

with lime and fly ash, are still being developed.

Another problem associated with sludge disposal is

the leaching of toxic metals from the residual fly ash into

nearby ecosystems. EPA is currently conducting research on the characteristics of leaching of metal compounds from sludge disposal sites to evaluate the seriousness of the problem .30

DRY PROCESSES OF FGD

Dry scrubbers are a new and fast growing segment

of the FGD market. The process involves injection of

a lime slurry or soda ash solution into a spray dryer concurrently with the flue gas. The lime or sodium carbonate reacts with the SO2 to form a dry, solid product

which is subsequently collected along with the fly ash

in an electrostatic precipitator or fabric falter (baghouse).

Dry scrubbers offer several advantages over wet

scrubbing. Although they generate more waste than wet

systems, they produce a dry waste product that is easier

to handle and recycle than wet sludge, and involve simpler equipment, less maintenance, lower capital costs,

and lower energy requirements. In addition, dry systems require less water than wet systems, and thus are

especially desirable in Western areas of the United States

where water supplies are limited. 31

There are, however, some disadvantages to using a

dry scrubber over a wet system. First, dry systems require lime, which is more expensive than limestone. Second, dry scrubbers are in the early stages of commercialization and have not demonstrated as high a degree

of removal as wet scrubbers. Their use has generally

been limited to medium- and low-sulfur coals. However,

pilot demonstration and commercial plant tests have

shown sulfur removal efficiencies exceeding 90 percent

for high-sulfur coal.

As of October 1983, six dry scrubber systems were

in operation, five at industrial plants, and one at a utility plant generating 430 MW of electricity. Four more

units will be installed on utility boilers in 1984, and approximately 16 units have been ordered for industrial

use.

32 A TVA study estimates that capital costs for dry

FGD systems range from $144 to $ 160/kW for low-sulfur Western coal, and from $180 to $188/kW for highsulfur Eastern coals. Annual revenue requirements are

estimated to range from 8.7 to 9.8 mills/kWh for Western low-sulfur coal, and 14.5 to 14.9 mills/kWh for highsulfur coal. These annual costs are between 10 and 25

percent lower than wet systems, as reported by the same

TVA study. An EPA survey of dry systems sold to util-

~~wOrk Group 3 ~ t ~P Clt.

~ I Ep,4-4 50/3-8 ] -004, Op ~ [t

~ZThecxjc)rt. ~rl=, L“ S F,nvlrc]nm~.mtal Protectmn ,@enc y, Research Tnandc

Park. N (; , pcrwmal comrnunlcatmn
166 Acid Rain and Transported Air Pollutants: Implications for Public Policy

ities, however, suggests that actual capital costs might

be lower. Reported capital costs for these systems range

from $80 to $130/kW.33

EPA is currently conducting research on the use of

other dry injected minerals to be used in place of lime.

If the research results are successful, dry scrubbing costs

could be considerably lower than wet systems.

REGENERABLE PROCESSES

Major research efforts by various Government agencies have gone into regenerable FGD processes, which

reclaim the SO2 in powerplant flue gases using chemicals to produce a marketable product. The major benefit of regenerable control systems is that the captured

sulfur can be sold, avoiding waste-disposal problems

associated with wet and dry processes. Eight regenerable

FGD systems are currently operating in the United

States, accounting for about 8 percent of the total FGDcontrolled electricity generation. The most prominent

regenerable FGD process in use in the United States

is the Wellman-Lord process. It involves scrubbing the

exhaust gas with sodium sulfite solution, resulting in

sodium sulfite-bisulfite, which is then heated to give off

concentrated SO2 gas that can be used to produce either

sulfuric acid or elemental sulfur. This process is already

in use by the New Mexico Public Service Co. One disadvantage of this process is its high ’energy requirements,

which are approximately 8 to 12 percent of boiler energy

input. 34

Other regenerable systems under development are the

Magnesia scrubbing process, which produces sulfuric

acid, and the Rockwell process, which produces sulfur.

Unfortunately regenerable processes cost approximately

30 to 50 percent more than nonrecoverable processes.

Controlling Nitrogen

Oxides Emissions

Oxides of nitrogen are formed during combustion by

two processes. Like sulfur dioxide, NOX are formed as

a result of the oxidation of nitrogen present in the fuel

(“fuel NO,”). NOX are also formed by the oxidation

of nitrogen in the surrounding air (’‘thermal NOX

’ ‘).

Both processes are controlled by the amount of oxygen

present; additionally, the thermal NOX formation is

controlled by temperature. The proportion of thermal

to fuel NO, produced during combustion varies from

fuel to fuel. For coal, the Electric Power Research Institute estimates that 20 to 40 percent of NOX emissions

are ‘ ‘thermal’ and 60 to 80 percent are ‘ ‘fuel. ’35

‘lU .S Environmental Prott’( tmn Agency, ‘ ‘Survey of Dry S0, Control S)slcrns, 11 I, EPA-60017-81-097

3~F:pA.450{3.8 I -004, OP Lit

‘~Ralph W’hltaker, ‘ ‘Trade-offs In NOx Control, EPR1 Journal, to] 7,

N(1 1

NOX emissions, being dependent on the amount of

oxygen present and the temperature of the combustion

process, can be most directly controlled by modifying

combustion conditions. The majority of NOX control

techniques focus on the combustion process. Postcombustion techniques (flue-gas treatment) are also being

developed to achieve even lower emission rates. Today

the two most promising combustion technologies for reducing NOX emissions are certain types of fluidized bed

combustion units, for plants up to 250 MW, and the

low-NO X burner. One precombustion technique, the

denitrogenation of fuel oil, is being researched, but will

not be discussed because of its early stage of development and limited potential.

Combustion Modifications

Thermal NOX formation can be minimized by regulating the combustion temperature through delayed

mixing of fuel and air in the combustion chamber. Limiting fuel NOx, is somewhat different, requiring control

of the fuel-air ratio throughout the entire combustion

process. Two of the major techniques used in combustion modification, low excess air (LEA) and low-NOX

burners, are presented below. Other combustion modification techniques include: staged combustion (offstoichiometric firing), overfire air, flue-gas recirculation,

low air preheat, and water injection.36

LEA involves reducing the combustion air to the minimum amount required for total combustion. Thus, less

oxygen is available for the formation of both thermal

and fuel NOX

. LEA requires no new hardware and can

achieve emissions reductions merely through changes

in operating practices. Also, the reduced airflow can

improve boiler efficiency.

The second-generation, low-NOX burners under development, which employ a staged combustion process,

have been shown to significantly reduce the formation

of both fuel and thermal NOX in experimental systems

and limited boiler applications. During the first stage

of combustion, less air is supplied to the burner than

is required to completely burn the fuel. Fuel-bound nitrogen is then released—but as nitrogen gas, because

it cannot be oxidized. The subsequent addition of air

causes the remaining fuel to be burned.

The amount by which NOX emissions can be reduced depends on very site-specific factors, including

the type of fuel burned, the type of boiler in use, and

the age of the plant. Installed on an existing coal-fired

plant which does not control NOx emissions, the lowNOX burner can reduce NOx emissions by as much as

50 percent. Potential NOx emissions reductions from

retrofitting an oil-fired burner range from 60 to 80 percent. 37

16A,] An& J,sis ~)f.tht. & Onornic In< ~.nll~.t.s 7’0 Control Emwions [)1’~Vllrw(.n

(1).wies From .Stafionari %ur(es, EPA-WO/7-79- 178[, .Jarruar} 1981, p A’}.

~zF,pA.600/7.7Cj.” 178!. OP ( it
App. A—Emissions and the Costs of Control ● 167

The low-NOX burner can achieve emissions reduction at relatively low cost. Capital costs for coal-fired

plants are approximately $1 to $5/kW if integrated into

new boilers, and $2 to $10/kW if retrofitted onto existing

plants .38

Potential problems such as corrosion and high maintenance requirements could delay large-scale use of the

low-NOX burner. Retrofitting old boilers can be difficult, but NOX controls on new boilers can be made an

integral part of boiler design without adding substantially to cost.

Another combustion modification approach for the

control of NOX is the LIMB, which is discussed in

further detail in the section on combustion alteration

approaches for SO2. EPA research goals for the LIMB

are to achieve a 50- to 70-percent removal of SO2 and

NOx, at a cost of $30 to $40/kW; however, the LIMB

is not expected to be commercially available for about

3 to 5 years.39

Postcombustion Approaches

FLUE-GAS TREATMENT

Flue-gas treatment (FGT) is an emerging postcombustion process for high levels of NOX removal. FGT

‘S II)I(l

“,]amu Abbott and Blalr \lartln, L“ S En\lronmen[al Prote( tlon Agency,

Rrw~r( h ‘1’rlanqlc Park, N (; , person<~] cornrnunicatlon

has been developed and applied extensively in Japan

for use on oil-fired boilers. But due to its operational

complexities and high costs for use on coal-fired boilers,

FGT has not become as popular as the low-NOX

burner in the United States.

At least 50 different types of FGT technologies are

available today. Of these, selective catalytic reduction

(SCR) achieves the highest reductions. SCR is a dry

process, produces no solid waste, and in most cases can

be retrofitted to existing burners. In SCR, flue gases

are mixed with ammonia and then passed over a catalyst. The catalyst assists in the reaction of ammonia and

NOx to form nitrogen gas and water vapor. While 90-

percent NOX removal during combustion is possible,

80-percent removal is preferable in order to minimize

capital and operating costs and maximize the burners’

reliability and lifespan. One estimate places the costs

of FGT at between $75 and $100/kW for a 60- to 80-percent reduction in NOX emissions .40

Two problems associated with SCR are the disposal

of spent catalysts, such as vanadium and titanium, and

the condensation of bisulfate and bisulfite residuals onto

equipment .41

~OEpRI Journal, op. ~~t

“j D. Moble), Assessment of NO~ F-Iuc Gas Trc>amwrl ‘1’elhrr(Jw. ~T s

Enwronmental Protection Agem ), Research Triangle Park, prmmrted al S} nposlum nf Stationary Combustion NO, Control, Denwr, Colo , (1 tober 1980

A.3 ALLOCATION OF SULFUR DIOXIDE EMISSIONS

REDUCTIONS AND THE COSTS OF CONTROL

Introduction

The costs and distributional consequences of various

control strategies are important factors in decisions

about controlling transported air pollutants. Costs are

affected both by the amount of emissions to be eliminated, and by the manner in which emissions reductions are to be achieved. For a given emissions reduction strategy, the greater the reduction, the greater the

cost. For a given emissions reduction target, alternative

implementation strategies may entail different costs, i.e. ,

one strategy may be more cost effective than another.

Alternative control strategies may also have different

distributional consequences. Certain approaches assign

a greater share of the emissions reduction burden to one

region or State or economic sector than to others. This

section examines the costs and distributional consequences of various emissions reduction strategies, concentrating on emissions reductions in the Eastern 31-

State region. Due to analytical limitations, only the

costs of reducing sulfur dioxide (SO2) emissions from

utilities are presented.

SO2 emissions for 1980 are estimated to be about 26

million tons nationwide and about 22 million tons in

the Eastern 31 States. Fossil fuel combustion by electric utilities accounts for about 17 million tons or 65 percent of the national total. In the Eastern 31 States, utilities produce 70 percent of the regional SO2 emissions,

or about 16 million tons. Under current regulations,

EPA-approved State implementation plans (SIPS) require utilities to reduce these emissions by approximately 1 million tons.

OTA has estimated the cost of further reducing utility SO2 emissions in the 31 -State region below the SIP99-413 0 - 84 - 12 : QL . 3
168. Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure A-5.—Comparison of Utility SO2 Control Costs

SO2 reductions (million tons/year, after SIP compliance)

SOURCE: Office of Technology Assessment from references listed in text.

compliance level under several different control strategies. The model used in generating these estimates is

described briefly at the end of this section. *

The Costs of Various Levels

of Emissions Reductions

To illustrate how the extent of emissions reductions

affects the costs of controlling emissions, figure A-5

displays estimates of 31-State aggregate control costs

● This analysis uses the AIRC;OSrI” model, run by E. H. Pechan & Assrxiates,

Inc AI RCOST was modified from a larger model used in several earlier major

assessments, including the New Source Performance Standards (NSPS) review,

the Obio River Basin Fmergy Study (OR BES), and tbe Acid Rain M ltigatlon

Study (ARMS)

made by OTA and several other groups. * * Costs are

presented for reducing SO2 emissions from utilities only,

and are in 1982 dollars. To reduce emissions by approximately 5 million tons beyond SIP compliance, the vari-

“ “Most uf tbese cost estimates are cited in ‘ ‘Costs TO Redu( e Sulfur D]-

oxide Emwons,” Department of Energy, DOE/PE-0042, 1!%2. DOE adjusted

each estimate using consistent economic assumptions, Cost esttmates are also

included from: “Summary of Acid Rain Analyses LTndertaken by ICF for the

E[fison Electric Insltute, Nation~ W’i]d]lfe Federation, and Envir(Jnment~ pro.

tectlon Agency, prepared by ICF,In{,, for the Edison Electric Institute, 1982;

and Chris Farrand, Peabody Coal Co , test imony before the Senate Environment and Public Works Committee, October 1981. O’I’A estimates are bdsr’cf

on analyses prepared by E H Pec han & Associates, Inc. , 1983. The PEDCO

study was preparmf for DOE, the Teknekron anal)sls was prepared for EPA

and DOF., and the ICF analyses were performed for EPA, DO F., the E{ilsors

Electric Institute, and the National Wildlife Federation C)”I’A’s estimates are

preseoteci as the costs of’ reductions beyond SIP compliance. “1’he Peabody,

PIIDC(j, and DOE estimates are reductions below actual 1980 cmlssinns, amf

tbe ICF and Teknekron model est irnates are displayed as emissions redu( t Ions

below proie[ ted 1990 crmssions levels
App. A—Emissions and the Costs of Control . 169

ous estimated annual costs range from about $1 to $2

billion per year. For reductions of 8 million tons beyond

SIP compliance (about 55 to 60 percent below current

utility emissions), the range increases to $2 to $3.5 billion annually. The largest emissions reduction calculated—a 13-million-ton reduction below projected 1990

levels— is estimated to cost approximately $7 billion per

year.

Table A-7 displays OTA’s control cost estimates for

a series of emission rate limitations ranging from 0.8

to 2.5 lb of SO2 emitted per million Btu (MMBtu) of

fuel burned. Eastern 31 -State emissions reductions

range from 4.6 million to 11.4 million tons per year,

including reductions already required under current

law. However, the costs presented consider only those

reductions that would be required beyond SIP compliance.

For each emission rate limitation, two sets of cost estimates are presented. The cost estimates in the top half

of the table assume that each utility chooses the least

expensive control method among those applicable to

plant conditions. This typically results in a statewide

mix of coal washing, switching to (or blending with) lower sulfur fuels, and wet and dry scrubbers. Cost estimates presented in the bottom half of table A-7 assume

that the legislation mandates the use of pollution control technologies such as wet scrubbers. Several recent

bills have included such a control technology restriction

to minimize job dislocations among high-sulfur coal

miners. (Section A.5 of app. A discusses the magnitude

of potential coal production and related employment

changes due to acid rain control legislation. )

As expected, costs increase as emissions reduction requirements increase. As shown in the top-half of table

A-7, the ‘ ‘least-cost’ method of control ranges from less

than $1 billion annually to eliminate less than about 5

million tons per year, to between $4 and $5 billion to

eliminate 11.4 million tons. * Moreover, the marginal

costs of control increase when larger emissions rollbacks

are required. That is, the cost of eliminating an additional 1 million tons of SO2 per year is greater for an

increase from 8 million to 9 million tons (approximately $700 million per year) than for an equal increase from

7 million to 8 million tons (approximately $450 million

per year).

As shown in the bottom half of table A-7, mandating

the use of control technology to achieve all required

emissions reductions increases the cost of control. For

emissions reductions in the range of 5 million tons per

year, such a requirement about doubles control costs.

For greater levels of emissions reductions (9 million to

“All { ost cstlmatcs are first -)eari annualized costs In 1982 {io]ldr~ ( :<ipItal

costs and Interest payments are spread cvenlv o\ cr each ~,t.w of the Ille (If t Ilt,

In\cstmcnt Bec ausc fuel and operation dnd nlaln[enan( t. ( c~it \ ( ~n \ ar) fl on)

vcar to year ( i e . real energy and labor { f)sts might either II]( reaw or [!e( reaw.

over the next two decades), current Iuel anci operation” an(i maln[enancc [ osts

( rather than an atvragc based on assume(i [ren(ii) art, ,i(i(ierit,] [ aplt,d ( (JSIS

t<) { alc uiatc yearl) total cr)nl r(]i costs

Table A-7.—Costs of Reducing SO2 Emissions in the Eastern 31 States (excludes costs to meet current SIPS or to

offset future emissions growth; all costs in 1982 dollars)

A. Assuming each utility chooses the most cost-effective control method:

Emission rate Emissions Average cost Marginal cost

limitation reduction Total cost of reductions of reductions

(lb SO,/MMBtu) (million tons S0,) (billions of dollars/yr) % ($/ton) ($/ton)

2.5 4.6 $0.6-0.9 $170-240 $320

2.0 6.2 1.1-1.5 200-280 440

1.5 8.0 1.8-2.3 260-330 700

1.2 9.3 2.6-3.4 310-400 740

1.0 10.3 3.2.4.1 350-440 830

0.8 11.4 4.2-5.0 400-480 1,320

B. Assuming utilities are required to install control technology (wet scrubbers):

Emission rate Emissions Average Cost Increased costs due to control

Iimitation reduction Total costb

of reductions technology requirement

(lb SO2/MMBtu) (million tons SO2) (billions of dollars/yr) ($/tons) (billions of dollars/yr) (percent increase)

2.5 4.6 1.4 360 0.7 110

2.0 6.2 2.0 380 1.0 90

1.5 8.0 3.1 430 1.2 70

1.2 9.3 4.0 480 1.4 55

1.0 10.3 4.8 510 1.6 50

0.8 11.4 5.9 570 1.8 40

aCost (in dollars per ton) to achieve the next increment of reductions.

bAssumes statewide emissions reductions are from those utility plants that can install scrubbers most cost effectively. Old and Small Units are exempt from the requirement to install scrubbers, but equivalent emissions reductions are obtained from other plants within each State,

cCompared to "least cost’ estimate in part A of this table

SOURCE Office of Technology Assessment, based on analyses by E H. Pechan & Associates, Inc.
170 . Acid Rain and Transposed Air Pollutants: Implications for Public Policy

11 million tons per year), mandating the use of scrubbers increases total control costs by about 50 percent.

State-by-State Emissions Reductions

and Costs of Control Strategies

Thus far, only aggregate, regional control cost estimates have been presented. Costs of control would vary

considerably from State to State, depending on each

State’s emissions reduction requirements, and the costs

of available emissions reductions in each State. The specific control strategy chosen affects both regional costs

and their State-by-State distribution.

Actual State-level costs are determined by: 1) the

amount of reductions allocated to each State, which depends on the chosen control strategy; and 2) the costs

of available emissions reduction opportunities in each

State, which depend on the type and number of electricgenerating plants in service, and their levels of current

emissions. States which already have relatively low utility emissions rates may not have as many opportunities

to use less expensive control options as States with higher

emissions rates. The latter States may be able to achieve

relatively large reductions at lower costs per ton.

Table A-8 presents data on utility SO2 emissions and

electricity generation. The first column displays 1980

utility SO2 emissions by State; the second column ranks

the 30 highest emitting States according to these emissions. States that generate more electricity from fossilfuel-fired utilities would be expected to emit more SO2

(all other factors being equal); thus, columns 3 and 4

present 1980 fossil-fuel-generated electricity and corresponding rank for the top 30 States. The last two columns present average SO2 emissions rates—the quantity of SO2 emitted per million Btu of fuel burned, and

the corresponding rank of States with average utility

emissions rates greater than or equal to 1.2 lb/MMBtu.

In general, the higher the emissions rate, the greater

the opportunity for reducing emissions and the lower

the cost per ton of SO2 removed.

However, statewide average emissions rates mask the

variation among plants within a given State. Table A9 examines the potential for reducing utility SO2 emissions in each State in greater detail. The table displays

the percentage of utility emissions that could be eliminated by mandating various emissions rate limitations,

ranging from 1.0 to 4.0 lb of SO2 per million Btu of

fuel burned. These estimates are calculated by assuming no facility may exceed the specified emissions rate.

Table A-10 displays the average cost, in dollars per

tons of SO2 removed, for reducing utility SO2 emissions

by 50 percent in each of the Eastern 31 States. While

much of the State-level variation is due to differences

in emissions rates, considerable variation results from

such other factors as distance from low-sulfur coal supplies, dependence on oil, and size and age of the utility

plants.

Comparison of Alternative Approaches

to Emissions Reductions

OTA has analyzed a number of approaches to allocating an 8-million-ton reduction of utility SO2 emissions among the Eastern 31 States. The regional costs

and distributional consequences of eight different allocation formulae—in terms of the reductions allocated to

each State and the cost of achieving those allocated reductions —are discussed below.

Table A-11 presents the overall cost of these eight alternative allocation approaches for the 31 -State region.

The costs are shown to range from a low of $1.8 billion

to $2.3 billion per year for reductions based on a maximum emissions rate (1. 5 lb of SO2 per MMBtu) to a

high of $3.7 billion to $3.9 billion per year for an allocation formula based on total SO2 emissions per land area.

Each approach eliminates about 8 million tons of SO2

per year; future emissions growth—estimated to be

about 1 million to 2.5 million tons per year by 1995—

is not offset. Cost to achieve emissions reductions

already required under current regulations (SIPS) are

not included.

Table A-12 shows the State-by-State emissions reductions required under each allocation approach; table

A-13 estimates State-average control costs, expressed as

a percentage of residential electricity costs. Some States

are consistently allocated relatively large costs— in particular, Georgia, Indiana, Kentucky, Missouri, New

Hampshire, Ohio, Pennsylvania, and West Virginia.

For other States—e. g., Delaware, New Jersey, and

Rhode Island—control costs are strongly influenced by

the allocation approach used. The approaches that allocate the widest State-by-State variations in required

emissions reductions—e. g., those based on emissions

per person or land area—cause State-level costs to vary

a great deal. In these cases, some States are allocated

very large costs and others incur no costs at all.

These estimates illustrate that both the regional and

State-by-State costs of control depend on the way in

which emissions reductions are allocated to States.

Therefore, the choice of allocation policy involves both

the political issue of who should bear the burden of reducing emissions as well as the national economic issue

of total cost.

A later section of’ this appendix (A.4) discusses an alternative method of allocating control costs. A trust fund

based on a tax on emissions or electricity generation

could be established to help pay for part of the costs of
App. A—Emissions and the Costs of Control 171

Table A-8.—Fossil-Fuel-Fired Electric Utilities: S02 Emissions, Electricity Generated,

Average S02 Emission Rate, 1980

Electricity generation

Utility S02 emissions (fossil-fuel-fired) S02 emission rate

State 103 tons/yr Rank (top 30) 109 kWh/yr Rank (top 30) lb/MMBtu Rank (top 30)

Alabama . . . . . . . . . . . . . . . . 543.1

Alaska. . . . . . . . . . . . . . . . . . 11.7

Arizona . . . . . . . . . . . . . . . . . 87.5

Arkansas . . . . . . . . . . . . . . . 26.6

California . . . . . . . . . . . . . . . 77.9

Colorado. . . . . . . . . . . . . . . . 77.5

Connecticut . . . . . . . . . . . . . 32.1

Delaware . . . . . . . . . . . . . . . 52.5

District of Columbia. . . . . . 4.6

Florida . . . . . . . . . . . . . . . . . 725.9

Georgia. . . . . . . . . . . . . . . . . 736.7

Hawaii . . . . . . . . . . . . . . . . . . 41.6

Idaho. . . . . . . . . . . . . . . . . . . 0,0

Illinois. . . . . . . . . . . . . . . . . . 1,125.6

Indiana , . . . . . . . . . . . . . . . . 1,539.6

lowa . . . . . . . . . . . . . . . . . . . 231.3

Kansas . . . . . . . . . . . . . . . . . 150.1

Kentucky . . . . . . . . . . . . . . . 1,007.5

Louisiana . . . . . . . . . . . . . . . 24.8

Maine . . . . . . . . . . . . . . . . . . 16.3

Maryland . . . . . . . . . . . . . . . . 223.2

Massachusetts . . . . . . . . . . 275.5

Michigan . . . . . . . . . . . . . . . 565.4

Minnesota . . . . . . . . . . . . . . 177.4

Mississippi, . . . . . . . . . . . . . 129.2

Missouri . . . . . . . . . . . . . . . . 1,140,5

Montana . . . . . . . . . . . . . . . . 23.4

Nebraska . . . . . . . . . . . . . . . 49.5

Nevada . . . . . . . . . . . . . . . . . 39.5

New Hampshire . . . . . . . . . 80.5

New Jersey . . . . . . . . . . . . . 110.2

New Mexico . . . . . . . . . . . . . 84.6

New York . . . . . . . . . . . . . . . 480.3

North Carolina . . . . . . . . . . . 435.4

North Dakota . . . . . . . . . . . . 82.5

Ohio . . . . . . . . . . . . . . . . . . . 2,171.6

Oklahoma . . . . . . . . . . . . . . . 37.7

Oregon . . . . . . . . . . . . . . . . . 3.3

Pennsylvania . . . . . . . . . . . . 1,466.1

Rhode Island . . . . . . . . . . . . 5.2

South Carolina . . . . . . . . . . 213.1

South Dakota . . . . . . . . . . . . 28.6

Tennessee . . . . . . . . . . . . . . 933.7

Texas . . . . . . . . . . . . . . . . . . 302.8

Utah . . . . . . . . . . . . . . . . . . . 22.1

Vermont . . . . . . . . . . . . . . . . 0.5

Virginia . . . . . . . . . . . . . . . . . 163.7

Washington . . . . . . . . . . . . . 69.4

West Virginia. . . . . . . . . . . . 944,2

Wisconsin . . . . . . . . . . . . . . 485.7

Wyoming . . . . . . . . . . . . . . . 120.9

National totals . . . . . . . . . 17.378.5

12

27

10

9

5

2

18

23

6

19

17

11

21

24

4

30

26

28

14

15

29

1

3

20

8

16

22

7

13

25

45.4

2.6

27.0

10.2

89.6

21.2

12.6

6.7

0.7

79.0

50.5

6.5

0.0

75.7

70.1

18.3

25.1

54.2

45.8

2.1

20.0

31.6

57.9

21.0

18.5

48.4

5.5

9.3

11.7

5.1

22.1

24.6

63.2

60.8

11.8

108.1

43.3

0.8

109.7

1.0

21.5

2.8

51.0

201.9

11.3

0.0

21.9

7.3

70,4

26.0

22.8

1.754.4

17

20

4

28

5

14

6

8

22

12

16

30

19

11

29

15

27

23

9

10

3

18

2

26

13

1

25

7

21

24

2.3

0.6

0.6

0.5

0.2

0.7

0.5

1.5

1.0

1.7

2.9

1.2

0.0

2.7

4.2

2.2

1.0

3.6

0.1

1.4

2.1

1.8

1.8

1.5

1.3

4.5

0.7

1.0

0.6

2.9

0.9

0.6

1.4

1.5

1.2

3.8

0.2

0.7

2.5

1.0

1.9

1.7

3.7

0.3

0.4

1.2

1.4

1.7

2.7

3.4

1.0

1.9

12

21

18

7

28

9

2

13

5

24

14

16

16

21

27

7

24

21

28

3

11

15

18

4

28

24

18

9

6

SOURCE: E. H. Pechan &. Associates, inc., ’’Estimates of Sulfur Oxide Emissions From the Electric Utility Industry;’ prepared for the Environmental Protection Agency, 1982,
172 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table A-9.-SO2 Emission Reductions Achieved by Emission Rate Limitations

(percent reduction in 1980 utility SO2 emissions)

SO2 emissions Percent reduction with emission limit (lb SO2/MMBtu)

State (103 tons) 1.0 1.2 1.5 2.0 2.5 3.0 4.0

Alabama. . . . . . . . . . . . . . . . . . . . . . . . . . .

Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Arizona. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Arkansas . . . . . . . . . . . . . . . . . . . . . . . . . .

California. . . . . . . . . . . . . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . . . . . . . . . . . . .

Connecticut . . . . . . . . . . . . . . . . . . . . . . .

Delaware . . . . . . . . . . . . . . . . . . . . . . . . . .

District of Columbia . . . . . . . . . . . . . . . .

Florida . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hawaii . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Idaho . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . . .

lowa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Kansas . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Kentucky . . . . . . . . . . . . . . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . . . . . . . . . . . . . . .

Maine ............,.. . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . . . . . . . . . . . . . .

Massachusetts . . . . . . . . . . . . . . . . . . . . .

Michigan . . . . . . . . . . . . . . . . . . . . . . . . . .

Minnesota . . . . . . . . . . . . . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . . . . . . . . . . . . .

Missouri . . . . . . . . . . . . . . . . . . . . . . . . . . .

Montana . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nebraska . . . . . . . . . . . . . . . . . . . . . . . . . .

Nevada . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Hampshire . . . . . . . . . . . . . . . . . . . .

New Jersey . . . . . . . . . . . . . . . . . . . . . . . .

New Mexico . . . . . . . . . . . . . . . . . . . . . . .

New York . . . . . . . . . . . . . . . . . . . . . . . . . .

North Carolina . . . . . . . . . . . . . . . . . . . . .

North Dakota . . . . . . . . . . . . . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Oklahoma . . . . . . . . . . . . . . . . . . . . . . . . .

Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pennsylvania . . . . . . . . . . . . . . . . . . . . . . .

Rhode island . . . . . . . . . . . . . . . . . . . . . . .

South Carolina . . . . . . . . . . . . . . . . . . . . .

South Dakota . . . . . . . . . . . . . . . . . . . . . .

Tennessee . . . . . . . . . . . . . . . . . . . . . . . . .

Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vermont . . . . . . . . . . . . . . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . .

Washington . . . . . . . . . . . . . . . . . . . . . . . .

West Virginia . . . . . . . . . . . . . . . . . . . . . .

Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . .

Wyoming . . . . . . . . . . . . . . . . . . . . . . . . . .

United States . . . . . . . . . . . . . . . . . . . .

543

12

88

27

78

77

32

52

5

726

737

42

0

1,126

1,540

231

150

1,008

25

16

223

276

565

177

129

1,141

23

49

39

80

110

85

480

435

82

2,172

38

3

1,466

5

213

29

934

303

22

1

164

69

944

486

121

17,379

57

51

0

5

0

1

0

37

0

50

65

31

3

67

76

58

53

72

0

29

54

44

48

42

58

78

11

21

0

65

37

13

51

32

24

74

0

0

62

0

50

40

73

10

0

17

27

41

64

72

11

61

49

44

0

2

0

0

0

30

0

44

58

22

0

63

72

51

47

66

0

15

46

36

39

34

53

74

6

14

58

32

0

44

19

13

69

0

0

55

0

42

29

67

4

0

5

15

29

57

67

6

55

38

37

0

0

0

0

0

20

0

34

48

9

0

58

66

47

38

58

0

9

35

24

31

25

45

68

0

5

0

48

24

0

34

4

3

62

0

0

45

30

13

59

0

0

0

4

12

50

60

1

47

24

25

0

0

0

0

0

7

0

23

32

0

0

50

55

39

23

45

0

4

18

6

20

32

59

0

0

0

30

17

0

18

0

0

51

0

0

30

0

12

0

49

0

0

0

0

0

39

50

0

36

11

12

0

0

0

0

0

0

0

16

17

0

0

42

45

31

8

36

0

0

4

0

10

5

19

51

0

0

0

20

11

0

8

0

0

41

0

0

17

0

2

0

40

0

0

0

0

0

29

40

0

27

0

o

0

0

0

0

0

0

10

6

0

0

34

35

24

28

o

0

0

0

1

0

9

43

0

0

0

11

6

0

3

0

0

32

0

0

8

0

0

0

30

0

0

0

0

0

19

31

0

19

o

0

0

0

0

0

0

0

0

3

0

0

0

20

19

12

0

15

0

0

0

0

0

0

0

28

0

0

0

0

0

0

0

0

0

19

0

0

0

0

0

0

16

0

0

0

0

0

7

13

0

10

SOURCE: E. H. Pechan &Associates, inc., ’’Estimates of Sulfur Oxide Emissions From the Electric Utility lndustry;’ prepared for the Environmental Protection Agency, 1982.
App. A—Emissions and the Costs of Control ● 173

Table A-10.—Statewide Average Cost of

Reducing Utility S02 Emissions by 50 Percent

(dollars/ton SO2 removed, 1982 dollars)

Alabama . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300-500

Arkansas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >1,500

Connecticut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >1,500

Delaware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750-1,000

District of Columbia . . . . . . . . . . . . . . . . . . . . . . . >1,500

Florida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350-450

Georgia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400-550

Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250-350

Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150-200

Iowa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100-250

Kentucky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300-450

Louisiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,000-1,500

Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,000-1,500

Maryland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ‘550-600

Massachusetts. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Michigan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Minnesota. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Missouri . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Hampshire . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Jersey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New York . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

North Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pennsylvania . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rhode Island . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

South Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tennessee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vermont . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

West Virginia.. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31-State reason . . . . . . . . . . . . . . . . . . . . . . . . . .

950-1,000

300-450

500-700

250-300

<150

500-600

700-800

700-800

750-900

200-300

450-500

>1,500

450-800

<150

—a

900-1,100

450-500

<150

320-410

a$ton costs not estimated

SOURCE: Office of Technology Assessment, based on analyses by E. H. Pechan

&Associates, Inc.

Table A-11 .—Regional Costs of Alternative Approaches to Allocating an 8-Million.Ton Reduction

in S02 Emissions (Eastern 31-State control region, ali costs in 1982 dollars)

SO2 reduction Regional costsa

Allocation approachb

(milliontons/yr) (billions of dollars/yr) ($/ton)

I. Allocation based on utility SO2 emissions:

1. 50% reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3-2.9 320-410

2.1.5 lb/MMBtu rate limitation . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.8-2.3 255-325

3. Lower of:

1.2 lb/million Btu rate limitation or 50% reduction . . . . . . 7.5 1.8-2.4 275-370

4. 1.3 lb/million Btu average . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.8-2.4 260-340

5.11 lb/MWhr (total) average . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.9-2.5 270-350

Il. Allocation based on total SO2 emissions:

1. 35% reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 2.6-3.1 385-465

2. 16 tons/square mile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.7-3.9 560-585

3. 200 lb/person . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.6-3.0 370-415

aCosts precalculated on the basis of emissions reductions below SIP compliance levels.

bAlternative approaches explained in text.

SOURCE Office of Technology Assessment, based on analyses by E. H. Pechan &Associates, Inc
Table A.12.—Emissions Reductions Required by Alternative Allocation Approaches

—.

1: Formulae based on utility S02 emissions

(percent below 1980 emissions)

Lower of:

1.2 lb/MMBtu cap,

500/0 reduction 1.5 lb/MMBtu cap 50°/0 reduction 1.3 lb/MMBtu avg. 11 lb/MWhr avg.

Percent below: Percent below: Percent below: Percent below: Percent below:

State Utility Total Utility

Alabama . . . . . . . . . . . .

Arkansas . . . . . . . . . . . .

Connecticut . . . . . . . . .

Delaware . . . . . . . . . . . .

District of Columbia. . .

Florida . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . .

lowa . . . . . . . . . . . . . . . .

Kentucky. . . . . . . . . . . .

Louisiana . . . . . . . . . . .

Maine. . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . .

Massachusetts. . . . . . .

Michigan . . . . . . . . . . . .

Minnesota. . . . . . . . . . .

Mississippi . . . . . . . . . .

Missouri . . . . . . . . . . . .

New Hampshire . . . . . .

New Jersey . . . . . . . . . .

New York. . . . . . . . . . . .

North Carolina . . . . . . .

Ohio . . . . . . . . . . . . . . . .

Pennsylvania . . . . . . . .

Rhode Island. . . . . . . . .

South Carolina . . . . . . .

Tennessee. . . . . . . . . . .

Vermont. . . . . . . . . . . . .

Virginia . . . . . . . . . . . . .

West Virginia . . . . . . . .

Wisconsin . . . . . . . . . .

Eastern 31-States. .

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

50

35 38

13 35

22 0

24 44

15 0

33 34

43 47

38 58

38 65

35 46

44 58

4 0

8 8

33 34

40 24

31 31

34 24

22 44

43 67

43 47

19 24

25 33

36 4

41 62

36 44

17 0

32 29

43 59

3 0

22 3

43 49

38 60

37 50

Total Utility Total Utility Total Utility Total

. .

27 48

9 35

0 0

21 44

0 0

22 43

41 50

44 50

50 50

32 50

52 50

0 0

1 15

22 45

19 35

19 39

16 33

20 50

59 50

41 50

9 32

17 43

2 18

50 50

32 50

0 0

19 41

51 50

0 4

1 15

43 50

45 50

37 47

35 42

9 35

0 0

21 44

0 0

28 24

43 53

38 51

38 67

35 40

44 62

0 0

2 8

30 38

28 25

24 28

23 13

22 0

43 69

43 53

12 0

22 7

13 11

41 65

36 48

0 0

27 32

43 63

0 0

6 5

43 51

38 60

35 50

SOURCE. Office of Technology Assessment, based on analyses by E. H Pechan & Assoclates, Inc

30 20

9 35

0 0

21 44

0 15

16 26

47 51

39 47

52 72

28 46

56 66

0 0

1 0

25 20

20 27

17 25

9 2

0 20

61 73

46 57

0 0

3 1

8 8

53 69

34 51

0 0

21 0

55 61

0 0

2 2

44 56

46 55

37 50

14

9

0

21

4

17

44

36

55

32

59

0

0

13

22

15

:

64

49

0

0

6

57

37

0

0

53

0

1

49

42

37

II: Formulae based on total S02 emissions

(percent below 1980 emissions)

35% reduction 16 tons/mi2

——— 200 lb/person

Percent below: Percent below: Percent below:

, utility total UtiIity

4 8

>10 0

78

73

>100

52

3 9

4 5

4 5

49

3 8

>10 0

>100

53

4 3

56

51

77

3 9

40

88

68

48

42

48

>100

53

40

>100

77

40

45

48

3 5 4

3 5 3 5

3 5 0

3 5 >10 0

3 5 >10 0

3 5 21

3 5 0

3 5 50

35 93

35 0

35 47

35 0

35 0

35 75

35 77

35 0

35 0

35 0

35 16

35 3

35 >100

35 31

35 0

35 91

35 88

35 0

35 0

35 43

35 0

35 2

35 74

35 0

35 50

Total UtiIity

3 6 5

9 3 5

0 0

70 90

93 0

14 16

0 38

38 27

71 90

0 15

42 71

0 0

0 0

50

61 20

o 0

0 0

0 24

14 67

3 3

55 0

16 1

0 3

75 69

64 54

0 0

0 6

37 63

0 0

1 2

64 90

0 32

37 50

Total

4 6

9

0

4 3

0

10

33

21

6 9

10

6 4

0

0

2

16

0

0

11

5 9

3

0

0

2

5 6

3 9

0

4

5 4

0

1

7 8

2 5

3 7
App. A—Emissions and the Costs of Control 175

Table A-13.—Costs of Alternative Allocation Approaches

(estimated percentage increase in residential electricity rates, assuming all emissions reductions from utilities)

500/0 1.2 lb/MMBtu 35 ”/0

reduction 1.5 lb/M MBtu cap or 50°/0 1.3 lb/MMBtu 11 lb/MWhr reduction 16 tons/ 200 Ib/

(utility) cap reduction average average (total) Mi2

person

. . . . ● ☛☛☛

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Alabama. . . . . . . . . . .

Arkansas . . . . . . . . . .

Connecticut . . . . . . . .

Delaware . . . . . . . . . .

D.C. . . . . . . . . . . . . . .

Florida . . . . . . . . . . . .

Georgia. . . . . . . . . . . .

Illinois. . . . . . . . . . . . .

Indiana . . . . . . . . . . . .

Iowa . . . . . . . . . . . . . .

Kentucky . . . . . . . . . .

Louisiana , . . . . . . . . .

Maine . . . . . . . . . . . . .

Maryland . . . . . . . . . .

Massachusetts . . . . .

Michigan . . . . . . . . . .

Minnesota . . . . . . . . .

Mississippi. . . . . . . . .

Missouri . . . . . . . . . . .

New Hampshire. . . . .

New Jersey . . . . . . . .

New York . . . . . . . . . .

North Carolina. . . . . .

Ohio . . . . . . . . . . . . . .

Pennsylvania . . . . . . .

Rhode Island . . . . . . .

South Carolina . . . . .

Tennessee . . . . . . . . .

Vermont . . . . . . . . . . .

Virginia . . . . . . . . . . . .

West Virginia . . . . . . .

Wisconsin . . . . . . . . .

31-State region . . . . .

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●

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●

2.0-2.6°\o 4.0-4 .20/o 2.8-3.20/o

— = No reduction required

. —– 0-2 ”/0

. . —– 1-3%

. . . = 2-4%

. . . . = 3-60/0

. . . . . = 5- 10 ”/0

. . . . . .

.– > 10 ”/0

SOURCE Off Ice of Technology Assessment, based on analyses by E.H. Pechan and Associates, Inc

control. Costs could then be distributed to a larger group

than those required to reduce emissions under each of

the scenarios discussed below.

Key aspects of each allocation approach—including

its rationale, costs, and distributional consequences—

are outlined below.

1. Equal percentage reduction in each State—

utility emissions only.

Description: Each State is required to reduce its

utility S02 emissions by an equal percentage.

Rationale: Requiring an equal percentage reduction in utility S02 emissions distributes relative

emissions reductions fairly uniformly among

States.

Formula for achieving an 8-million-ton reduction:

Eliminating 50 percent of 1980 utility emissions

in each of the Eastern 31 States.

Cost: Reducing utility S02 emissions by 50 percent in each State is estimated to cost $2.3 to $2.9

billion annually, at an average cost of $320 to $410

per ton of S02 removed (1982 dollars).

Distributional consequences: This formula requires an equal percentage reduction from each

State regardless of: 1) the relative costs of emissions control, or 2) the stringency of the State’s

existing emissions regulations. Five States—

Arkansas, Connecticut, Louisiana, Maine, and

Rhode Island—would not be able to reduce util-
176 Acid Rain and Transported Air Pollutants: Implications for Public Policy

2.

3.

ity emissions by the necessary 50 percent without setting extremely stringent emission rate limitations (less than 0.4 lb/MMBtu of SO2).

Utility emission rate limitation (limiting emissions per fuel burned).

Description: This approach sets some maximum

emissions limits (an emissions ‘‘cap’ for each fossil-fuel electric-generating plant. In this case, the

limit is an emissions rate specifying the amount

of allowable emissions per quantity of fuel burned.

Rationale: Setting an emissions cap would require

emissions reductions in States with powerplants

emitting over a certain rate. It would thus target

States with plants emitting large quantities of S02

per quantity of fuel burned, but not penalize

States simply for generating large quantities of

electricity.

Formula for achieving an 8-million-ton reduction:

Limiting emissions rates for all plants in the Eastern United States to 1.5 lb of S02 per MMBtu

of fuel burned.

Cost: Estimated annual costs under this approach

are $1.8 to $2.3 billion, at an average cost of $255

to $325/ton.

Distributional consequences: The largest costs and

percentage reductions are distributed to States

whose plants emit relatively large amounts of pollutants per unit of energy consumed—e. g., Missouri, Indiana, Ohio, and Tennessee. States with

plants emitting at low rates (usually through the

use of less polluting fuels, e.g., oil and natural

gas) —e. g., Louisiana, Arkansas, and Connecticut

—are allocated the smallest reductions.

Utility emission rate limitation, with a maximum reduction of 50 percent below current

utility emissions.

Description: This approach modifies the cap approach by limiting any State’s required reductions

to 50 percent of 1980 utility emissions.

Rationale: By placing a ceiling on reductions, this

approach reduces the impact on those States most

heavily targeted under a cap approach. It reduces

regional variations in cost by setting a maximum

relative reduction requirement for all States.

Formula for achieving a 7.5-million-ton reduction: A cap of 1.2 lb of S02 per MMBtu, with

a maximum reduction of 50 percent below 1980

emissions for each State. An alternative method

of stating the formula is a 50-percent reduction

in a State’s 1980 utility emissions, but requiring

no existing source to reduce emissions below 1.2

lb of S02 per MMBtu. Thus, the formula achieves

less than the 8-million-ton reduction of the first

allocation approach.

4.

5.

Cost: This approach is estimated to cost between

$1.8 and $2.4 billion per year, at an average cost

of $275 to $370/ton.

Distributional consequences: By placing a limit

on percentage reductions, this approach lessens

the impact on States required to reduce the most

under a cap approach. The States that benefit by

this approach as compared to a simple emissions

cap are Indiana, Kentucky, Missouri, and Ohio.

Average utility emissions per fuel burned.

Description: Each State is required to achieve a

specified average utility emissions rate. Under

this averaging approach, some plants within a

State are allowed to exceed the specified emissions

rate (unlike the cap case) as long as the State has

compensating plants emitting below the rate.

Rationale: Unlike the cap, the average emission

rate approach gives credit to States with plants

emitting below the specified emissions rate.

Formula for achieving an 8-million-ton reduction :

Each State is required to eliminate sufficient emissions to achieve a statewide utility emissions average of 1.3 lb of S02 per M MBtu of fuel burned

(based on 1980 emissions).

Cost: This strategy is estimated to cost $1.8 to

$2.4 billion per year at an average cost of $260

to $340/ton.

Distributional consequences: Emissions reductions are allocated in a manner similar to the cap

case. States in which a substantial number of

plants emit at rates below the specified average

(e. g., New York, Minnesota, and Mississippi)

would tend to prefer the average rate approach

over the cap; States in which most plants emit at

rates well above the average used for allocation

(e.g., Missouri and Kentucky) would tend to favor

the cap over the average (assuming that identical

regional reductions are required).

Average utility emissions per total electricity

ouput.

Description: This approach allocates emissions reductions on the basis of the amount of S02 emitted per unit of electricity generated by all plants,

including hydroelectric and nuclear powerplants,

Rationale: Allocating emissions reductions on the

basis of total electricity generation gives credit to

those States that generate electricity with fuels that

do not produce S02 emissions.

Formula for achieving an 8-million-ton reduction:

States are required to reduce utility emissions to

meet an average rate of 11 lb of S02 per megawatt-hour of total electricity output.

Cost: This approach is estimated to range in cost

from $1.9 to $2.5 billion annually, at an average

cost of $270 to $350/ton of S02 reduced.
App. A—Emissions and the Cosfs of Control ● 177

6.

7.

Distributional consequences: This approach

favors States in which relatively high proportions

of electricity produced by hydroelectricity or nuclear power—e. g., Alabama, Maine, Maryland,

Minnesota, and New York.

Equal percentage reductions in each State—

total SO2 emissions.

Description: Each State is required to reduce total

S02 emissions (i. e., emissions from all sectors,

not just utility emissions) by an equal percentage from some baseline level.

Rationale: Each State participates equally in reducing aggregate emissions.

Formula for achieving a 7.6-million-ton reduction: Each State reduces total 1980 S02 emissions

by 35 percent.

Cost: This approach is estimated to cost $2.6 to

$3.1 billion annually, at an average cost of $385

to $465/ton of S02 removed.

Distributional consequences: This allocation formula requires an equal percentage reduction in

each State regardless of relative costs of emissions

control or stringency of the State’s existing emissions regulations. Those States: 1) with the highest proportion of emissions from sources that are

difficult to control (e. g., certain industrial processes and small residential, commercial, or industrial boilers), and 2) that have relatively low S02

emission rates, would incur the highest per-ton

costs. This includes such States as Louisiana,

Maine, Rhode Island, and Virginia.

Total emissions per land area.

Description: This approach is based on emissions

densities, i.e., the amount of SO2 emitted per unit

of land area. Emissions densities are calculated

from an area’s total emissions, rather than just

its utility emissions.

Rationale: To the extent that acid deposition is

produced by local sources, limiting the density

of SO2 emissions would help to limit the amount

of sulfur deposited in the surrounding area.

Formula for achieving an 8-million-ton reduction:

Reductions are allocated by setting a maximum

average emissions density of 16 tons of S02 per

square mile.

Cost: This approach would cost $3.7 to $3.9 billion per year, at an average cost of $560 to $585/

ton of S02 removed.

Distributional consequences: The States with the

highest emissions densities, and thus the largest

proportional reductions and costs under this approach, are Delaware, D. C., Indiana, Massachusetts, Ohio, Pennsylvania, and West Virginia.

8. Total emissions per person.

Description: Emissions reductions are calculated

on the basis of the amount of pollution emitted

per person residing in the State. Reductions are

based on the region’s total emissions, not just

utility emissions.

Rationale: Giving credit to States with lower

emissions-to-population ratios takes into account

a wide range of factors, including reliance on

clean fossil fuel combustion, non-SO2-emitting

electricity generation, higher energy efficiency,

and presence of fewer SO2-producing industrial

activities.

Formula for achieving an 8-million-ton reduction:

Reductions are allocated according to an average rate of 200 lb of S02 per capita.

Cost: The costs of this approach are estimated to

range from $2.6 to $3.0 billion annually, with an

average cost of $370 to $415/ton of S02 reduced.

Distributional consequences: Those States with

a relatively high proportion of total S02 emissions

to the population supported by emissions-generating activities (both industrial and electricity

generation) are allocated the largest reductions.

These States include Indiana, Kentucky, Missouri, Ohio, Tennessee, and West Virginia.

Comparison of Utility Estimates of Emissions

Reductions Costs to Various Regional-Model

Estimates

The Edison Electric Institute (EEI) requested its

member utilities to estimate the cost of implementing

a control proposal reported by the Senate Committee

on Environment and Public Works during the 97th

Congress (S.3041, reintroduced as S.768 during the 98th

Congress). The acid rain control sections of this bill

would require eliminating about 9 million to 10.5 million tons of S02 per year in the Eastern 3 l-State region—8 million tons per year allocated to States based

on utility S02 emission rates and an additional 1 million to 2.5 million tons per year to offset expected emissions growth by 1995. * (S. 768 was subsequently

amended to require an additional 2-million-ton emissions reduction. )

● The amount by which a State rnust reduce its SO2 emission was determined by the following formula Calculate the difference between a State’s 1980

utility emissions and the emissions that would result if no electric-generating

plant m that State emitted SO2 at a rate greater than 1.5 lb/MMBtu. Repeat

this calculation for the Eastern 31 -State region as a whole. The State proportion of the total regional difference, multiplied by 8 million tons, is the amount

of SO2 emissions that must be eliminated m that particular State Any additonal growth in emissions due to new facilities or increased use of existing ones

by 1995 must also be offset
178 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Twenty-four utilities responded, accounting for about

3.5 million tons (about 45 percent) of the 8-million-ton

reduction specified by the bill.42 Table A-14 compares

these cost estimates to regional model-based estimates

prepared for EPA43 and OTA. * In general, the utilities

projected higher costs than the model-based statewide

averages. The OTA estimates are typically higher than

the EPA estimates. There are several reasons for these

differences. First, some of the utilities surveyed have

higher S02 emissions rates than the statewide average.

As a result, these utilities will have higher emissions reduction costs than the statewide averages estimated by

the models.

Second, EEI, EPA, and OTA used different accounting procedures. One major difference is the number of

years over which capital costs are averaged. The EEI

estimates reported in table A-14 are averaged (’‘levelized’ over 5 years;* both EPA and OTA average capital costs over time periods equivalent to the life of the

facility (about 20 years). The shorter averaging time

makes the utility estimates of annual costs somewhat

higher.

The estimates also make different assumptions about

scrubber costs, low-sulfur coal prices, and the choice of

control method. Some utilities project scrubber capital

costs about equal to the average costs assumed by the

models (about $150 to $250 per kilowatt of generating

capacity); however, several estimate costs almost twice

as high. EEI assumes that most of the emissions reduction would occur through scrubbing, whereas the model

used by EPA projects that most emissions reductions

would be achieved by fuel-switching at a considerable

cost savings over scrubbing. The OTA model calculates

a fairly even mix of scrubbing and fuel-switching to

achieve the required emissions reductions, with costs

typically between the EPA and utility estimates.

Overview of Model Used

in Cost Analyses

OTA’s cost estimates are based on a computer model

that calculates the cost of reducing emissions at each

major utility generating unit in the 31 -State region

+ZNat iona] F;( ononl ic Research Assoclatcs, Inc , 

L

‘.4 Report on the Results

From the Edison Electric Institute Study of the Impacts of the Senate Committee on En\,ironment and Public Works Bill on A( Id Rain I,egislatlon

(S.768), 1983.

‘lICF, Inc , “Analysls of a Senate Emission Re[iuctinn Bill” (S 3041) Prepared for EPA, 1983

● OTA’S cost estimates are from the AIRCOST model, E. H Pechan & Assoc iates, These estimates include the costs of emissions reductions required to

offset future cmlssrons growth, based on projections prepared for the Unite(i

States-Canada Memorandum of Intent, the Edison Electric Institute, and EPA

● EEI alsu reports utdity estimates of rate Increases based on first-year revt, -

nue requirements; though typic all) about 25 percent higher than the 5-year

averages, these are not representative of average costs for the Irfe of the program

(about 2,000 units in about 900 powerplants). For each

unit, the model determines the combination of emissions

reduction measures that minimizes the costs of complying with a series of alternative emissions rate limitations,

ranging from SIP compliance to a 0.4 lb SO2/MMBtu

limit. Emissions reduction opportunities are then ranked

on the basis of costs per ton of S02 removed. For each

alternative rate limitation, the model considers the costs

of the following control options for each unit:

For coal-fired powerplant emissions:

●

●

●

●

●

blending presently used coals with low-sulfur coals,

switching to low-sulfur coals,

physical coal cleaning to reduce the sulfur contents

of presently used coals,

installing dry scrubbers in conjunction with either

current or alternative coal types, and

installing wet scrubbers in conjunction with either

current or alternative coal types.

For plants burning residual oil:

. switching to a lower sulfur oil.

These results are in turn used to generate State and

regional cost estimates of various emissions reduction

measures. These costs can be calculated in two ways:

1. State Least Cost: Reduction opportunities are se9

lected in ascending order of per-ton costs within

each State until the reduction target is achieved.

Trading of emissions reductions among sources is

allowed within States, but not among States. This

approach assumes a ‘‘perfect market for the

exchange of emissions reductions obligations

throughout the State and provides a lower bound

model estimate.

Plant Cap: Each plant is required to comply with

a specified emissions limit. This approach to estimating costs chooses the least-cost approach at

each plant, but assumes no trading of reduction

obligations among plants or States.

The cost model considers only S02 emissions from

utilities. No estimates of the cost of reducing emissions

of NOX, nor estimates for controlling S02 or NOx from

the industrial sector, are calculated. Furthermore, existing utilities are the only sources considered, and are

assumed to be operating at their current level of capacity

utilization. The OTA analysis assumes that all reductions occur immediately, without accounting for new

plants being built, or old plants being retired. Finally,

the model does not include the following possible control alternatives:

1. early retirement of major sources,

2. energy conservation,

3. selective use of lower emitting plants, and

4. advanced control technologies.

In calculating cost increases, OTA’s model assumes

that each plant chooses the most cost-effective method

of reducing emissions. However, State regulatory poli-
,

App. A—Emissions and the Costs of Control ● 179

Table A-14.—Comparison of Estimates of Residential Electricity Rate Increases

(8-million-ton SO2 reduction program, plus offsets for future growth)

1. Utilities located in single States

Florida: . . . . . . . . . . . .

Illinois: . . . . . . . . . . . .

Indiana: . . . . . . . . . . .

Massachusetts:. . . . .

Michigan: . . . . . . . . . .

Missouri: . . . . . . . . . .

North Carolina: . . . . .

Ohio: . . . . . . . . . . . . . .

Pennsylvania: . . . . . .

Wisconsin: . . . . . . . . .

Florida Power & Light Co.

Tampa Electric Co.

Statewide averages

Illinois Power Co.

Central Illinois P.S.

Statewide averages

Public Service Indiana

Indianapolis P. & L.

Statewide averages

New England Power Co.

Statewide averages

Detroit Edison

Statewide averages

Union Electric Co.

Statewide averages

Duke Power Co.

Statewide averages

Cincinnati G. & E.

Statewide averages

Pennsylvania Electric

Pennsylvania P. & L.

Statewide averages

Wisconsin Power & Light

Wisconsin Electric Power

Statewide averages

Il. Multi-State utilities:

Florida, Georgia, Mississippi:

The Southern Company

Statewide averages:

FL

GA

MS

Virginia, West Virginia

VEPCO

Statewide averages:

VA

WV

Indiana, Kentucky, Michigan, Ohio

American Electric Power (AEP)

Statewide averages:

IN

KY

Ml

OH

EPA: 2-30/o, OTA:

EPA: 1-2°/0, OTA:

EPA: 7-80/o, OTA:

EPA: 1% OTA:

EPA: 2-40/o, OTA:

EPA: 5-7°/0, OTA:

EPA: 1-2°/0, OTA:

EPA: 6-70/o, OTA:

EPA: 3-5°/0, OTA:

EPA: 5-60/o, OTA:

12 ”/0

EPA

2-30/o

4-5 ”/0

3%

60/0

EPA

1-20/0

5-60/o

180/0 (6-38 °/o)b

EPA

7-80/o

4-60/o

2-40/o

6-7 %

5%

230/o

3-7 ”/0

18°/ob

21 “/0

2-11 “/0

250/o

26°/ob

8-130/o

4%

0-50/0

12 ”/0

2-60/o

180/0

8-21 0/0

4%

2-50/o

14 ”/0

8-120/o

200/0

100/0

30/0

11 .30/0

12.30/o

1 1-120/0

OTA

3-70/0

9-120/o

5-200/o

OTA

2-70/o

10-13 ”/0

OTA

8-130/o

5-90/0

2-60/o

,. 8-120/o —

aEstimates are for a control program requiring SO2 emissions reductions in the Eastern 31-State region such that 1995 emissions are 8 million tons below 1980 levels. Emission limits for each State are allocated by a 1.5 lb SO2/MMBtu emission rate

Iimitation for utilities. Including reductions to offset future growth, about 9 to 10.5 million tons of SO2 per year must be eliminated

from existing sources

bFor these utilities, about one.third to one-half of capital costs are for new utility construction to replace Prematurely retired

plants, or to compensate for electricity losses due to scrubbers

SOURCE Compiled by Off Ice of Technology Assessment See text for references.
180 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

cies can affect this choice—and hence the costs—in ways

not treated by the model. For example, in most States,

‘‘automatic fuel adjustment clauses’ allow utilities to

pass on increased fuel costs due to fuel-switching to consumers within a few months. However, for emissions

controls requiring capital investment, such as scrubbers,

most States require utilities to wait until the equipment

becomes operational before charging ratepayers. This

practice may create a bias against capital investment in

pollution control equipment in utility management decisionmaking, and increase a plant’s lifetime control costs.

The model used by OTA also assigns all control costs

to the State whose utility owns the facilities required to

reduce emissions. The accuracy of this assumption depends on the policy chosen for allocating costs. To relieve utilities or States that are allocated particularly

large emissions reductions, costs could be shared by electricity consumers in other areas.

A.4 ALTERNATIVE TAX STRATEGIES TO HELP

FUND ACID RAIN CONTROL

Several acid rain control bills introduced during the

98th Congress proposed establishing a trust fund to help

finance the costs of emissions reductions for controlling

acid deposition. The proposals were based on one of two

alternative approaches for raising revenues: a tax on pollutant emissions, or a tax on electricity generation. Each

of these approaches could be implemented in several

ways.

This section considers two alternative pollution taxes:

1) a tax on both sulfur dioxide (S02) and nitrogen oxides (NOX), and 2) a tax on S02 emissions only. Both

apply to nationwide pollutant emissions. The section

analyzes the distribution of the two taxes by emissions

source, and the electricity portion of the tax by State,

and compares them to two electricity-based approaches: 1) a tax on total electricity generation, and

2) a tax on nonnuclear electricity generation.

All four tax schemes are possible alternatives to requiring those sources that must reduce emissions to pay

the entire costs of control. Funds raised by a tax can

be used to pay part or all control costs. A pollution tax

would apportion control costs to a larger group of emitters, not just those required to reduce emissions. However, because so few sources are actually monitored,

such an approach would be administratively complex.

An electricity tax would also distribute control costs to

a larger group of emitters, but is not directly related to

actual emissions. However, because electricity generation is carefully monitored, this approach would be

much easier to implement.

The analyses presented below are approximate, intended to illustrate the relative distribution of costs for

raising an arbitrary $5 billion per year under each approach. The actual amount of the tax, and to some extent the distribution of the tax, varies with each specific control plan and trust-fund design.

Distribution of Emissions, Tax Rates,

and Tax Revenues by Source

About 90 to 95 percent of the Nation’s manmade S02

emissions originate from utility and industrial sources.

About 95 percent of the Nation’s manmade NO, emissions originate from utility, industrial, and transportation sources. Emissions from these sectors can be considered the potentially ‘ ‘taxable’ pollutant inventory

(though in practice assessing emissions from all sources

in each category with sufficient accuracy for tax purposes would be difficult). Emissions from residential,

commercial, and other small dispersed sources are not

considered taxable for this analysis.

For example, to raise $5 billion per year, by deriving two-thirds of the revenues from S02 and one-third

from NOX emissions, * the tax must be set at about

$135/ton of S02 and $85/ton of NOX emitted. A tax on

S02 emissions alone must be set at about $200/ton.

These rates are based on 1980 taxable emissions; revenues from a fixed tax rate would increase as emissions

increase, and would decrease if acid rain control legislation were enacted. To raise $5 billion per year through

taxes on electricity generation, the following rates must

be set: 2.2 mills/kWh for all electricity generated and

2.5 mills/kWh for nonnuclear electricity only. Total revenues in future years would follow changes in electricity demand.

Table A-15 displays each sector’s contribution to an

acid rain control trust fund based on the above rates.

The two-pollutants tax (i. e., on both SO2 and NOx)

would raise about $2.8 billion (55 percent) from utilities, about $1.4 billion (30 percent) from industry, and

● About twice as much precipitation acidity currently originates from sulfur

compounds as from nitrogen compounds in the Eastern United States.
App. A—Emissions and the Costs of Control 181

Table A-15.—Annual Contribution to Acid Rain Control Trust Fund From Alternative

Tax Approaches (billions of dollars/yr, see text for explanation of alternative taxes)

Emissions tax Emissions tax

(before control- (after control1980 emissions) 1995 emissions) Electricity tax

SO2 & SO2 SO2 & s o * Total Nonnuclear

NOx only NOX only electricity electricity

Electric utilities. . . . . . . . . . . 2.8 3.5 1.8 1.6 5.0 5.0

Industry . . . . . . . . . . . . . . . . . 1.4 1.5 1.6 1.8 0.0 0.0

Transportation . . . . . . . . . . . 0.8 0.9 0.9 0.0 0.0 0.0

Total United States. . . . . . 5.O 5.0 4.3 3.4 5.0 5.0

SOURCE: Office of Technology Assessment, based on data from Emissions, Costs and Engineering, Work Group 3B, United

States-Canada Memorandum of Intent on Transboundary Air Pollution, June, 1982 and the Statistical Year Book of

the Electric Utility Industry, Edison Electric Institute, 1980

$0.8 billion (15 percent) from transportation sources.

If only SO2 were taxed, about 70 percent of the fund

would come from utilities and about 30 percent from

industry.

The third and fourth columns in table A-15 estimate

tax revenues in 1995 after a hypothetical acid rain control program, assuming that the tax rates remain unchanged. Utility S02 emissions in the Eastern 31 States

are assumed to be 10 million tons below 1980 levels.

All other emissions are assumed to grow at rates calculated from emissions projections developed under the

United States-Canada Memorandum of Intent on

Transboundary Air Pollution. The share of annual trust

fund revenues derived from utilities would decline to

about 40 percent of the total for the two-pollutants tax,

and to about 45 percent of the total for the SO2 tax. Because total nationwide pollutant emissions decline, the

total tax collected drops by 15 and 30 percent, respectively.

A tax on electricity generation (either total or nonnuclear) is assumed to come entirely from the utility sector (i. e., industrial generation of electricity for internal

use is not taxed).

Geographic Distribution of

Electricity Rate Increases

Table A-16 presents State-by-State costs of the alternate tax approaches for the electric utility sector only.

Costs to industry are often borne by consumers from

a much larger area than the State in which the industry

is located, since many manufactured goods are distributed nationwide. A tax on mobile source emissions (e. g.,

a sales or registration tax) would be distributed on a

roughly per-capita basis.

The large variation in current pollution emission rates

among utility plants would cause a pollution tax to distribute costs unevenly both within a State and from State

to State. As shown in table A-16, though a pollution

tax to raise $5 billion per year would increase average

residential electricity rates by about 2 percent, Stateaverage increases would range from virtually no increase

to about 9 percent. Because utilities emit a larger share

of nationwide S02 than NOx emissions, electricity rate

increases are typically somewhat lower for a tax on both

S02 and NOX emissions (co1. 1) than on S02 emissions

only (co1. 2).

Assuming that emissions reductions are achieved, *

Eastern States would experience smaller rate increases

due to the pollution tax in 1995 (COlS. 3 and 4) than in

1980. Western-State rate increases would be higher in

1995 than in 1980 due to projected increased emissions.

The tax rate is assumed to be indexed to inflation,

so that rate changes shown in 1995 are due solely to

emissions changes and not to changes in the price of electricity.

The last two columns of table A-16 estimate residential rate increases from a fixed kilowatt-hour tax on

all electricity, and on nonnuclear electricity, generated

in each State. State-to-State variations are due solely

to differences in the average electricity rate currently

paid by consumers in each State. Large percentage increases imply low current rates for electricity. Nationwide, the rate increases from a tax on electricity generation are greater than for a pollution tax under which

a significant share of the total $5 billion per year tax

comes from other sectors. However, in several Midwestern States (e. g., Indiana, Kentucky, Missouri, and

Ohio) with high rates of pollutant emissions, an electricity tax would be less costly than an emissions tax during the years before emissions reductions are achieved.
182 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table A-16.—5O.State Taxes Raising $5 Billion per Year During the Early 1980’s

Average residential electricity rate increase (percent) from alternative tax approaches

Emissions tax Emissions tax

(before control- (after control1980 emissions) 1995 emissions) Electricity tax

S 02 & s o * so* & SO2 Total Nonnuclear

2.0

0.9

0.7

0.6

0.2

1.3

0.3

1.4

2.2

1.7

3.5

0.8

0.0

2.9

5.9

3.0

1.8

5.7

0.5

0.4

1.8

1.6

2.5

1.8

2.1

6.6

0.9

1.3

1.0

2.9

0.8

0.7

1.8

1.9

4.5

0.6

0.1

2.7

1.3

1.4

1.1

5.3

0.7

0.8

0.1

1.2

0.5

4.1

4.1

NOx only NOX ony~ electricity electricity

Alabama . . . . . . . . . . . . . . .

Alaska . . . . . . . . . . . . . . . . .

Arizona . . . . . . . . . . . . . . . .

Arkansas. . . . . . . . . . . . . . .

California . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . .

Connecticut . . . . . . . . . . . .

Delaware . . . . . . . . . . . . . . .

District of Columbia. . . . . .

Florida. . . . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . . . . .

Hawaii . . . . . . . . . . . . . . . . .

Idaho . . . . . . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . . .

lowa . . . . . . . . . . . . . . . . . . .

Kansas . . . . . . . . . . . . . . . .

Kentucky. . . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . . .

Maine. . . . . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . . .

Massachusetts. . . . . . . . . .

Michigan . . . . . . . . . . . . . . .

Minnesota. . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . .

Missouri . . . . . . . . . . . . . . .

Montana . . . . . . . . . . . . . . .

Nebraska . . . . . . . . . . . . . . .

Nevada . . . . . . . . . . . . . . . .

New Hampshire . . . . . . . . .

NewJersey . . . . . . . . . . . . .

New Mexico . . . . . . . . . . . .

NewYork . . . . . . . . . . . . . . .

North Carolina . . . . . . . . . .

North Dakota . . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . . . .

Oklahoma . . . . . . . . . . . . . .

Oregon . . . . . . . . . . . . . . . .

Pennsylvania . . . . . . . . . . .

Rhode Island . . . . . . . . . . .

South Carolina . . . . . . . . . .

South Dakota . . . . . . . . . . .

Tennessee . . . . . . . . . . . . .

Texas . . . . . . . . . . . . . . . . . .

Utah . . . . . . . . . . . . . . . . . . .

Vermont . . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . . .

Washington . . . . . . . . . . . .

West Virginia . . . . . . . . . . .

Wisconsin . . . . . . . . . . . . . .

SOURCE: Based on data from Emissions, Costs and Engineering, Work Group 3B, United States-Canada Memorandum of lntent,

June 1982; and the Statistical Year Book of the Electric Utility Industry, Edison Electric Institute, 1980,

2.5

1.4

0.7

0.5

0.2

1.2

0.3

1.8

2.7

2.2

4.5

1.1

0.0

3.6

3.5

2.0

7.3

0.2

0.6

2.3

2.1

3.0

2.0

8.8

0.9

1.3

0.9

3.6

0.9

0.9

0.9

2.1

2.0

5.9

0.3

0.1

3.5

1.5

1.7

1.1

7.0

0.5

0.6

0.0

1.4

0.7

5.1

5.2

1.3

1.2

0.5

0.3

1.7

0.3

1.0

2.3

1.2

1.8

1.1

0.0

1.5

2.3

1.9

2.4

2.6

0.6

0.4

1.1

1.1

1.9

1.6

2.3

1.3

1.7

1.4

1.6

0.7

0.4

1.7

2.5

1.9

0.9

0.1

1.5

1.5

1.0

1.4

0.9

1.1

0.1

1.1

0.7

2.3

1.9

1.2

1.8

0.9

0.3

0.2

1.5

0.3

1.0

2.7

1.2

1.7

1.4

0.0

1.2

1.8

1.6

2.6

2.2

0.2

0.6

1.2

1.3

1.7

1.3

1.1

1.9

1.1

1.7

1.1

1.4

0.6

0.5

1.7

2.6

1.6

0.5

0.1

1.5

1.5

0.9

1.4

2.0

0.7

0.8

0.0

1.2

0.9

2.0

1.5

4.0

4.0

3.1

4.4

3.0

3.7

2.5

2.4

4.5

3.1

4.2

1.8

8.2

3.6

3.8

3.6

3.7

4.5

3.3

3.6

2.9

4.3

3.8

4.0

4.1

6.4

4.7

3.9

2.9

2.6

2.9

2.1

3.7

4.1

3.3

4.5

3.1

3.0

3.6

3.6

4.9

3.7

3.6

3.5

3.3

9.5

4.2

4.4

3.1

4.4

3.5

3.0

3.3

4.0

1.5

2.7

5.0

2.9

4.1

2.0

9.2

2.9

3.6

4.1

5.0

4.7

1.6

2.6

2.9

3.8

2.9

4.5

4.6

7.2

3.4

4.4

3.3

2.1

2.0

3.9

4.6

3.6

5.0

6.9

3.2

3.3

2.4

4.1

5.5

4.1

0.9

2.5

10.5

3.6
App. A—Emissions and the Costs of Control 183

A.5 OTHER EMISSION SECTORS

This section addresses major nonutility sources of S02

and NOX emissions. It presents estimates of current

emissions, potential emissions reductions, and control

costs, where possible, for: 1 ) industrial and large commercial boilers, 2) industrial process emitters (e, g.,

smelters and petroleum refineries), and 3) mobile

sources. Together, these source categories account for

approximately 30 to 35 percent of S02 and 65 to 70 percent of NOx. emissions in the continental United States.

In general, data needed to estimate emissions from

these sources are scanty and of questionable accuracy.

In addition, emissions control methods, particularly for

industrial processes, are in earlier stages of development

than for utilities. Consequently, the estimates of emissions, potential emissions reductions, and estimated control costs presented in this section are subject to greater

uncertainty than those presented earlier for the utility

sector.

Industrial and Commercial Boilers

Industrial and large-commercial boilers emitted about

3.5 million tons of SO2 in 1980; table A-17 provrides

State-by-State emissions estimates for these sources.

Two estimates are presented; one is calculated from

State-levcl fuel deliveries, the other from data reported

to EPA .44 Though the national totals are quite close,

the difference at the State-levrel is often quite large.

Largest emitting States were New York (about 350,000

to 450,000 tons), Ohio (about 300,000 to 400,000 tons),

and Pennsylvania (about 250,000 to 300,000 tons); nine

additional States had nonutility boiler emissions greater

than about 100,000 tons of S02 per year.

Table A-17 also indicates the percentage of this sector’s 1980 emissions that would have to be eliminatcd

under various emission rate limitations. In comparison

to the utility sector, S02 emission rates from industrial

and commercial boilers are relatively low. Thus, control strategies based on emission rate limitations would

reduce emissions from this sector by a smaller proportion than comparable controls on the utility sector. For

example, an emission rate limitation of 1.5 lb of S02

per million Btu would eliminate slightly over a quarter

of this sector’s 1980 emissions (slightly under 1 million

tons of’ S02 annually); an identical cap on utility emissions would eliminate slightly less than half of that sector’s SO2 emissions (about 8 million tons of SO2 annually).

The lower S02 emission rates from nonutility boilers

are due to the lower sulfur content of the fuels burned.

A 1979 Department of Energy (DOE) survey45 found

that natural gas (which emits almost no S02) supplied

about 32 percent of the energy requirements of industrial boilers. Coal and oil each accounted for about 17

percent of boiler fuels (as compared to 58 and 12 percent, respectively, of fuels used by utilities). The remainder came from such fuels as wood, bark, coke oven

gas, and paper-pulping liquor.

Many nonutility boilers are capable of burning a wide

variety of fuel types. Thus, if emissions controls were

required for nonutility boilers, reductions in S02 emissions could be met by substituting lower sulfur fuels or

even changing fuel types. Boilers currently burning

high-sulfur oil might switch to low-sulfur oil. Natural

gas, which accounted for over 30 percent of commercial and industrial boiler fuel use in 1979, might also

be substituted, Federal and State regulations permitting.

For boilers equipped to burn coal, available strategies

for reducing emissions include switching to lower sulfur

coal, and cleaning exhaust gases with scrubbers. Switching to low-sulfur oil or gas may be possible in many

cases, but would probably not be as cost effective as lowsulfur coal. Table A-18 estimates per-ton costs associated

with three fuel-switching and two scrubber-installation

scenarios.

Industrial Processes *

Industrial processes are estimated to account for approximately 15 to 20 percent of the SO2 emitted nationwide and about 7 to 12 percent of those emitted in the

Eastern 31 -State region of the United States. Less than

5 percent of U.S. NOX emissions came from industrial

processes. Data on emission rates for individual sources

are scanty. Moreover, relatively little literature is available on the technical feasibility and costs of controlling

emissions from these sources. Consequently, emissions

and control cost estimates are subject to greater uncertainty than those associated with utility, industrial, and

commercial boiler operations. A study produced for

OTA by Energy & Resource Consultants, Inc., provides

preliminary estimates of S02 emissions and control costs

for five major industrial sectors: 1) pulp and paper,

99 -413 0 - 84 - I 3 ; g . ~
I&# . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table A-17.-Potential SO2 Reductions From Nonutility Boilers

Non utility boiler SO2 emissions Percent reduction in emissions with

(thousand tons/yr) emission limit (lb/MMBtu)

State U.S./Canada a NEDSb

1.0 1.2 1.5 2.0 2.5

Alabama. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Arizona. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Arkansas . . . . . . . . . . . . . . . . . . . . . . . . . . . .

California. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Connecticut . . . . . . . . . . . . . . . . . . . . . . . . .

Delaware . . . . . . . . . . . . . . . . . . . . . . . . . . . .

District of Columbia . . . . . . . . . . . . . . . . . .

Florida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Idaho . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

lowa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Kansas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Kentucky . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Massachusetts . . . . . . . . . . . . . . . . . . . . . . .

Michigan . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Minnesota . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . . . . . . . . . . . . . . .

Missouri . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Montana . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nebraska . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nevada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Hampshire . . . . . . . . . . . . . . . . . . . . . .

New Jersey . . . . . . . . . . . . . . . . . . . . . . . . . .

New Mexico . . . . . . . . . . . . . . . . . . . . . . . . .

New York. . . . . . . . . . . . . . . . . . . . . . . . . . . .

North Carolina . . . . . . . . . . . . . . . . . . . . . . .

North Dakota . . . . . . . . . . . . . . . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Oklahoma . . . . . . . . . . . . . . . . . . . . . . . . . . .

Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pennsylvania, . . . . . . . . . . . . . . . . . . . . . . . .

Rhode Island . . . . . . . . . . . . . . . . . . . . . . . . .

South Carolina . . . . . . . . . . . . . . . . . . . . . . .

South Dakota . . . . . . . . . . . . . . . . . . . . . . . .

Tennessee . . . . . . . . . . . . . . . . . . . . . . . . . . .

Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vermont . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Washington . . . . . . . . . . . . . . . . . . . . . . . . . .

West Virginia . . . . . . . . . . . . . . . . . . . . . . . .

Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . . . .

Wyoming . . . . . . . . . . . . . . . . . . . . . . . . . . . .

National totals . . . . . . . . . . . . . . . . . . . . .

86

9

32

56

24

34

26

97

44

11

188

290

57

11

66

76

65

56

58

154

44

48

55

25

4

2

10

74

2

334

116

13

310

15

254

8

84

3

83

106

16

5

142

41

84

107

30

3,491

119

4

7

153

19

14

20

14

97

66

5

111

129

56

0

32

78

93

23

33

122

49

46

17

9

4

2

20

78

9

455

130

5

403

13

14

314

4

76

2

97

121

16

2

129

28

94

150

32

3,514

51

32

0

15

16

1

3

11

48

56

22

45

59

72

0

52

13

59

0

0

50

47

0

40

80

34

15

51

0

58

14

47

32

70

32

0

12

7

45

19

50

5

27

39

49

24

57

60

45

37

44

29

0

6

13

1

2

4

41

48

16

40

53

67

0

46

11

51

0

0

43

38

0

35

77

29

10

43

0

53

7

37

66

27

0

11

0

35

13

44

3

18

30

40

18

50

55

36

32

35

27

0

3

10

1

1

2

31

38

8

34

45

59

0

41

38

o

0

35

26

0

28

71

20

5

29

0

48

5

24

9

61

20

0

10

0

22

6

37

1

7

17

27

13

41

49

24

26

23

22

0

2

6

1

0

1

17

22

0

26

35

47

0

33

7

19

0

0

26

14

0

20

65

11

0

7

0

40

3

7

4

53

8

0

7

0

8

0

27

0

1

0

10

9

31

38

7

18

15

15

0

1

5

1

0

0

9

10

0

19

28

35

0

27

6

2

0

0

21

0

15

60

6

0

0

0

33

2

1

4

46

5

0

6

0

1

0

21

0

0

0

1

7

22

30

2

13

SOURCES: Office of Technology Assessment, based on: admissions, Costs and Engineering Assessment, Work Group 3B, United States-Canada Memorandum of intent

on Transboundary Air Pollution, June 1982; and bEPA’s National Emissions Data System.
App. A—Emissions and the Costs of Control 185

Table A-18.— Representative Costs for Reducing

S02 Emissions From Coal-Fired Industrial Boilers

$/ton S02 removed

Industrial strategies (1982 dollars)

Shift from higha

- to Iowb-sulfur coal . . $ 250-$550

Shift from high- to mediumc

-sulfur

coal. . . . . . . . . . . . . . . . . . . . . . . . . . . . 300-500

Shift from medium- to low-sulfur

coal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400-1,000

Shift from unscrubbed high to

scrubbed high sulfur . . . . . . . . . . . . 800-1,000

Shift from unscrubbed medium to

scrubbed medium sulfurd 

. . . . . . . . . 1,200-2,000

aAbout 3 to 5 lb SO2/MMBtu

bAbout 1.5 to 25 lb SO2/MMBtu

CAbout 0.8 to 1.3 lb SO2/MMBtu

dBased on the costs of retrofitting a scrubber on a 170 MMBtu/hr coal-fired in -

dustrial boiler

SOURCE Analysis of Senate Emission Reduction Bill (S 3041) Report prepared for EPA by ICF, Inc , 1983

2) cement, 3) sulfuric acid production, 4) iron and steel,

and 5) nonferrous metal smelting. Emissions estimates

(but not control costs) are also presented for petroleum

refining.

Table A-19 presents estimates of SO2 emissions from

these six industries: 1 ) by EPA region for the 31 Eastern States, 2) for the remainder of the United States,

and 3) for the Nation overall. In nearly all cases, S02

emissions have been estimated indirectly, by applying

an emissions factor to estimated plant production or

production capacities derived from industry surveys. For

the cement and pulp and paper industries, in particular, the wide variability in potential emissions per unit

of production capacity leads to a range of emissions estimates. Estimates for the iron and steel industry are

derived from actual output levels, and are presented for

years of differing iron and steel production, to illustrate

the effects of production levels on emissions. Where

available, estimates of emissions calculated for other

studies are also included to further demonstrate the significant uncertainties in these estimates.

Production processes for five of these industries were

examined in some detail to determine how much S02

could feasibly be eliminated from their emissions, and

at what cost. As presented in table A-20, rough estimates

show that about 1 million tons of S02 could be eliminated from process emissions in the Eastern 31-State

region, at widely differing cost levels. Slightly more than

half these emissions—primarily from sulfuric acid plants

and coke ovens—could be eliminated at average costs

of $500/ton or less; an additional 300,000 tons might

be eliminated from cement plant emissions at an average cost of approximately $ 1,000/ton. However, estimates of potential emissions reductions, and associated

costs, for several of these industries are based on technologies that are theoretically feasible but not commercially proven. The computation methods used to derive

cost estimates mask significant variations from plant to

plant within each industry; only in the pulp and paper

industry was sufficient information available to present

a range of per-ton cost estimates, based on differences

in plant sizes, economies of scale, and differing production processes in use—the average per-ton cost of control is estimated to be $2,600, ranging from $450 to

$14,800/ton of S02 removed.

Only the cement industry, of the five surveyed, was

found to emit substantial quantities of NOX—

approximately 120,000 tons in the Eastern 31 -State region, and 80,000 tons in the Western portion of the

United States.

Mobile Sources *

Automobiles and other mobile sources produce substantial amounts of two pollutants, NO, and hydrocarbons (HC). NOx and HC are the primary pollutants

that react in the atmosphere to form ozone and other

oxidants. NOx can also be converted to nitrates, a

component of acid deposition.

Many recent studies suggest that ozone and ozone

precursors (NOX and HC) are transported long distances. The highest concentrations of ozone do not necessarily occur where emissions densities are greatest

(i.e., in cities), but, because of chemical transformations

over time, at locations that are several hours downwind.

The extent to which mobile sources contribute to acid

deposition is uncertain. Tailpipe emissions may not disperse sufficiently to reach the mixing layer of the atmosphere, where they are readily transported and transformed into acid compounds. However, mobile sources

have been linked to increases in acid deposition in urban

areas, e.g. , the Los Angeles Basin.46

Current Emissions: Mobile sources account for

major portions of both NOx and HC emissions nationwide, and a very small portion of S02 emissions. As of

1978, mobile sources contributed 40 percent of national NOx emissions (10.3 million tons), approximately 38

percent of total HC emissions (1 1.8 million tons), and

3 percent of national S02 emissions (0.9 million tons) .47

Of NOX emissions from mobile sources, approximately 40 percent came from automobiles, 10 percent

● This subsection is based on M P Walsh, “Motor Vehicle Emissions of

Nitrogen Oxides, ” contractor report submitted to the Office of Technologv

Assessment, 1981

46PEDCo Environmental, Inc., , and Paul W. Spaite Co., Perspective on the

Issue of Acid Rain, DOE contract No DE-AC21-81 MC16361, June 1981

+T,Narlon~ Air ~o)]u[anr Emission Estmafes, /970-J 978, offke of Alr @AltY’

Planning and Standards, U S Envmonrncntal Protec tmn Agwrcy, EPA-4.50/4-

80-002, ,January 1980
Table A-19.—SO2 Emissions From Industrial Processes (estimates for 1980 in thousand tons/yr)

Iron and steel

Sulfuric a b CokeaPetroleumb Copper a

EPA region Pulp and paperac Cementa

acid ovens only Tota l

a b refineries smelting

1 . . . . . . . . . . . . . . . . . . 7 (3-15) 3 (2-4) 1 4 — o 0

II . . . . . . . . . . . . . . . . . 7 (3-17) 36 (24-52) 8-22 7 20 42 0

Ill . . . . . . . . . . . . . . . . . 10 (4-22) 84 (57-130) 12-22 66 165 79 0

Iv. . . . . . . . . . . . . . . . . 63 (23-140) 96 (58-120) 130-270 15 36 29 7

v . . . . . . . . . . . . . . . . . 6 (3-15) 110 (75-160) 16-37 68 180 170 72

VI (partial). . . . . . . . . . 18 (7-40) 13 (8-18) 39-83 0 0 105 0

Vll (partial) . . . . . . . . . 1 (l-4) 63 (43-95) 5-11 1 1 8 0

Eastern 31-States . . . 110 (43-250) 410 (270-580) 210-450 160 250-400 430 79

West . . . . . . . . . . . . . . 26 (1 7-57) 240 (150-310)

United States total . .

53-160 16 23-26 565 1,380

150 (66-340) 650 (410-890) 263-610 180 280-400 1,000 1,460

NOTE Summed estimates have slight discrepancies from combining several sources of data.

SOURCES

aEnergy and Resource Consultants, Inc., “Background Documentation SOX and NOX Emissions From Five Industrial Process Categories, ” OTA contractor report, 1982

bWork Group 3B, “Emissions, costs and Engineering Assessment “ Report prepared under the Memorandum of Intent on Transboundary Air Pollution signed by the

United States and Canada, 1982.

CMitre Corp. estimates published in "Background Document on Sox and Nox Emissions From Five Industrial Process categories. ”

States within EPA regions: l—Maine, Vermont, Massachusetts, New Hampshire, Connecticut, Rhode Island; n-New York, New Jersey; 111—Pennsylvania, Maryland, Delaware, West Virginia; IV—Florida, Kentucky, Tennessee, North Carolina, South Carolina, Mississippi, Alabama, Georgia; V—Minnesota, Wisconsin, Indiana, Ohio, Michigan;

Vi—Arkansas, Louisiana, VIl —lowa, Missouri.
App. A—Emissions and the Costs of Control ● 187

Table A-20.—Potential S02 Emissions Reductions and

for Industrial Processes

——

Pulp

a n d Sulfuric Cok e

a

paper Cemen t acid oven s

Control Costs

Other irona Coppe r

b

and steel smelting

Total United States

Current emission s

(10 3 tons) ... . . . . . . . . . . . . . . 1 5 0 6 5 0 6 1 0 2 3 0 120 1,460

Potential emissions reduction s

(10 3 tons) . . . . . . . . . . . . . . . . 130 ’ 5 2 0

d

510 ’ 185’ 2 7

g

3 5 0

h

Eastern 31 States

Potential emissions reductions

(103 tons) . . . . . . . . . . . . . . . . . . 110 330 360 170 24 0

$/ton . . . . . . . . . . . . . . . . . . . . . . . . 2,600I 1,000 550 300 >3,000 —

West

Potential emissions reductions

(10 3

tons) . . . . . . . . . . . . . . . . . . . 20 190 150 15 3 350

$/ton . . . . . . . . . . . . . . . . . . . . . . . . 2,600i 1,000 500 300 >3,000 200

aEmissions estimates for the Iron and steel industry are based on 1976 production levels rather than 1980 levels due to I he

depressed production rates in 1980

bEmmissions estimates for copper smelting assume that all smelters still operational are producing at near-full capacity

‘Assumes that exhaust gases from recovery boilers are scrubbed with a removal efficiency of 85 percent

dAssumes that wet scrubbers are installed on cement kilns, with an 80. percent removal efficiency This is not a Commercially

proven technology.

eAssumes sodium sulfite scrubbing to achieve a 3 lb/ton of acid emissions limit.

fAssumes coke oven gas desulfurization with 90 -percent removal efficiency

gAssumes that wet scrubbers are installed on sinter plants with a 90-percent removal efficiency

hBased on the use of double contact acid plants at the Phelps-Dodge Ajo and Douglas smelters in Arizona

I Estimates range from $450 to $14 800/ton

SOURCE Energy and Resource Consultants, Inc , OTA contractor report, 1982.)

from light-duty trucks, 25 percent from heavy-duty

trucks, and 25 percent from other mobile sources such

as trains and off-highway vehicles. Of HC emissions,

60 percent came from automobiles, somewhat greater

than 10 percent each for light- and heavy-duty trucks,

and 15 percent from other mobile sources. State-level

estimates of NOX emissions from mobile sources are

shown in table A-2; NOX emissions from highway vehicles alone—about 7.5 percent of total mobile source

emissions—are presented in table A-21.

Trends in Highway Vehicle

Emissions

Since 1940, nationwide NOX emissions have approximately tripled; a fourfold increase in the number of

motor vehicles since 1945 contributed significantly to

this dramatic growth rate .48 In addition, NOX emissions per mile driven increased during the late 1960’s

and early 1970’s, due to the technologies used to implement the first generation of HC and carbon monoxide (CO) emissions control standards. Between 1970 and

1978, HC emissions from highway vehicles decreased

by about 10 percent, from 11.3 million to 10.2 million

tons, while NOX emissions increased by 25 percent,

from 5.8 million to 7.4 million tons.49

During the same period, vehicle miles traveled in the

United States increased by about 37 percent, showing

some decline in NOX emission rates due to controls

mandated by the Clean Air Act. Since the late 1970 ‘s,

overall amounts of NOX emissions from motor vehiclcs

have also begun to decrease slight]?’ as the proportion

of NOX

-controlled vehicles in the United States increases.

To estimate future NOX emissions levels for highway

vehicles, OTA has projected three alternative travel scenarios for 1995: a no-growth, a low-growth, and a medium-growth case. Estimates of \’chicle-miles traveled

under the three scenarios were then used to project nationwide 1995 NOX emissions from highway vehiclcs

under a variety of control standards. Table A-22 summarizes the effects of the various growth cases and emissions standards on 1995 NOX emissions projections.

Two cases have been selected from among the 18 projected emissions levels to represent a likely lower and

upper bound for emissions estimates. The lower-bound
188 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table A-21 .—1980 U.S. NOX Emissions

From Highway Vehicles (103 tons)

Eastern region Western region

State NOX State NOx

Alabama . . . . . . . . 127 Alaska. . . . . . . . . . 13

Arkansas. . . . . . . . 74 Arizona . . . . . . . . . 87

Connecticut . . . . . 87 California . . . . . . . 696

Delaware. . . . . . . . 20 Colorado. . . . . . . . 87

District of Hawaii . . . . . . . . . . 20

Columbia . . . . . 13 Idaho . . . . . . . . . . . 33

Florida . . . . . . . . . 328 Kansas . . . . . . . . . 74

Georgia. . . . . . . . . 194 Montana . . . . . . . . 27

Illinois . . . . . . . . . . 281 Nebraska . . . . . . . 54

Indiana . . . . . . . . . 174 Nevada . . . . . . . . . 27

lowa . . . . . . . . . . . 80 New Mexico. . . . . 47

Kentucky . . . . . . . 120 Oklahoma . . . . . . . 120

Louisiana . . . . . . . 100 Oregon . . . . . . . . . 80

Maine . . . . . . . . . . 33 South Dakota. . . . 27

Maryland. . . . . . . . 13 Texas . . . . . . . . . . 482

Massachusetts . . 154 Utah. . . . . . . . . . . . 40

Michigan. . . . . . . . 281 Wyoming . . . . . . . 20

Minnesota . . . . . . 120

Mississippi . . . . . . 74

Missouri . . . . . . . . 154

New Hampshire . 27

New Jersey . . . . . 221

New York . . . . . . . 341

North Carolina. . . 187

Ohio . . . . . . . . . . . 321

Pennsylvania . . . . 308

Rhode Island . . . . 27

South Carolina . . 107

Tennessee . . . . . . 147

Vermont . . . . . . . . 13

Virginia . . . . . . . . . 127

West Virginia. . . . 54

Wisconsin . . . . . . 147

31 + D.C. total . . 4,454 West total . .....1,934 0

U.S. total . ......6,388

SOURCE: Michael P Walsh, “Motor Vehicle Emissions of Nitrogen Oxides,” OTA

contractor report, Nov. 30, 1981.

Table A-22.—1995 Highway Vehicle NOX Emission Projections

Emissions standards 1995 nationwide emissions (1,000 tons)

Autoa

Light trucka Heavy truckb No growth L OW gowt h

c Medium growthd

1.0 1.2 1.7 3,067 3,759 4,767

1.0 1.2 4.0 3,633 4,608 5,725

1.0 1.2 6.0 4,104 5,287a

6,487

1.5 1.7 6.0 4,764 6,052 7,514

2.0 2.3 10.7 5,868 7,469 9,193b

None None None 7,950 9,880 12,438

%Grams/mile.

bGrams/brake horsepower-hour.

C

LOW growth:

Autos and light trucks grow 1% per year.

Heavy gasoline trucks decline 2% per year,

Heavy diesel trucks grow 4% per year.

‘Medium growth:

Autos and Iight trucks grow 3% per year.

Heavy gasoline trucks decline 2% per year.

Heavy diesel trucks grow 5% per year.

SOURCE: Michael P. Walsh, “Motor Vehicle Emissions of Nitrogen Oxides,” OTA contractor report, Nov. 30, 1981.
App. A—Emissions and the Costs of Control ● 189

scenario assumes low growth, retention of the 1.0 gram

per mile (gpm) automobile standard currently in effect

for 1981 and later model cars, and a tightening of lightand heavy-duty truck standards to 1.2 gpm and 6.0

grams per brake horsepower-hour respectively, as the

1977 Clean Air Act Amendments require. By 1995, this

would result in a 21 -percent reduction from current

NOX mobile-source emissions.

The upper-bound scenario assumes medium growth,

retention of the current light- and heavy-truck standards rather than any tightening, and a rollback of the

automobile standard to 2.0 gpm. This would result in

a 37-percent increase in NOX mobile-source emissions

over 1980. Assuming a low-growth scenario with these

same emissions standards would result in only a 12-percent NOX increase over 1980 levels.

costs

Estimates

of emissions

of Automobile Emissions

Controls

of the costs and fuel-economy implications

controls are highly controversial. The Bureau of Labor Statistics has estimated that between 1975

and 1979, pollution control devices have increased the

cost of new automobiles by about $ 165—approximately

10 percent of the total cost increase for new cars during

the same 5 years. EPA and manufacturers’ estimates

of the costs50 of meeting statutory automobile emission

standards of 0.4 gpm HC, 3.4 gpm CO, and 1.0 gpm

‘“( “I’he (;OSI of ~;(jn[rnlllng F.mlsslorss nf 1981 Model Year Autnmobilm,

u S F,nt.lrorlrIlen~a] Pr~)tt.{ IIon A~nc y, .Junc 1981, testimony bv Michae l

k$’alsh before the iiea]tb and Errvlronrnent Subcomml(tee, U S House of Rcprcsen[atl\e\, Sept. 21, 1 981, an[i letter from Betsy Ancker-Johnson, General

Nlotori t{) I) OUql<L\ (jostle, u s 1jn\ ,ronment.il Prntectinn Aqenc y, Sept 2,?,

]980

N OX are presented in table A-23. Control cost estimates vary widely; the General Motors’ (GM) estimate

of $720/car is about double that of EPA, and is 50 percent higher than Ford’s. Differences in technology

among manufacturers, and the difficulty of allocating

the costs of multipurpose components to particular objectives (e. g., emissions reductions, as opposed to the

resulting improvements in fuel economy or vehicle performance), probably account for a substantial amount

of the variation. The differences narrow when NOx

controls are looked at alone: Ford, EPA, and Chrysler

show only a $27/vehicle spread in estimates of savings

associated with a change in standards from 1 to 2 gpm

NOX—ranging from $48 to $75/vehicle. GM’s estimate

is still substantially higher, at $188/vehicle.

Inspection and maintenance (1/M) programs offer an

alternative approach to reducing NOX emissions from

mobile sources. A recent study concluded that adding

NO, testing to an existing I/M program for HC and

CO would add about $4/inspected vehicle, and that having 20 percent of the vehicles repaired (at an average

cost of $50 each) could result in about a 10-percent reduction in NOx emissions. 51 An EPA analysis concluded that the cost-effectiveness of an I/M program for

NOX control would range from $400 to $500/ton of

NOX eliminated if added to an existing HC/CO program, or $1,700 to $2, 700/ton if started up exclusively

for NOX control .52

5“(A Study of the Relationship Between Motor \rehicle Emiswms and Attainment of National Ambient Air Qua] itv Standards, Part 1 Nitrogen Dioxide, SRI International, Februar>. 1981.

~? Interna] EpA memo, Tom Cackette to M icbael P W’alsh, ,Jan 9, 1981.

Table A-23.—Costs of Emissions Controls for Automobiles

Cost differential per vehicle: NOx costs per vehicle: NOX costs per vehicle:

Autos 1983 cars v. uncontrolled 1 gpm v. uncontrolled 1 v. 2 gpm

EPA . . . . . . . . . . . . . . . . . . . . . . 370C

$123 50

Ford . . . . . . . . . . . . . . . . . . . . . 500 167 48*

GM . . . . . . . . . . . . . . . . . . . . . . 725 242 188

Chrysler . . . . . . . . . . . . . . . . . . — — 75

a1983 car costs are based on emissions standards of 0,41 HC/3.4 CO/1.0 NOX grams per mile.

bAssumes that emission control costs of 1963 cars are equally divided between HC, CO, and Nox

.

CEPA estimates that this would drop to $330 by 1966 as systems are refined.

dAssumes that 613 percent of cost estimated by Ford for CO, high altitude and NoX control— $80 per car—is attributable to NOx control, This is a high estimate, based

on Chrysler’s estimate that 60 percent of its costs for CO and NOX control Is due to NOx alone.

SOURCE: Michael P Walsh, “Motor Vehicle Emissions of Nitrogen Oxides,” OTA contractor report, Nov. 30, 1961.
190 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

A.6 POTENTIAL SECONDARY ECONOMIC EFFECTS

OF EMISSIONS CONTROL PROGRAMS

Emissions controls and the associated costs are likely

to have the greatest effects on three sectors of the

economy: high-sulfur coal mining, industries that depend heavily on electricity consumption, and the electric utility industry. This section discusses ways in which

these industries might be affected by a major program

to reduce sulfur dioxide (S02

) emissions in the Eastern

United States.

Potential effects on the coal industry are quantified

on the basis of several hypothetical S02 emissions reduction scenarios; qualitative estimates of the degree of

vulnerability are provided for electricity-intensive industries and the electric utility industry. However, it should

be noted that both the degree and nature of the potential impact on these sectors would depend on the type

and magnitude of the chosen control program, the way

in which reductions are allocated, and the way in which

control costs are allocated. Thus, the discussions provided below are intended to give only a general indication of these sectors’ relative vulnerability to the effects

of emissions controls.

Coal Production and Related

Employment

Coal Reserves and Current Production

Many legislative proposals for controlling acid rain

have focused on reducing S02 emissions in the Eastern

United States. Emissions reductions designed to control acid rain might cause significant shifts in the coal

market by increasing the value of low-sulfur coals as

compared to high-sulfur coals. Because the sulfur content of coal varies from region to region throughout the

United States, any emission reduction strategy that relies even in part on “switching’ to lower sulfur coals

can potentially affect the regional distribution of coal

production and employment. Social dislocations could

accompany these changes in the coal market, as some

areas experience rapid economic growth while others

decline.

Figure A-6 shows the location of the Nation’s coal

deposits. Three factors influence regional coal production from these reserves: 1 ) mine-mouth prices (the cost

of production), 2) transportation costs (the distance between the mine and the consumer), and 3) fuel characteristics (primarily a coal’s energy value and sulfur content). 53 Acid rain control measures would affect the

existing production patterns by increasing the value of

low-sulfur coal relative to high-sulfur coal, all other factors remaining equal.

Table A-24 displays the distribution of each State’s

coal reserves by sulfur content category. Figure A-7

shows a distinctive difference in the sulfur content of

coal reserves between the Eastern and Western United

States. A large majority (74 percent) of coal reserves in

the Eastern United States are high in sulfur (greater than

2.0 pounds per million Btu (lb/MMBtu) of S02

). By

contrast, the majority (72 percent) of Western reserves

are low in sulfur (less than 1.2 lb/MMBtu). The two

significant Eastern exceptions to this pattern are Kentucky and West Virginia, both of which have significant quantities of reserves above and below 1.2 lb/

MMBtu.

Table A-25 displays each State’s coal production for

the utility market. The first column presents each State’s

coal production, in millions of tons, for the utility market in 1980. The second column shows what proportion of that production would not allow utilities to comply with a 1.2 lb/MMBtu S02 emission limit without

applying control technologies. The third column presents the percentage of this ‘‘noncompliance’ coal sold

on the spot market, i.e. , sales not covered by a longterm contract between a utility and a mining company.

Noncompliance coal sold on the spot market is likely

to be most vulnerable to more stringent S02 regulations.

The final column shows the portion of noncompliance

coal exported to other States—an indicator of the potential efficacy of State-level policies designed to minimize coal market disruptions.

~IFIor ~ d,$( “ss, O1) ~~f the factors aflectrng the t hotce of ((MI i wc ~;cjngr~’ssmnal Budget of fic e, 7?re Lrtillty, Industry, thr Coal .tlarkrt, and (he CleM

Air A( t, April 1 !)82, and Martin Zlmrnerman, The L’ S Gal Industr} “1’hc

El onomlcs of Public Choice (Cambridge, Mass MI’1’ Press, 1981)

● ’l’he degree to wh)~h cuntracts usnstrain fuel-switching is a major uncertainty m this msalysls In 1980, 88 5 percent uf coal pure hased was purchased

on L ontrm t It is not t tear whether changes nr en\.lrunnlental re<qulatwns would

abscsl\c pure hasem uf their contractual obllgatmrrs A contract t an t ont~ln prw

vmwnf (c ~., ‘‘f[)~ e majeure’ clauses) whl( h d irtx tly a(idrms the (M]r+tlons

of pdrt ies [n the event uf [ hanges rn envlronmenta] regulatmns 13uver or seller

( ouki be re]m ed of a]] or part of the contra( tua] ob]l~dtbns See S( (It t, ‘ ‘(~odl

SupplY .Agreements, “ 23 Rock} Afountain i,aw [n~tlrure 107 ( 1979)
App. A—Emissions and the Costs of Control ● 191

0
192 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table A-24.—Demonstrated Reserve Base by Sulfur Category

(quantities in millions of tons, sulfur categories in lb SO2

/MMBtu)

State <0.9 0.9-1.2 1.3-1.5 1.6-2.0 2.1-3.0 3.1-4.0 4.1-5.0 5.1-6.0 >6.0 Total

Alabama . . . . . . . . . . . . . . . . . . . 5 1,775 -

- 

- ‘-

“ ‘-- ‘

-

Georgia. . . . . . . . . . . . . . . . . . . . 0 0

Illinois. . . . . . . . . . . . . . . . . . . . . 0 0

Indiana . . . . . . . . . . . . . . . . . . . . o 212

Kentucky . . . . . . . . . . . . . . . . . . 0 10,210

Maryland . . . . . . . . . . . . . . . . . . 0 1

Michigan . . . . . . . . . . . . . . . . . . 0 0

North Carolina . . . . . . . . . . . . . . 0 0

Ohio . . . . . . . . . . . . . . . . . . . . . . 0 0

Pennsylvania . . . . . . . . . . . . . . . 16 568

Tennessee . . . . . . . . . . . . . . . . . 0 189

Virginia . . . . . . . . . . . . . . . . . . . . 784 1,469

West Virginia . . . . . . . . . . . . . . . 3,407 13,724

Eastern U. S. total . . . . . . . . . 4,212 28,149

Alaska. . . . . . . . . . . . . . . . . . . . . 5,805 18

Arizona . . . . . . . . . . . . . . . . . . . . o 0

Arkansas . . . . . . . . . . . . . . . . . . 0 11

Colorado . . . . . . . . . . . . . . . . . . . 7,800 2,212

Idaho . . . . . . . . . . . . . . . . . . . . . . 0 0

lowa . . . . . . . . . . . . . . . . . . . . . . o 0

Kansas . . . . . . . . . . . . . . . . . . . . o 0

Missouri . . . . . . . . . . . . . . . . . . . 0 0

Montana . . . . . . . . . . . . . . . . . . . 84,247 32,786

New Mexico . . . . . . . . . . . . . . . . 1,277 508

North Dakota . . . . . . . . . . . . . . . 564 165

Oklahoma . . . . . . . . . . . . . . . . . . 8 750

Oregon . . . . . . . . . . . . . . . . . . . . 12 0

South Dakota . . . . . . . . . . . . . . . 0 0

Texas . . . . . . . . . . . . . . . . . . . . . o 0

Utah . . . . . . . . . . . . . . . . . . . . . . 399 4,733

Washington . . . . . . . . . . . . . . . . 843 16

Wyoming . . . . . . . . . . . . . . . . . . 33,527 8,560

Western U.S. total . . . . . . . . . 134,482 49,761

United States . . . . . . . . . . . 138,694 77,909

SOURCE: Adapted for Office of Technology Assessment by E. H. Pechan & Associates from U.S. Department of Energy, Demonstrated Reserve Base of Coal in the

United States on Jan l, 1979, DOE/ElA-0280(79) May, 1981.

1,712

4

0

992

3,846

0

11

0

587

135

458

2,932

10,681

332

0

23

4,841

4

0

0

0

1,410

2,701

1,961

280

0

193

0

158

0

1,007

12,911

23,592

1,074 1,756

0 0

4,359 1,581

1,304 503

1,473 410

296 65

0 95

0 0

0 1,119

1,992 8,581

154 154

561 148

2,791 6,029

14,005 20,440

0 0

399 25

260 43

213 1,150

0 0

0

0 o

0 0

1 1,527

7 48

2,908 2,244

26 332

6 0

74 0

0 12,693

0 178

578 0

24,214 2,606

28,685 20,845

42,690 41,285

438

0

3,151

453

749

175

0

1,294

12,203

62

118

3,084

21,726

0

0

74

0

0

0

190

0

0

0

1,524

144

99

o

1,033

143

4

3,212

24,938

0

0

3,107

2,018

1,556

178

26

0

6,684

3,757

234

0

3,535

21,096

0

0

0

0

0

0

123

518

0

0

604

0

0

0

0

0

0

0

1,246

22,341

0

0

14,248

1,976

7,524

107

0

0

4,429

1,684

31

0

355

30,353

0

0

0

0

0

71

210

0

0

0

0

21

0

0

0

0

0

0

302

30,655

o

41,260

3,161

8,472

0

0

5,509

1,039

39

0

4,128

63,616

0

0

0

0

0

2,127

472

5,559

499

0

0

83

0

0

0

0

95

8,835

72.451

6,760

4

67,705

10,621

34,240

826

128

11

19,035

30,428

998

3,538

39,985

214,277

6,155

424

411

16,215

4

2,199

995

6,077

120,469

4,541

9,971

1,644

17

366

12,693

6,502

1,580

70,014

260,279

474.556

Changes in Regional Coal Production,

Employment, and Economic Activity

METHODS OF PROJECTING REGIONAL

COAL PRODUCTION

This appendix projects regulation-induced changes

in regional coal production using results from a computer model modified by ICF, Inc., from the DOE National Coal Model. ICF’s Coal and Electric Utilities

Model (CEUM) makes it possible to compare: l) projected regional coal production in 1990 (and 2000)

assuming that current S02 emissions standards are

maintained, to 2) projected regional coal production in

1990 (and 2000) insignificant S02 emissions reductions,

designed to control acid rain, are required. The ICF

model has been used to project the effects of acid rain

control proposals by: the Environmental Protection

Agency, the Department of Energy, the Edison Electric Institute, and the National Wildlife Federation, and

National Clean Air Coalition. ICF did not perform the

model analyses discussed here for OTA, but for the

other groups mentioned above.

CEUM is a “least-cost optimization model” that

chooses the combination of scrubbers, coal washing, and

low-sulfur coal substitution or blending that minimizes

the utility industry’s emissions reduction costs. 54

Changes in utility coal consumption patterns alter regional patterns of coal production. These projected production shifts form the basis for OTA’s estimates.

This report uses four ICF S02 emissions reduction

scenarios, and their attendant regional coal production

scenarios, to analyze the potential magnitude of coal

market impacts:

1. Scenario I: a 5-million-ton decrease in utility S02

\~hIcJr ;l de~criptlon ~)f IC F’~ Coa] and E]ectnc Ut ill[ ies hf{)d~[ see the t’x~~ uti\’e summary m ICF, inc , Capabdltws and Experknre In the Cod] and E/et

(m Lrtillo lndustrws, May 1981 .
App. A—Emissions and the Costs of Control . 193

Figure A-7.—Demonstrated Reserve Base by

Sulfur Content

Pounds of sulfur dioxide per million Btu

● SOURCES: Off Ice of Technology Assessment, and E. H. Pechan Associates,

2.

3.

4.

1982.

emissions by 1990, allocated according to a ‘‘ regional (31-State) least cost” approach;

Scenario II: a 10-million-ton reduction of S02

emissions by 1990, allocated according to utility

emissions in excess of an emissions rate of 1.2 lb/

MMBtu;

Scenario III: a 13-million-ton reduction by 1990,

allocated according to a formula similar to (2)

above; and

Scenario IV: a 10-million-ton reduction, allocated

according to a ‘‘regional least cost’ approach,

showing regional coal production shifts out to

2000. 55

‘5S( cnarlf~ I wd\ perlorrrrcd by 1(:F for IX)E and EPA See itlterrra(l~re

S(rd(r,y](.s for Redu( {ny L“(dlr} .SC)~ and NO, Em~ssmns, draft repurt,

%.plembcr 1981 S( cnarios 11 and 111 were performed b, ICF for the Edison

F:le[ trlt Instlto[t SctI the EE1 rntmo {latecf Fell 8, 1982, on ICF anal, \Is of”

the hl II( hell BIII ( S 1706) SC eoant) 11’ way performed b} IC F for the Natlorral

k$’ii(]]ile }Jedcra[l(m and Na[r(jnal (Ilean A!r Coa]ltlon Sce Cos[ dncf CIMI Pro-

(III[ [J(JO F;ffe( rs (J/ R(YIu( Iny E/et trx L’ri/Ir} Sulfhr DmYIcfc Em Is,sI(Ins, Nm

14, 1981

The model cannot predict how various acid rain proposals would, in practice, be implemented. These scenarios merely illustrate the potential magnitude and

direction of coal market shifts associated with various

reductions in S02 emissions, when costs to the utility

industry are minimized. Some analysts assert that the

ICF model seriously underestimates the probable extent of fuel-switching, while others suggest that its fuelswitching estimates are overstated. *

In addition, changes in model assumptions cause

future coal production estimates to vary considerably.

OTA considers that the chosen scenarios reasonably represent the relative magnitude of fuel-switching and

scrubber use.

Several important factors that might influence the accuracy of ICF’s projections are:

Innovation in pollution control technology: The

likely extent of fuel-switching depends on the cost

of that approach as compared to other emission reduction options. The ICF model reflects the best

available estimates of current costs for various control options. If innovations were to significantly reduce the costs of control technology relative to fuelswitching, smaller changes in regional coal production would accompany any given level of emissions

reductions.

Utility regulatory policy: State regulatory policies

may make certain emissions reduction options

more attractive to utilities. For instance, provisions

that allow utilities to pass increased fuel costs

through to consumers without undergoing a rate

hearing may make fuel-switching more attractive

to utility managers than the ICF model would suggest. ” * The final section of this appendix addresses

potential effects of State regulatory policies in

greater detail.

Transportation costs: Railroad rates govern the

penetration of low-sulfur Western coal-into Eastern and Midwestern utility markets. A rapid escala-

“Ft)r anal)rscs asserting that ICf-- urrcferesttmate\ fuel -swltc hlng, see the tes-

(Imony of Chrrs Farrancf of Peabndy Cna] C() on S 1706 to the (;ornmlttee

on F.nvlronmcnt and Public }$’orks. LT S !$enate, ()( t 29, 1981 If thrs rj th e

case, the pr~~yx tt{ms prc-sentccf here hate urrdermt trnatecf the m,i~nltude of r<, -

gional redistribution of produc(lon

On the other band, utilit) analyses of how this bdl would he implemented

for their systems show little e~idence of potential coal market disruptions An

analysis by American F~ectrlc Power (the Natmn largest utd ity and coal cxJnsumer) states that cm]) 4 of their 27 units would switch to lower sulfur furls,

while the others would retrofit scrubbers or be retired See AEP, ‘‘ Eccsnom ic

Impact Summary of Mitchell Bd] (S 1706) on Customers of the AEP SY,stem,

Feb. 23, 1982,

● ● Many public utility commissions do not allow utilities [o earn a return

on capitaf investment (e. g., a scrubber) untd it becomes operational. Thus,

he{ auw ch:inges in fuel prices can be passed on immediately to cunsurners,

ut dlt ws mrght prefer fuel -swltchlrrg This could be counteracted somewhat b)

prn\lslons allow Ing ut Illtles I() earn cash returns on ‘‘construction work in prcr~-

rew’ before the mquipment be( nmcs operational The final sectmn of this appendm surve)s and discusses Sta(e rwg-ulatorypollcles for publi( utdltles m the

Eastern United States
194 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

●

Table A-25.—Coal Production for the Domestic Utility Market

Percentage Percentage

1980 production for noncompliance noncompliance

utility market Percentage sold on exported to

State (millions of tons) noncompliance spot market other States

Alabama . . . . . . . .

Arizona . . . . . . . . .

Colorado . . . . . . .

Illinois , . . . . . . . .

Indiana . . . . . . . . .

Iowa . . . . . . . . . . .

Kansas . . . . . . . . .

Kentucky . . . . . . .

East. . . . . . . . . .

West . . . . . . . . .

Maryland . . . . . . .

Missouri . . . . . . . .

Montana . . . . . . . .

New Mexico . . . .

North Dakota. . . .

Ohio . . . . . . . . . . .

Oklahoma. . . . . . .

Pennsylvania . . . .

Tennessee . . . . . .

Texas . . . . . . . . . .

Utah . . . . . . . . . . .

Virginia. . . . . . . . .

West Virginia. . . .

North . . . . . . . .

South . . . . . . . .

Wyoming . . . . . . .

15.8

10.5

13.6

53,4

27.3

0.4

0.7

112.4

73.9

38.5

1.2

5.0

27.9

17.0

15.3

34.3

2.7

50.9

7.6

27.0

8.5

13.8

53.1

30.8

22.3

89.7

82.50/o

0.0

7.1

99.9

99.9

95.9

100.0

89.9

83.2

100.0

100.0

100.0

63.6

69.8

99.2

100.0

98.6

99.1

86.7

100.0

20.0

87.5

81.3

97.8

58.5

16.6

17.3 ”/0

0.0

0.4

6.6

8.3

14.5

29.3

16.5

19.0

11.8

22.8

6.9

0.0

0.3

13.6

18.9

17.3

29.9

17.6

0.0

1.1

10.6

8.1

7.5

8.8

0.9

10.1%

0.0

2.8

66.0

22.1

0.0

81.7

72.9

75.1

68.7

24.7

33.5

51.9

1.2

20.8

26.5

98.6

30,1

34.6

0.0

7.1

71.0

39.4

46.1

30.1

9.9

a"Noncompliance" coal is defined as coal that would not permit utilities to comply with an emissions limit of 1.2 lb of SO2/MMBtu

without applying control technologies.

SOURCE: From DOE/EIA Form 423 data, supplied to OTA by E. H. Pechan & Associates.

tion in Western rail rates could raise the delivered

price of Western coal, thereby reducing the magnitude of regional shifts.

Electricity growth rates: While the rate of growth

in electricity demand should not significantly affect the extent of fuel-switching as opposed to other

control options, projected increases in the amount

of coal produced by 1990 are highly dependent on

assumptions about the rate of growth in electricity

demand.

FORECASTING COAL MINE EMPLOYMENT

AND ECONOMIC CHANGES

OTA combined production estimates from the ICF

model with coal-miner productivity and income data to

project the effects of acid rain control scenarios on regional employment and economic activity. Employment

in the coal-mining industry is determined by two factors: the level of coal production (tons of coal) and the

rate of worker productivity (tons of coal produced per

miner). Historically, employment levels have been affected more by changes in productivity than by changes

in production. * * * Therefore, employment forecasts .

must provide for uncertainties about future productivity y

levels. This analysis presents projected coal-mine

employment changes as ranges reflecting different

assumptions about future productivity levels: a lower

bound of a 10-percent decline from 1979 productivity

levels and an upper bound of a 30-percent increase. *

‘ ● ● Over the period 1960 to 1970, coaf-rnine employment declined from

190,(KN to 144,000, a 3-percent average annual decrease. over the same permd,

coal product lcsn increased from 434 million to 613 mdllon tons, an a\erage

annuaf int. rease of 4 pement The dtsc repancy between employment and pr{Jduction trends is accounted for by im reases in average coal-miner productivity

during this period ‘1’he average coal produc tmn per miner increased from about

12 to about 18.5 tons per day-an average annual increase of nearly 4 percent

The im reining proportion of surface minmg-from 32 per(tnt of annual production (or 139 million tons) In 1960 to 44 percent (or 270 million tons) in 1970

—accounts for some of the gains, since the average surface mmer produces about

three times as much coal per day as the average underground miner

“l”hese productivity ranges ha\e been chosen somewhat arbltraril}, The 30-

percent Inc rcase m producti\,ity was chosen as one bound because It reflects

the historic al maxrmum The 10-percent decrease was chosen to acc t)unt for

factors that may mntribute to decreased product l\ltY,, such as more stnntynt

mine health and safety or surface redamat ion regulations, or a shlf[ fr(}nl surface to underground mrning After a steady decline over the past 12 years, productivity is finally begiming to rise again, but future trends are uncertain For

a discussion of factors affecting worker prvductivlt), In coal mining see oflce

of Technology Assessment, Direct Use of’ Coaf, (MA-E-86, Aprd 1979, ( h

IYr See also Electric Pnwer Research Institute, 7’he Labor Outlook fi)r the

Blrumlnous Coal .\ fjning Indusrr?, EPR1 EA- 1477, final relx)rt, August 1980
App. A—Emissions and the Costs of Control 195

These employment projections are combined with miner

income data to estimate the ‘ ‘direct’ income effects of

acid rain controls.

However, direct income effects do not reflect the full

impact of changes in coal-mine employment. Economic

activities dependent on the coal-mining industry, such

as rail transport and retail services to coal-mine industry employees, are also affected. These indirect economic effects are likely to be quite significant, but are

extremely difficult to estimate. Indirect effects include

reduced employment, reduced income to the employed,

or some combination of both. In this analysis, direct income effects are combined with an income ‘‘multiplier’

—a very rough approximation of the regional economic

activity that depends indirectly on coal mining—to derive ‘‘total income effects of acid rain control scenarios. * *

PROJECTED PATTERNS OF CHANGE

Table A-26 summarizes how 5-, 10-, and 13-millionton S02 emissions reductions might affect regional coal

production, employment, and economic activity. Several generalizations emerge from the analysis. First, the

model projects significant growth in coal production nationwide (about 60 percent) between 1979 and 1990.

Second, regulations designed to control acid rain, even

those calling for the largest emissions reductions, do not

alter the projected increases in national production.

Even with the additional costs of acid rain controls, coal

is projected to retain its competitive advantage over

other fuels.

Third, while acid rain control measures are not projected to change nationwide production levels, the ICF

model projects a redistribution of coal production

among regions. Regions with low-sulfur reserves are

projected to experience production growth beyond what

would occur under current regulations. On the other

hand, between 1979 and 1990, production in regions

with high-sulfur reserves is projected to decline below

currently projected 1990 levels, and—in the case of the

10-million-ton and greater reductions of S02 emissions—below 1979 production levels as well. The projected redistributions increase in magnitude as S02

emissions reductions increase, but by less than linear

proportions. * Figure A-8 shows the projected change

in regional coal production from 1979 to: 1 ) 1990 levels,

● ““I’(J .irrl\ft at tnl!Jl(wrllcr]l c,\tlnldtts, ()’1’A rIl\ Idt.\ prx!]e{ ted productl{)rl

Inc rt,t\t.\ })} St,it(.-l)\-SMtc. pr(du[ t I\ rt} (],ita cie\.t.]npcd from Doh; data ‘1’ht.w

t.r]][)lf)~ ]i)cnt ( hanqcs ~rt. thcrr ( ornblncd with rnlncr salary data to arrrve at

dlrc( r )n( orr]t. rfl(.(1s In(ltrrt t {,( fmcmu( Impa( ts were rstlmatc{l uslrrg an ‘ ‘(.( ()-

r)f]rr] I( lj,i\[ ((( I]n](lut. ‘‘ ~:[~r c,t( h St.il(, rnul[lpllcrs wt, re dt. \ t.l(lptxi h\ t .II( [II.i[ rnq ( h(. r.it ]( ~ ()! ln( t)rrlt cl{.rl\{,cl ir~jrrl [h(, ‘ ‘ I),tst. ‘ {Jr ‘ ,}jrlrI1ar\‘‘ \{.{ [{)r [{1 III.

{ {)rf)t, flt,r]~ ({l Ir,)rrt tht ‘ ‘ wr\ J( t, ‘ or ‘‘ \(.( f)r](l<ir] ~(( tor ‘‘

● ,4$ [.m)\\ll,n\ ll,(lu{ tlon rt.qulr<nu.nt\ In( reaw Ix,}on(! A c crtarn IL,\{,l, II)t.

prt)p{~rtl(,n (It rt,(lu( tl~)n\ [h,i[ ,irt, [)rr)lt( t{.(1 (() h{ m{.t })} ‘‘ fue-s\\ II( hlrlq’ (lt-

( rt.a\t.s rrl,i[ I\ t, t f ) t ht. prr~~)ort ion rr){.[ I)\, S( rul)lx.rs

assuming no change in S02 standards; and 2) 1990 levels, assuming a 10-million-ton decrease in S02 emissions. * *

The areas most likely to experience significant growth

in production are southern West Virginia, eastern Kentucky, and the regions west of the Mississippi (particularly Colorado). The regions most likely to experience

significant production declines include northern West

Virginia, Ohio, western Kentucky, and Illinois. However, available model projections for 2000 suggest that

production declines below current levels may be reversed

in the decade following 1990. Production levels are projected to rebound due to general trends in the energy

market, such as growth in utility demand, and to the

fact that an increasing number of new plants regulated

under New Source Performance Standards will come

online after 1990.

Employment patterns are projected to correspond to

changes in production. However, uncertainties regarding future productivity trends create a larger range of

uncertainty for employment effects than for production

effects. The loss of portions of the market for high-sulfur

coal could reduce employment opportunities in Midwestern and northern Appalachian regions by about 10

to 40 percent of projected 1990 coal-mining work force

levels under current emissions standards. The areas of

northern West Virginia, Ohio, western Kentucky, and

Illinois are projected to experience actual employment

decreases below 1979 levels for emissions reductions of

10 million tons and greater.

Future employment changes would be accompanied

by proportional changes in direct miner income and

total monetary effects. For each of the high-sulfur coal

regions of northern Appalachia and the Midwest, these

costs range from $250 million to $500 million in direct

annual income losses to miners, and from $600 million

to $1,100 million in total (direct plus indirect) annual

monetary losses. The coal-related benefits in central

Appalachia range from $400 million to $550 million annually in direct income gains, and total annual income

gains of $750 million to $1,100 million. Estimates of

benefits in the West range from $100 million to $150

million in direct income gains and total income gains

of $500 million to $750 million per year. All estimates

are in 1981 dollars. These figures, particularlyin the

case of total monetary impacts, must be considered very

rough estimates.

Changes in coal-related employment and income may

cause some additional community-level social and economic repercussions. In areas projected to experience

significant declines in employment, decreases in tax re\~-

‘ “01 the 90 nlrlll(]n tons O! annual produ[ tlon lo\( h\ [h~. t-;.i~tt,rn ancl hl 1(1-

w,cstern hlqh -sulfur ( (MI rnarke[ h} 1 W(), alx)ut 50 rn dllon tons IS qalncd I)\,

Ila\tcrn low -\ullur pr[xlu( t.rs and 40 nldllt)n torls t)i ;%’cst{.rrl pr(}du( c,r~
Table A-26.—Summary Table of Regional Coal Market Effects of Acid Rain Control Legislation

5-million-ton sulfur 10-million-ton sulfur 13-million-ton sulfur

dioxide emission reduction dioxide emission reduction dioxide emission reduction

North Appalachia Region (Maryland, northern West

Virginia, Ohio, and Pennsylvania)

Under current environmental regulations, annual coal

production is projected to increase approximately 10

percent between 1979 and 1990; under a 5-million-ton

acid rain control program no change in production is

projected over this period. Employment opportunities

foregone are projected to range from 6,300 to 9,100

jobs (a 10-percent reduction); because there is no projected production change, employment changes from

1979 levels will be a function of productivity changes

only. Direct income opportunities foregone by the

regional economy are projected to be $160 million to

$230 million; total income opportunities lost could

range from $450 million to $640 million.

Central Appalachia Region (eastern Kentucky, southern

West Virginia, Tennessee, and Virginia)

Under current environmental regulations, annual coal

production is projected in increase by about 50 percent between 1979 and 1990); under a 5-million-ton

acid rain control program, a 62-percent increase is

projected over this period. Employment is projected

to be about 10 percent (8,800 to 12,700 jobs) greater

than it would have been in 1990 under current regulations; projected employment changes from 1979

levels range from 25- to 80-percent (21,800 to 69,900

jobs) increase. Direct annual income opportunities

created in this region range from $230 million to

$330 million; total annual income created ranges

from $450 million to $840 million.

Under a 10-million-ton acid rain control program, production is projected to decrease by about 10 percent

between 1979 and 1990. Employment is projected to

be 15 percent (9,800 to 14,100 jobs) less than it would

have been under the 1990 base case; projected

employment changes from 1979 levels range from no

change to a 30-percent (23,000 job) decrease. Direct

income opportunities foregone range from $250

million to $360 million; total income foregone ranges

from $630 million to $910 million. Available projections for the year 2000 suggest these declines may

only be temporary.

Under a 10-million-ton acid rain control program, production is projected to increase 70 percent between

1979 and 1990.1990 employment levels are projected

to be about 15 percent (15,000 to 21,700 jobs) greater

than they would have been in 1990 under current

regulations, and 38 to 99 percent (33,200 to 86,500

jobs) greater than 1979 employment levels. Direct income opportunities created are projected to be $390

million to $560 million; total income generated

ranges from $1,030 million to $1,490 million.

Under a 13-million-ton acid rain control program, production is projected to decrease by about 13 percent

between 1979 and 1990.1990 employment levels are

projected to be 20 percent (12,700 to 16,500 jobs) less

than what they would have been in 1990 under current regulations, and 14 to 35 percent (10,800 to

26,100 jobs) below 1979 employment. Direct income

opportunities foregone range from $330 million to

$470 million; total income foregone is projected to be

$810 million to $1,170 million.

Under a 13-million-ton emission reduction, production

is projected to increase 75 percent between 1979 and

1990.1990 employment levels are projected to be 16

percent (17,300 to 25,000 jobs) greater than what they

would have been in 1990 under current regulations,

and 40 to 100 percent (35,800 to 90,000 jobs) above

1979 levels. Direct income opportunities created by

the projected increase in coal production range from

$440 million to $640 million; total income generated

ranges from $1,200 million to $1,700 million.
Table A-26.—Summary Table of Regional Coal Market Effects of Acid Rain Control Legislation (continued)

.—5-million-ton sulfur

dioxide emission reduction

Midwest Region (Illinois, Indiana, and western

Kentucky)

Under current environmental regulations, annual coal

production is projected to increase 31 to 34 percent

between 1979 and 1990; under a 5-million-ton reduction, production is projected to increase 12 percent

over this period. 1990 employment levels are projected to be 16 percent (5,400 to 7,700 jobs) less than

what they would have been in 1990 under current

regulations, and between a 13-percent (4,200-job)

decrease and a 25-percent (8,000-job) increase from

1979 levels. Direct income opportunities foregone

range from $140 million to $200 million; total income

foregone ranges from $370 million to $530 million.

The Western United States

Under current environmental regulations, annual coal

production is projected to increase approximately 138

percent between 1979 and 1990; under a 5-million-ton

acid rain control program, production is projected to

increase 145 percent over this period. 1990 employment levels are projected to be 3 percent (1,200 to

1,700 jobs) higher than what they would have been in

1990 under current regulations, and 80 to 160 percent

(16,600 to 32,900 jobs) above 1979 levels. Direct income opportunities created by acid rain controls are

projected to range from $30 million to $40 million;

total income benefits are projected to be $120 million

to $170 million.

—— —

10-million-ton sulfur

dioxide emission reduction

Under a 10-million-ton acid rain control program, production is projected to decrease 10 percent between

1979 and 1990. 1990 employment levels are projected

to be 33 percent (10,500 to 15,200 jobs) below what

they would have been in 1990 under current regulations, and 6 to 35 percent (1,900 to 11,300 jobs) less

than 1979 employment. Direct income opportunities

foregone are projected to range from $270 million to

$390 million; total income foregone ranges from $770

million to $1,100 million. Projections for the year 2000

suggest these declines may be reversed in the period

1990 to 2000.

Under a 10-million-ton acid rain control program, production is projected to increase 158 percent between

1979 and 1990.1990 employment is projected to be

13 percent (4,600 to 6,700 jobs) greater than what it

would have been in 1990 in the absence of acid rain

controls, and between 95 and 180 percent (19,100 to

36,300 jobs) greater than 1979 levels. Increases in

direct income opportunities range from $120 million

to $170 million; total income increases are projected to range from $510 million to $740 million.

SOURCE: Office of Technology Assessment, based on coal production estimates from ICF, Inc.

1 3-million-ton sulfur

dioxide emission reduction

Under a 13-million-ton sulfur dioxide emission reduction, production is projected to decrease by 17 percent between 1979 and 1990. Employment is projected to be 38 percent (12,100 to 17,400 jobs) below

what it would have been in 1990 without an acid rain

control program; projected employment decreases

from 1979 levels range from 13 to 40 percent (4,200 to

12,900 jobs). Direct income opportunities foregone

range from $.310 million to $480 million; total income foregone ranges from $870 million to $1,200

million.

Under a 13-million-ton sulfur dioxide emission reduction, production is projected to increase 165 percent

between 1979 and 1990. Acid rain controls are projected to increase employment opportunities by 20

percent (6,800 to 9,800 jobs) over what they would

have been in 1990 without any change in environment

regulations. 1990 employment levels are projected to

be 105 to 196 percent (21,000 to 39,300 jobs) greater

than 1979 levels. Direct income opportunities created

in the region are projected to range from $180 million to $250 million; total income benefits range

from $750 million to $1,100 million.

.
198 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure A-8.— Regional Coal Production: Effects of a 10. Million. Ton Sulfur Dioxide Emission Reduction

enues could cause the quantity or quality of community services to decline. In areas projected to experience

rapid increases in employment, the capacity of communities to provide adequate health care, housing, education, etc. , may be strained.

RESULTS OF OTHER STUDIES

The United Mine Workers (UMW) has also calculated the potential effects of a 10-million-ton reduction

in S02 emissions, allocated as in OTA’s Scenario II.

The UMW analysis presents three sets of estimates of

effects on mineworker employment and economic activity in high-sulfur coal areas only, assuming that fuelswitching would account for 50, 75, or 100 percent of

the required reductions. However, the UMW analysis

made no calculation of gains in employment and economic activity in low-sulfur coal areas, or of the net effects of the 10-million-ton emissions cutbacks.

Table A-27 shows the UMW projections of job losses,

direct annual economic losses, and total annual economic losses for the three levels of fuel-switching. Using a

DOE estimate that between 50 and 75 percent of the

SOURCE: Office of Technology Assessment, adapted from ICF, Inc

reductions required under a major acid rain control program would be met by fuel-switching, the UMW ‘calculated that between 40,000 and 60,000 coal mining jobs

would be lost in high-sulfur coal areas, producing direct annual income losses of $1.1 billion to $1.6 billion,

and total economic losses ranging between $3.0 billion

and $4.6 billion.56

For comparison, OTA estimates of the net effects of

the 10-million-ton reduction on high-sulfur coal areas

are also presented in table A-27. Two factors must be

considered in comparing these estimates:

1. OTA used projections of increases in coal production, including increases due to construction of new

electricity plants, through 1990, and compared

them to projections of how further emissions controls would affect these new production levels.

UMW estimates are calculated from 1981 production levels, assuming that no changes in production occur up to the time that controls would be

implemented.

~~~r~ltc{l hf lne L%’orkers, ‘‘ F,mpl(n rnrnt In)pa( ts of A( id Rain. .Junc 1983
App. A—Emissions and the Costs of Control ● 199

Table A-27.—Employment and Economic Effects on High-Sulfur Coal. Producing

Areas of a 10-Million-Ton Reduction in S02 Emissions—

Comparison of UMW and OTA Analyses

UMW estimates

percent of emissions OTA estimates

reductions achieved

through fuel switching Change Change

from 1990 from actual

50 75 100 base casea

1979 levels

Employment Iossesb . . . . . . . . . . . . . 40,000 60,000 80,000 23,000-33,000 9,000-38,000

Direct annual economic losses

(millions 1981 dollars) c

. . . . . . . . . . . . $1,100 $1,600 $2,100 $600-$800 $200-$1,100

Total annual economic losses . . . $3,000 $4,600 $6,100 $1,600-$2,300 $600-$2,700

aOTA assumes, based on ICF analyses, that the requisite emissions reductions will be met by a combination of fuel-switching

and scrubbers The base case assumes no change in environmental regulations.

bThese employment losses occur over the period required to implement the pollution reductions. The ranges reflect uncertainty in future productivity levels OTA bounds employment and economic estimates by assuming that productivity might

rise as much as 30 percent or decrease by as much as 10 percent between 1979 and 1990,

cAnnual monetary estimates assume implementation of emissions reductions over 10 years, and that shifts in coal production are distributed equally over that period

SOURCE Office of Technology Assessment, based on coal production estimates by ICF, Inc

2. In the OTA estimates, employment losses in highsulfur coal areas are partially compensated for by

employment gains. Thus, the OTA estimates are

of the net effects in high-sulfur coal-producing

regions. No projected employment increases are

figured into the UMW analysis.

OTA’s best estimates of potential effects on highsulfur coal regions show employment impacts about half

as large as those estimated by UMW, assuming 50 to

7.5 percent fuel-switching. * The most pessimistic of the

OTA estimates—38,000 jobs lost from actual 1979 levels

—approximates the low-end UMW figure of 40,000.

Possible means of’ preventing or decreasing coal miner

unemployment that may ensue from acid rain control

legislation are discussed in chapter 7 under question 8.

They include mandating control technologies to achieve

emissions reductions, thereby prohibiting fuel switching and employing sect ion 125 of the Clean Air Act to

restrict coal consumption to ‘‘local or regional coals.

The net effect of acid rain legislation on nationwide

coal product ion, employment, and economic activity,

howevrer, also includes the offsetting increases in

employment and economic activity in low-sulfur coal

regions. When these are considered in aggregate, OTA

estimates that no significant changes in employment and

economic activity result from control-induced product ion changes.

Electricity-Intensive Industries

OTA used 1979 and 1980 data from the LT. S. Census

Bureau’s Annual Survrey of Manufacturers to assess the

electrical energy dependency of approximate}’ 450 types

of industries.57 Specific industries for which electricity

represents 4 percent or more of the total value of

shipments, and/or 10 percent or more of the total ‘‘value added, * are listed in table A-28. The 17 industries

identified in the table are largely concentrated in the

areas of primary metals; chemicals—particularly industrial inorganic chemicals; and stone, clay, and glass

products. The identified industries account for a disproportionate share of U. S. industrial electricity use—

although they account for only 2 percent of total value

of shipments and 2 percent of total value added by

American manufacturers, they purchase approximately

25 percent of the electricity sold to industry, and account

for about 16 percent of utility revenues from industrial

electricity sales.

Five of these industrial categories—electrometallurgical products, primary zinc, primary aluminum, alkalies and chlorine, and industrial gases—are especially

electricity intensive; the cost of purchased electricity

equals about 40 percent or more of their total value

added, and about 10 to 25 percent of their total value

of shipments. These industries might be considered most

99-413 0 - 84 - 14 : QL. 3
200 . Acid Rain and Transported Air Pollutants: lmplicationS for Public Policy

Table A.28.—Statistlcs on Electricity-intensive industries

Electricity cost as Electricity Ratio to

Value of Electricity percent of: rate industrial

SIC shipments purchased Value Value of ¢/kWh average rate

Industry code (10° 1980$) (106 kWh) added shipments (1982$) (3.84¢/kWh)

Cotton seed oil mills. . . . . . . . . . . . . . .

Manufactured ice . . . . . . . . . . . . . . . . .

Particle board . . . . . . . . . . . . . . . . . . . .

Alkalies and chlorine . . . . . . . . . . . . . .

Industrial gases . . . . . . . . . . . . . . . . . .

Other industrial inorganic

chemicals . . . . . . . . . . . . . . . . . . . . .

Carbon black. . . . . . . . . . . . . . . . . . . . .

Reclaimed rubber . . . . . . . . . . . . . . . . .

Cement, hydraulic . . . . . . . . . . . . . . . .

Lime . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mineral wool . . . . . . . . . . . . . . . . . . . . .

Electrometallurgical products . . . . . .

Malleable iron foundries . . . . . . . . . . .

Primary zinc. . . . . . . . . . . . . . . . . . . . . .

Primary aluminum . . . . . . . . . . . . . . . .

Other primary nonferrous metals . . . .

Carbon and graphite products . . . . . .

2074

2097

2492

2812

2813

2819

2895

3031

3241

3274

3296

3313

3322

3333

3334

3339

3624

1,033.7

169.6

512.4

1,354.1

1,539.6

12,095.9

498.0

38.3

3,962.4

598.8

2,235.4

1,249.3

521.2

413.1

6,979.9

1,906.6

1,183.3

540.7

460.7

825.1

10,679.5

11,958.6

37,092.0

540.4

75.4

9,237.9

813.8

2,703.5

6,814.3

1,015.5

1,487.8

72,279.1

4,279.4

2,171.8

10.7 2.0

15.6 11.0

11.4 4.8

45.5 19.6

42.4 24.5

13.9 7.5

13.3 3.5

12.2 7.8

15.3 8.2

10.8 5.1

7.3 4.0

42.0 13.8

11.9 7.0

51.7 8.3

39.3 15.6

15.6 5.1

7.5 4.2

4.61

4.70

3.44

2.89

3.66

2.86

3.78

4.62

4.08

4.38

3.82

2.94

4.17

2.67

1.75

2.66

2.64

1.20

1.23

0.90

0.75

0.95

0.75

0.99

1.20

1.06

1.14

0.99

0.77

1.09

0.70

0.47

0.69

0.69

SOURCE: US. Census Bureau, 1980 AnnualSurvey of Manufacturers: Fuels and Electric Energy Consumed, August 1982.

sensitive to potential increases in the cost of electrical

power resulting from further control of S02 emissions.

For all five of these industries, a substantial proportion

of production occurs in the 31 Eastern States.

Primary zinc is the most concentrated industrial category —only five producers currently operate in the

United States. The three largest manufacturers are

located in Pennsylvania, Illinois, and Tennessee, and

account for approximately three-quarters of the Nation’s

current production. The zinc industry appears to be particularly vulnerable to increases in the cost of production

—U.S. annual production capacity fell from about 1

million tons to 300,000 tons over the past decade, and

foreign producers have captured a substantial share of

domestic sales.58

Primary aluminum, by far the largest of these industries, is produced in 13 of the 31 Eastern States.

Although two non-Eastern States—Texas and Washington—currently have the largest production capacities,

the Eastern United States currently accounts for about

60 percent of national production capabilities. Major producers in the region include: Alabama, Arkansas, Indiana, Kentucky, Louisiana, Missouri, New York,

Ohio, and Tennessee.59

Production of alkalies and chlorine is about equally

divided between the Eastern and Western regions of the

United States. Louisiana accounts for nearly one-quarter of national output; the 17 other Eastern States in

~IJpc~~O~~ ~CJ~~u~lC~tlon, James Kennedy, Burcdu of Industrial F,(onoml{s,

U S Department of Commerce, October 1983

‘

g

Ibid

which these chemicals are produced together account

for a slightly smaller proportion of production. GO Alabama, New York, Michigan, and West Virginia are the

fifth, sixth, eighth, and ninth largest producing States

in the country, respectively.

Information on the distribution of industrial gas production is limited, due in part to confidentiality requirements for protecting individual manufacturers.

Available data indicate that Texas and California were

the highest producing States in the late 1970’s, and show

substantial amounts of production in the following Eastern States: Alabama, Delaware, Illinois, Louisiana,

New Jersey, New York, Ohio, Pennsylvania, and Tennessee.

61

Over 90 percent of U.S. electrometallurgical products (i. e., specialized metal alloys made with such metals

as molybdenum, manganese, and chromium) were produced in the 31 Eastern States in 1981. Ohio accounted

for about one-third of national production; six additional

States—Alabama, Kentucky, New York, South Carolina, Tennessee, and West Virginia—together accounted for slightly under one-half of national production. The industry is highly vulnerable to foreign

competition, as countries with deposits of the necessary

ores are rapidly developing their own production capabilities. 62

CoPerSorla] ~ommunlcatlon, Frank Maxey, Bureau of Industrial Et onon]ics,

U.S Department of Commerce, october 1983

b! Ibid

Ctpersona] ~ommuniatlon, I’om Jones, Bureau of Nlmes, U S Department

of the Interior. December 1983 ‘
App. A—Emissions and the Costs of Control ● 201

Uncertainties about how utilities might apportion

control-related increases in electricity rates make it difficult to assess the likely extent of financial effects on

electricity-intensive industries. As shown in columns 3

and 6 of table A-28, many of these industries are largescale electricity consumers, and pay relatively low electricity rates. If control costs were apportioned to users

primarily on the basis of current rates (i. e., increasing

existing rates by a uniform percentage for all users),

effects on these industries, although potentially significant, would not be disproportionate to cost increases

undergone by all electricity consumers. However, if control costs were apportioned primarily on the basis of electricity consumption (i. e., increasing existing rates by

a uniform mill/kWh fee for all users), percentage rate

increases would be highest for those industries currently

paying low electricity rates. Effects could be particularly

severe for those industries having both low rates and

high electricity dependency-primary aluminum, alkalies and chlorine, electrometallurgial products, and primary zinc.

Utilities in the Eastern 31 States*

The amount of SO2 that an individual utility must

eliminate from its emissions is, of course, the primary

determinant of the effect of acid rain control legislation

on a given company’s finances. Such factors as each utility’s ability to raise capital to cover construction costs

and regulatory policies in any given State further determine a utility’s ability to pay for required reductions

without adverse financial effects.

To address the utility sector’s vulnerability to further

emissions reductions, this section will: 1 ) present 1980

State-average S02 emissions rates for coal- and oil-burning plants to indicate the potential extent of additional

control requirements, 2) use available financial indicators for 1980 to assess the health of each State’s utility

sector, 3) assess the implications of State regulatory policies in 1980-81 for utility finances, and 4) integrate the

first three types of information in concluding observations, identifying areas of particular vulnerability, where

possible.

Current Emission Rates

and Generating Capacities

Figures A-9 and A-10 rank States in the Eastern

United States according to their coal- and oil-fueled electrical generating capacities, and by average 1980 emis-

“’1’h]s wc ti[}n hased prlmanly on Kathleen (;(,le, l)u,ine (;hapman, and

(Illfforci RossI, ‘‘ F’]nan{ Ial dn(l Rcqulat,,r) Fa( tors .Affc{ tln~ the State an d

R{glf,nal Econnml< Impa( t ,)1 Sulfur oxide Emlssiuns [:nntrol, prepare d

for the of fi{ c of ‘1’tw hnc)log} ,~ssc~smcnt. L’ S [;(]ngrcss, August 1982

sion rates for all coal- or oil-fueled plants in the State.

The greater a State’s dependence on either of these fossil

fuels, and the higher its average S02 emission rate, the

greater the likelihood that proposed emissions controls

would require additional utility expenditures to reduce

emissions. States with the greatest probability of extensive expenditures for emissions control appear in the

upper left portion of each table; those with the least,

appear at the bottom right. Overall, emission rates for

coal-fired utilities are substantially higher than for oilfired facilities; thus, many more States would be exposed

to significant control expenditures on the basis of current utility coal combustion than oil combustion. Detailed estimates of S02 emissions reductions required,

by State, under a number of alternative control scenarios, are provided in section A. 3 of this appendix.

Utility Financial Positions

Ultimately, a utility recoups its emission-reduction

expenditures by selling power to customers in its service area, or to other utilities. However, a utility must

shoulder the burden of pollution control expenditures

from the time they are made until it is allowed to begin

charging customers for them. Substantial capital investment is required to retrofit existing powerplants with

emissions control devices, or to build newer, cleaner

powerplants. Capital investment may also be necessary

to modify existing powerplant operations to permit the

burning of low-sulfur fuel. The utility’s capacity to finance these expenditures depends in large part on its

ability to attract investment capital.

To place the potential capital-raising burden associated with acid rain control into perspective, estimated

costs of major control programs can be compared to actual utility construction expenditures. Over 5 years

(1978 through 1982), electric utilities spent approximately $180 billion (1982 dollars) for construction in

the United States ;63 potential construction costs of major

acid rain control proposals over a similar 5-year period

might range from about 5 to 20 percent of this figure,

depending on the particular proposal. Control costs

would constitute a higher proportion of construction expenditures for particular States and/or utilities from

which large emission reductions would be required.

Such capital-raising burdens may be particularly critical

for those utilities already scheduled to replace or retire

a substantial proportion of plants over the period in

which further emissions controls would be implemented.

A number of indicators are in use to assess utilities’

competitive positions in capital markets, and no single

measure of financial well-being can adequately charac-

“>lrrrdl 1 ,ym h< Pwrx c, I:cnncr & Smith, [m ,

‘‘ UIIIItY lndustn,, A St.it iwl( ,il

R(A I(’W (Prcllmln.in ), April 1 %’;
202 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure A-9.—Coal-Based Generating Capacities and SO2 Emissions Rates

Coal dependency

(Share of total electric-generating capacity)

a Numbers in parentheses are state-average SO2 emission rates for coal-burning plants, expressed In Ibs. of S02 Per million Btu

SOURCE Off Ice of Technology Assessment, from E H Pechan & Associates, Inc., and K. Cole, et al., “Financial and Regulatory Factors Affecting the State and

Regional Economic Impact of Sulfur Oxide Emissions Control, ” OTA contractor report, August 1982.

Figure A-10. —Oil-Based Generating Capacities and S02 Emissions Rates

Oil dependency

(Share of total electric-generating capacity)

Average SO2 emission

rates from coal-fired

utilities (lb per

million Btu)

aNumbers in parentheses are State. average SO2 emission rates for oil-burning plants, expressed in Ibs. of SO2 Per million Btu.

SOURCE Off Ice of Technology Assessment, from E. H Pechan & Associates, Inc , and K. Cole, et al., “Financial and Regulatory Factors Affecting the State and

Regional Economic Impact of Sulfur Oxide Emissions Control, ” OTA contractor report, August 1982.
App. A—Emissions and the Costs of Control ● 203

terize a utility’s prospects. However, two major financial criteria were selected to describe utility financial conditions at the State level: 1 ) return on common equity

(ROCE), and 2) bond ratings. The first represents common stockholders net earnings during a given year—indicating the utility’s current profitability. The second

represents experts’ judgments about the utility’s longterm ability to reliably repay debt. The lower a utility’s bond rating, the higher the interest rate it will need

to offer to induce investors to purchase bonds.

Table A-29 categorizes States according to 1980 data

on whether more than 50 percent of their electrical power was generated by utilities with: 1 ) bond ratings of

A or better, and 2) ROCEs above the 1980 national median of 11.1 percent per year. Column A lists States

meeting both of these criteria; these States may be considered to have a relatively healthy investor-owned electric utility sector. Column D lists States that met neither of the above criteria. These eight States may be

regarded as particularly’ vulnerable to measures requiring utilities to generate additional capital for pollutioncontrol purposes. Columns B and C show States failing to meet either of the two criteria.

Utilities may be at greater risk from capital-raising

needs if control-related expenditures must be added to

significant amounts of non-control-related construction—either to replace retired plants or to accommodate

increasing electricity demand—during the period in

which further controls would be implemented. While

increasing demand for electricity could, in itself, positively influence utilities’ positions in capital markets, requirements for replacing retired plants carry high capital

costs without necessarily enhancing utility positions.

States in which more than 20 percent of current generating capacity is scheduled for replacement by 1995 include: Arkansas, District of Columbia, Maryland, Massachusetts, New York, and Rhode Island.

State Regulatory Policies

Public utility commissions (PUCs) in each State make

numerous regulatory decisions that affect a utilitys

ability to pass on costs associated with emissions control. PUC regulatory policies vary widely from State to

State; 65 they may also change over time in response to

Table A-29.—Summary of 1980 Utility Financial Conditions by Statea

A. High bond, high ROCE B. High bond, low ROCE

States in which more than 50 percent of States in which more than 50 percent of

generated power was from utilities with generated power was from utilities with

bond ratings of Aa or A, and ROCEs of bond ratings of Aa or A, and ROCEs

11.1 percent or lower: (national median): below the national median:

Iowa Delaware

Kentucky Illinois

Marylandb

Indiana

Massachusetts b New Yorkb

Minnesota Rhode Islandb

Mississippi South Carolina

New Jersey

Wisconsin

C. Low bond, high ROCE D. Low bond, low ROCE

States in which more than 50 percent of States in which more than 50 percent of

generated power was from utilities with generated power was from utilities with

bond ratings of Baa or lower, and ROCEs bond ratings of Baa or lower, and ROCEs

above the national median: below the national median:

Alabama Arkansas b

Georgia Connecticut

Louisiana Florida

Missouri Maine

New Hampshire Michigan

North Carolina Pennsylvania

Ohio Vermont

West Virginia Virginia

aBased on data from 106 surveyed utilities in the Eastern 31-State region Extremely small utilities, utilities with no generating

capacities (electricity distributors), and utilities with no coal or oil generating capacities have been excluded.

bStates in which more than 21) percent of current generating capacity is scheduled for replacement by 19%,

SOURCE Office of Technology Assessment, adapted from K Cole, et al., ’Financial and Regulatory Factors Affecting the

State and Regional Economic Impact of Sulfur Oxide Emissions Control, ” OTA contractor report, August 1982
204 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

changing economic and political conditions. Imposing

stricter emissions controls at the Federal level might induce considerable changes in affected States’ utility regulations; thus, current regulations may not reliably indicate how State-level policies would influence utility

finances. However, to demonstrate the range of current

regulatory conditions, survey information on five major

regulatory policies for each of the Eastern 31 States during 1980-81 is outlined in table A-30.

Two of the surveyed policies directly concern the delay required before adjustments in utility costs can be

passed on to consumers. Each involves short-term delays—the number of months required, on average, for

State utility commissions to rule on requests for rate increases (co1. 4), and the number of times per year that

utilities are allowed to adjust electricity rates according

to those utilities for which switching to more expensive,

low-sulfur coal or oil is a potential means of meeting

more stringent emissions limits.

Three of the policies assessed in table A-30 affect the

manner in which utility rates are calculated. PUCs must

determine a total amount of utility expenses and costs,

or calculated revenue requirements, allowed to be

passed on to consumers, in order to set a utility’s electricity rates. One major component of these costs is the

return on capital investments. The first column of table

A-30, “allowed return on common equity” or ROCE,

shows the maximum return to investors allowed by each

State, calculated as a percentage of a utility’s assets, or

rate base. The second column of the table, ‘ ‘amount

of CWIP allowed in rate base, indicates the extent to

which ‘ ‘construction work in progress’ (CWIP) is conto changes in fuel costs (co1.

lowable fuel cost adjustments

3). The frequency of al- sidered a part of the utility’s assets for ratemaking

is particularly significant purposes.

Table A-30.—Major State Regulatory Policies

Average number

Allowed Amount of Frequency of of months for

ROCE CWIP allowed adjustment for rate decisions Type of

State (median: 14.25) in rate base fuel price changes (median: 8.5) test year

Alabama , . . . . . . . . . . . . . .

Arkansas . . . . . . . . . . . . . . .

Connecticut . . . . . . . . . . . .

Delaware . . . . . . . . . . . . . . .

Florida . . . . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . . . . .

Indiana. . . . . . . . . . . . . . . . .

lowa . . . . . . . . . . . . . . . . . . .

Kentucky . . . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . . .

Maine . . . . . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . . .

Massachusetts. . . . . . . . . .

Michigan . . . . . . . . . . . . . . .

Minnesota . . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . .

Missouri. . . . . . . . . . . . . . . .

New Hampshire . . . . . . . . .

New Jersey . . . . . . . . . . . . .

New York . . . . . . . . . . . . . . .

North Carolina . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . . . .

Pennsylvania . . . . . . . . . . .

Rhode Island . . . . . . . . . . . .

South Carolina . . . . . . . . . .

Vermont . . . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . . .

West Virginia . . . . . . . . . . .

Wisconsin . . . . . . . . . . . . . .

12.85

15.0

14.8

15.0

15.5

13.33

16.5

15.83

13.35

14.25

14.33

15.13

14.0

14.31

13.25

14.0

12.85

13.71

14.75

14.0

15.5

13.87

15.86

15.63

14.13

13.88

14.5

15.0

14.0

12.72

100 ”/0

100%a

o

100 ”/0

Varies

Varies

Varies

o

0

100 ”/0

100 ”/0

o

100 ”/0

o

100%

100 ”/0

Varies

o

0

Varies

Small %

b

100 ”/0

Varies

Small 0/0

o

100%

Small 0/0

100%

Varies

o

Quarterly

Monthly

Monthly

Monthly

Monthly

Quarterly

Irregular-as needed

Quarterly

Monthly

Monthly

Monthly

Quarterly

Monthly

Quarterly

Monthly

Monthly

Monthly

No clause

Quarterly or monthly

Irregular-as needed

Monthly

3/year

Biannually

Yearly

Quarterly

Biannually

No clause

Biannually

Biannually

Monthly

6

10

5

7

8

6

11

6

12

10

12

9

7

6

9

12

6

11

6

8

11

7

9

9

8

12

21

5

10

8.5

Historical

Historical

Historical

Forecast

Forecast

Forecast

Forecast

Historical

Historical

Historical

Historical

Historical

Forecast

Historical

Forecast

Forecast

Forecast

Historical

Historical

Forecast

Forecast

Historical

Forecast

Forecast

Historical

Historical

Historical

Historical

Historical

Forecast

aCWIP to be in service within 1 year is allowed.

b"Small %” indicates that less than 1O% of CWIP IS allowed.

SOURCE. K. Cole, et al., “Financial and Regulatory Factors Affecting the State and Regional Economic Impact of Sulfur Oxide Emissions Control, ” Off Ice of

Technology Assessment contractor report, August 1982.
App. A—Emissions and the Costs of Control ● 205

If a State allows construction work in progress

(CWIP) to be included in the rate base, utilities begin

to earn returns on control-related expenditures as soon

as they are made; if not, capital improvements must be

financed by the utility until the scrubber or other plant

modification is actually operating—a period of up to 4

or more years. For utilities in weak financial positions,

the ability to recoup expenditures during a planning and

construction period of 4 years or longer may be a significant factor in deciding what means to use to comply

with stricter emissions controls. Consequently, States

allowing little or no CWIP in the rate base may make

capital-intensive approaches to S02 abatement less attractive, especially to financially troubled utilities. Such

utilities could choose to switch to higher priced, lower

sulfur fuels, even when costs for doing so are higher over

the long run. Although State PUCs vary considerably

in their CWIP expenditure policies, decisions on

whether to allow C WI P in the rate base are often made

on a case-by-case basis, except in States where allowing CWIP is prohibited by statute. Some analysts consider that States are considerably more likely to allow

CWIP for pollution control expenditures to enter a utility’s rate base.66

It should be noted, however, that some PUCs choose

to substitute higher allowed rates of return for allowing

CWIP in the rate base as a means of increasing utility

revenues during periods of construction activity. For example, table A-30 shows that the States of Indiana,

Maine, New York, and Pennsylvania allowed rates of

return to exceed 15 percent in 1980, while including little

or no CWIP in the rate base. Available data did not

permit OTA to estimate the probable effects of such a

substitution on control choices.

Finally, the kind of “test year’ selected to provide

data on expenses and costs (col. 5) can also influence

calculated revenue requirements. In times of rising

costs, historical test years may tend to understate utility expense estimates, while forecast test years can allow

for the projected effects of inflation.

State regulatory policies for 1980-81 are, of course,

an imperfect indicator of the probable regulatory climate

over the decade or more required to implement further

S02 restrictions. Public utility commissions could respond to control requirements by adopting policies more

favorable to capital construction or fuel-switching, particularly in States burdened with large S02 reduction

requirements. Such responses are virtually impossible

to predict, however; PUCs are affected by a broad array of political and institutional conditions, and must,

in their regulatory decision making, balance consumer

and producer interests. Concurrently, coal-producing

“’~(,r\lJnd] [ (,rnlnunl( df ll~n, ~11( hdr] ~’ol(>y, ~.it]onal A\\(x Idli(jn of ~ttqu],iIor} L’1 Il]lj ( :orrlr]lljsi(jrl{.rj, St. ptt, mtxr I ‘)8 1

States could constrain utility options for meeting tougher

emissions standards by requiring continued use of inState produced coal. Despite these uncertainties, the information provided in table A-30 can be used as a

general barometer of the favorableness or unfavorableness of a State’s current regulatory climate.

Combined Indicators

In this section, the three sets of State-level indicators

surveyed above- 1980 utility emission rates from coaland oil-burning plants, measures of short- and long-term

utility profitability for 1980, and State regulatory policies for 1980-8 1—are integrated to provide an overall

picture of current utility-sector vulnerability to stricter

emissions control. It is important to note, however, that

this provides only a surrogate for assessing the financial effects of controls at the same time they would be

implemented. In addition, changes in such factors as

demand for electricity, financial viability of nonfossil fuel

electricity generation, interest rates, inflation, and the

price of coal, oil, and gas could greatly affect the relative vulnerability of the region’s utility companies.

Eight States are identified in table A-29 as having financially weak utilities—Arkansas, Connecticut, Florida, Maine, Michigan, Pennsylvania, Vermont, and

Virginia. Three of these States have coal-fired utility

emission rates of at least 2 lb SO2

/MMBtu: Florida

(3.5), Pennsylvania (2.8), and Michigan (2.()). However, less than a third of Florida’s electricity-generating

capacity is coal-fired; more than half depends on oil,

with 1980 S02 emissions averaging 1.6 lb/M MBtu.

When emission rates from all utility fuel sources are considered, only Pennsylvania is among the upper 15 States

in the region, ranking 11th with an average rate of’ 2.5

lb S02/MMBtu.

Pennsylvania utilities may also be of particular concern due to current State regulations governing fuel cost

increases and calculated revenue requirements. While

Florida and Michigan utilities are allowed monthly fuel

cost adjustments, those in Pennsylvania are allowed only

one per year.

Utilities in Michigan are allowed relatively low

ROCEs, while 100 percent of CWIP is allowed in the

rate base; both Florida and Pennsylvania allow’ aboveaverage ROCEs, but Florida allows ‘‘varying’ amounts

of CWIP in the rate base, while Pennsylvania includes

only small portions of CWIP. The remaining five States

in the ‘ ‘highly vulnerable’ category rank so low in current emissions as to make the probable effect of additional control requirements on their utility sectors quite

small.

Utilities in an additional eight States are characterized

in table A-29 as having above-average rates of’ return

and relatively low bond ratings for 1980 (CO1. C), sug-
206 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

gesting potential concerns for long-term profitability. Six States are identified in table A-30 as having relaFour of these States combine heavy reliance on coal- tively high bond ratings, but low rates of return, for

fired plants with high average S02 emission rates from 1980. Of these, Indiana combines strong coal dependthese plants: Georgia (2.9 lb/MMBtu), Missouri (4.6), ency with a very high coal-fired, S02 emissions rate (4.2

Ohio (3.9), and West Virginia (2.7). A fifth State, New lb/MMBtu), while Illinois has both moderate coal deHampshire, relies on oil-fired plants for more than half pendency and a relatively high emissions rate (3.1 lb/

its generating capacity, and has an average oil-fired MMBtu).

emissions rate of 2.1 lb/MMBtu.
Appendix B

Effects of Transported Pollutants

B.1 AQUATIC RESOURCES AT RISK (p. 207)

B.2 TERRESTRIAL RESOURCES AT RISK (p. 217)

B.3 MATERIALS AT RISK (p. 239)

B.4 VISIBILITY IMPAIRMENT (p. 244)

B.5 HUMAN HEALTH RISKS (p. 255)

B.6 ECONOMIC SECTORS AT GREATEST RISK FROM CONTROLLING

OR NOT CONTROLLING TRANSPORTED POLLUTANTS (p. 261)

B. 1 AQUATIC RESOURCES AT RISK

Extent of Resources at Risk*

Scientists are concerned that acid deposition may be

damaging substantial numbers of U. S. and Canadian

lakes and streams. As part of its assessment of transported air pollutants, OTA contracted with The Institute

●

●

●

●

of Ecology (TIE) to:

describe mechanisms by which acid deposit ion

may be affecting sensitive 1akes and streams;

providc an inventory of Eastern U.S. lakes and

streams considered to be sensitive to acid deposit ion;

estimate the number of lakes and streams in these

scnsitive regions that have been affected and/or

altered by acidic deposition; and

examine three scenarios for future sulfate deposition levels to the year 2000, and project effects on

sensitive aquatic resources.

Because of’ scientific uncertainties and data limit ations, none of these tasks can be addressed at this time

with a high degree of accuracy. Each of’ these topics is

the subject of active research under the National Acid

Precipitation Assessment Program (NAPAP). To illustrate, the estimates of the numbers of lakes and streams

sensitive to acid deposition are based on eight separate

water quality surveys conducted at different times using

nonuniform procedures. NAPAP is currently planning

to undertake a national survey-sampling several thousand water bodies over a much wider geographic area—

to provide a more complete picture of the current magnitude of the problem.

——

‘ [ his w f I( III J(l<ipt(.(j froril I ht. In\(i(ufv 0! K( I)IIJ<J ‘‘ R(.ql( )Il<il ,A\\t\\rl][n(

(J! ,i(l(ici[ II R(, \I 111 r( (,\ ,1[ R l\k I I I JIII A( I(li( I )t, pIJ\lI 1( III, ( ) 1 ,A ( ( IIIt I ,i( 1( II I {-

,)( ,, I , 1‘IH.!

Because of the large area of a typical watershed, most

of the acid ultimately deposited in lakes and streams

comes from water that runs off or percolates through

the surrounding land mass, rather than from precipitation falling directly on water bodies. The amount of

acidifying material that actually enters a given lake or

stream is determined primarily by the soil and geologic

conditions of the surrounding watershed. Whcn the two

major chemical components of’ acid rain-nitric acid and

sulfuric acid—reach the ground, they may react with

soils is a variety of ways. * * For example, soils can neutralize the acids, exchange nutrients and trace metals

for components of the acids, and/or hold sulfuric acid.

Most soils contain amounts of counterbalancing (neutralizing) substances such as bicarbonate that may be

available to ‘ ‘buffer” acid inputs. Such nutrients as

calcium and magnesium, when present in soils, may be

leached by acidic deposition and enter water bodies,

while acidity remains in the soil. When soils are highly

acidic, similar leaching of toxic metals such as aluminum can occur, which may cause damage to aquatic life

in lakes and streams. In add it ion, the soils of some

watersheds are able to retain sulfuric acid to varying

degrees. For these areas, deposited sulfuric acid will not

pass into lakes and streams until the ‘ ‘adsorption”

capacity ‘‘ of the soils is exceeded.

The extent to which such reactions actually occur

depends on a number of geologic and soil conditions.

Where slopes are relatively steep, and soils are thin, less

opportunity exists for acid precipitation to infiltrate soil

‘ ● l;,)! { (]rrcn( ~ttcmpt\ (() ,i\s(~\ tht- rffc( ts of acid depositmn on aquat)[ m o-

\, \tem\. sulfurlc ac Id If ( ons}dercd the Prlnc Ipal suhstam c of{ oncern ‘1’hc InlI N ) I (<trt( ( ( )f ,i(]]tosf]h(rl( ]n[){]l \ ()! t]ltrl( ‘i{ 1(1 (() ,i{{tI<tfl( f} ~lemi 1, $t)ll unt (r

t<iln Ix( ,I(IW f h( n II I I( ,i( I( I ( dn }N uw(~ ‘i\ d pltint nut rlvnl .Alt h( IU + III( I 1(

,i( I(I (l<lx)\l(l(,rl rll<ik Ir)tlu(n{ f \lIr II)< .i( ldlti( ,it Ion ( (Icprvs.lon I)! })11 ) (l\]{. I(I

>rl( )tt rllt,l[,II r~ LInl Ik(.l\ t( ) }]ci\ e ,111 ,ippf (( Icit)l(, (.11(. ( I ( II) tII ldsun)mcr ,i( 11111 \

207
208 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

layers and react chemically with soil components. Further, the composition of soils—the availability of

neutralizing material, exchangeable elements, or sulfuric

acid adsorption capacity—also affects their overall

ability to mitigate acid deposition inputs to water bodies.

Watersheds in a number of regions are believed to provide aquatic resources with virtually complete protection from current levels of acid deposition. In other regions, however, watersheds have little capacity to

neutralize acidic substances, and much of the acid in

precipitation in these regions moves through the watershed into lakes and streams.

Under unaltered conditions, virtually all lakes and

streams also have some acid-neutralizing capacities.

Like soils, their waters contain such substances as bicarbonate, which neutralize the entering acids. Alkalinity

levels, which are expressed in microequivalents per

liter of water (μeq/1), measure the acid-neutralizing

capacity of lakes and streams. Lakes and streams defined

as very sensitive to acidic inputs have alkalinity levels

of O to 40 μeq/1, while a lake with high capacity for acid

neutralization can measure over 500 μeq/1. * If the surrounding watershed contains little neutralizing material, natural alkalinity levels in lakes and streams may

be quite low, making these aquatic resources highly sensitive to even low levels of acidic inputs.

When acids enter a lake or stream, available neutralizing substances are consumed, and alkalinity levels are

depressed. As water bodies become acidified, aquatic

plant and animal populations may be altered. A lake

or stream is considered to be acidified when no neutralizing capacity is left. Such bodies of water have been

measured as having negative alkalinity levels as great

as –100 μeq/1.

A multistep process was employed to develop an inventory of sensitive (but not necessarily altered) lakes

and streams in the Eastern United States. TIE (adapting a procedure developed by Oak Ridge National Laboratory) first used data on soil, watershed, and bedrock

characteristics in 27 Eastern States to generate a list of

individual counties whose freshwater resources were

likely to be sensitive to acidic deposition. The list of

counties was then aggregated into 14 acid-sensitive regions (fig. B-l). Using U.S. Geological Survey maps,

the contractor systematically sampled each region to esti-

“Reports by J. R. Kramer (3), H. Harvey, et al (4), and others have dl-

\lded the spectrum of their sensitivity measure into a series of intervals referred

tn as sensitlwty classes or categories Each approach differed slightly from the

others, Icadlng the authors of the U S -Canada Aquatlr Impacts Assessment

Subgroup (5) tu propose the fnllowing c]assiticatmn for lakes:

(:ldss Alkallnltv (IU@)

I At dlfid < 0

11 F.xtremt- Scnsllll II} 0-’39

111 Nf[xk. ra[c scnw(lvltv 40.199

I\’ IXM senstlliity 2oo-4w

L’ Not wn\lt]\c 2500

Figure B-1.—Areas Sensitive to Acid Rain (shaded

grey)

Lake and stream sampling areas modified from Braun

(1950) and Fenneman (1938). Region numbers correspond

to those shown in table B-1.

mate its total number of lakes greater than 15 acres in

size, and total miles of first- and second-order streams,**

The results show an estimated 17,000 lakes and 117,000

miles of first- and second-order streams in the 14 sensitive regions (table B-l).

Of this total number of lakes and streams in the sensitive regions, only a portion may be considered sensitive to acid inputs, Local variations in geology, soil

conditions, and runoff patterns cause alkalinity levels

of lakes and streams within a sensitive region to range

from less than zero μeq/1 (acidified) to over 500 μeq/1

(acid resistant). Regional water quality surveys*** were

used to estimate the percentage of the lakes and streams

in the 14 regions that can be considered sensitive to acid

● *The smallest unbranched tributary of a stream is a first-order stream; the

junction of two first-order streams produces a second-order stream segment,

* * “Eight surveys of lake and stream water quafity were used to evafuate the

regional sensitivity of aquatic ecosystems to acid deposition. Regional estimates

are bawd on measurements from about 40 New England streams (6), 430

Adirondack lakes (7), 45 Pennsylvania streams (8), 40 streams In North Carolina and Virglnla (9), 360 lakes in Wisconsin ( 10) and Minnesota (1 1), and

40 W’lsconsm streams ( 12)
App. B—Effects of Transported Pollutants 209

Table B-1 .—Total Estimated Lake and Stream Resources in the Acid-Sensitive

Regions of the Eastern United States (see fig. B-1)

Sensitive Total lakes Total streams (mi)

Region area (mi2

) Number Acres 1st order 2d order

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

Eastern Maine . . . . . . . . . . . . . . 26,398

Western New England . . . . . . . 29,666

Adirondacks . . . . . . . . . . . . . . . . 14,066

East Pennsylvania

South New England. . . . . . . . . . 20,947

West New York/Pennsylvania . 25,051

Appalachian Plateau . . . . . . . . . 16,190

Blue Ridge/Great Smoky

Mountains . . . . . . . . . . . . . . . . . . 20,964

Coastal Plain . . . . . . . . . . . . . . . 9,264

Lower Mississippi . . . . . . . . . . . 13,075

lndiana/Kentucky . . . . . . . . . . . . 8,603

Central Wisconsin . . . . . . . . . . . 12,141

Wisconsin/Michigan

Highlands . . . . . . . . . . . . . . . . . . 19,229

Northeast Minnesota. . . . . . . . . 10,560

Central Minnesota . . . . . . . . . . . 18,870

Totals . . . . . . . . . . . . . . . . . . . . . . 245.024

1,425

1,543

1,139

1,320

376

13

126

241

170

9

583

5,307

1,637

3,170

17.059

582,825

763,785

231,217

118,800

16,920

29,510

14,868

8,917

56,610

603

187,726

801,357

473,093

323,340

3.609.571

9,714

15,308

5,289

8,400

7,114

7,350

10,901

1,547

5,374

2,805

2,683

5,037

1,637

4,831

87,990

3,485

4,569

3,024

2,556

1,678

2,299

3,396

713

1,255

989

728

1,737

475

2.529

29,433

SOURCE: “Regional Assessment of Aquatic Resources at Risk From Acidic Deposition, ” prepared for OTA by The Institute

of Ecology, June 1982

deposition, using a 200-μeq/1 alkalinity level as the cutoff point between sensitive and nonsensitive lakes and

streams. Results show an estimated 9,400 lakes and

60,000 miles of streams that are currently sensitive to

further acid inputs (tables B-2 and B-3).

To estimate the portion of these sensitive lakes and

streams that already have been altered by acidic deposition, TIE compared data on the distribution of

alkalinity levels for two distinct geographic areas: 1 ) regions with little neutralizing capacity that currently receive high (resource-affecting) levels of acidic deposition; and 2) geologically similar areas of northwestern

Ontario and northern Minnesota having little neutralizing capacity, but that receive negligible amounts of acid

deposition. The difference between the two distributions

provides an estimate of the proportion of lakes and

streams that can be considered ‘ ‘acid-altered, rather

than simply sensitive. Only lakes with alkalinity levels

less than 40 μeq/1 and streams with less than 100 μeq/l—

already acidified or extremely sensitive to further

alteration—are considered in these calculations. Calculations using this approach show an estimated 3,000

lakes and 23,000 miles of streams with alkalinity levels

that can be described as already acid-altered. This corresponds to 18 percent of the lakes and 20 percent of

the streams located within the 14 sensitive areas (see

tables B-4 and B-5).

Finally, TIE employed a simple model to estimate the

effects on aquatic resources of three possible future acid

deposition scenarios. As an underlying assumption, the

model uses an empirical measure to project changes in

lake and stream alkalinities given a change in sulfate

deposition. This measure—the ‘ ‘alkalinity impact parameter’ —is based on both limited observations of

alkalinity changes through time in areas where sulfate

deposition has been increased or reduced, and on current theory about the processes involved. * Although not

yet fully tested, the model suggests that lake and stream

alkalinities are likely to respond to future changes in

sulfate deposition. The model cannot address further

changes in lake and stream water quality that might occur if deposition remains constant over the next several decades.

For scenario I, a 10-percent increase in sulfate deposition by 2000, the model projects that 5 to 15 percent

(depending on the region) of the most sensitive lakes

and streams worsen in condition—becoming either

‘ ‘acidified’ or ‘ ‘extremely sensitive’ to acid inputs.

*An empiric al ‘‘alkalinity Impac I parame[cr’ (.~[~) can be clcfincd as the

ra[ io of obser\ cd changes in lake and stream alkalinity levels [c} changes in

sulfate loadings. W’hen sulfate retcntlon b\ the watershct] approa{ hes zer[~,

n!tratt= uptake bv plants N h)~h, and for[her lossr~ of nu[rwrrt ( ,itt(m \—e y ,

calclum and magnc~lum-ar-e low or negl]glble, acldlt}, ( H~S()+) directl y a f -

fects alkalinity (H(~OS), and the expected .41P IS ‘2 For the c asc in w h[ch w)me

nmstrafizatmr of acid input occurs in the watershed, the AIP mould be les~ than

2. during the \,ery early stages of ac idic deposition. It should approa( h zero

Where s{)ils ha\e high sulfate adsorption capa[ lty, the AIP WOU]d als(J approach

zero during the early stages of an acidification process, later. if ac Id deposition

[o the w atershecl IS ciecreased, some of the sulfate prevmusly retained ( an bc

washed from thr sol]. and A[P values could exceed 2 Calculations using ,in

AIP of greater than 2 were not (onsidered, since many of the watershmls In

the re<qwrrs mapped as sensltl\re for this stud) ha\,e low sulfate adsorption

c apa[ Itle$

Thr- imp(]rtanc e of atmosphen( depnsltl{)n of calc Ium and maqneslum as potentldl neutrdflzlns aqents has been considered For the areas exarnmed, [ .d( lurn

and maqnmlum dep(mltlon appear t[~ he on]} one-tenth the n~~~n[tude UI \ull,Itt,

deposition. therefore, Its r[de has been t onsldered ne~llqlb]e for the present

( alf ulattons.
210 Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table B-2.-Estimated Lake Resources at Risk in the Acid-Sensitive Regions

of the Eastern United States

Sensitive

Region area (mi2

)

1. Eastern Maine . . . . . . . . . . . . . . . . . . . 26,398

2. Western New England . . . . . . . . . . . . 29,666

3. Adirondacks . . . . . . . . . . . . . . . . . . . . . 14,066

4. East Pennsylvania/

South New England. . . . . . . . . . . . . . . 20,947

5. West New York/Pennsylvania . . . . . . 25,051

6. Appalachian Plateau . . . . . . . . . . . . . . 16,190

7. Blue Ridge/Great Smoky Mountains. 20,964

8. Coastal Plain . . . . . . . . . . . . . . . . . . . . 9,264

9. Lower Mississippi . . . . . . . . . . . . . . . . 13,075

10. Indiana/Kentucky . . . . . . . . . . . . . . . . . 8,603

11. Central Wisconsin . . . . . . . . . . . . . . . . 12,141

12. Wisconsin/Michigan Highlands . . . . . 19,229

13. Northeast Minnesota. . . . . . . . . . . . . . 10,560

14. Central Minnesota . . . . . . . . . . . . . . . . 18,870

Totals . . . . . . . . . . . . . . . . . . . . . . . . . . . 245,024

Percentage Calculated

Total number of lakes number of

lakes <200 μeq/l lakes at risk

1,425 (80)a

1,140

1,543 (80)a 1,234

1,139 911

1,320

376

13

126

241

170

9

583

5,307

1,637

3,170

17,059

(80)a

(80a

—

—

—

—

1,056

301 —

—

.

245

2,228

786

1,522

9,423

aIn the absence of other data, alkalinities from the Adirondacks have been ‘Sea l.

bNo estimate is being made for regions with fewer than 250 lakes.

cIn the absence of other data, alkalinities from north Wisconsin have been ‘Seal

‘In the absence of other data, alkalinities from north Minnesota have been used.

SOURCE’ ‘(Regional Assessment of Aquatic Resources at Risk From Acidic Deposit ion,” prepared for OTA by The Institute

of Ecology, June 1982

Table B-3.—Estimated First- and Second-Order Stream Resources at Risk

in the Acid-Sensitive Regions of the Eastern United States

Calculated total

Percentage miles of:

Sensitive Total streams (mi)

Region

of stream 1

0 streams 20 stream s

area (mi2

) 1st order 2d order <200 μeq/l at risk at risk

1. Eastern Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . 26,398 9,714 3,485 81 7,868 2,823

2. Western New England . . . . . . . . . . . . . . . . . . . . 29,666 15,308 4,569 56 8,573 2,559

3. Adirondacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14,066 5,289 3,024 (56)a 2,962 1,693

4. East Pennsylvania/South New England . . . . . . 20,947 8,400 2,556 3,192 971

5. West New York/Pennsylvania . . . . . . . . . . . . . . 25,051 7,114 1,678 61 4,340 1,024

6. Appalachian Plateau . . . . . . . . . . . . . . . . . . . . . . 16,190 7,350 2,299 (61)b 4,484 1,402

7. Blue Ridge/Great Smoky Mountains. . . . . . . . . 20,964 10,901 3,396 6,977 2,173

8. Coastal Plain . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9,264 1,547 713 (43)C

665 307

9. Lower Mississippi . . . . . . . . . . . . . . . . . . . . . . . . 13,075 5,374 1,255 (43)’ 2,311 540

10. Indiana/Kentucky . . . . . . . . . . . . . . . . . . . . . . . . . 8,603 2,805 989 (43)c 1,206 425

11. Central Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . 12,141 2,683 728 1,154 313

12. Wisconsin/Michigan Highlands . . . . . . . . . . . . . 19,229 5,037 1,737 13 655 226

13. Northeast Minnesota. . . . . . . . . . . . . . . . . . . . . . 10,560 1,637 475 (13)d

213 62

14. Central Minnesota . . . . . . . . . . . . . . . . . . . . . . . . 18,870 4,831 2,529 (13)d

628 329

Totals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245,024 87,990 29,433 45,228 14,847

aIn the absence of other data, alkalinities from west New England and west New York/Pennsylvania have been used.

b

ln the absence of other data, alkalinities from west New York/Pennsylvania have been used.

cIn the absence of other data, alkalinities from central Wisconsin have been used.

‘In the absence of other data, alkalinities from northern Wisconsin have been used,

SOURCE’ “Regional Assessment of Aquatic Resources at Risk From Acidic Deposition,” prepared for OTA by The Institute of Ecology, June 1982.
App. B—Effects of Transported Pollutants ● 211

Table B-4.—Estimates of Extremely Sensitive or Acidified Lake Resourcesa in the Eastern United States

1980 number Historic number

of lakes with of lakes with 1980 number of

Total number alkalinities alkalinities acid-altered lakes

Region of lakes <40 μeq/l <40 μeq/l <40 μeq/l

1. Eastern Maine . . . . . . . . . . . . . . . . . . . . . . . . . .

2. Western New England . . . . . . . . . . . . . . . . . . .

3. Adirondacks . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4. East Pennsylvania/

South New England . . . . . . . . . . . . . . . . . . . . .

5. West New York/Pennsylvania . . . . . . . . . . . . .

6. Appalachian Plateau . . . . . . . . . . . . . . . . . . . . .

7. Blue Ridge/Great Smoky

Mountains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8. Coastal Plain ., . . . . . . . . . . . . . . . . . ., . . . . . .

9. Lower Mississippi . . . . . . . . . . . . . . . . . . . . . . .

10. lndiana/Kentucky . . . . . . . . . . . . . . . . . . . . . . . .

11. Central Wisconsin . . . . . . . . . . . . . . . . . . . . . . .

12. Wisconsin/Michigan

Highlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13. Northeast Minnesota . . . . . . . . . . . . . . . . . . . .

14. Central Minnesota. . . . . . . . . . . . . . . . . . . . . . .

Totals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1,425

1,543

1,139

456

494

456

43

46

34

413

448

422

1,320

376

13

423

150

40

11

383

139 — —

126

241

170

9

583

—

—

134

—

—

—

—

17 117

5,307

1,637

3,170

17,059

1,220

49

95

159

49

95

1,061

0

0

3,477 494 2,983

Total number of Iakes altered, Class I and II 2,983.

Percentage of lakes altered 18%.

a

Lakes with alkalinity less than 40 μeq/l, based on using 1980 calculated alkalinity depression and “historic” area alkalinity distributions as a control

SOURCE’’Reglonal Assessment of Aquatic Resources at Risk From Acidic Deposition,” prepared for OTA by The lnstitute of Ecology, June 1982

Table B-5.—Estimates of Extremely Sensitive or Acidified Stream Resourcesa in the Eastern United States

Historic stream

1980 miles with miles with Acid-altered

Total alkalinities alkalinities stream miles

Region stream miles <100 μeq/lb

<100 μeq/l <100 μeq/l

1. Eastern Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. Western New England . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3. Adirondacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4. East Pennsylvania/South New England . . . . . . . . . . . . . .

5.West New York/Pennsylvania . . . . . . . . . . . . . . . . . . . . . .

6. Appalachian Plateau . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7.Blue Ridge/Great Smoky Mountains . . . . . . . . . . . . . . . .

8. Coastal Plain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9. Lower Mississippi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10. lndiana/Kentucky. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11. Central Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12. Wisconsin/Michigan Highlands . . . . . . . . . . . . . . . . . . . .

13. Northeast Minnesota . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14. Central Minnesota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13,199

19,877

8,313

10,956

8,792

9,649

14,297

2,260

6,629

3,794

3,411

6,774

2,112

7,360

117,423

3,746

5,641

3,060

3,109

3,237

2,738

4,058

482

1,412

809

726

418

130

455

30,021

816

1,228

514

677

543

596

884

140

410

234

211

418

131

455

2,930

4,413

2,546

2,432

2,694

2,142

3,174

342

1,002

575

515

0

0

0

Totals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7,257 22,765

aStreams with alkalinity less than 100 μeq/l, based on 1980 calculated alkalinity depression and “historic” area alkalinity distributions as a control.

bA higher alkalinity level was used to denote extreme sensitivity for streams than for lakes

SOURCE “Regional Assessment of Aquatic Resources at Risk From Acidic Deposition,” prepared for OTA by The lnsttiute of Ecology, June 1982
212 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Under scenario II, which provides for a 20-percent decrease in sulfate deposition by 2000, 10 to 25 percent

of the most sensitive lakes and streams are estimated

to experience some recovery —i. e., ‘ ‘acidified’ aquatic

resources become ‘ ‘extremely sensitive’ or ‘ ‘extremely

sensitive’ resources become ‘ ‘moderately sensitive.

Scenario III, which involved a 35-percent decrease in

sulfate deposition by the year 2000, is estimated to result in some recovery for 14 to 40 percent of the most

sensitive aquatic resources. *

Figures B-2 and B-3 summarize the projected effects

of scenarios I, II, and III on lakes and streams in a number of the sensitive areas. Each bar graph illustrates

scenarios 1, II, and III in that order. The two figures

show the sum of the calculated shifts to or from the

most sensitive resource categories, expressed as a percent of the total lake or stream resource in each area.

The short, solid portion of each bar represents a highly

probable response; the shaded portion of each bar represents the upper bound of the probable response.

Scenario III (a 35-percent reduction in sulfate deposition by 2000) appears likely to result in relatively significant responses for the total resource. Recovery for

lakes is projected to range from a few to about 30 percent in each area, and up to 20 percent for streams, with

the greatest recovery in areas of highest current deposition.

While the model indicates some important prospects

for recovery, it cannot address certain long-term consequences of acidification. Soils that may have been

depleted of such nutrients as calcium and magnesium

by acid deposition might take a great deal longer to recover normal nutrient levels than water bodies take to

regain equilibrium alkalinity levels. If the soil’s ability

to mitigate acid deposition recovers slowly, “acid

shock ‘ ‘ episodes to water bodies from such events as

spring snowmelt may persist for some time. The magnitude of such consequences is unpredictable at this

time.

Lastly, some discussion of the implications of these

results for biological responses in aquatic systems is required. Scientists are gradually developing an understanding of how fish and other aquatic life are affected

by acid-induced alterations of their environments. Thus,

predictive statements about changes in water quality

over some period of abatement represent the first step

in making predictive statements about the potential

recovery of aquatic life.

“ Because the ‘1’lE model 1s most app]lcable to thnse lakes and streams m

the w tcf-altered (Class 1 < 0 ~eq/1) and ex{rcmely sensitive (Class 11 0 to 40

peq/1) c atcgorms, TIE used transfers into and out of each of these categorms

as the measure of c han~e fur aquatic resuurces in response to altered depow -

twn ‘1’o correct for diffa emes In Akalinlty dlstrlbutums bc.tweerr streams and

lakes, a defined portmn of the streams In Class 111 (40 to 100 pcq/1) was m-

( luded in the T1 F, c alc ulatlons

Figure B 2.—Lake Model Projections

,

Bar-graphs show the percent increase (or decrease) by

the year 2000 in lakes classed as “acidified” or

“extreme” for the three deposition scenarios I (a 10-

percent increase in deposition), II (a 20-percent decrease),

and Ill (a 35-percent decrease), represented by the bars,

in that order from left to right.

SOURCE: “Regional Assessment of Aquatic Resources at Risk From Acidic

Deposition,” prepared for OTA by The Institute of Ecology, June 1982.

Effects of Acid Deposition

on Aquatic Life

Losses of fish populations attributed to the effects of

acid deposition have received a great deal of public attention; however, the available evidence indicates that

acidic waters also affect many other forms of aquatic

life, from single-celled algae to large aquatic plants to

amphibians such as frogs and salamanders. Adverse effects on aquatic plants and animals can affect the availability of food to other animals such as fish, aquatic

birds, and mammals.

Fish reproduction requires water pH levels of above

4.5, according to numerous laboratory studies and field

surveys ( 13). The International Joint Commission has

recommended a water quality standard of greater than
App. B—Effects of Transported Pollutants ● 213

Figure B 3.—Stream Model Projections

I

(Where there is no black band, the lower bound is zero)

Bar-graphs show the percent increase (or decrease) by

the year 2000 in lakes classed as “acidified” or

“extreme” for the three deposition scenarios I (a 10-

percent increase in deposition), II (a 20-percent decrease),

and Ill (a 35-percent decrease), represented by the bars,

in that order from left to right.

SOURCE “Regional Assessment of Aquatic Resources at Risk From Acidic

Deposition, ” prepared for OTA by The Institute of Ecology, June 1982.

pH 6.5 for successful fish reproduction. Death of adult

fish does not generally occur until the pH is less than

5.0. Rapid decreases in stream and lake pH due to

spring snowmelt and release of acid accumulated over

the winter can be detrimental if they coincide with sensitive periods of the fish reproductive cycle. Several

reports have documented sudden fish kills in both rivers

and lakes associated with springtime pH depressions

(14).

Survival of fish in water of low pH is influenced by

temperature, presence of metals such as aluminum,

hardness of the water, and type of acid input. Aluminum increases the sensitivity of fish to low pH levels

(15). Increases in the concentration of aluminum are

correlated with decreasing pH. Fish mortalities have

been documented as a result of increased aluminum concentrations, increased acidity, and the combination of

these two factors. The hardness of the water (mineral

content) increases the ability of fish to withstand low

pH; fish communities disappear from soft waters at

higher pH than they do from hard waters (16).

A recent inventory (1980)(17) of the New York State

Adirondacks (one of the largest sensitive lake districts

in the Eastern United States receiving significant

amounts of acid deposition) indicates that the brook

trout fishery has been most severely affected by acidification. At least 180 former brook trout ponds in the Adirondacks will no longer support populations. A survey

of 214 Adirondacks lakes in 1975 revealed that 52 percent had surface pH levels below 5.0, and that 90 percent of these were entirely devoid of fish life. Some of

these lakes had been surveyed between 1929 and 1937,

when only 4 percent (or 10 lakes) were below pH 5.0

and devoid of fish; over the intervening forty years entire fish communities of brook trout, lake trout, white

sucker, prawn bullhead, and several cyprinid species

were eliminated (1 8).

Similar losses of fish species have been observed in

acidic lakes in the La Cloche mountain range of Ontario, Canada ( 19). These field studies performed over

time show that species vary in their susceptibility to declining pH, and that the mechanisms by which individual species are eliminated are complex. In Nova Scotia

there are nine rivers with pH less than 4.7 which previously had salmon that can no longer sustain trout or

salmon reproduction (20). Losses to brook trout populations in the Great Smoky Mountain National Park have

also been associated with the acidity of streams and aluminum concentrations (21 ).

In the field, mass mortalities of fish have been observed during the spring due to the ‘‘acid shock’ from

high concentrations of pollutants in snowmelt. Elevated

concentrations of aluminum mobilized from the soils by

strong acids present in snowmelt water are thought to

be a contributing factor to such large-scale fish mortality

(22). Increases in juvenile salmon mortality in Nova

Scotia hatcheries have also been associated with snowmelt-induced pH depressions (23).

Field surveys and laboratory experiments have shown

amphibian populations, such as frogs and salamanders,

to be extremely sensitive to changes in pH. Many species breed in temporary pools that may be formed from

low-pH meltwater in spring. Because of the great vulnerability of their habitat to pH depressions, damage

to amphibian populations may be one of the earliest consequences of acidification of freshwaters. Experiments

have shown correlations between pH and both mortality

and embryo deformity in frog and salamander populations (24).

Numerous invertebrate animals are known to be affected by the acidification of water, although individual
214 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

species may vary greatly in sensitivity. Of these, shellbearing organisms and molting crustaceans appear to

be the most sensitive to low pH (25). No molluscs are

known to inhabit waters of pH lower than 6.0, while

most crustaceans (e. g., crayfish) are absent from waters

of pH below 4.6 (26). Aquatic insects exhibit a wide

range of sensitivities to pH (27).

Single-celled algae are a basic constituent of the

aquatic food chain. Studies have shown that as pH

decreases, significant changes occur in the species and

diversity of algae that predominate (28). As lakes or

streams acidify, acid-tolerant algae proliferate (29). This

group of algae is not readily edible by zooplankton, the

animals that link algae and smaller fish in the food chain.

However, a recent study suggests that algal species have

some capability to adapt to acidic environments over

the long term. This may explain the observation that

a group of relatively recently acidified lakes in Norway

have less diverse algae than natural historically acidic

lakes (30).

Changes in algae community structure induced by

acidification may also alter zooplankton community

structure. Acidification of lakes is accompanied by

changes in abundance, diversity, and seasonality of

zooplankton which may reflect changes in their food

base (algae), predators (fish), and/or complex changes

in water chemistry, Since both population density and

average size of the animals are reduced, food availability to fish and other animals may be reduced (31).

Limited findings from New York State suggest that

acid-tolerant algae may cover submerged aquatic plant

communities in acidic lakes, thereby preventing them

from receiving the sunlight necessary for growth (32).

Studies of Swedish lakes and preliminary information

from New York, Nova Scotia, and Ontario have shown

that acidification tends to cause decline of aquatic plants

and replacement by growths of sphagnum mosses on

lake and river bottoms (33). Sphagnum moss creates a

unique habitat which is considered unsuitable for some

species of bottom-dwelling invertebrates or for use as

fish spawning and nursery grounds (34). Dense

sphagnum beds may also reduce the appeal of freshwater

lakes and rivers for recreational activities.

A number of studies have also found that acidic waters

are more favorable to fungi than to normal bacterial

populations. In many Scandinavian lakes studied to

date, an increase in bottom accumulation of organic

matter has been observed. This has been attributed to

a shift in dominance from bacteria to fungi, which are

less effective at decomposing organic material and which

delay the recycling of nutrients (35).

Table B-6 and figure B-4 summarize the effects of

decreasing pH on aquatic organisms. Table B-6

describes biological processes affected in different orgaTable B-6.-Effects of Decreasing pH

on Aquatic Organisms

p H Effect

8.0-6.0

6.0-5.5

5.5-5.0

5.0-4.5

4.5 and

below

In the long run, decreases of less than one-ha/f

of a pH unit in the range of 8.0 to 6.0 are likely

to alter the biotic composition of lakes and

streams to some degree. However, the

significance of these slight changes is not

great.

Decreases of one-ha/f to one pH unit (a threefold

to tenfold increase in acidity) may detectably

alter community composition. Productivity of

competing organisms will vary. Some species

will be eliminated.

Decreasing pH from 6.0 to 5.5 will reduce the

number of species in lakes and streams.

Among remaining species, significant alterations in the ability to withstand stress may

occur. Reproduction of some salamander species is impaired,

Below pH 5.5, numbers and diversity of species

will be reduced. Reproduction is impaired and

many species will be eliminated. Crustacean

zooplankton, phytoplankton, molluscs, amphipods, most mayfly species, and many stone fly

species will begin to be eliminated. In contrast,

several invertebrate species tolerant to low pH

will become abundant. Overall, invertebrate

biomass will be greatly reduced. Certain higher

aquatic plants will be eliminated.

Below pH 5.0, decomposition of organic detritus

will be impaired severely. Most fish species

will be eliminated.

In addition to exacerbation of the above

changes, many forms of algae will not survive

at a pH of less than 4.5.

SOURCE: International Joint Commission, Great Lakes Advisory Board (1979),

after Hendrey, 1979.

nisms as the pH of water decreases. Figure B-4 displays

the percent of each of 7 major categories (taxonomic

groups) remaining as pH decreases. For example, at pH

7, 100 percent of normal mollusc species are present.

As pH decreases, the number of species remaining

decreases rapidly. At a pH of 5.5, all mollusc species

have disappeared.

B. 1 References

1. Braun, E. 1.., Lkciduous Forests of L’as[ern i’Vorth

America (Philadelphia, Pa.: The Blakiston Co,, 19.tO).

2. Fenncman, N. M., Ph~sio~raph) of’ the ~astcrn United

States (New York: McGraw-Hill Book Co., 1938),

3. Kramer, J. R., ‘‘Geochemical and Lithological F’actors

in Acid Precipitation, USDA Forest Scr\icc’ General

Technical Report NE-23, 1976.

4. Har\e}, H. H., Piercej R, C., Dillon, P. J., Kramer,

J. P., and W’helpdale, D. M., ‘ ‘Acidification in the Canadian Aquatic En\’ironment: Scientific C ritcrion fbr Assessing I+; f-fkcts of Acidic I>epos it ion on Aquatic Ecosystems
App. B—Effects of Transported Pollutants ● 2 1 5

Figure B-4.— Relative Number of Taxa of the Major

Taxonomic Groups as a Function of Acidity

75

50

25

75

50

25

75

50

25

75

50

25

75

50

25

75

50

25

75

50

25

L

-

W Insects

-

-

- MolkIscs

-

-

- Sponges

-

- Leeches

-

-

- Zooplankton

F

Fish

/“

1= I

I , I I I

2 3 4 5 6 7

pH

SOURCE Impact Assessment, Work Group 1, United States ~ Canada Memoran.

dum of Intent on Transboundary Air Poll utlon, Final Report, January

1983

(Ottawa, Ontario, Canada: National Research Council

Canada, NRCC No. 18475, 1981).

5. U.S.-Canada Memorandum of Intent on Transboundary

Air Pollution, ‘ ‘Impact Assessment, Work Group I,

Phase II Interim Working Paper (Washington, D. C., and

Ottawa, Ontario, Canada, 1981).

6. Haines, T. A., ‘‘ Effects of Acid Rain on Atlantic Salmon

Ri\’ers and Restoration Efforts in the United States, Proceedings of the Conference on Acid Rain and the Atlantic Salmon, Portland Maine, IVovember 22-23, 1980, International Atlantic Salmon Foundation Special

Publication Series No. 10, March 1981 (New York: IASF,

1981 ).

7. Pfeiffer, M. H., and Festa, P. J., “Acidity Status of Lakes

in the Adirondack Region of New York in Relation to Fish

Resources. Progress Report’ (Albany, N. Y.: New York

State Department of Environmental Consem’ation, 1980).

8. Arnold, D. E., ‘ ‘vulnerability of Lakes and Streams in

the Middle Atlantic States to Acidification, Interim Prog9.

10.

11

12

13.

14

15

16

17

18

19,

ress Report (Uni\’ersit}’ Park, Pa. : Cooperat it’e Fisheries

Research Unit, Penns~l\ania State Uni\ersit~’, 1981).

Hendrey, G. R., Gal]owa}, J. N., Norton, S. A., Schofield, C. L., Shaffcr, P. W’., and Burns, D. A., ‘ ‘Geological and H}’drochernical Sensitivity’ of the Eastern United

States to Acid Precipitation” (Comailis, Oreg.: U.S. EP.4

En\’ironmental Research Lab, EPA-600/3-80-024, 1980).

Eilers, J. (with 12 other authors), “Acid Precipitation In-

\restigation for Northern W’ isconsin, Progress Report

(Duluth, Minn.: Wisconsin DNR, Rhinelander; and U.S.

EPA-ERL, 1979).

Glass, G. E., and Loucks, O. L. (ecis. ), ‘ ‘Impacts of Airborne Pollutants on k$’ilderness Areas Along the ~finnesota-Ontario Border , EPA-600/3-80-044 (Duluth,

N4inn.: U.S. EPA En\ironrnental Research Lab, 1980).

Andrews, L. M., and Thrcintm, C. W’., ‘‘Surface Water

Resources of Oneida Count?. ’ (hladison, Wis.: Wisconsin Conservation Department Report, 1966); and Klick,

T. A., and Threinen, C. W., ‘‘Surface Water Resources

of Jackson County, Lake and Stream Classification Project’ (Madison, Wis.: Department of Natural Resources,

1968).

Beamish, R. J., “Acidification of Lakes in Canada by Acid

Precipitation and the Resulting Effects on Fishes, ll’ater, Air, Soil Pollut. 6:50 1-514, 1976; and EIFAC (European Inland Fisheries Ad\isor?’ Commission), “Water

Quality Criteria for Freshwater Fish, Report on Extreme

pH Values and Inland Fisheries, Water Res. 3 :593-61 1,

1969.

Har\e), H. H., “The Acid Deposition Problem and

Emerging Research Needs in the Toxicology of Fishes,

Proc. 5th Annual Aquatic Toxicity Workshop, Hamilton,

Ontario, No\T. 7-9, 1978, Fish. Afar. Ser\. Tech. Rep.

862:1 15-128, 1979.

Davis, J. M., External Re\icnv Draft, Research Triangle

Park, N. C., U.S. Environmental Criteria and Assessment

Office, 1980; and Dickson, W., ‘ ‘Some Effects of the

Acidification of Swedish Lakes, \ ‘erh. Znt. Ircrein. L.imnoi, 20:851 -856, 1978.

Lei\’estad, H., Hendrcy, G., Muniz, I. P., and Snek\’ik,

E,, ‘ ‘Effects of Acid Precipitation on Freshwater Organisms, Impact of’ Acid Precipitation on Forest and

Freshwater Ecosystems in Norway, F. Braekke (ed. ),

SNSF Project, NISK 1432 Aas-NLH, Norway, 1976.

Pfeiffer, M. H., and Festa, P. J., “Acidity Status of Lakes

in the Adirondack Region of New York in Relation to Fish

Resources, Progress Report, Department of Environmental Conservation, New York State, Albany, 1980.

Schofield, C. L., “Lake Acidification in the Adirondack

Mountains of New York: Causes and Consequences, ”

Proc. 1st Int. Symp. on Acid Precipitation and the Forest Ecos)’s[em, USDA Forest Ser\’ice General Technical

Report NE-23, 477, 1976.

Beamish, R. J., ‘ ‘The Loss of Fish Populations From

Unexploited Remote Lakes in Ontario, Canada, as a Consequence of Atmospheric Fallout of Acid, Water Res.

8:85-95, 1974; Beamish, R. J., “Acidification of Lakes

in Canada by Acid Precipitation and the Resulting Ef’-

fects on Fishes, V1’ater, Air, Soil Pollut. 6:501 -514, 1976;

99-413 0 - 84 - 15 : QL. 3
216 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

20.

21.

22.

23

24

25.

26.

27

28.

and Beamish, R. J., and Harvey, H. H., ‘ ‘Acidification

of the La Cloche Mountain Lakes, Ontario and Resulting

Fish Mortalities, ’)J. Fish. Res. Bozud Can. 29:1 131-1143,

1972.

Watt, W. D., ‘ ‘Present and Potential Effects of Acid Precipitation on the Atlantic Salmon in Eastern Canada,

Acid Rain and the Atlantic Salmon, Special Publications

Series of the International Atlantic Salmon Foundation,

No. 10, 1981.

Herrmann, R., and Baron, J., “Aluminum Mobilization

in Acid Stream Environments, Great Smoky Mountains

National Park, U. S.A., ” Proc. Int. Conf. Ecol. Impact

of Acid Precipitation, D. Drablos and A. Tollan (eds. ),

SNSF Project, Norway, 1980.

Muniz, I. P., and Leivestad, H,, “Acidification—Effects

on Freshwater Fish, ” Proc. Int. Conl Ecological Impact

Acid Precipitation, D. Drablos and A. Tollan (eds.), SNSF

Project, Norway, 1980; and Schofield, C. L., and Trojnar, J. R., “Aluminum Toxicity to Brook Trout (Salvelinus fontinalis) in Acidified Waters, Polluted Rain (New

York: Plenum Press, 1980).

Farmer, G. J., Goff, T. T., Ashfield, D., and Samant,

H. S., “Some Effects of the Acidification of Atlantic

Salmon Rivers in Nova Scotia, ” Can. Tech. Rep. Fish.

Aquat. Sci., No. 972, 1980.

Pough, F. H., ‘ ‘Acid Precipitation and Embryonic Mortality of Spotted Salamanders, Ambystoma Mact.datum,

Science 192:68-70, 1976; and Stirjbosch, H., “Habitat

Selection of Amphibians During Their Aquatic Phase, ”

Oikos 33:363-372, 1979.

Okland, K. A., “Ecology and Distribution of Acellus

Aquaticus (L) in Norway, Including Relation to Acidification in Lakes, ” SNSF Project, IR 52/80, 1432 Aas-NLH,

Norway, 1980; and Wiederholm, T., and Eriksson, L.,

‘‘Benthos of an Acid Lake, ” Odcos 29:261-267, 1977.

Okland, J., “Om Fursuring av Vassdrag og Betydningen

av Surhetsgraden (pH) for Fiskens Naeringsdyr: Ferskvann, ” Fauna 22: 140-147, 1969; and Svardson, G., “Inform. Inst. Freshw. Res. Drottingholm’ (Cited in Almer,

et al., 1978), 1974.

Almer, B., Dickson, W., Ekstrom, C., and Hornstrom,

E., “Sulfur Pollution and the Aquatic Ecosystem, ” Sulfur

in the Environment: Part II Ecological Impacts, J. O.

Nriagu (cd. ) (New York: John Wiley & Sons, Inc., 1978),

Kwiatkowski, R. E., and Roff, J. C., “Effects of Acidity

on Phytoplankton and Primary Production of Selected

Northern Ontario Lakes, ” Can, J. not. 54:2546-2561,

1976.

29. Dickson, W., “Some Effects of the Acidification of Swedish Lakes, ” Verh. Int. Verein. Limnol, 20:851-856, 1978;

and Yan, N. D., “Phytoplankton of an Acidified, Heavy

30

31

32

33

34,

35.

Metal-contaminated Lake Near Sudbury, Ontario, 1973-

1977, ” Wat. Air Soil Pollut. 11 :43-55, 1979.

Raddum, G. G., Hobaek, A,, Lomsland, E. R., and

Johnson, T., “Phytoplankton and Zooplankton in Acidified Lakes in South Norway, Ecol. Impact of Acid

?+ecipitation, D. Drablos and A. Tollan (eds. ), SNSF

Project, Norway, 1980.

Yan, N. D., and Strus, R., “Crustacean Zooplankton

Communities of Acidic, Metal-contaminated Lakes Near

Sudbury, Ontario, ” Ont. Min. Env. Tech. Rep., LTS

79-4, 1979.

Hendrey, G. R., and Vertucci, F., “Benthic Plant Communities in Acidic Lake Colden, New York: Sphagnum

and the Algal Mat, Proc. Int. Conf Ecological Impact

Acid Precipitation, D. Drablos and A. Tollan (eds. ), SNSF

Project, Norway, 1980.

Harvey, H. H., Pierce, R. C., Dillon, P. J., Kramer,

J. P., and Whelpdale, D. M., Acidification in the Canadian Aquatic Environment: Scientific Criterion for an

Assessment of the Effects of Acidic Deposition on Aquatic

Ecosystems, Nat. Res. Coun. Canada Report No. 18475,

1981; Hendrey, G. R., and Wright, R. F., “Acid Precipitation in Norway: Effects on Aquatic Fauna, Proc.

1st Spec. Symp. on Atmospheric Contribution to the

Chemistry of Lake Waters, Int. Assoc. Great Lakes Res.,

Orillia, Ontario, Sept. 28-Oct. 1, 1975, J. Great Lakes

Res. 2, Suppl. 1: 192-207, 1976; Kerekes, J. J., “Summary of the 1980 Environmental Contaminants Control

Fund Investigation in the Calibrated Watersheds Study

in Kejmkujik National Park, unpublished manuscript,

Canadian Wildlife Service, Halifax, Nova Scotia, 1981;

and Grahn, O., “Macrophyte Succession in Swedish

Lakes Caused by Deposition of Airborne Acid Substances, Proceedings of the First International Symposium on Acid Precipitation and the Forest Ecosystem,

L. S. Dochinger and T. A. Seliga (eds. ), Ohio State

University, May 12-15, 1975, USDA Forest Service

General Technical Report NE-23, Upper Darby, Pa., Forest Service, U.S. Department of Agriculture, Northeastern

Forest Experiment Station, 1976.

Hultberg, H., and Grahn, 0,, ‘ ‘Effects of Acid Precipitation on Macrophytes in Oligotrophic Swedish Lakes,

Proc. First. Specialty Symposium on Atmospheric Contribution to the Chemistry of Lake Waters, Internat.

Assoc. Great Lakes Res. Sept. 28-Oct. 1, 1975.

Bick, H., and Drews, E. F., ‘ ‘Self Purification and Silicate

Communities in an Acid Milieu (Model Experiments), ’

Hydrobiologia 42:393-402, 1973; and Traaen, T. S., and

Laake, M., ‘ ‘Microbial Decomposition and Community

Structure as Related to Acidity of Fresh Waters—An Experimental Approach, SNSF Project, Norway, 1980.
App. B—Effects of Transported Pollutants . 217

B.2 TERRESTRIAL RESOURCES AT RISK*

The Effects of Ozone on

Agricultural Productivity

For over two decades, ozone has been known to harm

crops (27). * * Alone, or in combination with sulfur dioxide (S02

) and nitrogen oxides (NOX), it causes up to

90 percent of the Nation’s air pollution-related crop

losses (29). Previous studies estimated that 2 to 4 percent of total U.S. crop production was lost annually,

using limited available data and assuming that all areas

of the United States just met the current ozone standard. These efforts were limited by the unavailability of

field-generated data on crop loss, insufficient data on

ozone levels in various parts of the country, and a lack

of integration with available crop distribution and productivity data.

OTA’s analysis uses National Crop Loss Assessment

Network (NCLAN) field-experiment data on the effects

of ozone on crops (28), in combination with more recent crop and ozone data, to estimate the effects of ozone

on U.S. corn, wheat, soybean, and peanut production.

The selected crops range in susceptibility to ozone

from sensitive (peanut) to sensitive/intermediate (soybean) to intermediate (wheat) to tolerant (corn). Among

major U.S. agricultural commodities, these four crops

represent 62 percent of the acres harvested and 63.5 percent of the dollar value. The analysis compared countylevel agricultural data with estimated county-level nonurban ozone concentrations derived from measurements

at approximately 300 selected monitoring stations. Actual 1978 crop yields were assumed to represent potential yields minus reductions in productivity due to current levels of atmospheric pollutants including ozone.

Data from controlled field experiments were used to develop dose-response functions relating ozone level to

crop productivity. The functions were then used to estimate potential gains in productivity achievable by reducing ozone levels to an estimated natural “background” concentration of 25 parts per billion (ppb).

The assessment estimates that in 1978, corn yields

would have increased by 2.5 percent, wheat by 6 percent, soybeans by 13 percent, and peanuts by 24 percent if ozone levels had been reduced to natural background levels. As measured by 1978 crop prices, this

represents about $2 billion of agricultural productivity.

‘This sectmn adapted from Oak R]dge JNatlonal I,aboratory, Enwronmentaf Sciences Division, ‘ ‘An Analysls of Potential Agriculture and Forest Impacts of Long-Range Transport Alr Pollutants, ” C)”I’A contractor report, 1983,

● “Cltatlon numbers are keyed to Reference Ilst at back of this sectmn

Of the estimated dollar impact, soybeans represent 69

percent, corn 17 percent, wheat 6 percent, and peanuts

8 percent. The Corn Belt States of Illinois, Iowa, and

Indiana, plus Missouri, Arkansas, Minnesota, Ohio,

Kentucky, North Carolina, and Virginia were estimated

to have experienced the greatest agricultural effect.

Crop Response Data

Crop response data were obtained from the 1980

NCLAN Annual Report (77), or from earlier experiments using the methods later adopted for the NC LAN

project (22,24,25). Test plants were grown in uniform,

open-top field chambers and exposed to carefully controlled ozone levels. Yield data from plants receiving

charcoal-filtered air (25 ppb ozone) were used as controls. Three sets of soybean data, four sets of wheat data,

and one set each for corn and peanuts were used to estimate quantitative relationships between ozone levels

and crop damage.

Crop Yield Data

The Census of Agriculture, conducted approximately

every 5 years by the Department of Commerce, develops an extensive national inventory based on responses

to mail questionnaires. The 1978 Census of Agriculture

provided county-level yield statistics for the surveyed

crops. The analysis averaged winter and spring wheat

yields together, and excluded sweet corn production

from corn yields.

Ozone Data

The U.S. Environmental Protection Agency (EPA)

provided estimates of seasonal ozone concentrations for

the analysis (75). EPA selected approximately 300 from

a total of over 500 EPA monitoring stations as regionally

representative and free from urban influence. Stations

and observations were screened to eliminate those with

few or unrepresentative readings. The monitoring stations are irregularly distributed, and large areas of the

country lack monitoring data for rural areas. The available data were used to estimate values for counties without monitoring data using a statistical-averaging procedure called kriging. Seasonal averages were calculated

as the mean of the growing season months appropriate

for each crop (wheat, April-May; corn, peanuts, JuneAugust; and soybeans, June-September). The EPA estimates of average ozone concentration during June to

September 1978 are show in chapter 4 (fig. 15).
218 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Regional Impacts

Figures B-5 through B-8 show the general pattern of

productivity gains for each crop as potential yield increases (i. e., bushels/acre). Table B-7 summarizes these

yield increases (as percentage increases), and their market value at 1978 average crop prices, by State. However, these dollar values do not reflect the potential price

effect of the projected yield increases. Since increasing

crop production would tend to lower crop prices, the

dollar values in table B-7 should only be considered a

surrogate for ozone-related crop damage; the dollar values allow comparisons of yield increases across all four

crops, as well as comparisons of potential State-level productivity increases.

Projections of Economic Effects If Ozone Levels

Are Reduced in the Future

If ozone levels are reduced, the cost of producing an

ozone-sensitive crop will decrease, because the same

amount of land, fertilizer, labor, etc., will result in

greater crop yields. But the economic effects of reducing ozone levels also depend on how farmers and consumers react to these changes. Farmers could, for example, choose to grow the same amounts of these crops

as before, reducing their inputs of land, fertilizer, and

labor. Alternatively, they could increase their production, making greater crop supplies available in the marketplace, though presumably at somewhat reduced crop

prices.

Analysts at the U.S. Department of Agriculture

(USDA) used two econometric models to estimate how

OTA’s projected yield increases might affect farmers

and consumers (80). The models assessed the potential

effect of eliminating half the manmade ozone over a 10-

year period (i.e., reducing ozone concentrations to the

midpoint between measured 1978 levels and the estimated natural background level of 25 ppb by the early

1990’s).

One of the models focuses primarily on domestic agricultural trends and policies; it projected that increasing

the productivity of these three crops would cause supplies to increase moderately. However, it also projected

these increases to cause proportionately larger declines

in crop prices, reducing net farm income significantly,

while inducing only marginal declines in the Consumer

Price Index for food. The second model was designed

primarily to assess international trends in agricultural

production. While it also projected a moderate increase

in U.S. supplies of corn, wheat, and soybeans, changes

in production levels had significantly different economic

repercussions. Estimated price reductions and supply

increases were approximately in balance; supply increases outweighed price declines for corn and soybeans,

while price declines were proportionately larger than

supply increases for wheat. Gross farm receipts for the

three crops overall were estimated to increase slightly.

The two models provide a qualitative perspective on the

complex relationship between pollution and the agricultural sector of the economy; the economic effect of potential ozone reductions depends heavily on both farmer

response and Federal agricultural policy.

Effects of Acid Rain on

Agricultural Crops

Because several major U.S. agricultural regions experience elevated levels of acid deposition, researchers

are attempting to determine whether acid deposition affects crop productivity. Crops are more likely to be damaged through direct contact with acid deposition on

aboveground portions of plants than through soil-related

effects. However, some soil-mediated effects—e.g.,

changes in nutrient availability, microbial activity, or

metal toxicity—might also be important.

Research on how acid deposition affects crops has advanced about as far as research on ozone effects in the

late 1960’s. Acid deposition is a mixture of chemicals;

plants respond not only to the hydrogen ions (acidity)

but also to sulfate and nitrate ions that can act as fertilizers. Moreover, some researchers hypothesize interactions with other physical and biotic causes of plant stress

(e. g., air pollution and pests), but little definitive evidence exists on which to base conclusions.

Mechanisms of Acid Rain Effect on Vegetation

No direct, visible injury to vegetation in the field has

been demonstrated to result from exposure to ambient

acid deposition. Rather, information about effects comes

from a wide variety of approaches involving, in most

instances, some form of rain ‘‘simulation. Adding sulfate and nitrate to soil-plant systems can have both positive and negative effects. Each system’s response is affected by: 1) precedent conditions (e. g., soil nutrient

status, plant nutrient requirements, plant sensitivity,

and growth stage); and 2) the total loading or deposition of the critical ions (nitrate, sulfate, and hydrogen

ions).

Concentrations of hydrogen ions equivalent to those

measured in highly acidic rainfall events (i. e., pH less

than about 3), have caused tissue lesions on a wide variety of plant species in greenhouse and laboratory experiments. This visible injury is reported to occur at a

threshold of between pH 2.0 and 3.6. No evidence at

the present time suggests that hydrogen ion inputs have

any beneficial effect.
App. B—Effects of Transported Pollutants . 219

Table B-7.— Estimated Crop Gains (percentage increase and millions of 1978 dollars) Due to Ozone

Reduction—Based on 1978 Crop and Ozone Data

Wheat Corn Soybeans Peanuts

Percent Millions Percent Millions Percent Millions Percent Millions

increase of dollars increase of dollars increase of dollars increase of dollars

Alabama . . . . . . . . . . . . . . .

Alaska . . . . . . . . . . . . . . . . .

Arizona . . . . . . . . . . . . . . . .

Arkansas. . . . . . . . . . . . . . .

California . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . .

Connecticut . . . . . . . . . . . .

Delaware. . . . . . . . . . . . . . .

Florida. . . . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . . . . .

Hawaii . . . . . . . . . . . . . . . . .

Idaho . . . . . . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . . .

Iowa. . . . . . . . . . . . . . . . . . .

Kansas . . . . . . . . . . . . . . . .

Kentucky . . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . . .

Maine . . . . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . . .

Massachusetts . . . . . . . . .

Michigan . . . . . . . . . . . . . . .

Minnesota . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . .

Missouri . . . . . . . . . . . . . . .

Montana . . . . . . . . . . . . . . .

Nebraska . . . . . . . . . . . . . .

Nevada . . . . . . . . . . . . . . . .

New Hampshire . . . . . . . . .

New Jersey . . . . . . . . . . . .

New Mexico . . . . . . . . . . . .

New York . . . . . . . . . . . . . .

North Carolina . . . . . . . . . .

North Dakota . . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . . .

Oklahoma . . . . . . . . . . . . . .

Oregon . . . . . . . . . . . . . . . .

Pennsylvania . . . . . . . . . . .

Rhode Island . . . . . . . . . . .

South Carolina . . . . . . . . . .

South Dakota . . . . . . . . . . .

Tennessee . . . . . . . . . . . . .

Texas . . . . . . . . . . . . . . . . . .

Utah . . . . . . . . . . . . . . . . . . .

Vermont . . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . . .

Washington . . . . . . . . . . . .

West Virginia . . . . . . . . . . .

Wisconsin . . . . . . . . . . . . .

Wyoming . . . . . . . . . . . . . .

United States.. . . . . . . .

8.0 —

—

5.6 —

7.6 —

2.0 —

8.0 —

—

5.3

5.2

5.9

4.8

3.7

7.3 —

2.0 —

4.0

4.9

6.7

4.5

0.9

6.2

6.3 —

3.0

10.2

5.5

7.2

5.3

4.6

4.7

1.5

5.6

0.0

8.3

5.4

4.9

7.3

7.8 —

3.2

1.9

3.9

6.6

7.5

5.3

—

—

—

1

—

12

—

—

—

1 —

—

5

3

—

33

1 —

—

—

—

2

3

—

4

—

13

—

—

—

2

—

1 —

5

17

—

1 —

—

3

1

12

—

—

—

—

—

—

1

125

2.7

—

—

4.5

2.3

3.0

0.0

3.0

1.2

2.7—

—

2.6

3.0

2.3

2.8

2.4

2.3—

3.4—

1.6

1.1

3.7

2.7—

2.1—

—

1.9

3.6

2.1

4.1

0.7

2.8

3.0—

2.5—

4.1

1.3

2.9

2.9

3.7—

3.6—

2.1

2.3

3.0

2.4

1

—

—

—

2

5

—

1 —

5

—

—

68

42

73

10

6

—

—

4

—

7

15

—

11

—

32

—

—

.

—

2

10

—

22

—

—

7

—

2

5

3

7

—

—

4

—

—

15

—

361

13.3

—

—

18.8

—

—

—

12.0

9.2

15.8

—

—

13,0

13.7

11.3

9.9

12.8

10.8

—

14.1

—

6.3

9.6

18.0

12.7

—

8.4

—

—

9.4

—

—

20.6

—

12.1

17.9

—

10.1

0.0

21.7

8.1

13.2

11.5

—

—

19.1

—

—

12.0

—

28

—

—

132

—

—

6

5

29

—

—

262

123

200

17

30

54

—

11

—

9

76

89

120

—

21

—

—

3

—

—

48

—

97

6

—

2

—

37

6

43

12

—

—

15

—

—

5

—

1,485

19.5

—

—

—

—

—

—

—

14.9

22.3

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

35.9

—

—

26.3

—

—

—

35.9

—

—

12.7

—

—

38.9

—

—

—

—

23.8

21

—

—

—

—

—

—

—

5

72

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

34

—

—

10

—

—

—

2

—

—

10

—

—

21

—

—

—

—

175

SOURCE: Oak Ridge National Laboratory, 1983.
220 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

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224 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Recent research has found that vegetation is extremely responsive to the sulfur and nitrogen inputs in

acid precipitation. Evidence from studies of field-grown

soybeans (34) and forest tree species (2, 119) indicate an

apparent positive growth response to the sulfur and nitrogen in simulated acid rain. Other work suggests that

sulfur may have been a limiting factor in the nutrition

of experimental lettuce plots (37).

Pollutant deposition theoretically could affect soilplant systems over the long term through potential soil

changes—e.g., 10SS of calcium and magnesium or release of toxic metals. However, since croplands are

heavily managed and fertilized, such soil-related effects

due to acid deposition are unlikely.

Results of Field and Laboratory Studies

Several investigators have performed dose-response

experiments on a variety of plant species. Thresholds

for direct, visible injury to greenhouse foliage subjected

to simulated acid rain typically are about pH 3.1 (36).

However, field trials using the same treatment solutions

under both greenhouse and field situations yield significantly different estimates of species sensitivity.

Experimental evidence suggests that a plant’s

‘‘wetability’ is an important factor in its response to

acid deposition. Comparisons between studies of relatively wetable, nonwaxy bean cultivars (19,38,83) and

studies of very waxy citrus leaves (26) show that the bean

cultivars have a threshold of between pH 3.1 and 3.5

for developing foliar lesions, while a greater than 400-

times increase in hydrogen ion concentration—to near

pH 2.0—is required to induce visible symptoms in the

citrus leaves. Waxy leaves appear to minimize the contact time for acid solutions. Table B-8 summarizes results of field experiments that applied simulated acid rain

to nine crops: alfalfa, beet, corn, fescue, kidney bean,

mustard green, radish, soybean, and spinach. The table

lists effects on crop growth or yield rather than visible

injury. No consistent trends are observed. For example, experiments on different types of soybeans resulted

in positive, negative, and no growth effects. For both

alfalfa and mustard green, altering the chemical composition of the acid rain simulant (but keeping the pH

constant) drastically altered experimental results. Further complicating interpretation of these data, research

has shown that the experimental procedures used to

apply acid rain simulants also can affect results (18).

To summarize available information on how acid deposition affects crops: 1 ) visible injury thresholds for acid

precipitation lie between pH 2.0 and 3.6, depending on

species, and may vary from pH 3.0 to 3.6 within the

same species (e. g., bean); 2) total dose of hydrogen ions

appears to be most clearly related to visible injury; and

3) growth effects in the absence of visible injury have

been reported at a threshold of between pH 3.5 and 4.0,

but sulfur and nitrogen in the precipitation may cause

positive net growth effects, depending on soil nutrient

status, buffering capacity, other growth conditions, and

plant nutrient requirements.

Relationship of Acid Rain to Overall Crop

Damage From Pollutants

Because acid deposition occurs throughout the Eastern United States and Canada, vegetation is commonly

exposed both to gaseous pollutants such as ozone and

sulfur dioxide, and to wet deposition of acidic substances. Little information is available to evaluate how

plants respond to the combined effects of wet- and drydeposited pollutants.

The foliage of vegetation is wetted by rain, fog, or

dew formation during significant portions of the growing season in midlatitude temperate climates. During

these periods, leaf surfaces more readily take up drydeposited gases. For example, researchers found that

as S02 dissolved in the dew on leaf surfaces, the acidity

of the dew increased, suggesting the potential for drydeposited acidic pollutants to react directly with wet

vegetation surfaces ( 103).

Preliminary work suggests that acid deposition may

interact with other pollutants. One researcher observed

a significant growth reduction at harvest in plants intermittently exposed to ozone in addition to receiving

four weekly exposures to rainfall of pH 4.0 (85). Another

demonstrated that ozone depresses both growth and

yield of soybeans under three different acid rain treatments, and that the depression was greatest with the

most acidic rain (36). Experiments on field-grown soybeans found that simulated acid precipitation (pH 3.1)

appeared to lessen plant response to S02 (34). The

mechanisms of interaction are currently under investigation, but unknown.

Effects of Multiple Pollutants

on Forests

One-third of the total land area of the United States

is forested; two-thirds of that area—approximately 400

million acres—is classed as commercial timberland.

Nearly three-quarters of the country’s commercial timberland is located in the Eastern United States, distributed about equally between the North and South sections (fig. B-9). Nearly 80 percent of New England, and

greater than 40 percent of the Atlantic Coast States, are

forested.

Scientists have recently discovered productivity declines in several tree species throughout the Eastern

United States from New England to Georgia. Acid dep-
App. B—Effects of Transported Pollutants . 225

Table B-8.—Field Research on Effects of Acid Precipitation on Crop Growth and Yield

Species/variety Test pH As compared to: Effect

Alfalfa . . . . . . . . . . . . . . . . . . . . 3.0, 3.5,

4.0a

Beet . . . . . . . . . . . . . . . . . . . . . 2.7, 3.1, 4.0

5.7

Corn . . . . . . . . . . . . . . . . . . . . . 3.0, 3.5

4.0

Fescue . . . . . . . . . . . . . . . . . . . 3.0

3.5,4.0

Kidney bean . . . . . . . . . . . . . . . 3.2

Mustard green . . . . . . . . . . . . . 3.0a

, 4.0a

3.5

Radish ’’Champion’’ . . . . . . . . 2.8

3.5

4,2

5.6

Radish “Cherry Belle” . . . . . . 3.0,4.0

3.5a

Radish “Cherry Belle” . . . . . . 2.7, 3.1, 4.0

Soybean “Amsoy” . . . . . . . . . 2.3

2.7

3.1, 4.0

Soybean “Amsoy” b. . . . . . . . . 2.7a

3.3a

4.1a

Soy bean ’’Benson’’ . . . . . . . . . 2.8

3.4

Soybean “Davis”. . . . . . . . . . . 2.8, 3.2, 4.0

2.4, 3.2, 4.1

Soybean “Wells” . . . . . . . . . . 3.06

5.6

Soybean “Williams” . . . . . . . . 2.8

3.4

Spinach . . . . . . . . . . . . . . . . . . 3.0, 3.5, 4.0

Control: 5.6

Control: 5.6

Ambient: 4.06

Ambient: 4.06

Control: 5.6

Control: 5.6

Control: 5.6

Control: 5.6

Control: 6.0

Control: 5.6

Control: 5.6

Control: 5.6

Control: 5.6

Control: 5.6

Ambient: 3.8

Control: 5.6

Control: 5.6

Control: 5.7

Ambient: 4.1

Ambient: 4.1

Ambient: 4.1

Control: 5.6

Control: 5.6

Control: 5.6

Control: 4.0

Control: 4.0

Control: 5.3

Control: 5.4

Control: 5.6

Ambient: 4.1

Control: 4.0

Control: 4.0

Control: 5.6

No effect on yield

No effect; 9°/0 greater yield

Lower number of marketable roots

10°/0 greater shoot growth,

16°/0 greater yield

No effect on yield or growth

9°/0 lower yield, no effect on growth

No effect on yield

19°/0, 24°/0 greater yield

No effect on yield or growth

No effect; 31 to 33% lower yield

No effect on yield

13 to 17°/0 higher root weight

7 to 11 0

/0 higher root weight

3 to 7°/0 higher root weight

No effect; 12°/0 lower root weight

No effect on yield or growth

No effect; 25°/0 greater yield

No effect on yield or growth

No effect on yield, lower pods/plant

11 % lower seed weight, lower seeds and pods/plant

No effect on yield or growth

3 to 11 % lower yield

7 to 17°/0 lower yield

8 to 23°/0 lower yield

32°/0 greater yield, 17°/0 greater seed size

No effect on yield, 8°/0 smaller seed size

No effect on yield or growth

No effect on yield or growth

No effect on yield, 4°/0 greater weight/seed

No effect on yield, 4% greater weight/seed

No effect on yield, 17°/0 smaller seed size

No effect on yield, 22°/0 greater seed size

No effect on yield or growth

aDifferent acid rain simulants or treatment methods produced different results.

bSee reference 18 to text of this section.

SOURCE: Modified from U.S. Environmental Protection Agency, “Effects on Vegetation,” The Acid Deposition Phenomenon and Its Effects, Critical Assessment Review

Papers, Public Review Draft, 1983, except as noted above.

osition, ozone, heavy-metal deposition, drought, severe

winters or a combination of these are possible causes

under investigation.

By coring trees and measuring the thickness of annual growth rings, scientists have observed marked reductions in productivity beginning about 1960 in red

spruce, shortleaf pine, and pitch pine. Corings from

about 30 other species at 70 sites throughout the East

are currently being analyzed to determine the geographic extent and severity of the problem. Routine measurements of tree growth by the U.S. Forest Service have

shown productivity declines in loblolly pine and shortleaf

pine during the 1970’s in the Piedmont region of South

Carolina and Georgia. Again, the cause of these declines

is not yet known, but air pollution is a possible factor.

Air pollutants can influence plant health through a

complex process that depends not only on the level of pollution and duration of exposure but also on environmental factors that influence the plant’s overall response as

a living organism under stress. As with all stressinducing agents, air pollutants may initiate changes

within plant metabolic systems that cause extensive

physiological modifications; sufficient change may lead

to visible symptoms. In some instances, adding low pollutant levels to a plant’s environment may induce a

fertilizer-like response. This phenomenon has been

analyzed in agronomic crops; however, no studies have

shown beneficial effects on natural ecosystems.

Continual exposure to pollutants such as ozone and

sulfur dioxide can cause tree death. Other contributing

or mitigating factors also may be involved (i. e., abiotic

or biotic disease-inducing agents or insect attack).

Depending on the tree species, the seasonal stage of

growth, pollutant dose, and environmental conditions,

many forms of injury, varying widely in impact, may

occur. A given plant may exhibit symptoms of acute and

chronic injury simultaneously. However, injury does not

necessarily imply damage (i. e., economic loss).
226 Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure B-9.—Percent of Land Area Capable of Commercial Timber Production

aThe U.S. Forest Service deflnes commercial timberland as lands capable of producing greater than 20 Cubic feet of industrial roundwood per acre per year, in natural stands.

SOURCE: Oak Ridge National Laboratory from U.S. Forest Service inventory data.

The potential effects of acid deposition and gaseous

pollutants (e. g., ozone) on forest productivity can be discussed only qualitatively at present. Figure B-10 summarizes the various mechanisms by which such a combination of pollutants might affect forest productivity.

The top part of the diagram illustrates positive and

negative effects on exposed vegetation; the bottom part

of the diagram illustrates positive and negative effects

on vegetation through soil processes. For example, each

of the gaseous pollutants—ozone, SO2

, and NOX—has

a predominantly negative effect on vegetation. Acid

deposition may have both positive and negative

effects-fertilizing the soil with sulfur and nitrogen, but

potentially leaching nutrients from leaves and releasing

toxic aluminum from the soil.

Figure B-10 shows the net effect on the growth of

vegetation as the sum of a series of positive and negative

effects. Site-specific factors that control plant responses

to any individual mechanism are likely to determine the

net effect on plant productivity, assuming that different

mechanisms do not interact to produce additional

effects.

The greatest potential for negative pollutant impacts

on trees appears to occur in the commercial forests of

the Southeastern Coastal Plain, the Mississippi River

Valley, the Appalachian Mountain chain, and the upper Ohio River Valley. These regions experience both

high concentrations of ozone and elevated levels of acid

deposition. In each of these areas, nitrogen inputs to

forests would be expected to partially offset negative impacts, while sulfur inputs currently exceed forest growth

requirements and probably have neither a significant

positive or negative influence at this time.

To summarize the potential for long-term forest-productivity effects from both acid deposition and gaseous

pollutants, at the present time OTA can state only that

such interactions might occur and that their probability of occurrence is greatest in those regions of the Eastern United States outlined above. The mechanisms involved and the relative importance of those mechanisms

to forest growth response must be studied further in order to better describe and eventually quantify these potential effects.
App. B—Effects of Transported Pollutants ● 227

Implications of Potential Forest Productivity

Declines Due to Air Pollution

If air pollution is shown to significantly affect the productivity of commercially forested timber species,

potential long-term effects on forestry and related industries could be of concern. OTA used in-house information and analyses to identify significant factors

about the current forest industry and how it might be

affected by potential forest productivity declines due to

air pollution.

It is estimated that improved management practices

on suitable lands could double sustainable timber harvest levels on over 90 percent of forestland in the Eastern United States. Thus, significant potential for offsetting future forest productivity declines exists.

However, if timber harvest levels do not increase, potential forest-productivity losses due to air pollution

could be of particular significance for regional timber

markets in the South. Lack of softwood reforestation on

many private nonindustrial forest lands over the past

two decades may decrease softwood-timber harvests in

the South, beginning about 1995. Timber supplies in

the Northeastern United States appear to be adequate

for the foreseeable future. Productivity declines, whether

of regional or local scale, could threaten the economic

viability of individual lumbermills and papermills. Significant reductions in harvests over a sustained period

●

could cause mill closures; papermills are particularly

vulnerable, since they represent large capital investments, and must operate very close to capacity (in general, over 90 percent) to break even. ●

Potential losses in timber production in the Northeast

and South, if realized, could alter opportunities to increase forest-product exports, and could, at the extreme,

result in increasing imports of timber from the Canadian Northwest.

Effects of Ozone on

Forest Productivity

Considerable literature is available to describe ozone

effects on forest vegetation. Most studies examined

foliar (leaf) injury rather than yield loss. Table B-9 lists

tree species that have been determined to be sensitive,

of intermediate sensitivity, and tolerant of ozone. However, researchers caution against overreliance on these

relative rankings, because the individual experiments

varied in study methods used (exposure chamber, ambient air), age of trees, and type of response measured

(injury, growth).

Most of the few studies examining yield loss exposed

forest tree seedlings to ozone under controlled laboratory or greenhouse conditions. One field study, how-
228 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table B-9.—Relative Susceptibility of Trees to Ozone Damage

Sensitive Intermediate Resistant

Tree-of-Heaven Boxelder Balsam fir

juneberry eastern redbud white fir

white ash Japanese larch sugar maple

swamp ash incense cedar Norway maple

honey locust sweetgum European white birch

European larch knobcone pine flowering dogwood

tulip poplar Iodgepole pine European beech

jack pine short leaf pine American holly

coulter pine South Florida slash pine black walnut

Jeffrey pine sugar pine western juniper

Austrian pine pitch pine swamp tupelo

ponderosa pine eastern white pine Norway spruce

monterey pine Scotch pine white spruce

Ioblolly pine Torrey pine blue spruce

Virginia pine scarlet oak red pine

American sycamore pin oak digger pine

Japanese poplar black oak Rocky Mountain Douglas fir

black cottonwood common lilac common pear

quaking aspen Chinese elm ●

shingle oak

white oak bur oak

European mountain ash English oak

lilac northern red oak

black locust

redwood

giant sequoia

northern white cedar

American basswood

Iittleleaf linden

eastern hemlock

SOURCE: D. D. Davis and H. D. Gerhold, “Selection of Trees for Tolerance of Air Pollutants,” Better Trees for Metropolitan

Landscapes Symposium Proceedings, U.S. Forest Service General Technical Report, NE-22:61-66, 1976.

●

ever, has measured yield reductions in mature white

pine in the Blue Ridge Mountains of Virginia.

The study compared annual radial-increment growth

in tolerant, intermediate, and sensitive varieties of white

pine (Pinus strobus) (6). Observed within-species variations in ozone-induced foliar injury were used to classify

trees into the three sensitivity categories. The trees were

then compared to determine how much less growth had

occurred in the sensitive and intermediate varieties than

in their tolerant counterparts. Growth in the sensitive

and intermediate varieties was reduced by 45 percent

and 15 percent for 1 year (1978), by 40 percent and 20

percent over a 10-year period (1968-78), and by 28 percent and 15 percent over a 25-year cumulative period.

These figures may be conservative, as they are based

on comparisons to ozone-tolerant tree growth in areas

of known ozone occurrence (50 to 75 ppb, 7-hour average, May-September yearly).

Several field studies related significant changes in

forest ecosystem response to ambient oxidant concentrations (88). The San Bernardino Mountain Study documented mortality of sensitive ponderosa (Pinus ponderosa) and Jeffrey (P. Jeffreyi) pines after bark beetles

infested air-pollution-stressed trees (63,65). Air pollution stress appears to be shifting forest species composition toward more tolerant species such as white fir.

Other examples of shifts in species composition associated with oxidants or mixtures of air pollutants also have

been reported (21,60),

Fate and Effects

in Forest

Upon entering a forest

of Acid Deposition

Ecosystems

ecosystem, acidic pollutants

such as sulfate and nitrate become part of a chemical

system regulated by a variety of natural processes, The

chemical constituents of acid deposition should be

viewed as an addition to the hydrogen, sulfate, and

nitrate ions produced and cycled naturally within forest ecosystems.

This section discusses ways in which atmospherically

deposited hydrogen, sulfate, and nitrate ions could affect forest nutrient cycles. The section also examines the

fate and effects of deposition in excess of amounts that

can be biologically used, or chemically trapped or neutralized by forest soils.
App. B—Effects of Transported Pollutants 229

Effects on Forest Sulfur and Nitrogen Status

Acid deposition contains readily usable forms of the

essential plant nutrients sulfur and nitrogen. Nitrogen-deficient forests are common throughout the United

States, but sulfur-deficient forests are much less common, occurring primarily in the Pacific Northwest

(98,99,1 14,120).

Atmospheric inputs of nitrate and ammonium could

improve nitrogen nutrition substantially in forests of the

North Central and Northeastern States, especially in

areas near the eastern Great Lakes. In most areas of

the West, atmospheric nitrogen inputs are much less significant when compared to the total nitrogen requirements of Western forests.

The sulfur deposited in some forested areas of the

Western United States may be less than that required

for optimal growth, but data to quantify how widely this

occurs are scanty. Much of the Eastern United States

appears to receive inputs equal to or in excess of tree

sulfur requirements. Moreover, trees require nearly 15

times as much nitrogen as sulfur, on a weight basis, to

synthesize protein. The ratio of nitrogen to sulfur in atmospheric deposition is far from this ideal value

throughout the United States, with greater amounts of

sulfur than nitrogen deposited over most of the Eastern

United States. Thus, it would appear that substantially

greater quantities of sulfur are being deposited than can

be used as fertilizer over the long term, and that many

forests would have to be heavily fertilized, or otherwise

enriched in nitrogen, to benefit at all from sulfur deposition (99).

Forests do not depend entirely on atmospheric inputs

to meet nutrient requirements, as they recycle nutrients

—e. g., by reclaiming them from decomposing leaves.

When atmospheric nutrient inputs fail to meet growth

requirements and soil-available nutrient supplies are low

(as is often the case for nitrogen), recycling processes

within forest ecosystems and nutrient translocation from

one part of a tree to another help supply nutrients to

growing tissues. Thus, while increased atmospheric nitrogen and sulfur inputs might benefit forests limited

in those nutrients, under undisturbed conditions atmospheric inputs do not have to equal plant uptake to

maintain site fertility. However, to maintain site fertility in harvested forests, inputs must compensate for the

amount of nutrients removed by logging.

Effects on Forest Cation Nutrient Status

In addition to supplying some nutrients, acid deposition (and naturally produced acids) can remove other

nutrients stored in leaves, the litter layer on the forest

floor, or the soil. The hydrogen ions (i. e., the “acidity’ of acid deposition can replace or ‘‘leach’ nutrient cations, * removing these essential nutrients from

the forest ecosystem.

Acid deposition can remove essential nutrient cations

(e. g., calcium) directly from tree foliage. If the rate of

nutrient loss is greater than can be replaced through the

roots, nutrient deficiency will result. Scientists do not

know which tree species are most susceptible to foliar

nutrient loss, or the level of acid deposition at which

such loss becomes harmful. For any given species, the

rate of loss probably depends on both the total amount

and concentration of acid-producing substances (sulfate

and nitrate) deposited on leaf surfaces.

Nutrient leaching from soils is somewhat different.

No cation leaching will occur unless the acid-producing

substances can travel freely through the ecosystem (47).

Since forest nitrogen deficiencies are very common and

nitrate is taken up readily by forest vegetation (1 ,74),

atmospheric nitrate inputs are unlikely to be mobile

enough to leach significant amounts of nutrient cations

from most forest soils. Sulfate, the other major acid-producing substance in rainfall, can travel through many

types of forest soils and is, therefore, of greater concern.

While acid deposition can accelerate cation leaching

rates, the magnitudes of these increases must be compared to losses from natural leaching processes. The relative importance of deposition-induced leaching depends

on: 1 ) the amount of acid input at a given site, 2) the

rate of soil leaching by natural processes (8, 10,66), and

3) the ability of soils to buffer against leaching (e. g.,

by “adsorbing” or trapping sulfate onto their surfaces)

(46). Furthermore, a number of variables govern how

accelerated leaching ultimately affects forest cation nutrient status, most notably: 1) the amount of exchangeable cations, 2) the rate at which nutrients are replaced

through mineral weathering (74,9 1), 3) forest cation nutrient requirements, and 4) management practices such

as harvesting (44).

If the quantities of soil cation reserves within a forest

ecosystem are large relative to leaching rates (e. g., in

calcareous soils), a doubling or tripling of leaching rates

due to acid rain probably would be of little consequence.

If reserves are small (e. g., in highly weathered soils),

doubling or tripling of leaching rates may have longterm significance. Soils in which current input levels of

acid deposition can significantly deplete nutrient reserves over less than many decades are probably rare,

however. Nonetheless, given a sufficiently large input

for a sufficient amount of time, acid rain must eventually deplete these reserves.

Currently, few forests of the United States have cation deficiencies, although notable exceptions are known

in certain forests of the Northeast (90). An intensive

“Nutrients [hat have the same chemical charge as hydrogen Ions, e g.,

calcium, magnesium, and potassium
230 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

study of a central Adirondack Mountain forest indicates

that atmospheric sulfate deposition has increased rates

of soil nutrient-cation leaching substantially (66). Since

these soils are quite low in available cation reserves, the

researchers concluded that, “Chronic leaching by [sulfuric acid] combined with internally generated organic

acids may represent a real threat to the nutrient status

of many Adirondack forest soils’ (66). However, the

authors acknowledge that total soil cation reserves and

weathering rates (or rates at which these reserves become

available to trees) are unknown, and that a complete

assessment must encompass these factors. Acid rain itself

may cause soil weathering rates to increase, potentially

offsetting accelerated nutrient leaching to some extent.

Effects of Aluminum Mobilization

Soil scientists have long known that soils release aluminum under sufficiently acid conditions (5, 121 ). Aluminum is also known to be toxic to plant roots in sufficient concentrations, either killing them directly or

interfering with nutrient uptake (especially phosphorus

and calcium) (71, 73). Researchers recently found a

marked increase in soil aluminum concentrations over

a 13-year period in a beech and Norway spruce forest

soil at the Soiling site in West Germany (58, 101). They

attributed the change to a combination of natural acidifying processes within the forest ecosystem and atmospheric acid inputs. Furthermore, the authors believe that

aluminum levels have become toxic to tree roots, posing a situation with ‘‘serious consequences for forestry

in Central Europe.

The findings of these West German researchers are

cause for concern, but they may not apply to all forest

types. Acid and sulfate inputs are very high at the Solling site, as would be necessary to further acidify a soil

that was initially very acid. Moreover, species vary

widely in their susceptibility to aluminum toxicity. *

Similar declines have been observed in red spruce in

the Northeastern United States. However, recent work

fails to support the soil aluminum hypothesis in these

cases. Specifically, researchers found no changes in soil

pH over a 15-year period (1965-80) and no relationship

between tree vigor and root or foliar aluminum concentration. The causes for the decline in red spruce are unknown as of this writing. Acid rain, aluminum concentrations, and forest decline, but acid rain (perhaps via

other mechanisms) remains one of several working hypotheses under investigation.

“Researchers repon great variations m toxicity thresholds among several tree

species, ranging from 10 mg/1 Al in solution for a poplar hybrid to 80 to 120

mg/1 in oak, birch, and pine (61 ). Others report Al concentrations in

‘‘equ ilibrium soil solution (i. e., solution obtained after extraction of soil with

water for 24 hr) of less than 3 mg/1 (101 ) More recently, Al concentrations

of nearly 20 mg/1 in soil solutions were reported from the spruce stand at Soiling (58).

It must be emphasized that acid rain effects are sitespecific, depending on the amount of acid input and on

the vegetation, soils, and nutrient status of the site

receiving such inputs. Forest ecosystems in general cannot be expected to respond to acid rain in any single

way.

The Regional Distribution of Soils

at Risk From Acid Deposition

Analysts have proposed and used several sets of sensitivity criteria to define geographical regions most susceptible to acid deposition effects. Each set is based on

scientific concepts that aim at particular target organisms or ecosystems (e. g., forests or aquatic ecosystems).

Those directed toward aquatic effects emphasize bedrock geology (3 1,67), while those directed toward soils

effects emphasize cation exchange capacity (C EC) and

base saturation (52,59).

Scientists at Oak Ridge National Laboratory have

classified unmanaged (i. e., forest or range) soils according to their sensitivity to three types of acid-deposition-induced changes: 1) losses of essential nutrients

such as calcium and magnesium, 2) release of toxic

metals such as aluminum, and 3) further acidification.

The classification scheme uses three soil properties:

1) whether the soil adsorbs (chemically traps) sulfate;

2) the soil’s cation exchange capacity (CEC); ** and 3)

the PH (acidity) of the soil, which also indicates base

saturation, i.e., the relative proportion of basic cations

(nutrients such as calcium and magnesium) to acidic cations (hydrogen and aluminum).

Table B-10 outlines the relative sensitivities of various soil types; figures B-11 and B-12 describe the chemical exchanges that acid deposition produces in each of

these soils. Figure B-13 maps the extent and location

of these soils in the Eastern United States. The three

types of potential soil changes attributable to acid deposition are discussed separately below.

RELEASE OF ALUMINUM

As shown in table B-10, soils that are naturally acidic

(i.e., pH below about 5) and that do not adsorb sulfate,

are considered most likely to release toxic metals such

as aluminum. Figure B-11 illustrates the mechanism

schematically. Sulfate and hydrogen ions from acid

deposition reach the soil layer. Because the soil does not

trap sulfate, the sulfate is free to move through the soil.

The associated hydrogen ion can either: 1) travel with

the sulfate, or 2) be exchanged on the soil surface for

a base cation (e. g., calcium or magnesium) or an acid

“ “The total amount of cations (positively charged ions such as calclum,

magnesium, atuminum, and hydrogen) the soil can hold.
App. B—Effects of Transported Pollutants ● 231

Table B-10.—Theoretical Sensitivities of Forest Soils to Acid Deposition

Soil properties Terrestrial sensitivity to:

Soil

Base acidification

pH CECacation loss (surface soils)

I. Non-sulfate-absorbing soils

1. >6 High High Low

2.> 6 Low High Low-moderate

3. 5-6 High High Moderate

4. 5-6 Low High High

5.< 5 High Moderate Moderate

6.< 5 Low Moderate Moderate

IL Sulfate-absorbing soils

7. >6 High Moderate Low

8.> 6 Low Moderate Low-moderate

9. 5-6 High Low Moderate

10. 5-6 Low Low High

11. <5 High Low Moderate

12. <5 Low Low Moderate

Al

solubilization

Low

Low-moderate

Moderate

Moderate

High

High

Low

Low

Low

Low

Low

Low

%Cation Exchange Capacity (CEC).

bHigh CEC = above 9.0 meq/ml, low CEC = below 9.0 meq/ml

SOURCE: Oak Ridge National Laboratory, 1983.

cation (aluminum or another hydrogen ion). Because

aluminum both dissolves most easily and is most plentiful in acid soils (fig. B-11c), these soils release the greatest amounts of aluminum.

Figure B-12 illustrates soil processes in sulfate-adsorbing soils. Because these soils can trap both sulfate and

the associated hydrogen ion from acid deposition, less

aluminum is released.

Figure B-13 shows the distribution of soils considered

susceptible to aluminum release, based on county-level

soil data. The medium-grey areas are the naturally acid,

nonsulfate adsorbing soils discussed above. These cover

New England, and parts of northern New York State,

the upper Midwest, and the South. Acid soils that can

adsorb sulfate are shaded as light grey. These cover large

areas of the South and South Central States. Because

soils classified as adsorbing sulfate often do so only in

deeper soil layers, the surface layers in these regions still

might be susceptible to aluminum release.

SOIL ACIDIFICATION

Soils thought to be sensitive to further acidification

are moderately acid (pH about 5 to 6) with low CEC.

Such soils occur to a very minor extent in those regions

receiving significant inputs of acid deposition. As shown

as the darkest areas on figure B- 13, these soils predominate in scattered counties east of the Mississippi (i. e.,

counties in Illinois, Indiana, Georgia, and Tennessee).

Other areas of the East receiving higher deposition levels

(e.g., parts of the Adirondacks) probably have some soils

of this type, but not in sufficient quantities to constitute

a county’s predominant soil type.

For these moderately acidic soils, concerns over further acidification include: 1 ) potential effects on soil

biota, 2) release of aluminum if acidity increases to

below a pH of about 5, and 3) the loss of nutrients from

these soils, as discussed below.

NUTRIENT DEPLETION

As shown in table B-7, those soils most susceptible

to nutrient cation (calcium, magnesium, and potassium)

loss are soils with a moderate to high pH that do not

adsorb sulfate. Again, figures B-11 and B-12 show the

mechanisms of nutrient loss. As sulfate and associated

hydrogen ions enters the soil layer, the hydrogen ions

can be exchanged for base cations. Sulfate-adsorbing

soils trap hydrogen ions (fig. B-12), while lower pH soils

(e. g., fig. B-11c) exchange most of the hydrogen ions

for aluminum and remove fewer nutrient cations.

Of the soils listed as most susceptible to nutrient loss

in table B-9, only the moderate pH, nonsulfate adsorbing soils with low CECs have both a high potential for

nutrient loss and low enough nutrient levels so that this

loss might be significant. These are the same soils discussed above as being susceptible to further acidification, and are shown on figure B-13 as the darkest

regions.

Though listed as only moderately susceptible to nutrient loss in table B- 10, naturally acid, nonsulfateadsorbing soils typically have the lowest quantities of

stored nutrient cations. Some of these areas may have

such low nutrient levels that further loss might affect

forest productivity. Such areas might be located within

the medium-grey regions shown in figure B-13; how99 -

413 0 - 84 - 1 fj s QL . 3
232 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure B-n .—Schematic Diagrams of Soil Leaching in Non-Sulfate-Adsorbing Soils

(c) Cation-exchange

capacity

Input

Soil

interactions

output

Soil

interactions

output

Input

Soil

interactions

output
App. B—Effects of Transported Pollutants ● 233

Figure B-12. -Schematic Diagrams of Soil Leaching in Sulfate-Adsorbing Soils

(b)

(c)

Cat ion-exchange

capacity

/

Fe, Al oxides

100

‘/0 Bas e

saturation

Input

Soil

interactions

output

Input

Soil

interactions

output
234 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure B-13.-Soil Sensitivity to Acid Deposition (nonagricultural)

Forested and range areas with soils thought to be susceptible to the effects of acid deposition. Shaded areas represent counties

in which a susceptible soil type predominates. The three levels of shading correspond to different soil types, and potential

effects, rather than to degrees of susceptibility.

Soils most susceptible to further

acidification and nutrient loss

Naturally acidic soils most

susceptible to aluminum release;

nutrient loss might be significant

Naturally acidic soils potentially

susceptible to aluminum release;

surface soils might allow aluminum

release, but subsurface soils might

not be susceptible
App. B—Effects of Transported Pollutants ● 235

ever, whether nutrient loss rates exceed natural replacement rates from weathering is unknown.

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Report PSW-43, 1980.

Sollins, P., Grier, C. C., McCorison, F. M., Cromack,

K., Jr., Fogel, R., and Fredrickson, R. L., “The Internal Element Cycle of an Old-Growth Douglas-Fir Ecosystem in Western Oregon, “ Ecol. Monogr. 50:261-285,

1980.

Stone, E. H., and Kszystyniak, R., “Conservation of

Potassium in the Pinus Resinosa Ecosystem, ” Science

198:192-193, 1977.

Stuanes, A. O., ‘‘Release and Loss of Nutrients From

a Norwegian Forest Soil Due to Artificial Acid Rain of

Varying Acidity, Ecological Effects of Acid Precipitation, D. DrablA and A. Tollan (eds. ) (Mysen, Norway:

Johs. Grefslie Trykkeri A/S, 1980).

Tingey, D. T., and Taylor, G. E., Jr., ‘ ‘Variation in

Plant Response to Ozone: A Conceptual Model of Physiological Effects, Proceedings of the 32d University of

Nottingham Conference of the School of Agriculture

Science Symposium on Effects of Gaseous Air Pollution

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Townsend, A. M., and Dochinger, L. S., “Relationship of Seed Source and Development Stage to the Ozone

Tolerance of Acerrubrum Seedlings, ’ Atmos. Environ.

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Troiano, J., Colavito, L., Heller, L., and McCune, D.,

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Troiano, J., Colavito, L., Heller, L., McCune, D. C.,

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Turner, J., Johnson, D. W., and Lambert, M. J.,

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App. B- Effects of Transported Pollutants ● 2 3 9

B.3 MATERIALS AT RISK

Air pollutants are one of a number of environmental

factors—including humidity, temperature fluctuations,

sunlight, salts, and micro-organisms—known to cause

materials damage. Studies have demonstrated that a

broad range of materials, including building stone, rubber, zinc, steel, paint, leather, textiles, paper, and

photographic materials are affected by such pollutants

as sulfur oxides (SOX

), nitrogen oxides (NOX), and

ozone. For most of the materials under discussion, S0x

(i,e., sulfur dioxide and its transformation products, including sulfates and sulfuric acid) are the chief anthropogenic cause of damage; however, rubber is affected

chiefly by ozone, while ozone and NOX have the greatest effect on textile dyes. Table B-11 summarizes the

types of damage that occur to various categories of materials, as well as natural causes of deterioration, methods of measurement, and available mitigation measures.

Pollutants generally damage materials in ways that

are not qualitatively different from the weathering effects caused by the natural environment. Consequently,

estimating how much of observed damage is contributed by pollution sources is extremely difficult. The diverse pollutant mix characteristic of heavily industrialized urban areas-where greatest amounts of materials

damage would be expected—increases the difficulty of

pinpointing the cause and mechanisms of damage. In

addition, environmental legislation and changes in manufacturing processes have caused pollution patterns to

change over time; in particular, concentrations of large

particulate have decreased dramatically over the last

decade. As a result, pollutant-atmospheric conditions

that may have contributed significantly to such notable

effects as the deterioration of sculptural stone may no

longer prevail in the United States. Finally, the relative contribution of local v. transported pollutants to

observed materials damage is unknown. However, since

both pollution sources and quantities of sensitive materials tend to be concentrated in urban areas, most researchers consider that local-scale pollutants account for

the bulk of currently recognized materials damage.

Two kinds of materials damage are of concern: 1)

damage to culturally significant structures and monuments, and 2) damage to reparable or replaceable ‘ ‘common construction material items. The effects of air

pollutants on unique or historically important statuary,

monuments, buildings, or other artifacts are often irreparable; consequently, their cost to society cannot be

described completely in monetary terms. Damages to

sculptural stone and bronze, and to historic buildings

constructed of such sensitive materials as marble, sandstone, and limestone, are frequently of this nature.

Pollution-induced damages to replaceable materials,

and their economic costs, are potentially quantifiable.

However, a great deal of information must be taken into

account in estimating pollution-related losses. Since

those damages tend to be similar in form to other environmental damages to materials, they are likely to affect the rate at which preventive, mitigative, or replacement activities occur, but not to be their sole cause.

Little information is available on how pollutant-related

damages affect normal maintenance and repair activities. Analysts also need information on the amount of

materials damage for which specified pollutant levels are

responsible. Most of our knowledge about the rates at

which specified pollutant levels cause individual materials to deteriorate is based on field and laboratory experiments using small samples of materials rather than

measurements from actual structures. Knowledge about

pollutant-material interaction is further limited by the

failure of many studies to consider (and measure) important environmental factors. Moreover, estimates of the

total quantities of materials exposed and their distribution are limited, so that little information is available

to evaluate the extent or the economic consequences

of such damage over large geographic areas. Information gaps in each of these areas have, to date, prevented

investigators from developing reliable estimates of the

overall economic effects of materials damage.

Other factors that may affect how much damage takes

place, and about which little is currently known, are:

1) microclimatic variations, 2) the physical placement

of materials, and 3) chemical and physical variations

in seemingly similar materials. For example, rain may

wash sulfate and nitrate particles from exposed surfaces

and remove the build-up of soluble pollutant-material

residues, while the particles that remain on rain-sheltered surfaces may cause greater damage. Variations

in the properties of stone might cause samples from even

the same quarry to deteriorate at significantly different

rates under similar atmospheric exposure conditions.

Several laboratory and field experiments have estimated ‘ ‘dose-response’ relationships for a limited number of specific pollutant-material interactions. Greatest

amounts of data are available on the effects of S0x on

such metals as zinc and steels under different weather/atmospheric conditions. Sulfur oxides corrode metals; the

volubility of a given metal, and its ability to form stable,

protective metal oxide coatings when exposed to the atmosphere, determine its ability to withstand corrosion.

Metal corrosion always requires moisture, and tends to

accelerate above critical humidity levels that range from

60 to 80 percent, depending on the particular metal.
Table B-Il.—Air Pollution Damage to Materials

Principal air

Materials Type of impact Pollutants Other environmental factors Mitigation measures

Metals

Building stone

Ceramics and

glass

Paints and

organic coatings

Paper

Photographic

materials

Textiles

Textile dyes

Leather

Rubber

Corrosion, tarnishing Sulfur oxides and

other acid gases

Surface erosion,

soiling, black crust

formation

Surface erosion,

surface crust

formation

Surface erosion,

discoloration,

soiling

Embrittlement,

discoloration

Microblemishes

Reduced tensile

strength, soiling

Fading, color change

Weakening,

powdered surface

Cracking

Sulfur oxides and

other acid gases

Acid gases,

especially fluoridecontaining

Sulfur oxides,

hydrogen sulfide

Sulfur oxides

Sulfur oxides

Sulfur and nitrogen

oxides

Nitrogen oxides,

ozone

Sulfur oxides

Ozone

Moisture, air, salt, particulate

matter

Mechanical erosion,

particulate matter, moisture,

temperature fluctuations,

salt, vibration, CO2

, microorganisms

Moisture

Moisture, sunlight, ozone,

particulate matter,

mechanical erosion, microorganisms

Moisture, physical wear,

acidic materials introduced

in manufacture

Particulate matter, moisture

Particulate matter, moisture,

light, physical wear, washing

Light, temperature

Physical wear, residual acids

introduced in manufacture

Sunlight, physical wear

Surface plating or coating, replacement with

corrosion-resistant material, removal to

controlled environment

Cleaning, impregnation with resins, removal

to controlled environment

Protective coatings, replacement with more

resistant material, removal to controlled

atmosphere

Repainting, replacement with more resistant

material

Synthetic coatings, storing controlled

atmosphere deacidification, encapsulation,

impregnation with organic polymers

Removal to controlled atmosphere

Replacement, use of substitute materials,

impregnation with polymers

Replacements, use of substitute materials,

removal to controlled environment

Removal to a controlled atmosphere,

consolidated with polymers, or replacement

Add antioxidants to formulation, replace with

more resistant materials

SOURCE: U.S. Environmental Protection Agency, “The Acidic Deposition Phenomenon and Its Effects,” Critical Assessment Review Papers, vol. II, EPA-600/8-83-016B, May 1983.
App. B—Effects of Transported Pollutants ● 2 4 1

However, results from certain recent studies suggest that

the rate of pollutant-induced corrosion depends most on

‘‘time-of-wetness’1—i.e., the relative length of time a

metal surface is wet (e. g., from morning dew).

Studies have shown that current ambient concentrations of sulfur dioxide (S02

) can accelerate the corrosion of exposed ferrous metals, and that higher relative

humidities significantly increase the extent of SO2

-

induced corrosion. However, most uses of ferrous metal

products involve the application of such protective

coatings as paint and zinc, or the addition of protective

alloys. Zinc coatings, used primarily for galvanizing

steel, are also corroded by atmospheric S02 concentrations, potentially allowing steel underneath to rust, and

accelerating maintenance or replacement.

‘J E }’ocum and N S Baer, “Effects on Matermls,” T-he AcJd~c Deposi-

[mn Phenomenon and [M Eflecrs, Cr~tlcaf Assessment Review Papers, public

review draft, U. S Envlronmenta] Protectmn ,Agency, 1983

The extent of zinc corrosion at given ambient S02

levels depends on such climatic factors as relative humidity, windspeed, and time-of-wetness; and on the surface geometry of the product. The economic importance

of zinc has caused its reaction to sulfur pollutants to be

extensively studied. A number of researchers have developed dose-response estimates for zinc coatings. For

example, figure B-1 4 shows an experimental estimate

of the difference between rates of zinc corrosion for large

sheets of roofing and siding and those for wire fencing,

under different environmental conditions. Rates for galvanized wire and fencing are approximately double

those of galvanized sheet exposed to the same environment. The figure suggests that differences between relative humidities in various areas of the country are more

significant to corrosion rates than differing S02 levels.

One researcher has calculated that, for an area with an

average humidity of 70 percent, rust could first appear

on fencing after 10 years at S02 concentrations of 80

Figure B-14.– Estimated Corrosion Rates for Zinc Coatings

on Galvanized Steel

— Galvanized roofing and siding

SOURCE: Derived from equations in: “Review of the National Ambient Air Quality Standards for Sulfur

Oxides: Assessment of Scientific and Technical Information, ” US. Environmental Protection

Agency, 1982.
242 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

μg/m (the primary ambient air quality standard), as opposed to an interval of about 30 years required for rust

to appear in the absence of S02. First rust would occur

later on most products, depending on the surface geometries and/or coating thicknesses involved.2

A variety of paints has been found to be susceptible

to SO2

-induced damage. However, the available evidence suggests that climate tends to play a far more significant part in determining deterioration rates than

SO2 concentrations. Sulfur oxides appear to accelerate

normal erosion processes in paint, and to interfere with

drying processes of certain paints. Experiments have

found that oil-based paints are the most susceptible to

damage, probably because they use extenders that react readily with acidic pollutants. No recent studies of

the effects of pollutants on paints are available; a limited

number of earlier studies were performed during the

early 1970’s under atmospheric/pollutant conditions that

may differ substantially from current ones.

Extensive qualitative information is available on the

effects of SO2 on stone and masonry. In general, the

greater the porosity or permeability of stone and masonry, the greater its vulnerability. Such carbonate

stones as limestone and marble are particularly sensitive

to damage from acidic pollutants. Water serves as a medium for bringing acidifying pollutants into contact with

these materials. Crumbling of stone through “normal’

deterioration (i. e., through freezing and thawing) may

further expose stone surfaces to sulfur pollutants. Sulfur

oxides react with calcite, the major constituent of carbonate stone and a cementing material in some sandstones, to form calcium sulfate. Calcium sulfate deposits

can form crusts and/or be dissolved by runoff waters,

washing away or eroding a layer of stone in the process. Alternatively, calcium sulfate can be transported

into the body of the stone or masonry, where it may

crystallize and cause the material to crumble or

fragment.

In addition, bacteria on the surface of buildings convert atmospheric S02 into sulfuric acid for use as a digestive fluid. This fluid can react with the calcium carbonate in limestone, marble, or sandstone to produce

calcium sulfate, eroding the building surface when it

flakes off or dissolves. The various processes have the

same net effect: accelerated stone weathering that causes

statues to lose detail and reduces the structural integrity

of stone buildings.

A recent study of marble deterioration in the United

States has measured decay rates on the order of 2.0 mm/

100 years; however, studies of more reactive stones in

European cities have yielded substantially greater de-

‘U S Environmental Protectmr Agency, Review of the National Ambient

Air Qualltj’ Standards fbr Sulfur ox]des Assessment of.% ientific and Technical lnfbrmarmn, OAQPS Staff Paper, EPA-4501 5-82-007, 1982

terioration rates. Ongoing investigations of 3,900 marble tombstones located in 21 U.S. National Cemeteries

are developing data on marble decay in headstones exposed to the environment for 1 to 100 years. Since the

marble for these tombstones is supplied from only a few

quarries, the effects of climatic and pollutant conditions

on a relatively standardized stone can be examined

across several regions. Preliminary results show the size

of grain in the marble, total amount of precipitation,

and local air quality to be significant factors affecting

decay.

Efforts to estimate aggregate materials damage to the

Eastern United States, whether in physical or economic

terms, are hampered by the lack of available information on the distribution of sensitive materials throughout the regions subject to elevated pollution levels.

Materials at risk may not be distributed simply as a

function of population density; limited field surveys suggest that the period of settlement and urban development, and the local availability of particular materials,

also may be influential, For example, a recent field

survey of the quantities of paint, galvanized steel, and

structural concrete exposed to different concentrations

of S02 inthe greater Boston area suggests that substantially smaller quantities of galvanized steel may be exposed to atmospheric conditions than generally has been

assumed. 3 OTA attempts to develop regional materials

inventories and/or reliable surrogates for estimation purposes were unsuccessful.

An estimate of U.S. historic resources exposed to elevated ambient concentrations of S02 has been prepared

under the United States-Canada Memorandum of In -

tent on Transboundary Air Pollution. 4 Using data from

the National Register of Historic Places, which includes

sites either associated with an event or person, having

architectural or engineering significance, or potentially

contributing to historic studies, researchers estimated

that approximately 16,800 of the 18,300 sites registered

as historic places in the 31 Eastern States are in counties that experience average ambient S02 concentrations

less than 60 μg/m3

. About 900 sites experience S02 concentrations ranging from 60 to 80 μg/m3

, and about 600

sites are in counties experiencing concentrations above

80 μg/m3

. Historic places in eight States—Maine, New

Hampshire, New York, Pennsylvania, West Virginia,

Illinois, Indiana, and Ohio—are exposed to the highest

levels of S02 concentrations. However, only in two

States—New York and Illinois—are more than 20 percent of the registered historic places exposed to annual

average S02 concentrations above 80 μg/m3

. While such

1’I’RC Environmental Consultants, Air Pollurion Damage CO Msrs-Made Materials. Ph,vsmal and Economic Esr~mates (Pato Alto, Calif.: Electric Power Research Institute, EPRI EA-2837, 1983).

‘“ Impact Assessment, ” Work Group 1, U.S. -Canadian Memorandum of

Intent on Transboundary Air Pollution, January 1983.
App. B—Effects of Transported Pollutants 243

a survey can be helpful in indicating an area’s relative

exposure to potential damages, the ambient S02 levels

chosen to categorize levels of exposure are arbitrary, representing convenient indicators rather than some known

threshold below which materials damage would not take

place.

Predicting human responses is perhaps the most significant difficulty in estimating the consequences of

pollution-induced materials damage. Individuals confronted with obvious deterioration may choose to ignore

it, accelerate cleaning, painting, or replacement, or substitute a less susceptible material. Unless the damage

causes some change in the material’s utilization or results in some cost to owners, it will have no measurable

economic significance. For example, metal guardrails

on highways are likely to suffer damage from air pollutants; however, highway accidents generally restrict

a guardrails useful life to a greater extent than does air

pollution. Ozone causes rubber and other elastomers to

lose elasticity prematurely, and become brittle. Consequently, automobile tires and other exposed products

are routinely manufactured with antioxidant agents—

the cost of these additives, rather than a shortening of

usable life, represents this economic effect of air pollution.

Since the early 1970’s, a number of studies have calculated annual costs of materials damage due to air pollutants by estimating amounts of damage and deriving

some monetary equivalent for these damages. While the

availability of dose-response relationships for certain

pollutant-material interactions permit this type of analysis, the uncertainties involved are quite large. Moreover, such studies still must rely on broad hypotheses

about material exposure and individual economic

behavior.

For example, a recent study estimated the amount

by which materials damage would be reduced if European OECD member countries decreased S0x emissions by about 20 percent and 50 percent from projected

emissions of about 24 million tons in 1985.5 Estimates

were made only for corrosion to zinc and galvanized

steel, and for damage to paint coatings. The study assumed that each of these materials was used in proportion to the population, using OECD annual statistics

on the use of paint and of zinc for galvanizing in member countries. Galvanized materials were assumed to

be unpainted initially; sheet and products manufactured

from sheet were assumed to be painted, and wire

replaced, after some corrosion occurred. Repainting was

j{)rqanizat ion for Economl[ Cooperation and Development (OECD), 7’he

(.’[tsts and Benefits of.~u]phur OXKIC Corr[ml A ,we(hod[~lqq”cal StU~~J’ [Paris

OECD, 1981).

assumed to occur at the economically optimal time; however, materials older than 25 years were excluded, and

no consideration was given to withdrawal of materials

prior to that time. These assumptions yielded an estimate that costs of damage would be reduced by $450

million annually (1979 dollars) if emissions were reduced

by about 20 percent, and by $960 million annually if

emissions were reduced by about 50 percent, by 1985.

A recent study commissioned by EPA’s Office of Air

Quality Planning and Standards used macroeconomic

and statistical techniques—rather than physical doseresponse approaches—to estimate pollution-related economic losses from materials damage.6 The method statistically estimates how much of the observed variations

in expenditures for goods and services sensitive to differing air pollution levels is due to a variety of economic

and climatological factors, and how much of the remaining variation can be attributed to differing S02 levels.

This methodology has the advantage of taking into account a wider variety of potential responses to pollution-related damages (e. g., relocating, substituting pollution-resistant materials, doing nothing) than studies

assuming that all perceived damages would be remedied

by repair or replacement. The study has the further

advantage of taking into account costs due to air pollution, but not perceived as such—e.g., accelerated depreciation of machinery. However, such statistical methods can show only that a correlation exists between

pollution and the materials-related costs, and cannot

prove that pollution causes the economic effect.

The EPA-sponsored study calculated the value of reducing SO2 levels nationwide from the primary NAAQS

(365 μg/m3

, 24-hour averaging time) to a hypothetical

secondary standard of 260 μg/m3 (24-hour averaging

time). * Calculations of benefits were made for households in 24 standard metropolitan statistical areas for

electric utility maintenance; for agriculture; and for six

selected industries for which adequate economic data

were available— 1 ) meat products, 2) dairy products,

3) paperboard containers and boxes, 4) fabricated structural metal products, 5) metal forging and stampings,

and 6) metalworking machinery. * * Results were then

b~. H. Manuel, Jr. , et al. , ‘

c Benefits Analysls of Alternate Secondary National Ambient Air Quafity Standards for Sulfur Iloxide and Total Suspended

Particulate, produced by Mathtech, Inc., under contract to U.S Envu-onmental Protection Agency, OAQPS, Research Triangle Park, N .C., 1982

*The current secondary standard—1 ,300 pg/mJ, 3-hour averaging time—

was found to be less restrictive, for most Ioeations, than the primary standard.

Using statistical averaging techniques to match 3-hour to 24-hour standards,

only 5 counties in the country (out of 182 counties for which air quality data

were available) would require additional controls to meet the secondary standard, as compared to the primary standard.

● *These mdustrir=s correspond to Standard Industrial Classdication (SIC)

codes 201, 202, 265, 344, 346, and 354.
244 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

extrapolated to households throughout the United in the United States. These results cannot be extrapoStates, comparable manufacturing sectors, and electric lated to provide estimates of benefits to the Nation overutility operation and maintenance. The study concluded all; the lack of necessary data precludes analyzing the

that reducing S02 emissions in urban areas to meet the remainder of the Nation’s economy in this manner.

260 μg/m3 standard would create benefits of approximately $300 million annually for about half of the

households and 7 to 9 percent of the producing sector*

“The study defines the ‘ ‘producing sector’ to include agriculture, t’orestrv,

and fisheries; mining and construct ion, manufacturing; transportation, communication, and util itles, commercial and services, government; and other

B.4 VISIBILITY IMPAIRMENT*

Introduction

An observer’s perception of “visibility” integrates

several factors—general atmospheric clarity or haziness,

the total distance over which objects can be seen, their

apparent color and contrast with the sky, and discerned

details of line, texture, and form. Visibility degradation

is one of the most obvious effects of air pollution. The

present Clean Air Act (CAA) addresses the impairment

of visual range in pristine areas, atmospheric discoloration, and the presence of actual smoke plumes (’‘plume

blight’ ‘). The reduction in visibility from many and diverse sources spreading over a large area-regional haze

—has not yet been addressed. Regional haze reduces

visibility in all directions from an observer, is relatively

homogeneous, and can occur on a geographic scale

ranging from a city to a multi-State region. Haze conditions can reduce contrast, cause distant objects to

disappear, and nearby objects to appear discolored and

‘ ‘flattened, add brown or grey discoloration to the atmosphere, and decrease the number of stars visible in

the night sky.

Visibility impairment is of concern both for esthetic

reasons (especially in areas of great natural beauty) and

practical concerns (transportation operations). Limited

studies suggest that actual measurements of visibility

correlate with: 1) perceived air quality, and 2) perceived

property values in Los Angeles and the rural Southwest.

Preliminary attempts to quantify visitors’ “willingness-to-pay’ to preserve scenic vistas have been quite

variable. The major effects of visibility on transportation are related to air traffic. Available data show that

episodic regional haze over large segments of the East

tends to curtail some segments of general aviation aircraft and slow commercial, military, and other instrument flight operations on the order of 2 to 12 percent

of the time during the summer. The Federal Aviation

Administration (FAA) restricts visual flight operations

when visibility falls below 3 miles. Table B-12 summarizes efforts to characterize the social, economic, and

psychological value of various levels of visibility.

A variety of natural and anthropogenically produced

particles are capable of interfering with the passage of

light and contributing to regional haze. Liquid or solid particles* * ranging from 0.005 micrometer (pm) to coarse

dusts on the order of 100 μm can either scatter or absorb light, reducing visibility through the extinction of

light. Theoretical and empirical results provide strong

evidence that visibility reduction caused by urban and

regional haze normally is controlled by fine particles,

primarily sulfates (smaller than 2.5 μm in diameter).

The only important situations in which large particles

dominate are such naturally occurring phenomena as

precipitation, fog, and dust storms, or manmade phenomena like construction, agricultural and forest slashburning, and open-pit mining.

Factors Affecting Visibility

Natural

Natural causes of impaired visibility include dust, fog,

low clouds, precipitation, elevated humidity, seaspray,

volcanic emissions, and forest fires. Humidity is a particularly significant visibility determinant, as it not only

reduces visibility levels in itself, but also affects the visibility-reducing properties of other airborne materials.

At high humidity levels, fine airborne particles take up

● This appendix is based primardy on the OTA background paper “Review “ ● Nitrogen dioxide is the only gaseous pollutant in the atmosphere capable

of the I_ong-Range Transport of Sulfate Contribution to Vlsibilitv Impairment, of contributing to the extinction of light; however, its concentrations are rarely

by Brand L Niemann, 1983. large enough to result in a substantial contribution.
Table B-12.—Summary of Qualitative Evidence for Visibility-Related Values

Effect of increased visibility Affected groups Averaging timesa Supporting observation

Transportation:

More efficient, lower risk operations, visual

approach permitted

Increased opportunity to operate aircraft

Aesthetic:

1) Social criteria:

Decreased perception of air pollution

Options values; maintaining or increasing

opportunity to visit less impaired natural

and urban settings

Improved view of night sky

2) Economic criteria:

Increased property values

Enhanced enjoyment (user or activity values)

of environment in:

a) Urban settings

b) Natural settings

3) Psychological criteria:

Existence values; maintaining pristine

environments

Less concern over perceived health effects

Airport users, operators

civilian and military

General aviation aircraft

(noninstrument capable

pilots, aircraft)

Substantial percentage of

general population; urban

areas

Outdoor recreationists,

campers, tourists

Amateur astronomers,

other star watchers

Home owners

Urban dwellers

Outdoor recreationists,

campers, residents of

nonurban areas

General population

General population, urban

areas

1-3 hr. readings

1-3 hr. readings

Daily to annual

Daily, peak visitation

summer months

Nightly

Long term

Long term

Daily, peak visitation

summer months

Long term

Daily to long term

in

in

Visual approaches permitted when visibility

>3-5 miles; airport specific (FAA, 1980b)

VFR permitted when visibility >3 miles (FAA,

1980a)

Perception of air pollution in Los Angeles

significantly related to visibility for all

averaging times (Flachbert and Phillips,

1980). Perception, annoyance significantly

related to particulate matter (Schusky, 1966)

Aggregate of activity values in iterative

bidding studies suggests importance of

options values (Rowe and Chestnut, 1981)

Decrease in star brightness by fine particles

(Leonard, et al., 1977)

Property values related to perception of air

pollution, hence visibility (Rowe and

Chestnut, 1981; Brookshire, et al., 1979)

Willingness to pay for increased visibility in

urban (Brookshire, et al., 1979) and

nonurban settings (Rowe, et al., 1980)

Existence values may far outweigh activi

user values (Rowe and Chestnut, 1981)

About two-thirds of bid for improved visi

ty or

bility

in Los Angeles was related to concern over

potential health effects (Brookshire, et al.,

1979)

aRepresents EPA staff judgment of most important averaging time based on supporting observatlon Because averaging times are related it IS difficult to specify single (long or short) averaging time as most

significant, Perception of visibility IS essentially instantaneous.

SOURCE: U.S. Environmental Protection Agency, “Review of the National Ambient Air Quality Standards for Particulate Matter,” EPA-45015-82-001, January 1982
246 ● Acid Rain and Transposed Air Pollutants: Implications for Public Policy

water directly from the atmosphere; this can cause fineparticle scattering to increase by a factor of 2 as relative humidity increases from 70 to 90 percent. The annual mean relative humidity is greater than 70 percent

east of the Mississippi, and greater than 80 percent in

Maine and several Atlantic coastal areas. Dense fog is,

of course, most frequent in coastal and mountainous

areas, with the northern Appalachian mountains, northern California coast, and Nantucket Island showing 50

to 80 days/year of dense fog. Blowing dust is a significant cause of visibility impairment only in the southern Great Plains and Western desert regions.

On a regional or national basis, the frequency of relevant meteorological phenomena has been determined

by the National Oceanic and Atmospheric Administration (NOAA) and individual researchers. However,

reports from individual sites usually have not included

information on the occurrence of these natural phenomena during impaired visibility. Without such information, it is difficult to evaluate how much of observed

visibility degradation is due to natural causes.

Manmade

Anthropogenic particles contributing to reduced visibility originate from stationary and mobile sources and

may be emitted directly or formed in the atmosphere

through transformation of such gaseous pollutants as

S02

. The origin and composition of fine particles (less

than 2.5 pm) is generally different than that of large or

coarse particles. Fine particles tend to originate from

the condensation of materials produced during combustion (e. g., lead) or atmospheric transformation of gases

(e.g., sulfates). (See app. C, “Atmospheric Chemistry. Atmospherically formed fine particles—particularly sulfates—can circulate in moving air masses, and

subsequently be dispersed over large geographic areas

far from source regions. Since larger particles settle out

most rapidly, elevated levels of coarse particles usually

occur only near strong emissions sources.

Evidence for Anthropogenically

Caused Decrease in Visibility

Both current and historical data bases can provide

insight into the relationship between manmade air pollution and visibility degradation.

Current information on amounts and location of S02

and NOX emissions can be related to the monitoring

data for air concentrations and deposition of sulfates and

nitrates. In conjunction with meteorological data and

visibility measurements, this information allows detailed

analysis of factors contributing to short-term (e. g., seasonal) changes in visibility.

Historical visibility data can be used to infer longterm trends in air quality, because changing patterns

of visibility reflect variation in natural and anthropogenic emissions and meteorology over the long term.

General Conclusions

Based on: 1) current assessments of natural sulfur

sources and regional fine-particle levels, 2) long-term

historical visibility data in the Northeast from 1889 to

1950, and 3) examination of airport visibility trends after

deleting data potentially influenced by natural sources

(fog, precipitation, blowing dust), anthropogenic sulfate

levels appear to be the dominant component of Eastern

regional haze. Investigations over the past decade, using

a variety of data bases, show several areas of agreement:

●

●

●

●

Examination of airport data, pollution ‘measurements, and satellite photography indicates that region-scale hazy air masses move across the Eastern United States and cause significant visibility

reduction in areas with little or no air pollutant

emissions. In addition, aircraft measurement of the

plumes of large powerplants, smelters, and major

urban areas have tracked the visibility impairment

by sources for 30 to 125 miles downwind.

Light scattering by anthropogenic particulate pollution—of which fine sulfate particles are the most

important—appears to be the predominant cause

of Eastern regional haze. Recent studies indicate

that sulfate in the Eastern United States is responsible for about 70 percent of visibility impairment

in the summer, and 50 percent on an annual basis.

Nitrates rarely contribute substantially to visibility

degradation in the East, while carbon particles appear more important within urban areas than in

suburban or rural areas.

Contributions to visibility degradation in the West

appear to be more varied. Depending on the site

analyzed, substantial contributions have been

shown for nitrates, carbon, sulfates, and dust.

Analyses of the relationship between copper-smelter

emissions and regional visibility degradation in the

Southwest, however, have shown correlations between S02 emission levels and the percent of time

during which reduced visibility occurs.

Currently highest average visual ranges for the

United States occur in the mountainous Southwest

(annual visibility generally greater than 70 miles).

Annual median risibilities east of the Mississippi

and south of the Great Lakes are less than 15 miles,

with the Ohio River Valley showing the lowest visibility range (fig. B-15). While some of this difference stems from lower relative humidity levels

in the West, a more important factor is the higher

regional fine-particulate loadings in the East (e. g.,
App. B—Effects of Transported Pollutants . 247

Figure B-15.— Median Yearly Visual Range (miles) for Suburban and Nonurban Areas

Data from 1974-76 estimated from visual observations and other methods

SOURCE: J. Trijonis and R. Shapland, 1979: Existing Visibility Levels in the U. S.. Isopleth Maps of Visibility in Suburban/Nonurban Areas During 1974-76, EPA 450/5-79-010,

U.S. Environmental Protection Agency, Research Triangle Park, N.C.

about 25 μg/m3 in the summer) than in the West

(about 4 μg/m3 in the summer). (See fig. B-16.)

National visibility maps show that summertime visibility is much lower than annual-average visibility

levels in the East, and that the largest regional gradients in visibility are found in California. In

California, the two major pockets of impaired

visibility (Los Angeles Basin and southern San Joaquin Valley) are due more to local- or mediumrange transport than to long-range transport, while

in the East, the major area of impaired visibility

(Ohio River Valley) is undoubtedly related to the

high density of SO2 emissions. The cause of pockets

of impaired visibility found in the Gulf and midAtlantic coasts is less apparent, but probably

reflects a combination of natural and anthropogenic

factors.

Trend analyses of visibility at Eastern airports for

the period of 1950-80 indicate that while wintertime risibilities improved in some Northeastern locations, overall regional visibility declined until

1974, then slightly improved. However, summertime, often the best season for visibility in the

1950’s, is currently marked by the worst episodic

regional haze conditions. * (See fig. B- 17. )

From the early 1960’s through the mid-1970’s,

U.S. control programs resulted in substantial reductions in total suspended particles (TSP) and S02

levels in most of the more polluted urban areas.

However, during this same period, available information suggests that Eastern U.S. regional concentrations of summertime fine particles, particularly

sulfates, increased.

● \\’hlle ies than O 1 are 

 air are i\+ at 

 present 

 ent t substantially

99-413 0 - 84 - 17 : QL. 3
248 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure B-16.—Airborne Fine-Particulate Concentrations (μg/m3

) (summer 1977-81)

Mechanisms of Visibility Degradation

In a completely “pure” atmosphere, visual ranges

across the horizon can extend up to 200 miles; such conditions are occasionally approached on clear days in the

Southwestern United States. The extent of visibility degradation is determined both by the size and concentration of particles in the atmosphere. For example,

adding 10 μg/m3 of coarse particles-greater than 2.5

μm in diameter— to clean air would reduce visibility

moderately, from 130 km to about 108 km. If, however,

the particles were very small (in the optically critical

size range of O. 1 to 1.0 pm), the addition of 10 μg/m3

would reduce visibility significantly, from 130 km to

about 44 km. (Table B-13 shows how the relative contribution of fine and coarse particles varies from location to location. )

Adding even low concentrations of substances to

pristine environments has a profound effect on visibility.

The addition of 1 μg/m3 of fine particles to a clean atmosphere can reduce visual ranges by about 30 percent.

As the atmosphere is degraded, each additional increment of particulate matter has a smaller effect on visibility-adding 1 μg/m3 of fine particles to an atmosphere

with a 20-mile visual range reduces visibility by only

3 percent (see fig. B-18).

Two fine-particle components, hydroscopic (waterabsorbing) sulfates and elemental carbon, generally tend

to be most important in reducing visibility. In the East,

sulfate compounds are the predominant component in

the fine particles causing light scattering over wide

regions, while elemental carbon accounts for most light

absorption in urban areas.

Fine particles between 0.1 and 2.0 μm diameter are

the most efficient at scattering light, and appear to account for the bulk of visibility degradation due to light

scattering. * Sulfates and nitrates, the transformation

products of S02 and NOX, exist in the atmosphere

primarily as particles ranging from 0.1 to 1.0pm in size

before being deposited to the earth in wet or dry form.

● Recent evidence suggests that at least some of the difference may be due

 shorter and less frequent episodes of elevated humidity during the 1950’s

than occurred in the 1970’s, C, Sloane, “Summertime Visibility Declines: 

 Influences, ” Atmospheric 1983
App. B—Effects of Transported Pollutants ● 249

c

n

.
250 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy
App. B—Effects of Transported Pollutants ● 251

Q

Q
252 Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table B-13.—Characterization of Airborne Particulate.

Matter Concentrations, 1977.81a

Figure B-19. —The Relationship Between Relative

Humidity and Light Scattering by Aerosol Sulfate

FPC

Long-term (6-12 months) average T S P

b (<2.5 μm)

Eastern locations:

Undisturbed . . . . . . . . . . . . . . . . . . . . . . . 30-40 15-20

Downtown . . . . . . . . . . . . . . . . . . . . . . . . . 60-90 20-30

Industrial . . . . . . . . . . . . . . . . . . . . . .....60-110 25-45

Add Western locations:

Undisturbed . . . . . . . . . . . . . . . . . . . . . . . 15-20 3-5

Downtown , . . . . . . . . . . . . . . . . . . . . . ...75-130 15-25

West coast:

Los Angeles area. . .................90-180 30-40

Pacific Northwest . . . . . . . . . . . . . . . . . . 45-95 15-25

aThe data used from the three networks include: EPA’s Inhalable Particulate Network, 35 urban sites, April 1980-March 1981; EPA’s Western Fine Particle Data

Based, 40 nonurban sites, Summer 1980-Spring 1981; Electric Power Research

Institute SURE data base, 9 rural sites, 15 months, 1977-1978.

bTotal Suspended Particulates.

c

Fine particulate

SOURCE: Pace, T. G. (1981). Characterization of Particulate Matter Concentrations. Memorandum to John Bachmann, Strategies and Air Standards

Division, Office of Air Quality Planning and Standards (Dec. 30, 1981).

Figure B.18.—The Effect of Fine Particles

on Visual Range

10 20 30 40

Fine particle concentration, μg/m-3

In clean areas (where visual range is greater than 200

km), adding small quantities of fine particles to the

atmosphere degrades visibility markedly; the same

increment added to an area with low visibility has little

effect.

SOURCE: U.S. Environmental Protection Agency, Protecting Visibity, An EPA

Report to Congress, 1979.

The strong light-scattering properties of sulfate and

nitrate particles are due to their affinity for water vapor;

moreover, the greater the relative humidity of the atmosphere, the greater the capacity of sulfate particles

to scatter light, especially when relative humidities rise

above 70 percent (see fig. B-19).

Measurement Techniques

The physics and chemistry of light scattering and absorption is well understood. A variety of techniques is

available to measure scattering and absorption with reasonable accuracy. The simplest of these involves estimation of visual range, using objects at specified distances from an observer as reference points for

estimating the distance beyond which distinct visual
App. B—Effects of Transported Pollutants 253

phenomena cannot be observed. Such estimates are inherently imprecise, and can be affected by such subjective factors as the observer’s visual acuity. * However,

the availability of such observations for a wide variety

of sites over a multiyear period—visual ranges have been

recorded on a daily basis at hundreds of U. S. and Canadian airport sites in urban, suburban, and rural locations since 1948—makes this data base indispensable for

performing time-trend analyses of visibility. Comparisons of historical patterns for visibility in the Eastern

United States such as those in figure B-17 necessarily

derive from such data.

Telephotometry provides statistical measurements

analogous to perceived visual ranges, while affording

greater precision. The technique involves the use of a

telescope capable of measuring the contrast between the

brightness of a faraway object and the horizon sky surrounding it. In addition, direct measurements of the

portion of a light source lost to atmospheric interference

are made with such devices as sun photometers, instruments to measure direct solar radiation intensity, and

integrating nephelometers. This last device passes a light

source through a given air sample to determine how

much light scattering occurs. While nephelometers are

not capable of measuring light absorption, and may distort measurements as a consequence of air sample manipulation, they are currently a widely used method of

measuring visibility, and are the primary means available for determining how individual pollutants or pollutant mixes affect visibility. The nephelometer has been

the basis for most of the experimental data relating cause

and effect in visibility degradation studies.

No single measurement technique is adequate at present for assessing all significant factors involved in visibility impairment. The most productive areas of recent

research have involved comparing two or more of the

available monitoring techniques at selected sites or in

new networks where fine particulate and meteorological

measurements are made concurrently.

Until recently, visual-range/pollutant-concentration

studies dominated the visibility literature; a number of

studies completed over the past few years, however, have

relied on nephelometer and related measurements to determine correlations with pollutant levels. Imprecision

may be introduced into either of these analytical techniques by discrepancies between pollution- and visibility-monitoring locations, as well as by limitations in

measurement techniques mentioned above. However,

a large group of studies have found consistent patterns

pointing to sulfates as the major cause of regional-scale

visibility degradation.

“Prior to 1970, observations beyond 15 miles were not reported at most

stat ions In the M Ideastern States The coarseness of dmtant observations increases with dwtance due to fewer available targets Visibifitles greater than

15 males are now estimated m mul[iples of 5 miles

Key Studies

A description of some of the key studies will illustrate

three different ways researchers have used incomplete

data to examine the visibility/sulfate relationship:

● the integrated use of multiple data bases,

. specific case studies, and

● modeling efforts.

Use of Multiple Data Bases: “Capita”

The most extensive analyses of spatial and temporal

patterns of visibility impairment in the Eastern United

States have been performed by the Center for Air Pollution Impact and Trend Analysis (CAPITA).7 The

CAPITA analyses have used four historical data bases:

airport visual range at 147 U.S. and 177 Canadian sites

from 1948 to 1980; Blue Hill Observatory visual-range

data (3 mountaintops—32, 72, and 107 km from the

observatory) for 1889 to 1959; the NOAA/WMO** turbidity network of 25 to 35 sites during 1960 to 1975;

and direct solar radiation intensity measurements at

Madison, Wis., from 1920 to 1978. Significant findings

of the trend analysis were:

the region of lowest visibility in the 1970’s was

along the Ohio River Valley;

the strongest increase in haziness occurred in the

summer season in the States adjacent to the Great

Smoky Mountains (a decrease in annual average

visibility of 15 to 6 miles since 1948);

around the Great Depression, the visibility at Blue

Hill, Mass., improved, and two peaks of haziness

around 1910-20 and 1940-50 coincide with two

peaks of coal- and wood-burning. Likewise, a

strong peak in turbidity corresponding to a decrease

in visibility was present in the Madison, Wis. , data

coinciding with the increase in national coal consumption. However, direct cause-effect relationships have not been established; and

regional visibility in Eastern Canada and in both

the Eastern and Western United States apparently

has improved somewhat since 1972, but not to pre1960 levels; whether this improvement relates to

more favorable meteorology or reflects the slight

reduction achieved in particulate and S02 emissions in the last 10 years is unclear.

‘R B Husar, et al , “Spatial and Temporal Pattern of Eastern United States

Haziness A Summary, ” report prepared by the Center for Air Pollution Impact and Trend Analysis, Washington Unwerstty, St Louis, Mo., for the U .S

Environmental Protection Agency, 1981

* “National Oceanic and Atmospheric Administration/World Meteorological Organization
254 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Case Studies: Southwestern United States

A number of factors combine to make visual ranges

in the “four corners’ region of the Southwestern United

States a promising means of assessing the effects of sulfates on visibility. Pollutant concentrations and relative

humidity levels in most parts of Arizona, New Mexico,

Colorado, and Utah tend to be quite low; consequently,

visibility levels are among the highest known throughout the United States, and changes in pollutant concentrations make significant differences in perceived visual ranges. In addition, over 90 percent of the region’s

sulfur emissions come from a single industry—copper

smelters—which experienced a total shutdown during

1967-68, and a partial shutdown in 1980. However, ambient sulfate levels have not been monitored extensively

in the region, as they have in the Eastern United States.

Thus, while airport visual ranges show marked increases

in these four States during the two copper-smelter shutdowns, relationships between sulfate and visibility have

been difficult to establish.

Initial investigations found substantial decreases in

sulfate levels at monitoring sites both near major smelting operations, and at remote areas up to 300 miles from

the major smelting area in southeast Arizona, during

the 1967-68 shutdown. a Visibility conclusions from this

study have been criticized on the basis that sufficient

data were lacking to document a consistent sulfate/visibility relationship. During a second strike in the summer of 1980, mean sulfate concentrations dropped to

one-third of normal levels within 60 miles of the smelter;

between 60 and 400 miles away, sulfate levels were

about half of nonstrike conditions. Trajectory analyses

of sulfate episodes in both the northern Great Plains and

Grand Canyon areas show that some ultra-long-range

transport from southern California occurs.

To further test the sulfate/visibility hypothesis, and

to extend the information base on Southwestern visibility, an OTA contractor analyzed visual range and

sulfate concentration data in 22 case studies covering

pollution episodes and nonepisode periods before, during, and following the two shutdown periods. In addition, the RCDM long-range-transport model was used

to estimate sulfate levels more generally over the ‘‘four

corners’ region, and to provide preliminary estimates

of the extent of sulfate contributions from sources outside the four-State region for the period 1979-81. The

analysis strongly confirms the relationship among copper smelter emissions, sulfate levels, and visual ranges;

in addition, it suggests that substantial portions of the

sulfate levels measured during the 1980 shutdown can

be traced to more distant sources, primarily those in

southern California.

‘J C. Trijonis, ‘ ‘Visibility in the Southwest: An Exploration of the Hlstorlcal Data Base, Atmos. Environ. 13:833-43, 1979.

Modeling: Extinction Budget

While there are limitations in the use of regression

models for determining extinction budgets and aerosol/

visibility relationships, these techniques show that overall, sulfates account for over half (53 percent) of the extinction budget, nitrates account for only 8 percent, and

a significant part of the budget is not accounted for at

most of the sites analyzed. The nitrate contribution to

the extinction budget is very uncertain (but small) due

to uncertainties in the conventional nitrate filter-concentration measurements. More comprehensive studies of the extinction budget are needed, using special

air quality and visibility measurements rather than relying on conventional air quality monitoring and airport

data.

Sulfate was known to contribute significantly to light

extinction 10 years ago. Subsequent efforts to determine

the relative importance of nitrate and carbon to visibility

impairment were hampered by measurement techniques

and inherent spatial (urban v. rural) and temporal (seasonal) variability. There still is not enough high-quality

data of nonsulfate measurements to generate complete

regional budgets of the various pollutants’ contribution

to visibility impairment. Most recent information suggests that carbon may contribute to light extinction in

heavily urban areas, such as Houston (17 to 24 percent

of light extinction), Denver (about 40 percent of light

extinction10), and New York (35 percent of light extinction”). Nitrate is an important factor in the West–

e.g., in Riverside, Calf., it is responsible for about 20

to 25 percent of light scattering.12 Nonetheless, at most

Eastern U.S. sites, sulfate is the single most important

pollutant responsible for visibility degradation. Under

typical Eastern summertime conditions, sulfate accounts

for 70 percent or more of light extinction in the Great

Smoky Mountains, 13 the Shenandoah Valley, 14 

a n d

Detroit, 15 On an annual basis, sulfates contribute an

average of about 50 percent to visibility impairment in

the Eastern United States.l6

W. G, Dzubay, R. K. Stevens, C. W, Lewis, D. H. Hem, W. J. Courtney,

J W. Tesch, and M, A. Mason, “Visibility and Aerosol Composition in Houston, Tex., Environ Sci. Technof. 16:514-525, 1982.

‘“P. J. Groblicki, G. T. Wolff, and R. J, Countess, “Visibility-Reducing

Species in Denver ‘Brown Cloud’ —I. Relationships Between Extinction and

Chemical Composition, ” Atmos. Environ. 15:2473-2483, 1981.

j !G, T, wolff, p. J, Groblicki, S. H. Cadle, and R. J. Countess, ‘‘particulate

Carbon at Various Locations in the United States, Particulate Carbon: Atmospheric Life Cycle, G. T. Wolff and R. L. Klimisch (eds. ) (New York:

Plenum Press, 1982).

1’J. N. Pitts, Jr., and D. Grosjean, ‘ ‘Detailed Characterization of Gaseous

and Size-Resolved Particulate Pollutants at a South Coast Air Basin Smog Receptor Site’ (Springfield, Va.: National Technical Information Service, #PB

302294, 1979).

13M, A.Fermm, G, T. Wolff, and N, A. Kelly, ‘‘The Nature mcf Source

of Haze in the Shenandoah Valley/Blue Ridge Mountains Area, ‘J. Air Pollution Control Aawc. 31: 1074-1082, 1981,

1+R, K, Stevens, T. G, Dzubay, C. W. Lewis, and R. W. Shaw, Jr., ‘‘Source

Apportionment Methods Applied to Determination of the Origin of Ambient

Aerosols That Affect Visibility 

in Forested Areas, Atmos, Environment (in

press).

1

5

W

olff, et al, , op. cit.

ICU,S Environment~ Protection Agency, Protecting Visibility, An EpA Report to Congress, EPA 450/5-79-008, Research Triangle Park, NC., 1979,
App. B—Effects of Transported Pollutants ● 2 5 5

B.5 HUMAN HEALTH RISKS*

Sulfur Oxides

National Ambient Air Quality Standards (NAAQS)

have been established for gaseous sulfur dioxide (SO2

),

recognizing that it is harmful to human health in high

concentrations. The current primary standard for S02

is 365 μg/m3 (24-hour average concentration), a level

considered to pose no significant health risk. Though

currently unregulated, concern also exists about health

risks from sulfate particles—e. g., sulfuric acid and ammonium sulfate—that form through reactions between

S02 and other substances in the atmosphere. Because

these particles are extremely small (mostly under 1 μm

in diameter), they can be transported over long distances

in the atmosphere and can readily be inhaled into the

deep passages of the lung.

Acute exposures to sulfates (greater than 315 μg/m3

)

constrict lung passages and lengthen lung clearancetimes in humans and laboratory animals; chronic exposure of laboratory animals to sulfuric acid mist produced evidence of the onset of chronic lung disease. In

addition, numerous epidemiological studies have found

correlations between ambient sulfate concentrations and

mortality rates. Adverse effects at current ambient levels

(less than about 25 μg/m3

) have not been directly

observed.

Researchers at Brookhaven National Laboratory (under contract to OTA) have estimated that about 2 percent (a range of O to 5 percent) of the deaths per year

in the United States and Canada might be attributable

to atmospheric sulfur-particulate pollution. The range

reflects uncertainties within the scientific community

about the causal relationship between air pollution and

mortality. Some researchers conclude there is a negligible effect at prevailing sulfate concentrations, while

others have found a significant association with mortality.

Sulfur Dioxide

S02 emissions currently are regulated under the

NAAQS of the Clean Air Act (CAA); the primary

standard for S02 is 365 μg/m3 (24-hour average concentration). Air pollution episodes characterized by particulate and very high levels of S02 have resulted in

increased deaths in people with preexisting heart and

lung disease. Changes in the function of the lungs have

been seen in sensitive groups at concentrations above

“This appendix IS based primarily on the OTA background paper ‘‘ LongRange Transport kr Pollutlon Health Effects, ” Biomedical and Environmental

Assessment Divls.ion, Brookhaven National Laboratory, 1982

5,220 μg/m3. Recently, a study of asthmatics has shown

that constriction of bronchial passages during periods

of moderate exercise can occur at concentrations as low

as 1,300 and 260 μg/m3

. 

17

Experimental Evidence of Sulfate-Related

Health Damages

Once in the atmosphere, S02 is converted into sulfate

particles. Two main types of sulfate particles are known

to be produced: sulfuric acid (H2S04

) and ammonium

sulfate [(NH4

)2S0 4]. Both types of particles are extremely small and may be inhaled deep into the lung.

The high acidity of sulfuric acid particles make them

of primary concern for medical researchers, although

ammonia in human breath may neutralize sulfuric acid.

Ammonium sulfate has not produced the pulmonary effects in animal and clinical studies that are seen with

sulfuric acid mist.

In laboratory experiments, acute exposures to high

concentrations of sulfuric acid particles have a variety

of adverse health effects. Concentrations of about 750

μg/m3 have irritated eyes and temporarily decreased

vision; concentrations of 350 μg/m3 have increased

breathing rates and altered lung function in asthmatics.

Changes in lung clearance rates have been observed in

healthy nonsmokers at concentrations of 100 μg/m3

.

Populations at special risk from particulate sulfates are

the elderly and adults with preexisting chronic heart or

lung disease. Children also appear to be especially susceptible to increased lower respiratory-tract illness and

decreased lung function. However, there is no direct evidence showing detectable effects on human health from

maximum likely environmental concentrations of sulfate

particles alone, although laboratory and chemical

studies have verified that these small sulfate particles

concentrate deeper in the lung than larger inhaled particles. In addition, there is evidence that acid sulfates

(and S02

) render lung tissues more susceptible to the

carcinogenic effects of polycyclic organic matter.

Evidence of Sulfate-Particulate-Related

Health Damages

Substantial evidence has been gathered over more

than 30 years indicating injury from some aspect of the

sulfate-particulate mix in air pollution. At high exposure

levels, sulfur-particulate air pollution can aggravate

17D Sheppard, A. Saishcs, J. A Nodel, and H A. Boushey, ‘‘Exercise Increases Sulfur Dioxide-Induced Bronchocons trlction in Asthmatic Subjects,

Am Ret, Resp Lhs 123:486, 1981
256 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

asthma, chronic bronchitis, and heart disease.18 There

also is evidence that sulfur-particulate air pollution

causes increased acute respiratory disease in children.

Many analyses of cities with different air pollution

levels, comparing death rates among specific population groups, or cohorts, have shown strong correlations

between pollution levels and mortality. Evidence is

strongest for correlation between acute episodic effects

and severe air pollution incidents; evidence of long-term

effects at comparatively low levels of pollution is more

limited and more controversial.

Nonetheless, scientists generally have been unable to

attribute effects to any single element of the pollution

mix. During the early 1970’s, evidence seemed to point

to sulfate particles as the health-damaging agent in the

sulfate-particulate mix. More recent evidence suggests

that the combination of sulfates and other associated

particles such as metallic ions, nitrates, and fine soot

particles may cause the observed effects.

Quantitative Estimates of Health Damages From

Long-Range Transport Air Pollutants

To derive quantitative estimates of damage caused

by long-range pollution transport, Brookhaven National

Laboratory used sulfate concentrations as an index of

the sulfur-particulate air pollution mix, acknowledging

that its use in this manner remains controversial, but

it is the best indicator of health risk currently available.

Several reports have discussed problems with the use

of the sulfate surrogate model. They indicate that other

surrogates, e.g., respirable particles, may prove better

but, at this time, the sulfur surrogate still remains a

reasonable choice, and possibly the best choice, for air

pollution health effects risk assessment. A detailed study

by the Harvard School of Public Health for DOE concluded that a fine particulate (FP) measure would be

preferable, but ‘‘in the absence of FP data, . . . sulfates

may be applied with caution. * The contractor used

a previously developed health-damage function that

specifically addresses uncertainties in knowledge by projecting a range of mortality estimates for a given population exposure level. * *

1 sEnvironmentaf protection Agency, ‘ ‘Review of the National Ambient Air

Quality Standards for Particulate Matter: Draft Staff Paper, ” Strategies and

Air Standards Dwision OAQPS/EPA/RTP, Januaq 1982; Lester B. Lave and

E P. Seskm, Air PolJution and Human Health, 1977, Johns Hopkins University Press, Baftimore, Md. , Frederica Perera and A. K. Ahmed, Respirable

Particles: impact of Airborne Fine Particulate on ffeafth and the Ersvironment (Cambridge, Mass.: Ballinger Publishing Co. , 1979).

“Spengler Final Report to DOE, October 1983, p. 5, and contsvbution of

Spengler and Evans at DOE/HERAP Workshop on Health Effects of Air Pollution, Brookhaven National Laboratory, August 1982.

● *The function, developed by Morgan et af., is a probabilistic one with a

90-percent confidence interval of 0-11 excess deaths per 100,000 person-pg/m3

sulfate exposure (i. e , deaths that would not occur in the absence of sulfate).

M. G. Morgan, S. C Morris, A. K. Meier, and D. L. Shenk, “A Probabafistlc Methodology for Estimating Air Pollution Health Effects From Coaf-Fired

The health-damage function used is essentially a compilation of expert opinion about the relationship between

sulfate pollution and premature mortality (e. g., due to

aggravation of preexisting respiratory or cardiac problems). The range reflects a controversy over the validity

of epidemiological (i.e., statistical) studies indicating a

relationship between mortality and air pollution levels.

It includes estimates from scientists who believe there

is a negligible effect at prevailing sulfate concentrations

as well as those believing there is a significant

association.

These studies, carried out and extensively examined

over the past decade, examine mortality statistics from

areas of the country exposed to different levels of air

pollution. The value of these studies is that they examine human health directly, without the necessity of extrapolating from animal studies or small samples of people. They indicate that there are regional differences in

mortality, and that regional patterns of mortality are

similar to air pollution patterns. While it is possible that

factors not considered in these analyses may be more

important than the sulfur-particulate mix, none have

been demonstrated to date. Such studies are most useful

for examining the potential effects of chronic, low-level

exposure—what might be happening and what might

result from future air pollution levels.

The mortality estimates developed for OTA assume

that there is no damage threshold (i. e., minimum exposure level at which air pollution begins to affect mortality). If there is a threshold—which available medical

evidence neither confirms nor refutes—the mortality

estimates will decrease.

Sulfate-concentration data were derived from S02

emission inventories developed for the OTA study,

using the Regional Climatological Dispersion Model

(RCDM-2) developed at the University of Illinois–

one of the models evaluated by the U. S, -Canadian

Work Group on Transboundary Air Pollution. Population estimates and projections were derived from the

U.S. Census Bureau and Canadian Ministry of Industry, Trade, and Commerce data.

Figure B-20 displays current State-by-State sulfateexposure levels weighted by population. The map shows

that some of the Northeastern States with the highest

population density (e. g., New York, Pennsylvania, and

Ohio) also are exposed to the highest ambient sulfate

concentrations.

Estimates of excess deaths due to sulfate-particulate

air pollution were made for: 1 ) 1980 population levels

using 1978 emissions data; 2) populations in 2000, asPower Plants, ” Energy Systems and Pohcy 2:287-310, 1978. The current range

of scientific judgment on the issue has not narrowed, but still spans the range

of the 1978 subjective distribution (Morgan, M., et al., Technological Uncertainty in Policy Analysis, Report to the National Science Foundation, August

1982).
App. B—Effects of Transported Pollutants ● 257

Figure B-20.— Population Exposure to Airborne Sulfate (an indicator of potential health effects from sulfates

and other airborne particulate in each State)

suming that total emission levels are held constant at

1978 levels; and 3) populations in the year 2000, assuming that sulfate-particulate levels are reduced by 30 percent from 1978 levels. Results of these three scenarios

are presented in table B- 14.

Total pollutant emissions in the United States and

Canada have been estimated to result in about 50,000

premature deaths under the first scenario, increasing

1978 mortality rates by about 2 percent—an amount

approximately equivalent to the number of deaths attributable to infectious lung diseases. While increases

in population by 2000 would cause 1978 emissions levels

to induce slightly higher levels of premature deaths (scenario 2), a 30-percent decrease in the overall sulfate-particulate mix by 2000 is estimated to reduce the number

of deaths annually attributable to air pollution to about

40,000, or 1.6 percent of the total mortality rate.

Estimating mortality attributable to pollution exposure does not necessarily imply that the mortality impacts are the most significant. Mortality dose-response

.
258 Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table B-14.—Summary of Scenario Results

Population Excess deaths Rate (deaths/10s

Scenario (millions) total (103 deaths) Range population)

1.1980 population, 1978 emissions, United States

and Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 51 0-150 20.4

2.2000 population, emissions unchanged, United States

and Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 57 0-170 19.8

3.2000 population, sulfate-particulate mix 30% below

1978 levels, United States and Canada. . . . . . . . . . . . . . . . . . 291 40 0-120 13.8

SOURCE: Brookhaven National Laboratory, Biomedical and Environmental Assessment Division, “Long Range Transport Air Pollution Health Effects,” OTA contractor

report, May 1982.

functions are used because the available data on morbidity (illness) are inadequate for detailed

epidemiological analyses.

Nitrogen Oxides

The term nitrogen oxides (NOX) refers to a number

of compounds—NO, N02

, and such secondary byproducts as nitric acid, nitrate aerosols, and nitrosamines*—

all of which have the potential to affect human health.

Of the several NOX compounds, by far the greatest

amount is known about the effects of N02

, a pollutant

that has been studied over the past 30 years and is

presently regulated under NAAQS.

The principal target of NOX pollution is the respiratory system. Episodic or peaking concentrations of NO2

(possibly augmented by NO) have been shown to cause

immediate and short-term irritation to such sensitive

subgroups of the population as asthmatics and individuals recovering from acute respiratory infections.

Chronic exposure to lower concentrations of N02 has

been associated with increased occurrence of acute respiratory infections in infants and children. Some scientists have hypothesized that such repeated low-level exposures also are associated with chronic lung disease and

increased ‘ ‘aging’ of the lung in adolescence and

adulthood.

Health effects directly attributable to NO2 generally

are considered to result from localized sources of pollution. Combustion of coal, oil, and gasoline is estimated

to be responsible for local outdoor concentrations of

NOX 10 to 100 times naturally occurring background

levels in areas of high emissions.** Indoor sources of

NOX

, such as gas cooking stoves, some home heating

systems, and cigarette smoking, also are known to contribute to population exposure, and in some cases may

exceed outdoor concentrations of NO,.

● These secondary byproducts are produced from photochemical transformation of NO and NOZ in the atmosphere; nitrosamine formation has been

theoretically suggested but not conclusively proven.

● ● Mobile-source combustion was estimated to contribute 44 percent of anthropogenically produced NO, for 1976 in the United States, whife stationarysource combustion accounted for 56 percent. USEPA, Air Quality Criteria for

Oxides of Nitrogen, June 1979, pp. 1-2 and 1-3,

Byproducts of NOx are known to be transported

over long distances, contributing to acid deposition and

ozone formation. Some of these secondary pollutants are

more toxic on a per-unit basis than N02

; however, it

is not currently known whether they are present in sufficient concentrations—or persist long enough—in the

atmosphere to endanger human health. Recent studies

performed for the EPA and the National Academy of

Sciences suggest that nitrosamines and similar chemical species may be found in sufficient concentrations in

polluted urban air near certain industrial areas to warrant concerns for health. Not enough is known yet about

the effects of NOX

, or their concentrations in the

atmosphere, to permit quantitative estimation of the

health-related damages for which NOX may be responsible, or of the population at risk from these pollutants.

Summary of Medical Research

Clinical studies of the short-term effects of NOx on

human volunteers have been conducted on asthmatics,

patients with bronchitis, and healthy subjects. The

studies generally have shown that the sensitivity of

asthmatics to irritants such as cold air or air pollutants

can be heightened by short-term concentrations of NO2

as low as 940 μg/m3 (the primary NAAQS for N02 is

100 μg/m3 annually; there is no shorter term standard).

Recovery from these effects tends to be rapid, and it

is not known whether repeated exposures of this kind

have any cumulative effects or predispose the lungs to

permanent damage. Most studies do not show increased

sensitivity or irritation in either healthy or bronchitis

subjects when NO2 concentrations are at or below 2,820

μg/m3

.

Laboratory experiments have tested the reactions of

animal tissues to similar and higher concentrations of

N02

. These experiments have provided significant insight into the mechanisms that govern human reactions

to NO2 exposures, and suggest more serious consequences of long-term human exposure to NO2 than have

appeared in short-term clinical studies.

Prolonged exposure to N02 has been observed to

cause damage to lung tissue in laboratory animals. The

principal consequences of such damage appear to be de-
App. B—Effects of Transported Pollutants ● 259

velopment of emphysema-like conditions and reductions

in resistance to respiratory infection. For a fixed dosage,

greater concentrations have been shown to cause greater

increases in mortality rates for animals exposed to respiratory infection than greater duration of exposure.

This suggests that fluctuating levels of N02

, such as are

found in community air, may prove more toxic than

sustained levels of the gas.

Epidemiologica1 studies of populations of children exposed to N02 concentrations, primarily via indoor air

pollution, confirm laboratory findings of reduced resistance to respiratory infection in exposed animals. Children exposed to additional quantities of NO2 (and possibly NO) from gas stove combustion—in particular,

infants under the age of 2—show significantly greater

incidence of acute respiratory illness and changes in lung

function than counterparts living in homes with electric stoves. Similar findings have not been observed in

adults.

Indirect

Acid

Health Effects

Precipitation

Acidified waters are known to be capable of dissolving toxic metals—e. g., aluminum, copper, lead, and

mercury-and releasing such toxic substances as asbestos, from soils and rocks in watersheds and lakes, and

from drinking water distribution systems. Researchers

are attempting to determine the extent to which the total

body burden of these substances in humans might result from acidic deposition, as opposed to direct inhalation or occupational exposure.

No direct relationship has yet been established between acid deposition and degradation of drinking-water

quality. Potentially harmful levels of asbestos and lead,

however, have been found in “aggressive’ (i. e., corrosive) acidified waters in the Eastern United States.

Scientists have encountered difficulty in pinpointing the

direct source of concentrations of toxic materials found

in acidic tap waters. Acidic precipitation can scavenge

toxic materials from the atmosphere during rainfall

events, leach them from soils and rocks as they pass

through the watershed, or leach them from pipes and

conduits used to distribute water to users.

The aggressiveness of municipal water supplies can

be monitored and corrected fairly easily. A recent

amendment to the National Interim Primary Drinking

Water Regulations has established the initial steps in

a corrosion control program.19 Public water systems are

now required to identify the presence of specific mate19~nY.lrOnmen(~ protection Agency, Interim Pnmar-y Drmkmg Water Regulat Ions, Amendment Final Rule, Fed. Reg 45( 168). 57332-57357, Aug 27,

1980

rials (e. g., lead and cadmium) within the distribution

system and to monitor corrosiveness characteristics for

at least 1 year. Also, the types of materials used in the

distribution system and home plumbing must be reported.

A recent study sponsored by EPA20 of 119 surface water supplies in the 6 New England States indicates that

84 to 92 percent of the water bodies are highly aggressive. Anti-corrosion treatment is currently practiced in

specific areas (e. g., Boston) where acid precipitation is

known to affect water quality. * However, aggressive

well water in rural areas where soils have little capacity

to counteract acid deposition is more difficult to detect

and mitigate, and potential health effects remain of

concern.

Asbestos

Asbestos occurs widely in natural rock formations

throughout the east and west coasts of the United States.

In addition, asbestos fibers are mixed in concentrations

of 10 to 25 percent with cement to reinforce pipe used

to distribute water supplies. While studies have shown

that water can corrode asbestos-cement materials and

release fibers into the drinking water, data showing a

direct association between precipitation pH and asbestos content of drinking water are not available. Howt ever, preliminary estimates of asbestos in drinking water from asbestos/cement distribution pipes suggest that

approximately 11 percent of the total U.S. population

is exposed to asbestos concentrations greater than 10

million fibers/liter.21

Correlations between above-average incidence of certain abdominal cancers and elevated concentrations of

asbestos in drinking water recently have been found in

the San Francisco Bay area, where abundant natural

supplies of asbestos occur in bedrock.22 EPA has used

data from studies of workers exposed to airborne asbestos to estimate that one additional cancer will be caused

for every 100,000 people exposed to drinking water containing 300,000 asbestos fibers/liters for 70 years.**

20 Flovd B. ‘1’aylor, ‘ ‘Impact of Acid Rain on Water Supplies in Terms of

EPA Drinking Water Regulations, ’ Proceedings of the Amerscan iVater J$’orks

Association, Las Vegas, June 1983, In press

“Boston has a high percentage of lead service lutes and plumbmg. During

1976-77, prior to pH adjustment, 44 percent of the top water samples exceeded

the maximum contaminant level (MCL) of 0.05 mg/1 lead.

“J R Millette, M. F. Pansing, and R. L Boone, “Asbestos-Cement Materials Used in Water Supply,, Water Engineering and Management, 128:48,

51, 60, 97, 1981

~2M, S Kanarek, p. M Con fortl, L A. <Jackson, R. C. Cope I_, and J ~

Murchio, ‘ ‘Asbestos in Drmkmg Water and Cancer Incidence m the San Franc isco Bay Area, Am j .Epldemml , 112 54-72, 1980.

*“Federal Register 44(191) 56634, Oct 1, 1979
260 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Lead

Lead enters aquatic ecosystems from wet and dry precipitation, mineral erosion, street runoff, leaded gasoline, and municipal and industrial discharge, as well as

from corrosion of lead in pipes and plumbing systems.

Corrosion of lead from lead-containing materials is

facilitated by waters of low pH (less than 6.5) —especially when the waters are also of low alkalinity. Individual water samples in isolated areas characterized

by low pH values have shown lead concentrations of up

to 100 times the 50 μg/1 ambient water quality standard.23 Early morning water samples from New England

distribution systems showed 7 percent exceeded the

standard for lead. 24

While elevations in human blood lead levels will result directly from ingesting contaminated drinking water, the human body also absorbs lead from a number

of other sources, including food, ambient air, cigarettes,

paint, dust, and dirt. *

Mercury

Studies in Scandinavia, Canada, and the United

States have found correlations between elevated levels

of mercury in fish and increasing acidity of lake and

stream habitats. However, no cases of mercury poisoning are known to be associated with freshwater fish in

the United States. Lakes in acid-sensitive regions of

Minnesota, Wisconsin, and in the Adirondacks of New

York have yielded fish with mercury concentrations

above the FDA public health standard of 0.5 ppm.25 26

Studies are currently under way to assess correlations

between observed mercury levels and lake pH levels.

A number of recent efforts to neutralize acidic lakes

through the application of lime appear to be successful

23P, Mu~hak Multimedia Pollutants. Report to the National Commission

on Air Quality, ’Contract No, 232-AQ-6981, 1981; G. W. Fuhs and R. A, 01-

sen, ‘ ‘Technical Memorandum: Acid Precipitation Effects on Drinking Water

m the Adirondack Mountains of New York State, New York State Dept, of

Health, Albany, N, Y,, 1979.

2+ Tav]or,F, B , OP. cit

“EPA has defined approximately 2.5 million people-inner-city children

under 5 and pregnant women—as being at special risk from elevated levels of

lead in the bloodstream While aggressive drinking waters can leach lead from

pipes and contribute to lead levels in the blood, such effects may constitute

a greater threat to rural populations using acidified groundwaters than to urban populations using waters that can be treated readily, Preliminary investigations m the New York State Adirondacks region have found isolated cases of

human exposure to lead-contaminated drinking water resulting in lead concentrations in blood as high as 59 pg/dl. (Blood lead levels should be maintained below 30 pg/dl to avoid deleterious heafth effects, ) New York State

Department of Health, Technical Memorandum: “Lead Poisoning Related

to Private Drinking Water Sources, Oct. 23, 1981.

lsAcld Precipitation in Minnesota, Minnesota po]]ution control AgmCy,

Minnesota Department of Natural Resources, Minnesota Department of

Heafth, Jan. 26, 1982, pp. 7-67; Letter from G. Wolfgang Fuhs, Director, New

York State Department of Health, to Congressman Toby Moffett, July 16, 1980,

p. 3.

lfJper~[)na]C[)nlmunlcatlon, James Wiener, U. S. Fish and Wildlife Service,

La Crosse Field Research StatIon, La Crosse, Wis,, May 1982,

in reducing mercury levels in fish. Favorable results

have been reported for various locations in Sweden, and

for Nelson Lake in Ontario, Canada.27

Other Metals

Acidified waters are known to leach substantial

amounts of aluminum from watersheds, and the

volubility of aluminum increases as pH decreases below

6.0. Concentrations of aluminum in acidified well water in the United States have been found as high as 1.7

mg/1, which could represent a substantial portion of an

individual’s daily aluminum intake. Little is known

about the toxicity of aluminum to most human populations; no restrictions have been established in the United

States on aluminum concentrations in drinking waters

or foods.

Several studies have shown, however, that elevated

aluminum concentrations may be toxic to individuals

with impaired kidney function—e. g., water containing

more than 50 μg/1 of aluminum is thought to be unsafe

for dialysis treatment. Sixty-one percent of surface water samples in New England contained aluminum equal

to or greater than 100 μg/l; 24 percent exceeded 200

μg/l. 28

For normal human beings, copper deficiency is more

widespread than copper toxicity. A limit of 1 mg/1 for

copper concentration in U.S. drinking water has been

set on the basis of taste; no regulatory limit exists for

copper concentrations in food. Acidic waters have been

shown to be capable of corroding copper from pipes in

household distribution systems—elevated copper levels

have been reported in several drinking water samples

from sensitive areas of the Adirondacks. *g Additionally,

a recent survey of New England distribution systems

showed 29 percent of early morning water samples exceeded the standard for copper .30 While several cases

of copper toxicity have been reported in the United

States among individuals with Wilson’s disease, a oncefatal disorder of copper metabolism, the hazard to the

general population from currently observed copper

levels appears quite small.

In its natural state, cadmium occurs as an impurity

in zinc, copper-zinc, or lead-zinc deposits. In concentrated or pure form it is very toxic. Little evidence of

cadmium corrosion from galvanized pipe or plumbing

alloys currently exists, although studies of municipal wa27’’ The Role of Clouds in Atmospheric Transport of Mercury and Other

Pollutants, ” G. H. Tomlinson, R. J. P. Brouzes, R. A, N, McLean, and John

Kadlecek, m Ecological Impact ofAcid Precipitation, Proceedings of an International Conference, Sandefjiord, Norway, Mar, 11-14, 1980, Oslo-As.

28 Tay]or, F. B. , op. cit.

“(;. W. Fuhs and R. A. Olson, ‘ ‘Technical Memorandum: Acid Precipitation IMIects on Drinking Water in the Adirondack Mountains of New York,

New York State Department of Heafth, Albany, 1979.

‘FI’aylor, F, B, op. cit.
App. B—Effects of Transported Pollutants . 261

ter systems have shown levels to occasionally exceed the trial exposure conditions. Based on the infrequent

U.S. health standard of 10 μg/1. The concentrations occurrence of cadmium in drinking water at levels above

found in drinking water, however, represent only a min- 10 μg/1, such exposures are not considered a threat to

ute fraction of the amounts known to cause acute cad- many people.

mium poisoning or chronic health effects under indusB.6 ECONOMIC SECTORS AT GREATEST RISK FROM

CONTROLLING OR NOT CONTROLLING

TRANSPORTED POLLUTANTS

Throughout this report, five sectors of the U.S. economy have been identified as sensitive to the potential

effects of decisions to control or not to control transported air pollutants: 1) farming and agricultural services, 2) forestry and related products, 3) coal mining,

4) freshwater fishing-related recreation, and 5) the electric utility industry. This appendix presents information about the magnitude and geographic distribution

of these activities in the Eastern 31 -State region. OTA

assembled data from the Department of Labor, the U.S.

Fish and Wildlife Service, and the Edison Electric Institute to estimate levels of economic activity for each,

and levels of participation, where appropriate, in recent

years. These tabulations are of total income, expenditures, employment, and resource utilization for a given

sector. They are provided to indicate the relative importance of each sector to the economy and people of

the Eastern 3 1-State region, not as estimates of the number of people or amount of economic activity that might

be affected by decisions regarding transported air

pollutants.

The amount of available information on the potential effect of controlling or not controlling transported

air pollutants varies substantially among sectors. Moreover, for sectors dependent on resources potentially susceptible to transported pollutants, reliable estimates of

the financial losses associated with resource damage cannot presently be attempted, even for resources for which

damages can be estimated. Estimates of losses in crop

production from ozone, and of the potential susceptibility of aquatic resources and forests to acid deposition,

are provided in chapters 3 and 5, and are treated in detail in appendix B, section 2. Estimates of the economic effects of emissions control on coal mining and electric utilities, and of the coal-mining employment effects

of emissions controls, are also presented in chapters 3

and 5, and detailed in appendix A. In general, the costs

associated with emissions controls are better known than

those associated with potential resource damage. As

the available measures of potential effects are expressed

in different forms, and represent disparate levels of

knowledge, they cannot be compared directly across the

five sectors. However, the importance of the economic

sectors themselves can be compared, both in monetary

and participatory terms, as well as among sectors and

States.

Table B-15 presents State-by-State estimates of the

personal income and expenses for which the five sectors directly account, in millions of dollars and as a percentage of the state total. U.S. Department of Labor

data on wages, salaries, and proprietary income, averaged over the years 1978-80, are presented for farming

and agricultural services, forestry and related products,

and coal mining. Freshwater fishing-related recreation

expenses are compiled from U.S. Fish and Wildlife

Service survey data on expenditures for travel, lodging,

food, fees, and light equipment used exclusively for fishing in 1980. For electric utilities, data from the Edison

Electric Institute on the percentage of personal income

spent on residential electricity consumption in each State

are provided.

Farming- and forestry-related income each account

for slightly less than 2 percent of the Eastern U.S. region total, or an average of $21.8 billion and $20.5 billion, respectively, for the 1978-80 period. Intraregional

variations are significant: farming and agricultural services accounted for over 3 percent of personal income in

Kentucky, Mississippi, Missouri, North Carolina, Vermont, and Wisconsin, and over 5 percent in Arkansas,

Iowa, and Minnesota. Similarly, forestry, lumber,

wood, and paper products accounted for over 3 percent

of personal income in Alabama, Georgia, Minnesota,

Mississippi, New Hampshire, South Carolina, Vermont, and Wisconsin, over 5 percent in Arkansas, and

over 10 percent in Maine.

The greatest regional variation is found in the distribution of income due to coal mining, which accounted

for an average of nearly $7 billion in the region during
262 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Table B.15.-lncome or Revenues From Farming, Forestry, Coal, Fishing, and Utilities

(in millions of dollars per year and percent of State total income)

Forestry, lumber, Freshwater

Farming and wood, and fishing-related Utility revenues

agriculture services paper products Coal-mining recreation (residential only)

Region/State Income Percent Income Percent Income Percent Expenses Percent Revenues Percent

New England:

Maine. . . . . . . . . . . . . . . . . . 110.2

New Hampshire . . . . . . . . . 27.3

Vermont . . . . . . . . . . . . . . . 131.1

Massachusetts. . . . . . . . . . 48.9

Rhode Island . . . . . . . . . . . 20.4

Connecticut . . . . . . . . . . . . 35.1

1.7

0.5

4.3

0.1

0.3

0.1

678.2

208.1

103.6

687.9

58.2

272.0

10.5

3.6

3.4

1.6

0.9

1.0

0.3

0.0

0.3

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

83.6

36.2

32.1

86.3

12.0

61.3

1.3

0.6

1.1

0.2

0.2

0.2

179.7

166.8

81.2

830.0

135.6

543.8

2.9

2.9

2.8

1.9

2.2

2.1

Middle Atlantic:

New York . . . . . . . . . . . . . . 719.0

New Jersey. . . . . . . . . . . . . 231.7

Pennsylvania . . . . . . . . . . . 951.3

0.5

0.4

1.1

1,349.4

846.2

1,331.1

1.0

1.5

1.6

1.5

—

1,215.3

0.0—

1.4

240.8

99.2

272.7

0.2

0.2

0.3

2,322.4

1,294.4

1,784.2

1.7

2.3

2.2

East North Central:

Ohio . . . . . . . . . . . . . . . . . . . 911.0

Indiana . . . . . . . . . . . . . . . . 1,017.1

Illinois . . . . . . . . . . . . . . . . . 1,805.7

Michigan . . . . . . . . . . . . . . . 779.9

Wisconsin . . . . . . . . . . . . . . 1,424.8

1.1

2.5

1.9

1.0

4.2

1,123.7

641.7

1,005.3

767.7

1,520.4

1.4

1.6

1.1

1.0

4.5

481.5

210.3

564.5

1.3

0.2

0.6

0.5

0.6

0.0

280.2

268.7

321.5

394.9

440.5

0.4

0.7

0.4

0.6

1.4

1,737.4

839.0

1,690.0

1,197.4

641.5

2.2

2.2

1.9

1.7

2.0

West North Central:

Minnesota. . . . . . . . . . . . . . 1,664.0

lowa . . . . . . . . . . . . . . . . . . . 1,670.7

Missouri . . . . . . . . . . . . . . . 1,308.3

5.3

8.1

3.7

2.3

0.0

0.9

1.2

0.5

3.8

1.7

2.1

2.7

1,109.2

171.4

416.4

3.5

0.8

1.2

1.2

8.7

54.5

0.0

0.0

0.2

383.5

111.6

301.6

1.3

0.6

0.9

504.8

481.3

807.9

1.7

2.5

2.4

South At/ant/c:

Delaware . . . . . . . . . . . . . . .

Washington, D. C.. . . . . . . .

Maryland . . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . . .

West Virginia . . . . . . . . . . .

North Carolina . . . . . . . . . .

South Carolina. . . . . . . . . .

Georgia . . . . . . . . . . . . . . . .

Florida. . . . . . . . . . . . . . . . .

116.2

3.4

265.9

426.4

52.8

1,410.9

304.2

760.0

1,564.5

0.0 0.0—

0.1

1.6

15.0

0.0

0.0

0.0

0.0

7.8

3.7

61.1

174.1

100.5

209.3

135.7

300.8

483.9

0.2

0.0

0.2

0.5

0.9

0.6

0.8

0.9

0.8

11.6

229.6

499.5

1,075.8

266.8

1,043.7

548.4

903.2

2,377.3

2.3

1.7

1.7

3.0

2.4

2.9

3.1

2.6

4.1

—

0.9

261.1

681.8

104.6

984.1

566.3

1,149.7

736.4

—

0.0

0.9

1.9

0.9

2.6

3.1

3.2

1.3

—

28.2

583.7

1,747.3

3.3

0.6

1.9

1.3

East South Central:

Kentucky. . . . . . . . . . . . . . . 757.5

Tennessee . . . . . . . . . . . . . 418.5

Alabama ., . . . . . . . . . . . . . 661.3

Mississippi . . . . . . . . . . . . . 650.9

West South Central:

Arkansas . . . . . . . . . . . . . . . 1,042.0

Louisiana . . . . . . . . . . . . . . 506.4

3.5

1.5

2.9

5.0

299.0

639.8

979.9

564.3

1.4

2.3

4.3

4.4

1,532.0

135.2

389.2

0.1

7.0

0.5

1.7

0.0

235.8

268.5

285.8

170.3

1.1

1.0

1.3

1.4

511.9

872.2

765.5

434.5

2.5

3.2

3.5

3.5

8.4

1.9

1.9

639.2

644.2

20,541.6

5.1

2.4

1.8

7.1

0.1

6,969.7

0.1

0.0

0.6

237.9

224.3

6,326.2

2.0

0.8

0.6

384.8

717.5

3.3

2.6

25,980.3 2.3

SOURCES: U.S. Department of Labor; U.S. Fish and Wildlife Service, Department of the Interior; Edison Electric Institute,

Eastern 31-State total . ...21.797.2

1978-80, or 0.6 percent of the total. Nearly two-thirds

of this income was earned in Kentucky, Pennsylvania,

and West Virginia; coal mining accounted for over 1

percent of personal income in Alabama, Pennsylvania,

and Virginia; 7 percent in Kentucky; and 15 percent

in West Virginia.

Expenditure data for electrical power show that residential consumers spent nearly $26 billion to purchase

electricity in the region in 1980. In general, the proportion of income spent on electricity is higher in Southern States, reflecting greater use of electrically powered

cooling equipment. As a proportion of personal income,

expenditures range from a low of 1.7 percent in the

District of Columbia, Maryland, Michigan, Minnesota,

and New York, to a high of 4.1 percent in Florida.

Freshwater fishing accounted for expenditures of approximately $6.3 billion in the region in 1980, or 0.6

percent of the region’s total personal income. States in

which these expenditures exceeded 1 percent of personal

income included Alabama, Arkansas, Kentucky,

Maine, Minnesota, Mississippi, Tennessee, Vermont,

and Wisconsin. As shown in the table, freshwater fishing
App. B—Effects of Transported Pollutants 263

generated at least $250 million in 1980 expenditures in

12 States: Alabama, Florida, Georgia, Illinois, Indiana,

Michigan, Minnesota, Missouri, Ohio, Pennsylvania,

Tennessee, and Wisconsin.

Table B-16 presents Department of Labor estimates

of the number of people employed in farms and agricultural services, forestry and related products, and coal

mining in 1980. In the Eastern region overall, agriculture employed slightly over 3 million people, or 4 percent of the regional total. Variations within the region

are substantial—agriculture employed over 5 percent

of the work force in Alabama, Indiana, Minnesota, Mississippi, Missouri, North Carolina, South Carolina,

Tennessee, Vermont, and Wisconsin; and over 10 percent of the work force in Arkansas, Iowa, and Kentucky.

Total Eastern employment in forestry, lumber, wood

and paper products was slightly over one million, or 1.4

percent of the regional total. These industries employed

Table B-16.—Number of People Employed in Farms and Agricultural Services,

Forestry and Related Products, and Coal Mining in 1980

Farms and Forestry, lumber, and

agricultural servicesa wood and paper productsb Coal mining

Percent of Percent of Percent of

Number of people State total Number of people State total Number of people State total

..- . . . --- --- 4.3 1,404,000 1.0 251,000 0.2

—

—

—

—

—

—

—

0.1—

—

0.7

0.3

0.2—

0.3—

—

—

0.0

0.7—

—

—

3,1—

—

—

—

0.2

0.7

8.6

0.3

us. total . . . . . . . . . . . . .

New England:

Connecticut . . . . . . . . . . .

Maine . . . . . . . . . . . . . . . .

Massachusetts . . . . . . . .

New Hampshire . . . . . . .

Rhode Island . . . . . . . . . .

Vermont . . . . . . . . . . . . . .

Mideast:

Delaware . . . . . . . . . . . . .

District of Columbia. . . .

Maryland . . . . . . . . . . . . .

New Jersey . . . . . . . . . . .

New York . . . . . . . . . . . . .

Pennsylvania . . . . . . . . . .

Great Lakes:

Illinois . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . .

Michigan . . . . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . .

Wisconsin . . . . . . . . . . . .

Plains Region:

lowa . . . . . . . . . . . . . . . . .

Minnesota . . . . . . . . . . . .

Missouri . . . . . . . . . . . . . .

Southeast:

Alabama . . . . . . . . . . . . . .

Arkansas . . . . . . . . . . . . .

Florida . . . . . . . . . . . . . . .

Georgia. . . . . . . . . . . . . . .

Kentucky . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . .

Mississippi . . . . . . . . . . .

North Carolina. . . . . . . . .

South Carolina . . . . . . . .

Tennessee . . . . . . . . . . . .

Virginia. . . . . . . . . . . . . . .

West Virginia. . . . . . . . . .

4,628,300

20,436C

23,069

25,670C

7,987

3,121

15,220

7,116

161

38,293

30,570

117,351

118,613

168,380

134,314

116,823

154,279

163,400

177,130

161,453

165,696

101,110

103,621

135,023

119,319

154,212

72,610

104,257

177,556

76,427

144,397

100,666

30,607

1.3

4.4

0.9

1.8

0.7

6.1

11,872

32,188

33,395C

11,066C

3,901

6,409

0.7

6.2

1.2

2.5

0.9

2.6

—

—

—

—

—

4,082C

384C

13,824

38,599

64,965

63,580

2.4

0.0

1.9

0.9

1.5

2.2

1.4

0.1

0.7

1.1

0.8

1.2

1,049 —

—

37,911 C

3.1

5.3

3.1

3.2

7.2

47,079

32,791

32,218

52,404

68,842

0.9

1.3

0.8

1.1

3.0

18,147

6,060

15,490

12.3

7.6

7.2

8,464

43,415

23,910

0.6

2.0

1.0

—

—

1,049

6.0

10.6

3.2

4.6

10.0

3.9

9.6

6.1

5.1

6.7

3.8

4.1

4.0

49,056

34,104

39,191

59,375

16,749

28,516

31,218

57,191

30,150

37,106

38,351

7,350

1,020,724 (73%)d

2.9

3.5

0.9

2.3

1.1

2.9

2,0

2.0

1.7

1.4

1.0

1.4

12,539

—

47,319

—

—

—

4,184

19,107

64,096’

227,252 (91%)d Eastern 31-State total . . 3,010,885 (65%)d

aIncludes farm proprietors; excludes manufacture and sale of farm equipment.

blncludes construction of prefabricated buildings and mobile homes; excludes manufacture of furniture, printing and publishing industries, and Sale of building materials,

c1980 data not available for all data points—estimates may be slightly low due to use of data from mid-1970’s

dFigures in parentheses represent the proportion of the U.S. total employed within the Eastern 31-state region.

SOURCE: U.S. Department of Labor.

99-413 0 - 84 - 18 : QL. 3
264 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

2 percent or more of the work force in Alabama, Georgia, Minnesota, Mississippi, New Hampshire, North

Carolina, South Carolina, and Vermont, and 3 percent

or more in Arkansas, Maine, and Wisconsin.

Employment in coal mining is the least evenly distributed of those sectors surveyed. It accounted for

slightly under a quarter-million jobs, or 0.3 percent of

the Eastern U.S. work force, in 1980. Coal mining employed greater than 0.5 percent of the work force in Alabama, Pennsylvania, and Virginia, and employed 3.1

and 8.6 percent of the work force in Kentucky and West

Virginia, respectively. Estimates of shifts in coal mining employment that might accompany stricter SO2

-

emissions controls are presented in appendix A.

The 1980 National Survey of Fishing and Hunting

conducted by the Fish and Wildlife Service is the basis

for estimates in table B-17 of the number of participants

in freshwater fishing in the Eastern region. Counting

only in-state fishing participants, to avoid double counting, over 21 million people are estimated to have taken

part in freshwater fishing, devoting an average of somewhere between 11 and 21 days per year to this form of

recreation. Counting only in-State residents, Florida,

Georgia, Illinois, Michigan, Minnesota, New York,

Ohio, Pennsylvania, and Wisconsin each had over a

million freshwater-fishing participants; when out-ofState anglers are included, Alabama, Indiana, Kentucky, Missouri, North Carolina, and Tennessee are

added to this list.

Table B-17.-Number of Residents and Nonresidents

Participating in Freshwater Fishing in 1980a

Number of Total number

residents of participants

Alabama . . . . . . . . . . . . . .

Arkansas. . . . . . . . . . . . . .

Connecticut . . . . . . . . . . .

Delaware . . . . . . . . . . . . . .

District of Columbia . . . .

Florida. . . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . .

lowa. . . . . . . . . . . . . . . . . .

Kentucky. . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . .

Maine . . . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . .

Massachusetts. . . . . . . . .

Michigan . . . . . . . . . . . . . .

Minnesota. . . . . . . . . . . . .

Mississippi . . . . . . . . . . . .

Missouri . . . . . . . . . . . . . .

New Hampshire. . . . . . . .

New Jersey . . . . . . . . . . .

New York . . . . . . . . . . . . .

North Carolina . . . . . . . . .

Ohio. . . . . . . . . . . . . . . . . .

Pennsylvania . . . . . . . . . .

Rhode Island . . . . . . . . . .

South Carolina. . . . . . . . .

Tennessee . . . . . . . . . . . .

Vermont . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . .

West Virginia . . . . . . . . . .

Wisconsin. . . . . . . . . . . . .

874,952

574,351

271,488

30,221

10,361

1,193,583

1,117,544

1,264,434

913,212

592,242

734,630

752,110

214,505

268,716

333,680

1,292,682

1,175,026

538,349

998,667

115,357

229,175

1,036,257

927,341

1,412,022

1,168,907

60,143

490,089

903,633

113,256

637,681

341,293

1,109,738

21,760,645

1,117,099

895,619

307,217

35,136

15,006

1,550,406

1,253,265

1,401,922

1,111,095

646,180

1,052,587

955,567

364,062

321,687

414,012

1,666,295

1,639,131

689,901

1,230,423

224,998

383,375

1,225,313

1,096,338

1,500,525

1,400,689

72,633

639,259

1,161,467

182,753

823,369

416,874

1,674,219

Eastern 31-State total . . b

aDoes not include fishing In the Great Lakes.

bTotal not calculated due to potential double-counting of participants.

SOURCE: U.S. Fish and Wildlife Service, Department of the Interior.
Appendix C

Atmospheric Processes

C.1 ATMOSPHERIC CHEMISTRY (p. 265)

C.2 SOURCE-RECEPTOR RELATIONSHIPS (p. 274)

C.1 ATMOSPHERIC CHEMISTRY*

The atmosphere is a mixture of chemicals—some of

natural origin, some anthropogenically generated, and

some that are produced by nature as well as by man.

These chemicals can react with each other to varying

degrees under varying conditions. Because the atmosphere is dynamic, the particular chemical environment

it represents is different for every location, every season,

and every meteorological condition.

Both acid deposition and ozone are produced by

transported air pollutants. The dominant precursors of

acid deposition are sulfur dioxide (S02

) and nitrogen

oxides (NOX

). Ozone formation involves NOX and reactive hydrocarbons (RHC). Anthropogenic sulfur oxides

(S0x

) are produced primarily by burning such sulfurcontaining fossil fuels as coal and oil. Nitrogen oxides

also result from the burning of fossil fuel by utility, industrial, and mobile sources. Anthropogenic hydrocarbon emissions result primarily from petroleum refining

and storage, other industrial process emissions, and

mobile sources.

After release into the atmosphere, the particular sequence of changes a pollutant undergoes depends on the

physical and chemical characteristics of the air mass in

which it travels, Ultimately, though, because the atmosphere is 20 percent oxygen, emitted S0x and NOx will

oxidize * * and can form acid when combined with water.

This can occur while the pollutants are in the air, or

following deposition on the Earth. The acids formed

may subsequently be neutralized if appropriate chemical

species are available.

Which of many chemical routes is actually followed

depends on: 1) the initial concentrations of all pollutants;

and 2) a number of physical factors, such as wind speed,

air turbulence, sunlight intensity, temperature, and

rainfall frequency.

While scientists know a great deal about individual

● ’1%[$ appertcf[x IS based on (he 0’1’,4 con[ra((or repot-(, ‘ ‘An Asses~mrn(

of the Atm{xpherlc Chernlst ry of Oxlcit-s of Sulfur and Nitrogen A{ ld Deposition and Ozone, by B ,J FinlaYson-P,tts and J N Pitts, Jr , 198 2

*“Oxidatmn is the procrss of adding ox> gen to a chemical oxidl~ing agents

or ‘ ‘oxidants’ are ( hemt( als that supply the extra nxvgen needed to ( onj ert

S02 to sulfate, or NOX to nitrate W’hen sulfate and nitrate cnmblne with water,

sulfurlc M Id and nltrlc acid are formed unless neutralized by other chemlc als

present

chemical reactions and specific physical processes, they

cannot precisely characterize the detailed path of a pollutant from its origin or ‘ ‘source’ to its removal or

“sink. Reactions can occur when pollutants exist as

gases, are dissolved in liquids, or adhere to particles.

In general, gas-phase reactions predominate in the

transformation of NOX and the production of ozone,

while all three phases—gas, liquids, and solids—are

presently believed to play a part in S0x transformations

under different atmospheric conditions. Nonetheless, the

key atmospheric reactions involved in producing acid

deposition and ozone have some common features and

are closely interrelated.

Energy from sunlight triggers chemical reactions that

transform SOX and NOX (which includes NO and NO2

)

into sulfuric and nitric acid, respectively. Such ‘ ‘photochemical’ processes, which also form ozone, require the

presence of RHC. For example, hydroxyl (OH) radicals—a very reactive chemical species— initiate the gas

phase transformation of S02 to sulfuric acid. Since concentrations of OH depend, in turn, on concentrations

of ozone, NOX

, and RHC, as well as on sunlight intensity, the atmospheric chemistry of ozone, NOX

, S02,

and RHC must be considered together. Altering the

concentrations of any one of these will affect pollutant

transformation and deposition rates.

Deposition of Sulfur and Nitrogen

In the East, approximately two-thirds of the acid deposited results from sulfur compounds, and one-third

results from nitrogen compounds. Over much of the

West, NOX emissions play a relatively greater role in

acidification than in the East. To become acids, emitted

S02 and NO, must be oxidized either: 1) in the gas

phase, 2) after absorption into water droplets, or 3) after

dry deposition on the ground.

These materials can be deposited on the ground unchanged (as primary gaseous pollutants), or in a transformed state (as secondary pollutants). Transformed

pollutants can be deposited in wet form (as rain, fog,

or snow), or dry form (due to particles containing these

materials settling out). The amount of time a pollutant

remains in the atmosphere, and therefore, how far it

265
266 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

is transported, depends significantly on its chemical

form. For example, S02 gas is dry-deposited at a greater

rate than sulfate particles (products of oxidation). If S02

is quickly converted to sulfate, a smaller fraction of

emitted sulfur will be deposited locally, in the absence

of precipitation. The rate of conversion of S02 to sulfate

depends on the chemical composition of the atmosphere.

The frequency and intensity of precipitation controls the

rate of wet sulfur deposition.

Dry deposition is believed to occur at a fairly constant rate over time (i. e., a certain percentage of the

S02 in the air is dry-deposited each hour), but varies

somewhat over different terrain. Wet deposition is episodic, and the amount deposited varies considerably

even within a rainfall event. For example, a short rain

may deposit heavy doses if pollutants are concentrated—

e.g., if they have been forming and accumulating in the

air over time. Without sufficient time for pollutant concentrations to accumulate and be transformed, a second

rain in quick succession may deposit little new acid material. The product of concentration times rainfall determines the total dose of wet-deposited acidic material.

For this reason, acid fogs (recently identified in the

Los Angeles basin) may expose the area to a very high

concentration of acid (a large quantity of acid per

amount of water), but significantly smaller amounts of

acid may be deposited than would occur from a rainfall. On an annual basis, the contribution to total acid

loadings depends on the percent of time that fog covers

an area. Particularly in high-altitude regions (e. g., the

Northern Appalachian mountains) where cloud cover

and fog persist for about 50 percent of the time, precipitation may account for less acid deposition than fog.

The relative effect of high acid concentrations (but low

total doses) as compared to high total doses of acid (at

low concentrations) depends on the nature of the receptor or ecosystem in question. (See app. B, “Aquatic

Resources, Terrestrial Ecosystems, and Materials.”)

In general, areas close to emission sources receive

significant proportions of their pollution from steady dry

deposition of S02

. In locales remote from emission

regions, much of the S02 available for dry deposition

has been depleted or converted to secondary pollutants.

In these areas, wet deposition delivers a greater share

of the total pollutant dose than does dry deposition (see

fig. C-l). Over most of the nonremote Eastern United

States, the contribution from wet and dry deposition is

estimated to be about equal, Air over any particular area

will carry some residual pollution from distant areas,

as well as infusions received from more recently passed

areas. The continued replenishment and depletion of

pollutants along the path of an air mass makes precise

source-receptor relationships extremely difficult to determine.

Atmospheric Chemistry of the Oxides of Sulfur

About 26 million tons of manmade S02 are emitted

in the continental United States. About 22 million of

these tons are emitted in the Eastern 3 l-State region.

The oxidation of natural sulfur compounds could contribute significantly to atmospheric S02 concentrations

in regions where natural emissions are high (e. g., from

volcanoes, or some types of marshes) and manmade

emissions are low. However, on a nationwide basis, less

than 5 to 10 percent of sulfur emissions are attributed

to natural sources.

The following discussion of the various fates of

emitted S02 is summarized in figure C-2. One way in

which sulfate is formed involves S02 gas interacting with

OH radicals in a homogeneous gas phase reaction—i.e.,

the reactants are all in the gas phase. Because OH is

highly reactive with many atmospheric components,

each OH radical has a short lifetime in the atmosphere.

Sunlight is necessary for triggering the chain reaction

leading to OH production. Consequently, the greatest

quantity of SO2 gas is oxidized by OH radicals during

periods of intense sunlight—i.e, at midday, and in the

summer. The maximum rate at which this reaction converts S02 to sulfate is estimated to be about 1 to 4 percent per hour. However, field experiments show conversion rates significantly greater (10 to 30 percent per

hour) than homogeneous gas-phase reaction rates.

Therefore, significant quantities of sulfate must be produced by aqueous (liquid) phase reactions or heterogeneous reactions involving two phases (i. e., reactions of

gases on either liquid droplets or solid particles).

In aqueous phase reactions, S02 is dissolved in water

droplets, where oxidants convert the SO2 to sulfate.

There is little agreement as to which oxidizing agent (the

candidates include dissolved oxygen, ozone, metals, hydrogen peroxide, free radicals, and NO,) is most important under particular conditions. The rate of each

oxidizing process may depend on the acidity of the solution; the relative importance of particular oxidizing

agents may, therefore, change as acid is formed and the

pH* of the water droplet decreases. As acidity increases,

S02 is also less easily dissolved, which slows down some

aqueous phase reactions significantly. (For example, the

presence of nitrate compounds can increase the acidity

of droplets, allowing less S02 to dissolve; the presence

of ammonia in the atmosphere can buffer such increases

in acidity, allowing more S02 to dissolve. ) Current

research suggests that the major aqueous phase oxidation route for S02 under typical ambient conditions is

“pH is related to acidity. Decreasing pH corresponds to increasing acid, The

pH scale is not linear; a drop of one pH unit reflects a tenfold increase in acidity. Compared to a pH of 7 (neutral), a solution of pH 6 is 10 times more acid,

pH 5 is 100 times more acid, and pH 4 is 1,000 times more acid.
App. C—Atmospheric Processes ● 267

Figure C-1 .—The Effects of Time and Distance on Conversion and Deposition of Sulfur Pollution

Sulfur can be deposited in both its emitted form, sulfur dioxide (lighter shading), and as sulfate, after being chemically

transformed in the atmosphere (darker shading). Both compounds can be deposited in either dry or wet form. The relative

amount of sulfur deposited in these forms varies with distance from emission sources. Dry deposition predominates in areas

close to emission sources. Wet deposition is responsible for a larger percentage of pollutant load in areas distant from

source regions.

sulfur

dioxide

gas

Dry Wet I Dry Wet I Dry

SOURCE: Office of Technology Assessment

the reaction with the oxidant hydrogen peroxide, because this reaction occurs quickly and appears to be

relatively independent of pH.

A variety of measurements indicate that S02 gas can

be adsorbed onto particles (e. g., carbon soot in plumes)

and then oxidized to sulfate. These types of heterogeneous reaction rates may be particularly significant in

urban plumes.

Gas phase, liquid phase, and heterogeneous reactions

may all be important under differing atmospheric conditions, For example, if there is no condensed water and

the concentration of particulate surfaces is low, gas phase

oxidation will predominate during daylight hours. However, if clouds or fog are present, oxidation in the

aqueous phase can predominate. In either case, heterogeneous reactions on surfaces may also be important if

sufficient surfaces associated with particulate are available. Such conditions are most likely near an emissions

source—e.g. , in a powerplant plume.

Overall, current estimates based on empirical observation and model results suggest that homogeneous gasphase reactions account for 25 to 50 percent of sulfate

formed, and aqueous phase reactions account for the

remaining 50 to 75 percent on a regional scale. SOX can

be converted to sulfate quickly in the aqueous phase or

in concentrated plumes (e. g., more than 10 percent per

hour) or slowly (e. g., less than 1 percent per hour in

the dry winter) in the gas phase. Thus, SOX are available for atmospheric transport for periods of 1 day to

about a week, and will travel varying distances depending on meteorology and precipitation frequency. The

form in which it is deposited depends on the chemistry

described above. Ultimately, dry-deposited S02 and sulfate may also produce acid on the surface of the Earth

following oxidation and combination with available

water (e. g., dew).

Atmospheric Chemistry of Oxides of Nitrogen

Manmade NOX emissions result both from nitrogen

bound in fuels and from compounds formed from nitrogen and oxygen in the air during combustion. Anthro-
268 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure C-2.—Schematic Diagram of Possible Fates

of Emitted Sulfur Dioxide Gas

SOURCE: Office of Technology Assessment, modified from Finlayson-Pitts and

Pitts, OTA contractor report, 1982.

pogenic sources emitted about 21 million tons of NOX

in the continental United States during 1980. About 14

million tons were emitted in the Eastern 31-State region.

Additionally, natural sources produce several forms of

nitrogen compounds, primarily from soil processes, organic decay, and lightning. Natural sources of reactive

NO, emissions are estimated to produce less than 15

percent of total NOX emitted in the Eastern United

States. In North America as a whole, the natural background of NOX may represent 5 to 35 percent of the

total NOX produced.

Gas phase reactions of NOx have been studied for a

number of years because of their role in forming ozone

in photochemical smog. The importance of NOX as a

source of acid has only been investigated more recently.

Both ozone and nitric acid formation involve RHCs.

The homogeneous gas phase reaction leading to nitric

acid (involving the OH radical) occurs about 10 times

as rapidly as the corresponding reaction with S02

. Consequently, nitric acid formation and deposition should

occur at distances closer to the source, constituting more

of a local phenomenon than sulfuric acid deposition. A

recent modeling study of a very polluted area, the Los

Angeles basin, suggests that 40 percent of emitted NOX

are transformed into nitric acid over the course of 1 day.

Similar rapid conversion occurs in plumes from the

northeast moving over the Atlantic Ocean, a much less

polluted area.

In addition to nitric acid, other nitrogen-containing

species are formed in polluted atmospheres—e.g., peroxyacetylnitrate (PAN), a nitrogen-containing chemical

known to be toxic to plants. In the winter, when PAN

is less likely to be decomposed by heat, it may serve as

a reservoir for NOX

, allowing substantial transport

before either decomposition or deposition occurs.

Recent experimental evidence indicates that uncatalyzed aqueous phase reactions of NOX compounds are

too slow to be important under most atmospheric conditions. However, catalyzed aqueous reactions (e.g., due

to the presence of metals or surfaces) may proceed quickly and therefore be important.

Ozone

Ozone is regulated by National Ambient Air Quality Standards under the current Clean Air Act, and has

been the focus of most oxidant control studies. NOx

react with sunlight and hydrocarbon-produced radicals

to form ozone. Because ozone as well as its precursors

can travel substantial distances, ozone concentrations

downwind of emissions sources commonly exceed natural background levels.

Naturally produced hydrocarbons, including terpenes

from pine trees, and methane from termites and wetland

areas, can play a role in forming ozone. Also, additions

of ozone from the upper atmosphere (the stratosphere)

will contribute directly to observed levels. Such natural

contributions can result in ozone concentrations on the

order of 10 to 50 parts per billion (ppb), with common

background measurements of about 20 to 30 ppb. At

midlatitudes in the summer, natural ozone is augmented

by photochemical ozone produced when pollutant precursors react with sunlight. (See app. B, “Terrestrial

Resources at Risk From Ozone and Acid Deposition,

for seasonal ozone levels throughout the United States. )

Recent evidence2 suggests that air masses with very low

concentrations of NOX and RHC (by air quality standards) produce high ozone values in the mountains of

Colorado—up to or exceeding the ozone standard. Such

concentrations may be quite common in the rural Midwestern and Eastern United States; high ozone levels

may be produced at these sites, especially during the

summer.

‘F. C, Fehsenfeld, M. J, Ballinger, S, C. Liu, et al., ‘‘A Study of Ozone

in the Colorado Mountains, ” JournaJ of Amsospheric Chemistry, in press
App. C—Atmospheric Processes . 269

Some of the secondary pollutants (e. g., nitrous acid

and formaldehyde) formed along with ozone can themselves facilitate further ozone production. These secondary pollutants can remain in a stagnant air mass overnight and react in the presence of sunlight the next

morning.

IMPLICATIONS FOR CONTROL STRATEGIES

A nonreactive primary pollutant such as carbon monoxide (CO) emitted in an urban atmosphere does not,

on the time scale of 1 day, undergo significant chemical

reactions during diffusion, dispersion, and transport

processes. For this pollutant, reducing emissions by 50

percent will reduce CO concentrations in ambient air

by 50 percent. Thus, in California’s South Coast Air

Basin, although the number of vehicle miles traveled

has increased substantially over the last decade, exhaust

emission controls put on light-duty vehicles have reduced ambient CO levels..

However, primary pollutant emissions that can react

relatively rapidly in the air to form secondary pollutants

present an entirely different situation. Oxides of nitrogen and RHCs react in the presence of sunlight to form

ozone and a host of other secondary pollutants such as

formaldehyde, PAN, hydrogen peroxide, nitrous acid,

and nitric acid, along with respirable particles. In such

a complex system, the effect of reducing emissions is

not as easy to determine as in the case of CO, i.e., it

may not be ‘‘linear.

The term “linear‘‘ is used in connection with acid

deposition to indicate that a given percentage reduction

(or increase) in emissions would cause the same percentage change in acid deposition at a specific location.

However, a number of factors may cause emissions reductions (of SOX

, N OX, or RHC) at one location to

result in reductions in acid deposition that are not directly proportional at a particular site downwind. For example, introducing fresh supplies of NOX and RHC

(either individually or together) between controlled

sources and a receptor could increase or decrease quantities of acid (both nitric acid and sulfuric acid) deposited

at that site. In addition, the relative rates at which the

various chemicals are deposited (e. g., S02 v. sulfate)

may also influence the effect of emissions reductions on

acid deposition at a particular location.

One of two possible fates occurs to sulfur and nitrogen

pollutants: 1) oxidation to sulfuric and nitric acids (or

sulfates or nitrates), followed by deposition at the Earth’s

surface; or 2) deposition in their emitted form (i. e., unchanged). In the latter case, chemical oxidation on the

Earth’s surface may cause the same net result—i.e.,

acidification.

Elevated concentrations of oxidizing chemicals such

as ozone and hydrogen peroxide are found in atmospheres containing anthropogenic emissions. However,

it is possible that at certain times and places, the amount

of S02 or NOX may exceed the supply of available oxidants in the atmosphere; when the supply is exhausted,

additional acid cannot be made in the air until more

oxidants become available. This would tend to delay

acid deposition until the pollutants travel further downwind. Such conditions of ‘‘saturation’ are thought to

be episodic, and can generally be discounted in regional

descriptions of transport and deposition.

Until recently, it had been assumed that “natural”

water would have an acidity level, or pH, of about 5.6

(a pH of 7.0 being neutral, O to 7 being acidic, and 7

to 14 basic), due to atmospheric carbon dioxide dissolved

in it. However, even ‘ ‘clean’ atmospheres contain a

host of other chemical constituents as well, which can

interact to produce solutions more or less acidic than

a pH of 5.6. For example, it has been shown recently

that rainwater pHs of less than 5 might be expected in

‘ ‘clean air’ environments under certain conditions

when naturally produced sulfur and chlorine compounds

are present (e. g., in coastal environments).

In determining whether the oxidation of SOX and

NOX will actually cause acids to be deposited, the availability of neutralizing species such as ammonia and

calcium (e. g., from windblown dust) must also be considered. Sufficient quantities of neutralizing species will

reduce the actual acid formed in the atmosphere. Thus,

while two sites may be subjected to identical concentrations of anthropogenically produced sulfate and nitrate,

quite different levels of acid may be deposited if significant concentrations of neutralizing species are available

at one location, but not at the other.

The ultimate effect of the deposited compounds, however, is of prime concern. Nonacidic sulfates are probably less damaging to materials than acid sulfates.

However, these compounds could eventually act to acidify a natural ecosystem. For example, if ammonia combines with sulfates, the deposition will not be acidic. Yet

ammonia, when used by plants and micro-organisms

in soils, produces acidity, which can subsequently affect soils, lakes, and streams.

Altering Emissions of Primary Pollutants

Characterizing the “chemical soup” of the atmosphere at any specific location requires integrated information on the concentrations of all pollutants, the availability of oxidants, the predominance of gas or aqueous

phase chemistry, and detailed meteorological information. The complexities involved in the various chemical

and physical processes allow OTA to make only a very

general description of the effect of changing emissions

of various pollutants. The discussion refers to regional-
270 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

level response over time, and should not be interpreted

as applying to particular episodic events or specific receptor sites.

REDUCING REACTIVE HYDROCARBON EMISSIONS

If NOX concentrations remain at a freed level, reducing RHC emissions subsequently reduces ozone concentrations, by decreasing production of the free radicals

necessary for ozone production. The peak ambient concentrations of ozone are then expected to be lower.

The only mechanism for producing nitric acid believed to be significant in urban areas and powerplant

plumes is the oxidation of NO2 by the hydroxyl radical

(and possibly by ozone) to produce other oxides of nitrogen which then form nitric acid. Reducing concentrations of RHC would lower the concentrations of the free

radicals as well as of ozone; this should slow down the

rate at which NOX is oxidized to nitric acid. This slowing could in turn cause nitric acid formation and deposition over a larger geographical area, but at lower concentrations.

Reducing RHC emissions will similarly reduce the

rate of gas phase oxidation of S02

. The rate of liquid

phase oxidation by hydrogen peroxide may also decrease

because its formation rate is proportional to the concentration of OH radicals. The effect on other liquid phase

transformations of S02 are difficult to assess but are currently thought to be insignificant.

REDUCING NITROGEN OXIDES EMISSIONS

The question of how decreasing NOX emissions while

keeping RHC emissions constant would affect ozone

levels is much more controversial than questions associated with the effects of RHC control. This is because

the effect of reducing NOX emissions depends on the

resulting ratio of hydrocarbons to NOX

. Figure C-3

shows how ozone levels change with varying levels of

NOX and hydrocarbon emissions. Thus, when the ratio

of RHC/NOX is greater than indicated by the diagonal

line in figure C-3 (i.e., for the right lower portion of

the diagram), reducing NOX emissions reduces ozone

concentrations. However, at lesser ratios (i. e., for the

upper left of the diagram), reducing NOX emissions

while holding RHC levels constant, leads to increases

in ozone concentrations. *

Figure C-3 implies that in the vicinity of emissions

centers like downtown Los Angeles, where the RHC/

NOX ratio is less than that of the diagonal line, reducing NoX emissions might increase ozone concentrations

slightly. However, over an entire air basin, including

regions several hundred kilometers downwind, reduc-

● Peak ozone levels decrease because at higher NOX concentrations, a larger

portion of the available free radicals react with NOZ to form nitric acid, and

become unavailable for the chain reactions leading to ozone formation.

ing NoX emissions should decrease ozone concentrations overall. Since NO2 is the sole precursor to anthropogenic ozone, this must hold true over a large region.

Because NOX concentrations affect the availability of

hydroxyl radicals, decreasing NOX emissions may

change the oxidation rate of S02

. The change probably

also depends on the RHC/NOX ratio, but is poorly

understood at present. However, reducing NOX concentrations, regardless of the ambient hydrocarbon concentration, decreases the NOX available for nitric acid

formation and deposition.

REDUCING REACTIVE HYDROCARBON AND

NITROGEN OXIDES EMISSIONS

SIMULTANEOUSLY

Smog chamber and modeling studies (fig. C-3) show

that simultaneous control of both RHC and NOX—

keeping their concentration ratio constant—would reduce ozone concentrations. As mentioned above, less

nitric acid formation is also expected since the reduced

NOX limits how much acid can be formed. In this case,

the oxidation rate of S02 is also likely to be reduced.

REDUCING SULFUR DIOXIDE EMISSIONS (ALONE)

Available knowledge of atmospheric chemistry suggests that if: 1) there is no shortage of oxidizing agents

(i.e., saturated conditions do not prevail); 2) levels of

RHC and NOX remain constant; and 3) deposition

processes and meteorology remain constant, reducing

S02 emissions will reduce the total amount of acid

formed in the atmosphere. Furthermore, given these

conditions, a decrease in S02 emissions should decrease

the atmospheric formation of sulfuric acid by an approximately equal proportion.

REDUCING SULFUR DIOXIDE EMISSIONS

CONCURRENTLY WITH REACTIVE

HYDROCARBONS AND NITROGEN OXIDES

There are substantial uncertainties in even qualitatively predicting how simultaneously reducing S02

,

NOX

, and RHC emissions from given sources would

affect acid deposition at a distant receptor site. Altering the concentrations of RHC and NOX in an urban

plume that interacts with S02 from a powerplant plume

may well alter the amount of acid deposition at a particular downwind location, but the meteorological and

chemical factors involved are so complex that no reliable

quantitative estimates can be made at the present time.

For example, changing RHC and NOx emissions

without changing S02 emissions could affect the deposition of sulfuric acid at a given location by changing the

concentrations of available oxidants needed for converting S02 to sulfate. Further effects could arise if alterations in RHC and NOX concentrations affected the pH
App. C—Atmospheric Processes . 271

Figure C-3.—Typical Ozone Concentrations Formed From RHC-NOX Mixtures

Oxidant/0 3, ppm

0.08 0.200.30 0.400.50 0.55 0.60 0.6 5

of existing cloud droplets, e.g., through the formation

and dissolution of nitric acid in the cloud. For the

aqueous phase oxidation of S02

, in which the major

processes are pH-dependent, changes in cloud acidity

levels could change the rate of sulfuric acid formation.

If the net result of changed RHC and NOX emissions

is faster conversion of S02

, sulfuric acid will form and

be deposited closer to sources. If the concentrations of

RHC and NOX are altered such that less oxidizing material is initially available, sulfuric acid is deposited further from emission sources. Therefore, alterations in the

rate of oxidation could change the amount of acid deposition to a specific location, but not the total amount

of sulfur deposited (e. g., the sum of S02 and sulfates)

over the entire downwind area. The sulfur emitted will

eventually return to the surface at some point. If NOx

and RHC emissions are decreased such that their ratio

remains constant while S02 emissions are decreased,

total deposition of both sulfuric and nitric acid will

decrease and total ozone production will decrease.

INCREASE NITROGEN OXIDES, HOLDING

HYDROCARBON AND SULFUR DIOXIDE

EMISSIONS CONSTANT

This scenario is likely to occur without major changes

in current air pollution control regulations. Future increases in NOX levels are projected (primarily from utilities and the industrial sector), while S02 emissions are

projected to remain fairly constant or increase slightly

over the next 20 years (see app. A). Chamber studies

show that increasing NOX from very low levels, holding

RHC levels constant, causes peak ozone concentrations

to increase. As NOX levels are further increased, ozone

concentrations reach a maximum and then decrease

with further increases in NOx (see fig. C-3).

The concentrations of other nitrogenous pollutants

such as nitrous acid also generally increase with increased NOX

. Increasing NOX emissions while S02

emissions are held constant will augment local acid deposition due to nitric acid. Since emitted NOX are oxidized more readily than S02 in the gas phase, increas-
272 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

ing NOX concentrations may expand the geographical

area over which sulfur deposition occurs.

Source-Receptor Relationships

A major goal of atmospheric science is to predict for

a given pollution source, the dose of pollutants at a

specific location downwind, and how changes in that

source’s emissions would change the pollutant burden

at the receptor site. Source-receptor relationships are

determined by the location and nature of the primary

pollutant emissions (e. g., S02

, NOX, RHC) and by associated meteorological, chemical, and physical processes that occur as the pollutants travel from the source

to the receptor. Current long-range transport models

that incorporate sophisticated meteorology (i. e., those

used in the Canadian-American Work Group effort

under the Memorandum of Intent) attempt to simulate

chemical conversions of S02 to sulfate by assuming that

the complex set of chemical processes will balance out

over time and distance to approximate a constant average rate of transformation. This simplifying assumption

makes regional-scale calculations tractable; crude source

regions and receptor regions can be identified for sulfur

compounds. Because they are linear models, reducing

emissions in source regions results in a proportional

reduction of deposition in receptor regions. These models appear to characterize the current situation for wet

deposition fairly well. They use actual emissions as input, and can reproduce observed levels of regional wet

sulfate deposited within a factor of 2.

The first attempt to incorporate multiple chemical

reactions involving NOX

, S02

, and RHC into a longrange transport model—called the Rohde model—contains 19 chemical equations but virtually no meteorology. Three of the equations concern sulfuric or nitric

acid production. Sixteen of the equations describe the

gas phase photochemistry associated with the RHC/

NOX systems, ozone, hydroxyl radical, and hydrogen

peroxide—all compounds involved in actually forming

the acid. All of the aqueous and heterogeneous phase

reactions are combined into one simplified equation.

This model assumes that dry deposition decreases in

proportion to emissions. However, it predicts that reducing emissions might cause wet deposition to decline

less than proportionally -e.g., a response 60 percent as

great. *

Recently, a Committee of the National Academy of

Sciences altered the chemistry in the Rohde model to

incorporate new laboratory results. It found that the new

assumptions greatly reduced the nonlinearity in the rela-

“See appendix C.2, “Source-Receptor Relationships, ” for further explanation. Note that OTA specified the model with conservative assumptions; subsequent runs using different background concentrations for pollutants over time

show that wet deposition may respond more directly to emissions reductions.

tionship between ambient S02 concentrations and ambient sulfate concentrations. Using currently available

data, the NAS report concludes that, “there is no evidence for strong nonlinearity in the relationships between long-term average emissions and deposition.

Very specific source-receptor relationships cannot be

defined unless the behavior of all other pollutants is

known. Given the complexity of the atmospheric chemistry alone, as well as the need to develop detailed emission inventories (especially for NOX and RHC), and inherent meteorological variability, it is unlikely that a

definitive model integrating S02

, NO2, and RHC will

be developed in the next decade or two. Decisions to

control or not to control precursor emissions over this

time period will have to be made without the benefit

of such precise information.

Selected References

The following list of references includes recent review

articles and several very recent key papers that may not

be included in the review articles cited.

Barrie, L. A., ‘‘The Prediction of Rain Acidity and S02

Scavenging in Eastern North America, Atmospheric

Environment 15:31-41 (1981).

Calvert, J. G. (cd.), Acid Precipitation: SOZ, NO, and

N02 Oxidation Mechanisms: Atmospheric Considerations (Ann Arbor, Mich.: Ann Arbor Science Publishing, Inc., 1982).

Culvert, J. G., and Stockwell, W. R., “The Mechanism

and Rates of the Gas Phase Oxidations of Sulfur Dioxide and the Nitrogen Oxides in the Atmosphere,

Acid Precipitation: S02, NO, and N02 Oxidation

Mechanisms: Atmospheric Considerations (Ann Arbor, Mich.: Ann Arbor Science Publishing, Inc.,

1982).

Chamberlain, J., Foley, H., Hammer, D., MacDonald,

G., Rothaus, O., and Ruderman, M., “The Physics

and Chemist~ of Acid Precipitation, Technical Report No. JSR-81-25, prepared for the U.S. Department of Energy, September 1981.

Chameides, W., and Davis, D. D., “The Free Radic~

Chemistry of Cloud Droplets and Its Impact Upon

the Composition of Rain, J. Geophys. ~es. 486,

1982.

Charlson, R. J., and Rodhe, H., “Factors Controlling

the Acidity of Natural Rainwater, Nature 295, 683

(1982).

Eldred, R. A., Ashbaugh, L, L., Cahill, R. A., Flocchini, R. G., and Pitchford, M. L., “Sulfate Levels

‘Acid Deposition, Atmospheric Processes in Eastern North America, Committee on Atmospheric Transport and Chemical Transformation in Acid

Precipitation, National Research Council (Washin@on, D. C.: National

Academy Press, 1983).
App. C—Atmospheric Processes ● 273

in the Southwest During the 1980 Copper Smelter

Strike , paper submitted to Science.

Electric Power Research Institute, Aircraft Measurements of Pollutants and Meteorological Parameters

During the Sulfate Regional Experiment (SURE)

Program, EPRI Report EA-1909 (Palo Alto, Calif.:

Electric Power Research Institute, 1981).

Finlayson-Pitts, B. J., and Pitts, J. N., Jr., “The

Chemical Basis of Air Quality: Kinetics and Mechanisms of Photochemical Air Pollution and Application to Control Strategies, Advan. Environ. Sci.

Technol. 7, 975 (1977).

Graedel, T. E., and Weschler, C. J., “Chemistry Within Aqueous Atmospheric Aerosols and Raindrops,

Rev. Geophys. Space Phys. 19, 505 (1981).

Hegg, D. A., and Hobbs, P. V., “Oxidation of Sulfur

Dioxide in Aqueous Systems With Particular Reference to the Atmosphere, “ Atmos. Environ. 12, 241

(1978).

Hoffman, M. R., and Jacob, D. J., “Kinetics and

Mechanisms of the Catalytic Oxidation of Dissolved

Sulfur Dioxide in Aqueous Solution: An Application

to Nighttime Fog Water Chemistry, Acid Precipitation: S02, NO, and NOP Oxidation Mechanisms:

Atmospheric Considerations (Ann Arbor, Mich.:

Ann Arbor Science Publishers Inc., 1982).

Larson, T. B., “Secondary Aerosol: Production Mechanisms of Sulfate Compounds in the Atmosphere,

Ann. N, Y. Academy of Sciences 338, 12 (1980).

Martin, L. R., ‘ ‘Kinetic Studies of Sulfite Oxidation

in Aqueous Solutions, “ Acid Precipitation: S02, NO,

NOP Oxidation Mechanisms: Atmospheric Considerations (Ann Arbor, Mich. : Ann Arbor Science

Publishers, Inc., 1982).

National Research Council, Acid Deposition, Atmospheric Processes in Eastern North America, Committee on Atmospheric Transport and Chemical Transformation in Acid Precipitation (Washington, D. C.:

National Academy Press, 1983).

Oppenheimer, M., ‘ ‘The Relationship of Sulfur Emissions to Sulfate in Precipitation, Atmos. Environ.,

in press.

Platt, U., and Perner, D., “Detection of NOt in the

Polluted Troposphere by Differential Optical Absorption , Geophys. Res. Lett. 1, 89 (1980).

Platt, U., Perner, D., and Kessler, C., “The Importance of N03 for the Atmospheric NOX Cycle From

Experimental Observations, paper presented at the

2d Symposium on the Composition of the Nonurban

Troposphere, Williamsburg, Va., May 25-28, 1982.

Platt, U. F., Pitts, J. N., Jr., Biermann, H. W., and

Wirier, A. M., ‘ ‘Spectroscopic Measurements of the

Nitrate Radicals at Four Rural Sites in Southern California: Implications for Acid Precipitation,

manuscript in preparation.

Rahn, K. A., “Elemental Traces and Sources of Atmospheric Acidity for the Northeast—A Statement of

New Evidence, ” Statement of Nov. 3, 1981; “Tracing Sources of Acid Rain Causes Big Stir, note in

“Research News” section of Science, February 1982.

Rodhe, H., Crutzen, P., and Vanderpol, A., “Formation of Sulfuric and Nitric Acid in the Atmosphere

During Long Range Transport, ” 7’eilus 33, 132,

1981.

Russell, A. G., McRae, G. J., and Cass, G. R., “Acid

Deposition of Photochemical Oxidation Products—

A Study Using a Lagrangian Trajectory Model,

paper presented at the 13th International Technical

Meeting on Air Pollution Modeling, Toulon, France,

Sept. 14-18, 1982.

Spicer, C. W., ‘‘The Distribution of Oxidized Nitrogen

in Urban Air, ” Scie. Total Environ. 24, 183 (1982).

Tuazon, E. C., Wirier, A. M., and Pitts, J. N., Jr.,

Environ. Sci. Technol. 15, 1232, 1981.

U.S. Environmental Protection Agency, “The Acidic

Deposition Phenomenon: Transformation Processes, chapter A-5 in the Critical Assessment Document entitled ‘‘The Acidic Deposition Phenomenon

and Its Effects, draft copy, May 10, 1982.

Waldman, J. M., Murger, J. W., Jacob, D. J., Flagan,

R. C., Morgan, J. J., and Hoffmann, M. R.,

“Chemical Composition of Acid Fog, ” Science, in

press.
274 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

C.2 SOURCE-RECEPTOR RELATIONSHIPS

Introduction

Broad regions of North America receive acidic deposition both in wet form—acid rain—and as dry deposition of acidic substances. Because acidifying substances

reach the Earth from the atmosphere both through removal by rainfall and as directly deposited gases and

particles from the air, the term acid rain is misleading.

The acidity of rainfall per se is generally considered less

significant than the quantity of ‘acid-producing’ substances added to the environment—onto soils, vegetation, and materials, and, after passing through watersheds, into lakes and streams. The term acid-producing

substances as used in this report refers to sulfur oxides

(SOX

) and nitrogen oxides (NOX) and other substances

that have the potential for producing acidity, although

they may not be deposited in an acid form. For example, sulfate can be deposited in a neutral form—ammonium sulfate—but end up as sulfuric acid by the time

it reaches a lake or stream if the ammonium is used by

plants in the watershed.

The chain of physical and biological processes from

emissions of pollutants to eventual deposition of acidproducing substances in the environment is complex and

not fully understood. However, several lines of evidence

can be combined to express the likely relationship between emissions and deposition.

Acid deposition results from both local and distant

sources of SOX and NOX

, Current scientific understanding suggests that reducing sulfur dioxide (S02

) emissions throughout the Eastern 3 l-State region would

reduce the deposition of acid-producing substances; but

that this will occur in the areas sensitive to acid deposition cannot be stated with certainty. For the Eastern

United States, no other control strategy offers greater

potential for reducing acid deposition than reducing S02

emissions. While curbing other pollutant emissions

could be considered simultaneously, and might ultimately be necessary to achieve a desired level of deposition

reduction, most scientists would focus initial attempts

to control acid deposition on S02

.

By considering preliminary information drawn from

several alternative approaches, one can piece together

a plausible relationship between pollutant emissions and

deposition of acid-producing substances. This appendix addresses four key issues. The discussion begins with

regional-scale deposition of acidifying substances, and

then identifies the major constituents of deposition and

the relative magnitude of current sources. Model-based

estimates of how pollutant emissions from parts of the

Eastern United States affect deposition in other areas

are then discussed. Two complementary modeling approaches are used to estimate the magnitude of potential reductions in acid-producing substances reaching

the environment due to reductions in S02 emissions.

Finally, the analysis addresses the question of whether

these potential reductions in acid-producing substances

might be enough to meet ‘‘target’ deposition rates to

protect sensitive resources.

Current Deposition of

Acid-Producing Substances

The best information on patterns of acidic deposition—both its chemical composition and spatial distribution over affected parts of North America—comes from

monitoring networks collecting rainfall samples. Though

wet deposition may account for only about half the deposited SOX and NOX

, ” dry-deposited gaseous and particulate pollutants are not monitored extensively enough

to determine their precise distribution. This discussion

focuses primarily on acid-producing substances deposited through precipitation.

The balance of chemical species originating from such

natural sources as seaspray, windblown soil, and carbon dioxide in the air, and such manmade sources as

SOX and NOX pollutants, determine the acidity of rainfall. Rainfall acidity can be decreased either by removing acid-producing substances, or by adding acidneutralizing substances. The major acid-producing

substances in rainfall in the Eastern United States are

S OX and NOX from both natural and manmade

sources. However, the presence of these substances in

rainfall does not necessarily indicate acidity since they

can be counterbalanced by such airborne acid-neutralizing substances as calcium and magnesium from soil

and ammonium from natural sources and fertilizers.

Patterns of acidity, sulfate, and nitrate deposition in

rainfall over Eastern North America are mapped in

figures C-4 through C-6. Figure C-4 presents the deposition of hydrogen ions—the substance actually measured

to determine acidity. More than 40 milliequivalents per

square meter per year (meq/m2

/yr) of hydrogen ions are

● Most long-range transport air pollution models estimate that dry deposition is about equal to wet deposition when averaged over the Eastern United

States. The ratio of dry to wet deposition varies with distance away from sources

of pollution, with ratios on the order of 8 to 12 in areas with high S02 concentrations, to about 0.2 to 0.4 in the Adirondack Mountains (D. Fowler, “Removal

of Sulphur and Nitrogen Compounds From the Atmosphere, Ecological Impact of Acid Precipitation, SNSF project, October 1980. A.H. Johannes, et

al., “Relationships Between Wet Deposition, Dry Deposition and Throughfall Chemistry, ” Air Pollution Control Association Annual Meeting, New

Orleans, June 1982.
App. C—Atmospheric Processes ● 275

milliequivalents per square meter)
276 Acid Rain and Transported Air Pollutants: Implications for Public Policy

per square meter)

SOURCE: Impact Assessment, Work Group 1, United States-Canada Memorandum of Intent on Transboundary Air Pollution, final report, January 1983.
App. C—Atmospheric Processes . 277

Figure C6.—Nitrate in Precipitation During 1980

(weighted by precipitation-milliequivalents per square meter)

●

SOURCE Impact Assessment, Work Group 1, United States-Canada Memorandum of Intent on Transboundary Air Pollution, final report, January 1983
278 Acid Rain and Transported Air Pollutants: Implications for Public Policy

deposited over broad regions of the Eastern United

States, in contrast to deposition rates under 10

meq/m2

/yr throughout much of the West. The highest

deposition rates exceed 80 meq/m2

/yr, and are centered

around eastern Ohio, western Pennsylvania, and northern West Virginia.

Of the major acid-producing substances in rainfall,

only two originate in substantial amounts from

manmade sources in the Eastern United States: sulfates

and nitrates. The patterns of deposited acidity and

deposited sulfate (fig. C-5), are quite similar. A larger

part of the Eastern United States receives deposition in

excess of 40 meq/m2/yr. The highest deposition rates

again exceed 80 meq/m2

/yr, centered in about the same

region. Nitrate deposition patterns are similar (figs. C-5

and C-6), but deposition rates are about one-half those

for sulfur. More than 20 meq/m2

/yr of nitrates are

deposited over broad regions of the Eastern United

States, with peak deposition exceeding 40 meq/m2

/yr.

About two-thirds of the total sulfate and nitrate

deposited in the Eastern United States is sulfate.

By comparing figures C-4 through C-6, one can see

that the deposition of acid-producing substances (sulfate

and nitrate) exceeds the deposition of acidity by about

25 to 50 percent; this portion of the sulfate and nitrate

is neutralized by such other constituents as calcium and

ammonium.

Reducing sulfate deposition might be the most likely

way to begin reducing the deposition of acidity, given

that about twice as much sulfate as nitrate is present

in rainfall. Similar patterns are assumed to occur for

dry deposition of acid-producing substances, but far

fewer observations are available to substantiate this.

The most significant indicator for assessing alterations

in lake- and stream-water quality is the acidity of water

after it flows through a surrounding watershed—i.e.,

the total amount of acid-producing substances that eventually reach and travel through aquatic environments.

Figure C-7 illustrates the relationship between the quantity of acid-producing substances in rainfall and the

quantity of acid-producing substances in water flowing

out of a watershed. Figure C-7A shows that the amount

of sulfate leaving a watershed is about equal to, and in

many cases greater than, the amount entering a watershed in rainfall, when averaged over a period of one or

several years. That more sulfur leaves a watershed than

enters from rainfall is probably due to the amounts that

enter as dry-deposited gases and particles.

For nitrogen-containing substances such as nitrate

and ammonium (as shown in fig, C-7 B), the picture is

different. Only about one-third of the nitrogen entering a watershed from rainfall leaves the watershed. If

the nitrogen input from dry deposition is included, the

ratio of nitrogen leaving to nitrogen entering a watershed becomes even lower. As discussed in the forest

Figure C-7.—Sulfur and Nitrogen: Quantities in

Precipitation Versus Quantities in

Outflow From Watersheds

A: Annual input of SO~-

– S by precipitation versus the leaching

losses from forest watersheds and Iysimeters with forest soils. Solid

line is the regression line, dotted line is the 1:1 line.

resources section, these results might be expected—while

both nitrogen and sulfur are essential nutrients for forest

growth, most eastern forests require far greater inputs

of nitrogen than sulfur.

In summary, about twice as much sulfate is generally present in rainfall as nitrate. When considering the
App. C—Atmospheric Processes ● 279

acid-producing substances that travel through the environment (and effects such as altered lake- and streamwater quality), sulfate may predominate even more.

This can vary from region to region, and certainly varies

for short periods. For example, the nitrate component

of spring snowmelt can be as great as or even greater

than sulfate levels in some watersheds. However, over

broad regions on an annual time scale, sulfates comprise a much larger share of acid-producing substances

than nitrates.

Manmade and Natural Source

Contributions to Acidic Deposition

Relatively low background levels of acidic deposition

are thought to originate from natural sources (and

possibly global-scale transported air pollutants), when

averaged over large regions (e. g., the Eastern United

States or the North American Continent). This “natural

background” deposition of wet sulfur in North America

(excluding Mexico) has been estimated to be about 4

to 10 meq/m2

.

4 This is about 20 to 40 percent of the

average sulfur deposition from precipitation over all of

North America. Natural sources contribute relatively

smaller proportions in areas of highest deposition. Averaged over Eastern North America (east of the Mississippi and south of James Bay in Canada), natural background sources might contribute about 12 to 25 percent

of the total. Another group has estimated natural sources

of sulfur to be about 5 to 10 percent of manmade sources

in this same region. 5 Over parts of the Eastern United

States, where wet sulfur deposition exceeds 50 meq/m2

and is as high as 80 meq/m2 in some areas, the natural

background contributes even less.

This natural background comes from several different

sources: Husar estimates that 6 percent of the wet sulfur

deposition in North America originates from seaspray.

The Electric Power Research Institute (EPRI) has

estimated that about 5 percent of SO2 emissions originate from natural, biological sources.6 In addition,

geologic sources such as volcanoes are thought to contribute to natural background.

When averaged over the North American Continent,

the acid-producing potential of manmade SO2 emissions

far exceeds total wet sulfur deposition. The over 30

million tons of S02 emitted by manmade sources in

North America is 2.5 times total wet sulfur deposition

and 6 to 10 times the natural background. The portion

*R. B. Husar and J. M. Holloway, “Sulfur and Nitrogen Over North

America , presented at 1982 Stockholm Conference on Acidification of the

Environment

5Atmospheric Sciences and Anafysls, Work Group 2, United States-Canada

Memorandum of Intent on Transboundary Air Pollution, Final Report,

November 1982

cElectrlc Power Research Institute, “ Biogenic Sulfur Emissions m the SURE

Region’ EA-1516, 1980

of manmade sulfur that is not deposited in rainfall is

either deposited dry or exported off the continent.

Natural background is estimated to contribute similar

proportions of total wet nitrate deposition—about 20 to

40 percent when averaged over the North American

Continent, and about 10 to 25 percent when averaged

over Eastern North America.

The Relationship Between Current

Emissions and Deposition

One of the major controversies in the acid rain debate

is the effect that pollutant emissions from any source

(or group of sources) will have on ambient air quality

and pollutant deposition at some other location. The

relationship between emissions and deposition is determined by a complex chain of chemical and physical

processes that occur as primary pollutants (e. g., S02

)

are emitted, transformed into secondary pollutants (e. g.,

sulfates), transported, and finally deposited.

Computer models, called transport models, are used

to mathematically simulate the transformation,

transport, and deposition processes. Models describing

long-range transport of S0x have been available for

several years; preliminary models of NOX transport are

just now being developed. Transport models are the only

practical procedure available to estimate the relationship between areas of origin and areas of deposition for

long-range transport pollutants, unless newly developed

tracer techniques prove reliable. Large-scale regional

transport cannot now be measured directly for the large

number of sources of emissions and deposition regions

of interest, and under the variety of meteorological conditions needed to perform the analysis.

The major long-range transport (LRT) models describing SOX transport incorporate six atmospheric

processes:

1. release of emissions,

2. horizontal transport and dispersion,

3. vertical mixing of pollutants in the atmosphere,

4. chemical transformation,

5. dry deposition, and

6. wet deposition.

The models themselves are composed of submodels

which simulate chemical and physical processes within

these broader categories. The main data requirements

of LRT models are: emissions inventories of pollutants,

meteorological data, ground cover data, and a host of

values (parameters) representing chemical reaction rates

and other physical processes.

Eight LRT models were evaluated under the U. S.-

Canada Memorandum of Intent (MOI) on Transboundary Air Pollution; 7 results indicate that the models

7Atmospheric Sciences and Analysis, op cit,

99-413 0 - 84 - 1 9 s QL . 3
280 . Acid Rain and Transported Air Pollutants: lmplications for Public Policy

appear to reproduce large-scale patterns of observed wet

sulfur deposition. However, the size and quality of the

data base precludes a complete evaluation of LRT models at this time. *

This section presents modeling results to provide a

plausible description of the current relationship between

sources and deposition of SOX in the Eastern United

States. This is only one of the acid-producing substances

currently deposited; however, as discussed earlier, sulfate is currently the major acid-producing substance in

precipitation.

The model used in this analysis is the Advanced

Statistical Trajectory Regional Air Pollution Model

(ASTRAP) developed by Argonne National Laboratory

under DOE and EPA funding. The ASTRAP model

includes several components of the source-receptor

relationship not included in the other models. * *

OTA has used another model that incorporates more

realistic atmospheric chemistry and considers the effects

of co-pollutants such as NOX and hydrocarbons (but at

the expense of sophisticated meteorology), to assess how

the simplifying chemical assumptions used in ASTRAP

might affect its resulting projections. This comparison

indicates that the ASTRAP model might adequately

represent dry deposition of sulfur, but that variations

in ambient concentrations of other pollutants might significantly affect wet sulfur deposition. (These results are

discussed in the preceding subsection, “Atmospheric

Chemistry.”)

Because of its sophisticated treatment of the regional

patterns of emissions and meteorology, the ASTRAP

model can be used to investigate the current relationship between regions of S02 emissions and regions of

sulfur deposition. The model is best used in a relative

sense—e.g., estimating the proportion of deposition one

region contributes to another—rather than for projecting

the

the

not

the magnitude of deposition quantitatively: Again

following discussion of sulfur deposition describes

general pattern of current relationships, and must

be interpreted as making quantitative predictions.

“Even if the models were ‘ ‘perfect, ” one would expect the model simulations to deviate from the obsemations since the latter are influenced by both

the factors treated in the model and the factors that are not treated (e. g., smallscafe precipitation variations). In addition, part of the difference between model

simulations and observations is due to the inherent variability of the real world.

The model is of necessit y designed to simulate an average of the observations

whife the monitoring data base at this time is insufficient to calculate a representative average (i. e., the average over a number of years with similar emissions,

meteorological conditions, etc.),

● “The ASTRAP model includes: the abifity to account for seasonal differences

(the ASTRAP model simulates January and July average conditions); release

height of emissions; the use of detailed meteorological data; consideration of

vertical atmospheric processes in addition to horizontal movement; wet deposition rates that vary with rainfall intensity; and dry deposition rates that vary

temporally and spatially. The other models evafuated include some of these

components, but ASTRAP is the only model that includes all of them.

Acid deposition has often been characterized as ‘ ‘acid

in Adirondack lakes from powerplants in Ohio. The

ASTRAP model can be used to show that such statements are overly simplistic: pollutants do travel from

one region to another, but in all directions, not just west

to east. In addition, while pollutants can travel long

distances, emissions within a region contribute a large

share to total deposition in that region.

To illustrate these points, figure C-8 divides eastern

North America into four regions. The intersection of

the regions has been chosen to correspond to the area

of peak wet sulfur deposition in 1980. Figure C-8 also

displays the percentage of S02 emitted in each region,

and the percentage of total sulfur deposited (as simulated

by ASTRAP) in each of the regions. Sulfur dioxide

emissions are roughly comparable in the northeastern

region (I), southeastern region (II), and southwestern

region (III). Emissions in the northwestern region (IV)

are over twice the amount of any of the other regions.

Deposition is lowest in the southern regions (II and III)

and highest in the northern regions (I and IV).

Figures C-9 through C-12 show model-based estimates of: 1 ) the percentage of each region’s deposition

originating from within its borders, and from each of

the other regions; and 2) for deposition originating outside a region, the percentage of deposition traveling less

than 500 km, 500 to 1,000 km, 1,000 to 1,500 km, and

greater than 1,500 km.

For example, figure C-9 illustrates these relationships

in region I (the northeastern region). The pie chart in

the upper right projects that approximately 80 percent

of the deposition comes from emissions in two regions—

from within its own borders and from the northwestern

region in about equal amounts. The bar graphs placed

in regions II, III, and IV illustrate each region contribution to deposition in the northeastern region, according to its distance from the sources of emissions.

For example, the bar graph in the lower right shows

model estimates that 40 percent of the deposition coming from the southeastern region travels less than 500

km to its eventual area of deposition in the northeast;

another 40 percent travels between 500 to 1,000 km,

and the remainder travels over 1,000 km.

Figures C-9 through C-12 demonstrate the following

general observations:

1.

2.

3.

4.

All regions contribute to deposition in all other

regions.

At the spatial scale used in this analysis, each

region generates as much or more of its own deposition as any other single region contributes to it.

Substantial quantities of deposition originate from

sources over 500 km away.

Pollutants are transported further from west to east

and south to north than from east to west or north

to south.
App. C—Atmospheric Processes 281

Figure C-8.—1979 Sulfur Dioxide Emissions and Estimated Sulfur Deposition—Percent Contributed

and Received in Four Subregions Covering the Eastern Half of the United States

SOURCE” J Shannon, personal communication, Argonne National Laboratory and E. H. Pechan & Associates, Inc., 1982
282 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy
Figure C-10. —Deposition

PERCENT DEPOSITION FROM REGION IV TO II BY DISTANCE

PERCENT DEPOSITION FROM REGION Ill TO II BY DISTANCE

in Region II

PERCENT DEPOSITION FROM REGION I TO II BY DISTANCE

SOURCE: J. Shannon, personal communication, Argonne National Laboratory and E, H. Pechan & Associates, Inc., 1982
284 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

a

w
App. C—Atmospheric Processes . 285

1
286 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

The Effectiveness of Emissions Reductions

for Achieving Deposition Reductions

Assumptions concerning the physical and chemical

processes involved in transforming S02 to sulfate are

inherent in the use of regional-scale models such as

ASTRAP. Linear regional-scale models assume that

sulfate production is proportional to the concentration

of S02

. The source-receptor relationships described by

these models can simulate expected changes in deposition only to the extent that deposition would actually

change in linear proportion to changes in emissions.

While the preceding source-receptor relationships

may provide reasonable estimates of inter- and intraregion transport, they may not be reliable for developing control strategies unless chemical transformation and

deposition processes can be shown to behave in a linear

manner. This section first discusses linear model projections of the effects of different emissions scenarios and

then considers how the addition of more realistic atmospheric chemistry might alter the results.

OTA used the ASTRAP model to simulate atmospheric concentrations and surface deposition of sulfur

pollutants for three alternative levels of S02 emissions. *

These include: current emissions levels in the United

States and Canada; a representative 8-million-ton-peryear emissions reduction; and a representative IO-million-ton-per-year emissions reduction. * *

The model was used to simulate deposition levels during January and July, to investigate the effects of both

winter and summer conditions. Figure C-13 displays

model projections of how extensively both wet and dry

sulfur deposition would be reduced by a representative

10-million-ton reduction in S02 emissions. The reductions shown apply only to emissions originating in the

United States (i.e., deposition from emissions in Canada

are not considered). Similar projections for an 8-millionton reduction are shown in figure C-14. The pattern of

deposition reductions is similar for both scenarios.

Deposition is reduced by the greatest percentage in the

Midwest—the region with both the highest current emissions and the greatest reduction requirements under

both scenarios. Proportional reductions in deposition

decline with distance away from this region. Because

the ASTRAP model assumes a linear relationship between emissions and deposition, both scenarios show

● Personal communication, J. Shannon, Argonne National Laboratory,

December 1981.

● ● Senate bills S. 1706 and S. 1709 (97th Congress) were two of the earliest

legislative proposah to control acid deposition. S. 1706 (introduced by Senator

Mitchell of Maine) and S. 1709 (introduced by Senator Moynihan of New York)

were both referred to the Senate Committee on Environment and Public Works

October 1981. The State-level reductions specified by these bills were used as

the basis for the 10- and 8-million-ton reduction scenarios, respectively. These

scenarios assume that reductions in emissions from each point source within

a State are proportional to the reduction assigned that State in the OTA analysis

of these bills.

that total deposition is reduced almost in proportion to

reductions in total emissions when averaged over the

entire Eastern United States.

Assuming a linear relationship—i.e., that a specified

percentage reduction in emissions will lead to the same

percentage reduction in deposition—is a simplification

adopted for computational advantages. No one would

argue that this simplified relationship realistically

represents the complex transformations occurring in the

atmosphere. Over 100 chemical reactions may potentially play a role in transforming S02 to sulfate. Unfortunately, the chemical transformation process cannot be

completely evaluated at present, since important

elements of many of the equations are not known. The

importance of understanding the full ensemble of

chemical reactions cannot currently be evaluated. A

more pertinent question is: how accurately can a linear

relationship approximate these reactions over the large

time and space scales involved in regionwide emissions

and deposition?

Clearly the total amount of sulfur emitted to the atmosphere is eventually deposited; thus, ultimately,

reductions in deposition will approximate emissions

reductions. (Deposition from natural sulfur sources,

though small, would remain. ) The crucial question is

where sulfur deposition would be reduced—i.e., in

about the same regions as predicted by the linear models, closer to emissions sources, or further away?

To examine the linearity of the chemical transformation system, a second model, capable of simulating the

interactions of several pollutants that may affect sulfur

deposition, was run for OTA.8

This model, developed by Rodhe, et al. (1981), allows

a reasonable qualitative evaluation of pollutant interactions while remaining computationally tractable. The

model’s limited description of atmospheric mechanisms

(e. g., mixing of pollutants with surrounding air) could

affect its quantitative results. In addition, it does not

incorporate the meteorology necessary to describe complex patterns of deposition. Nonetheless, it represents

a useful step forward from linear modeling, by simulating chemical transformations that occur in the atmosphere, through a series of 19 chemical equations.

The Rodhe model can provide a qualitative picture of

how changes in other primary pollutant emissions—

principally reactive hydrocarbons (RHC) and nitrogen

oxides (NOX

)—might affect downwind sulfur deposition.

Dry sulfur deposition depends highly on the concentration of S02 in the atmosphere. Changing the concentrations of RHC and NOX might alter the rate at

which S02 is converted to sulfate, and change the reser6Perry J Samson, ‘‘On the Linearity of Sulfur Dioxide to Sulfate Conversion in Regional-Scale Models, OTA contractor report, June 1982.
App. C—Atmospheric Processes ● 287
288 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure C-14.– Estimated Deposition Following an 8-Million-Ton-per-Year Reduction in Sulfur Dioxide Emissions
App. C—Atmospheric Processes ● 289

voir of S02 available for dry deposition. However, the

model simulations indicate that dry sulfur deposition is

fairly insensitive to the NOX and RHC mixture in the

atmosphere. Figure C-15 illustrates this by showing how

much dry sulfur deposition changes per unit change of

primary pollutant concentrations as a function of time

downwind of a source region, as predicted by the Rodhe

model. It shows that, of the three pollutants considered,

S02 has by far the greatest effect on dry sulfur deposition. In addition, the figure shows that, for pollutant

travel times of less than 2 days, a given percentage

reduction in emissions appears to reduce dry sulfur deposition comparably. Thus, since most dry deposition occurs within this time period, omitting co-pollutants and

assuming a linear relationship in regional-scale models

such as A STRAP may be a reasonable assumption for

predicting changes in the dry sulfur component of deposition.

Wet sulfur deposition may respond to changes in

pollutant emissions differently than dry deposition. As

shown in figure C- 16, changing the initial amounts of

S02 by 50 percent might result in roughly a 30-percent

change in wet sulfur deposition. ● One must keep in

mind that these results are highly dependent on the

model’s approximation of chemical transformations in

clouds. Because such processes cannot yet be simulated

in detail, the accuracy of this result cannot be evaluated

at this time.

However, like dry deposition, wet sulfur deposition

is affected more by changes in S02 concentration than

by changes in other pollutant concentrations. Nonetheless, it should be noted that wet sulfur deposition is

relatively sensitive to changes in RHC. Reducing RHC

emissions could decrease wet sulfur deposition, although

the effect would not be as pronounced as equivalent reductions in S02

. The sensitivity of wet sulfur deposition to changes in NOX concentrations is less pronounced, but in the opposite direction—i.e., reducing

N OX emissions might lead to a small increase in wet

sulfur deposition. However, this increase might be offset by decreased dry sulfur deposition and reductions

in nitrate deposition.

The Rodhe model is not intended to estimate pollutant deposition quantitatively. It was employed to

evaluate pollutant interactions qualitatively and assess

how they might affect dry and wet sulfur deposition.

The results suggest that wet sulfur deposition is relatively

sensitive to the mix of RHC and NOX, while dry sulfur

deposition is not.

‘This estimate is for 1 ) relatively high initial concentrations of pollutants,

such as those found in the Ohio River basin during pollution episodes, and

2) an ‘‘average’ rainfall event ( 1 hour at 1 mm/hr) 24 hours downwind of the

source.

An analysis performed by a committee of the National

Research Council/National Academy of Sciences9

(NAS) came to a similar conclusion. This committee

slightly modified the Rodhe model used by OTA to reflect some recent laboratory results and to change some

assumptions about mixing of chemicals in the atmosphere. Their results suggest that the role of NOX and

RHC are somewhat less important than indicated by

the “worst-case” assumptions used by OTA.

Both the OTA and NAS analyses suggest that if

reducing total sulfur deposition is a desired goal, reducing S02 emissions would likely be an effective strategy.

The NAS report concludes,

If we assume that all other factors, including meteorology, remain unchanged, the annual average concentration of sulfate in precipitation at a given site should

be reduced in proportion to a reduction in S02 and sulfate

transported to that site from a source or region of sources.

If ambient concentrations of NOX, nonmethane hydrocarbons, and basic substances (such as ammonia and calcium

carbonate) remain unchanged, a reduction in sulfate deposition will result in at least as great a reduction in the

deposition of hydrogen ion.

“Target” Deposition Rates

To Protect Sensitive Resources

The previous discussion considered only the extent to which decreasing S02 emissions by 8 million

and 10 million tons per year in the Eastern 31 -State

region would reduce total sulfur deposition. No attempt was made to relate these estimates to preventing potential damage to sensitive resources. At least

three separate groups have estimated deposition

‘‘targets’ ‘—i.e., levels of deposition below which

sensitive lakes and streams are not expected to further acidify. * *

The Impact Assessment Working Group established under the U.S. -Canada Memorandum of Intent on Transboundary Air Pollution suggested the

first of these targets. 10 Both the U.S. and Canadian

members agreed that for North America:

There have been no reported chemical or biological effects for regions currently receiving loadings of sulphate

in precipitation at rates less than about 20 kg/ha-yr

[kilograms per hectare per year]. Evidence of chemical

change exists for some waters in regions currently

estimated or measured to be receiving about 20-30 kg/hayr sulphate in precipitation . . . . Long-term chemical

‘NRC INAS, Acid DepositIon. Atmospheric Processes in Eastern North

America, National Academy Press, Washington, DC,, 1983

● *OTA estimates of the effects of changes m deposluon on acid-altered aquatl{

resources are presented In app B Rather than presenting specltic deposition

targets to prevent aclddication of sensltwe resources, the effects of three scenarios

of changes in wet sulfur deposition are discussed

I o~mpact Assessment, work croup 1, U S -Canada Mmmandm of intent on Transboundary Am Pollution, Finaf Report, January 1983
290 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure C-15.—Changes in Wet Sulfur

1.0

0.8

0.6

0.4

0.2

0.0

–0.2

–0.4

–0.6

–0.8

– 1.0
App. C—Atmospheric Processes ● 291

Figure C-16. —Changes in Dry Sulfur Deposition
292 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

and/or biological effects and short-term chemical effects

have been observed in some low alkalinity surface waters

experiencing loadings greater than about 30 kg/ha-yr.

Based on these observations, the Canadian members of

the group proposed that

. . . deposition of sulfate in precipitation be reduced to

less than 20 kg/ha-yr [about 18 lbs/acre-yr] in order to

protect all but the most sensitive aquatic ecosystems in

Canada.

The U.S. members concluded that based on the current status of scientific understanding about the mechanisms that lead to surface water alteration, ‘‘it is not

now possible to derive quantitative loading/effects

relationships. *‘

A recently published National Research Council/National Academy of Sciences (NAS) report uses the acidity of precipitation, rather than the concentration of

sulfates, to specify a level that would protect sensitive

freshwater ecosystems.11 NAS states:

It is desirable to have precipitation with pH values no

lower than 4.6 to 4.7 throughout such areas, the value

at which rates of degradation are detectable by current

survey methods. In the most seriously affected areas

(average precipitation pH of 4.1 to 4.2), this would mean

a reduction of 50 percent in deposited hydrogen ions,

Evans, Hendrey, Stensland, Johnson, and Francis

presented a third estimate in a recent paper.l2 This

group states:

For aquatic ecosystems, current research indicates that

establishing a maximum permissible value for the volume

weighted annual H+ concentration of precipitation at 25

ueq/1 may protect the most sensitive areas from permanent lake acidification. Such a standard would probably

protect other systems as well.

This last estimate is quite similar to the National

Academy estimate; a H+ concentration of 25 ueq/1 is

equal to a pH of 4.6.

Maps of the decrease in wet sulfur deposition required

to reach each of these targets can be derived from the

measured deposition levels presented in figures C-4 to

C-6. The three statements can be summarized into four

plausible targets:

1. 20 kg/ha (42 meq/m2

) wet sulfate,

2. average precipitation pH of 4.6 (25 ueq/1 H+

),

3. average precipitation pH of 4.7, and

4. 50-percent reduction in H+ (hydrogen ion) deposited in rainfall.

It should be noted that these target values all use wet

deposition as a surrogate for total (wet plus dry) deposition, because of the larger data base from which to draw

comparisons to ecological effects.

1 f NRCIN.AS Atmospfsere.ll;oSplsere Interactions: Toward a Better

Understanding of the Ecological Consequences of Fossil Fuel Combustion, National Academy Press, Washington, D. C,, 1981,

121.. S. Evans, et al , ‘ ‘Acidic DepositIon: Considerations for an Air Quality

Standard, Water, Air and Soil Pollution 16, 1981, pp. 469-509,

Several assumptions are required for calculating the

reductions in sulfate deposition necessary to reach the

last three target values. First, if wet sulfate levels are

reduced, a corresponding quantity of hydrogen ions (in

absolute units, not percentage) must be eliminated to

preserve the required charge balance. Second, one must

assume that other ions, especially neutralizing ions such

as calcium and ammonium, will remain at constant levels. Both assumptions are reasonable simplifications

given the current chemical constituents in rainfall.

Figures C-1 7 to C-20 present maps of the percentage

decrease in wet sulfur deposition required to reach the

four deposition targets. These figures are derived from

1980 data—a year in which the annual precipitation was

about average in most regions. Figure C-17 estimates

regional wet sulfur-deposition reductions needed to meet

the first target value (20 kg/ha wet sulfate). Figure C-1 7

shows that to reach this target, wet sulfur deposition

would have to be reduced by about 50 percent in the

areas of heaviest deposition, and by over 30 percent

across broad regions of the Eastern United States.

Figures C-18 and C-19 show the wet sulfate-deposition reductions needed to meet target values of average

rainfall pH of 4.6 and 4.7. The more stringent target

of pH 4.7 requires greater than 70-percent decreases in

areas of highest deposition. The less stringent target

of pH 4.6 would require reductions about 10 percent

smaller in the peak deposition areas; the required reduction drops by a larger percentage in areas of lower deposition.

Figure C-20 displays wet sulfate deposition reductions

needed to meet target 4—a 50-percent reduction in hydrogen ion concentration in precipitation. The peak

reductions required are on the order of 50 percent, with

broad regions of the Eastern United States requiring wet

sulfate reductions of 40 percent to reach this target.

Errors in sampling and chemical analysis lead to uncertainty about the position of the mapped lines showing required decreases of wet sulfate. These errors,

which might be on the order of 10 percent, would translate into uncertainty about the position of the lines by

about 50 to several hundred km,

Year-to-year weather variations could also shift the

position of the lines on the maps. For comparison, projections of decreases in wet sulfur deposition necessary

to meet target values 3 and 4 are shown in figures C-21

and C-22. These projections are based on 1979 data,

rather than on 1980 data. For both target calculations,

the 1979 data show lower required reductions, with the

peak reductions shifted to the northeast. It is not possible to determine how much of the difference is attributable to sampling error, the smaller number of sampling

stations operating in 1979, or differences in weather

patterns.
App. C—Atmospheric Processes 293

Figure C-17. —Target Value: Wet Sulfate Loadings of 20 kg/ha-yr

Estimated percent reduction in wet sulfate deposition necessary to reduce wet sulfate loadings

to less than or equal to 20 kg/ha-yr (1980 data)

SOURCE: Office of Technology Assessment
294 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure C-18.—Target Value: Average Precipitation pH of 4.6
App. C—Atmospheric Processes . 295

Figure C-19.—Target Value: Average Precipitation pH of 4.7

Estimated percent reduction in wet sulfate deposition necessary to

greater (1980).

99-413 - 84 - : QL. 3
296 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure C-20.—Target Value: 50°/0 Reduction in Hydrogen Ion Deposition

Estimated percent reduction in wet sulfate deposition so that hydrogen ion deposition is

reduced by 50 percent (1980 data).
App. C—Atmospheric Processes ● 297

Figure C-21 .—Target Value: Average Precipitation pH of 4.7

This figure illustrates the estimated percent reduction in wet sulfate deposition necessary to

reach the same target value as in fig. C-19—average precipitation pH of 4.7 or greater—however,

the estimates are based on 1979 data.
298 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure C-22.—Target Value: 50°/0 Reduction in Hydrogen Ion Deposition
App. C—Atmospheric Processes . 299

As figures C- 17 through C-22 illustrate, the range of

reductions required to reach each of the four targets—

and the same target in two successive years—varies considerably. However, these figures permit some general

qualitative statements to be made about the wet sulfate

reductions needed to reach the suggested targets.

In regions of highest deposition, target deposition

reductions range from 50 to 80 percent. For New

England, deposition reductions required to reach the

targets vary from about 30 to 70 percent. For sensitive

areas south of the peak deposition region (e. g., the

southern Appalachians in Tennessee), wet sulfur-deposition reductions needed to reach the targets are on the

order of 20 to 50 percent. In the upper Midwest (e. g.,

the lake regions of Wisconsin and Minnesota), deposition would have to be reduced by O to 40 percent to

reach the targets.

The previous section characterized the uncertainties

inherent in using models to predict deposition reductions resulting from emissions reductions. Plausible

model-based estimates of how much both wet and dry

sulfur deposition might be reduced by an 8-million to

IO-million-ton-per-year reduction in S02 emissions were

presented. Because the deposition targets are expressed

as decreases in wet sulfur deposition, and due to the

large uncertainties in both sets of analyses, the deposition reductions that might result from reducing S02

emissions can only be compared tentatively to the deposition reductions required to meet targets for protecting sensitive resources. In areas of highest deposition,

for example, western Pennsylvania, the suggested target

reductions to protect sensitive resources might not be

achievable with an 8-million to 10-million-ton reduction in S02 emissions; in areas of lower deposition, such

as northern New England, the southern Appalachians

and the upper Midwest, the target deposition reductions

might be achievable with S02 emissions reductions of

this magnitude.

Thus, the uncertainties about reaching target deposition levels are greater in those areas that receive most

of their sulfur deposition in wet form (e. g., the Adirondack Mountains). As discussed above, for a given level

of S02 emissions reductions, the reduction in wet deposition may be less than for dry deposition. Moreover,

changes in wet sulfur deposition resulting from a given

change in S02 emissions may also depend on levels of

such co-pollutants as NOX and RHC.
Appendix D

Existing Domestic and

International Approaches

D.1

D.2

D.3

INTERSTATE AND INTERNATIONAL

PROVISIONS OF THE CURRENT CLEAN AIR ACT (p. 300)

INTERNATIONAL PROGRAMS FOR

CONTROLLING EMISSIONS OF SULFUR DIOXIDE (p. 305)

MITIGATING THE EFFECTS OF

ACID DEPOSITION ON AQUATIC ECOSYSTEMS (p. 312)

D.1 INTERSTATE AND INTERNATIONAL

PROVISIONS OF THE CURRENT CLEAN AIR ACT

Provisions in the existing Clean Air Act (CAA) address both interstate and transboundary pollution; however, the effectiveness of these statutory mechanisms

is subject to question. The act also provides affected parties with a means to seek remedy for interstate pollution not adequately regulated by existing control programs. It does not directly provide other nations a

means of remedy for transboundary (international) pollution; however, actions taken by the previous administration under the act’s international provision may

have created a right to legal recourse. In addition, avenues other than the CAA could potentially be pursued

to remedy transboundary pollution.

Interstate Pollution Control and the

Clean Air Act

The Environmental Protection Agency (EPA) and the

courts have taken action under the interstate provisions

of the CAA to abate interstate air pollution resulting

from local sources. However, considerable uncertainty

exists over how these provisions should be interpreted

with regard to longer range transported air pollutants.

EPA currently takes the position that analytical techniques addressing transported pollutants are not reliable

for regulatory purposes; the courts have yet to rule on

this issue. The statutory language of the interstate provisions does not provide a direct means of controlling

acidic deposition.

The NAAQS SIP Process

The CAA requires that States adopt implementation

plans to: 1) attain and maintain national ambient air

quality standards (NAAQS) within their borders and

2) prevent significant deterioration (PSD) in areas already meeting NAAQS. Section 110 also specifically requires that State implementation plans (SIPS)

include provisions prohibiting any stationary source

from emitting pollutants that would prevent attainment

and maintenance of NAAQS or interfere with PSD

measures in another State. The Administrator may not

approve a SLP that does not comply with these interstate

control requirements.

Utility of the interstate Provision for

Controlling Transported Air Pollutants

LIMITATIONS OF SECTION l o

Section 110 has several limitations for controlling interstate pollution: It applies only to air pollution, and offers no direct means of controlling acidic

deposition. It gives little guidance as to how much interstate air pollution is prohibited, and does not outline

the level of proof of causation required to substantiate

regulation by EPA. As written, the section leaves open

such questions as: 1) whether pollution must be linked

to individual sources to justify control, and 2) whether

analytical techniques (including models) that estimate

the relationship between emissions from ‘‘source’ re300
App. D—Existing Domestic and International Approaches 301

gions and the resulting air quality of “receptor’ regions

can be used to justify regulating individual sources.

Finally, the section applies only to stationary sources;

it does not control mobile-source emissions.

THE INTERSTATE PROVISION AS APPLIED BY EPA

Since section 110 was enacted in 1977, EPA

has initiated no review of SIPS to assess their compliance

with the provision. The agency has issued no regulations to spell out how a State can determine if its SIP

complies with section 11 O(a)(2)(E). EPA has reviewed

and approved a number of revisions to SIPS since 1977,

but the agency has not articulated definitive policies for

determining whether an individual source relaxation

complies with section 11 O(a)(2)(E). Current EPA procedures, however, limit the scope of SIP review to that

portion of the plan undergoing revision. Hence, where

SIP revisions propose emissions relaxations for individual plants, EPA considers only the local air quality impact resulting from the change in emissions for these

plants.

EPA also has taken the position that there are no adequate tools to assess long-range transport effects, and

EPA practices reflect this position. First, in reviewing

emissions 1 imitations with respect to the interstate provisions, the agency only considers impacts that can be

estimated by models approved under its modeling guideline. This effectively limits consideration of impacts to

within 50 km of the source, because there are no approved models to estimate long-range transport impacts. Second, the agency does not consider potential

impacts of the transformation products of the pollutant

for which a SIP relaxation is being considered. For example, the agency reviews the interstate effect of a sulfur

dioxide emissions relaxation solely for its impact on sulfur dioxide air concentrations in downwind states. However, sulfur dioxide also is transformed to particulate

sulfates in the atmosphere. Sulfates cause visibility degradation, and contribute to total suspended particulate

(TSP), for which there are national air quality standards. EPA does not consider the effect of increased sulfur

dioxide emissions on total suspended particulate levels

or on visibility.

REMEDIES FOR INTERSTATE POLLUTION

UNDER THE CLEAN AIR ACT

CAA currently contains two means of remedy for interstate air pollution. The first relies on general judicial review provisions under section 307 allowing

litigants to challenge EPA actions. The second initially

relies on administrative review provisions under section 126, allowing States and political subdivisions to

petition EPA on matters dealing specifically with interstate pollution. Since 1977, a number of suits and petitions have been filed under these provisions of the act

to remedy interstate air pollution. Early actions sought

remedy for interstate air pollution in situations where

pollutants were traceable to individual sources in the

near vicinity. In later actions, attention has shifted from

the ‘ ‘local-source problem’ and focused on interstate

pollution allegedly caused by long-range transport.

JUDICIAL REMEDIES: SECTION 307 SUITS

INVOLVING THE TRANSPORTED AIR POLLUTANTS

States and other litigants seeking remedies for interstate pollution have challenged EPA approval of SIP revisions for single sources under section 307 of the act.

In these suits, litigants have attempted to obtain judicial

review of EPA’s practice of not addressing regional

emissions through the SIP process. They also have attempted to compel EPA to use models and other techniques to assess long-range transport effects.

Litigants have advanced the following reasons for

challenging EPA approval of the SIP revisions: 1 ) the

Administrator failed to properly review the long-range

effects of the individual source for which a relaxation

was approved; 2) EPA failed to consider the air quality

impacts of the transformation products of sulfur dioxide;

and 3) the Administrator failed to review the whole SIP

to determine whether the cumulative emissions of

sources governed by the SIP do not cause pollution in

violation of section 110.

SECTION 126: THE ADMINISTRATIVE

PETITION PROCESS

Section 126 is a companion section to 110.

It requires States to provide notice to nearby States of

sources that ‘ ‘may significantly contribute’ to air pollution in excess of NAAQS. In addition, it provides an

administrative remedy for interstate pollution through

petition to the EPA Administrator. The section provides

in part that:

. . . a State or political subdivision may petition the Administrator for a finding that any major source emits or

would emit any air pollutants in violation of the prohibition of section 110 .

Within 60 days of receipt of a petition, the act requires

the Administrator to hold a public hearing and either

make such a finding or deny the petition.

PETITIONS UNDER SECTION 126 SEEKING

REMEDY FOR TRANSPORTED AIR POLLUTANTS

States seeking remedy for interstate pollution caused

by the long- range transport of emissions from multiple sources have fried section 126 petitions in tandem

with suits under section 307. At least nine petitions of
372 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

the State of New York, and the petitions of Pennsylvania

and Maine, have been consolidated into a single proceeding, which places before EPA the gamut of issues

involved in the long-range transport controversy.

The consolidated petitions claim that sulfur dioxide

and particulate emitted by sources governed by SIPS

in Illinois, Indiana, Kentucky, Michigan, Ohio, West

Virginia, and Tennessee are causing interstate pollution in violation of section 110. The petitioners

allege that such pollution prevents attainment and maintenance of NAAQS for both total suspended particulate

and sulfur dioxide, and interferes with PSD requirements. Petitioners further allege that the conversion of

sulfur dioxide to particulate sulfates contributes to the

aforementioned problems and, in addition, that sulfates

present a hazard to health and cause acid rain, resulting

in damage to aquatic and terrestrial ecosystems. Maine

specifically claims that transformed products of sulfur

dioxide cause visibility degradation in the mandatory

Class I area of Acadia National Park in violation of the

act. These three States have asked that EPA review the

SIPS for long-range transport effects and have requested

major reductions in emissions in the Eastern United

States.

These States have presented extensive information on:

the air quality problems and alleged environmental

problems resulting from acid rain in their States; air

quality data and modeling results allegedly demonstrating that interstate pollution contributes significantly to

these problems; air quality models and analytical techniques available to assess the long-range transport of air

pollutants; the relative stringency of emissions controls

in the Midwestern States versus New York, Pennsylvania, and Maine; and finally, the different levels of

emissions limitations that petitioners claim are needed

to control interstate pollution.

Extensive comments have been filed concerning the

information presented by the petitioners and the issues

raised. Although the New York-Pennsylvania-Maine

petitions were filed between fall, 1980, and summer,

1981, as yet, EPA has issued no preliminary findings

in the proceeding. Six Northeastern States recently sued

EPA (March 1984) to rule on the outstanding petitions,

but no court action has yet been taken.

REVIEW AND REMEDIES UNDER SECTION 307, SIP

CHALLENGES, AND SECTION 126 PETITIONS

A recent court ruling suggests that the types of review

obtainable under judicial and administrative remedy

provisions may differ. EPA has asserted, and the Second Circuit Court of Appeals has ruled, that EPA is not

required to review the whole SIP for its compliance with

the Act when it reviews proposed revisions amending

only portions of the SIP. Accordingly, plaintiffs might

not be able to obtain review of an implementation plan

as a whole in the context of SIP revisions for individual

sources. Thus, section 126 administrative proceedings

may be the only way for States to seek remedy for pollution caused by cumulative emissions from all stationary

sources regulated by a SIP.

It is not clear what relief the petitioners could win in

the suits pending before the courts or in the section 126

proceedings before the agency; however, a wide range

of results is possible. Neither route offers a means to

compel direct control of acidic deposition. Litigants

under section 307 seeking EPA review of SIP relaxations might obtain court decisions requiring the agency

to consider long-range transport effects using ‘ ‘state-ofthe-art” techniques. The scope of the New York-Pennsylvania-Maine section 126 petitions is wider; the petitioners could, if successful, win a reversal of EPA SIP

review policies, leading EPA to require broad-scale reductions in emissions of sulfur dioxide and particulate

from Midwestern States.

An appeal from any EPA determination on the New

York-Pennsylvania-Maine section 126 petition could

come before the District of Columbia Court of Appeals.

Thus, in the absence of further congressional direction

to EPA and the courts on long-range transported pollutants, the appeals court could become the arbiter of

pollution-transport controversies between the Midwestern and Northeastern States.

Control of Transboundary Pollution:

The U.S.-Canadian Context

The problems of interstate and transboundary pollution control are strongly linked. Winds that transport

pollutants over State lines can also carry them across

the border between Canada and the United States, from

both sides. A number of mechanisms are currently in

place for resolving transboundary pollution issues.

Means of control are potentially available: 1) through

a bilateral accord, 2) under the CAA, and 3) under both

domestic common law and international law. The efficacy of these mechanisms to deal with transboundary

pollution depends substantially on the combined commitment of the United States and Canada to control

such pollution.

Diplomatic/Legal Context of the U.S.-Canadian

Transboundary Air Pollution Issue

The United States and Canada have a long history

of cooperation concerning environmental affairs and

joint commitments to principles for controlling transboundary pollution. Beginning with the Boundary Wa-
App. D—Existing Domestic and /international Approaches . 303

ters Treaty of 1909, the two countries have expended

considerable efforts to negotiate and/or arbitrate transboundary pollution problems, most recently in negotiations culminating in the 1978 Great Lakes Water

Quality Agreement. Both the U.S. Congress and the

executive branch have made repeated commitments to

bilateral research, consultation, and negotiations on

transboundary air pollution, as well as to the multilateral

Declaration of the U.N. Conference on the Human

Environment (Stockholm Declaration 1972), and the

1979 Economic Commission for Europe’s “Convention

on Long-Range Transboundary Air Pollution.

No agreement between the United States and Canada

directly governs transboundary air pollution; however,

cooperative activities have culminated in a Memorandum of Intent. 1 Under the Memorandum the two countries have agreed to begin negotiations to reach a bilateral accord. The Memorandum also states the two

countries’ commitments to take interim control actions.

Although the status of the Memorandum is unclear, it

does not appear to be legally binding on Canada or the

United States. Its force derives from the good intentions

of both countries.

The MOI also established several Work Groups to

prepare technical information as a background for conducting negotiations. Final drafts of three Work Group

reports— impact assessment, atmospheric sciences and

analysis, and emissions costs and engineering assessment—were released in February 1983.

U.S. Government officials state that reasonable progress toward reaching a bilateral accord is being made.

However, many Canadian officials are dissatisfied with

the progress made in the negotiations and, in 1982,

threatened to withdraw from the talks altogether.2 Federal and provincial Ministers of the Environment have

recently pledged to reduce sulfur dioxide emissions 50

percent (from 1980 levels) in Eastern Canada by 1994

and have urged the United States to do the same. Acidic

precipitation resulting from the long-range transport of

air pollution has emerged as one of the most significant

bilateral issues between Canada and the United States.

Transboundary Pollution Control

Under the Clean Air Act

SECTION 115

Congress adopted section 115 of CAA to provide a

mechanism for dealing with transboundary air pollu1 Memorandum of Intent between the Government of Canada and the

(;uvernment of the United States of America concerning Transboundar}, Air

Pollution, Aug 5, 1980

‘I. , Mosher, ‘ ‘Congress May Have to Resolve Stalled L’ S -Canadian Acid

Rain Negotiations, ,VatlonafJourrral, Mar 13, 1982, p 456, ‘ ‘Canada May

End Talks With U.S for Accord to Combat Acid Rain, The Wall Streer,Journal, June 16, 1982, pp 1-7, COl 3

tion. The section is invoked by the Administrator of

EPA on his own initiative or at the request of the Secretary of State. The Secretary must allege, or the Administrator must determine, that pollution emitted in

the United States causes or contributes to air pollution

that ‘‘may reasonably be anticipated to endanger public

health or welfare in a foreign country. The section provides that the Administrator can make such a determination ‘‘upon receipt of reports, surveys or studies from

any duly constituted international agency”; however,

it does not specify how the Secretary of State will be apprised of a problem.

Once the Secretary of State has requested the Administrator to activate the section 115 process, or the Administrator has made a finding of ‘endangerment, the

statute requires the Administrator to give formal notice

to the Governor(s) of the State(s) in which the emissions

causing the pollution originate. The Administrator must

take this step, however, only if he “determines the

foreign country receiving the pollution has given the

United States essentially the same rights with respect

to the prevention or control of air pollution occurring

in that country as is given that country by [section

1 15]. “ Thus the Administrator must make a determination of reciprocity y to trigger the mandatory duty under

section 115.

Section 115 relies on the SIP revision process as the

means to abate international pollution prohibited by the

section. Section 115 provides that notice given to the

governor constitutes a finding with respect to section

110(a)(2)(E)—i.e., that the State implementation plan

is inadequate to comply with the requirements of the

CAA and must be revised.

UTILITY OF SECTION 115 FOR CONTROLLING

TRANSPORTED AIR POLLUTANTS

Section 115 can be construed to permit the control

of transboundary pollution caused by acidic deposition.

However, the language of section 115 provides no guidelines on how to implement the section. It does not detail

the procedures for the Administrator to follow in identifying which State or States are the source of the transboundary emissions, and offers no guidance on allocating control responsibilities when emissions from more

than one State create transboundary problems. The legislative history of section 115 is also silent on these issues.

EPA’s current practices for reviewing the SIP control of interstate pollution, if applied to transboundary

pollution, would limit the efficacy of section 115 for controlling possible acidic deposition and air pollution in

Canada. As yet, EPA has not chosen to activate the

transboundary pollution control provision of the act.
304 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

ACTIVITY UNDER SECTION 115

The Mitchell Request. —The Canadian Clean Air

Act was amended by unanimous vote in both Houses

of Parliament in December 1980 to provide clear authority for the Canadian Federal Government to take steps

to control the emission of pollutants affecting another

country. The amendment was designed primarily to

allow “mutual recourse between Canada and the United

States. ”

On December 23, 1980, Senator George Mitchell of

Maine sent letters to the Administrator of EPA and the

Secretary of State calling their attention to the recently

enacted legislation, and to reports prepared by the International Joint Commission (IJC) and the U.S.-Canada Research Consultation Group on Long-Range

Transboundary Air Pollution (RCG). The Senator reviewed the information in the reports and concluded his

letters with a strongly worded request that action be

taken under section 115.

The Costle Response: Determination To Activate

Section 115. —In January 1981, Administrator Costle

of EPA responded to the Mitchell request and sent letters to both the Senator and the Secretary of State announcing his findings, 3 He found, based on his review

of the IJC reports and CAA, that section 115 could be

activated to control acidic deposition in Canada. He also

determined that the Canadian Clean Air Act provides

Canada with authority to give the United States essentially the same rights as Canada under section 115, and

that at present Canada was so interpreting the act. He

noted that this second aspect of EPA’s determination

is necessarily a dynamic one and would continue to be

influenced by Canadian actions. Thus, having made the

requisite determination to activate section 115, the Administrator instructed EPA staff to begin work to identify which States should receive formal notification, and

to lay the groundwork to assist those States in appropriately revising their SIPS.

There have been no indications that the work initiated

by Administrator Costle is proceeding under the present EPA administration. As yet, section 115 notification has not been given to any State, and EPA appears

not to have continued the process leading up to notification. EPA has issued no statement, however, that reverses the Costle determination. No court has yet reviewed the legal significance of Costle’s action.

Remedies for Transboundary Pollution

RECOURSE UNDER THE CLEAN AIR ACT

The initial decision to activate section 115 clearly is

discretionary. Thus, the statute does not explicitly pro-

‘Letters from Douglas Costle, EPA Administrator, to Edmund Muskie,

Secretary of State, Jan 13, 1981, and to Senator George Mitchell, Jan. 15, 1981.

vide a course of action that Canada or others could pursue in domestic courts to remedy transboundary pollution. An argument can be made, however, that the

actions of former Administrator Costle ‘‘activated’ section 115 and created a legal obligation for the present

Administrator to revise SIPS to control acidic deposition in Canada.

Section 304 of CAA authorizes “any person” to bring

suit to compel the Administrator to perform nondiscretionary duties under the act. Under this citizen suit provision a number of different groups could bring suit to

compel action under section 115—among them are environmental organizations and Northeastern States that

might “benefit’ from activation of the section, The eligibility of Canada or the Province of Ontario to bring

suit is less clear. Section 302(e) does not specifically mention foreign governments, and the issue of whether foreign governments are considered to be ‘‘persons’ under

sections 302(e) and 304 remains unsettled.4 However,

standing to sue would not be a barrier to litigation by

plaintiffs having interests similar to those of Ontario or

Canada.

If a suit were initiated under section 304 to compel

the present Administrator to notify States under section

115 to revise their SIPS, a court could be faced with the

question of whether Costle’s determinations were arbitrary and capricious, or in excess of statutory authority

and, as such, unlawful. The present Administrator

would have the burden of convincing a court that the

previous Administrator’s determinations were invalid.

Since the statute gives the Administrator great discretion, and courts as a rule defer to administrative determinations, this would be a difficult burden to overcome.

RECOURSE THROUGH DIPLOMATIC CHANNELS

The Canadian Government could choose to link the

transboundary issue to other areas of bilateral concern

in an effort to encourage adoption of policies to reduce

the long-range transport of air pollution. Canada is an

important ally and neighbor. The United States’s involvement with Canada is probably greater than with

any other foreign country. The two-way trade is about

$77 billion, which is greater than that between the

United States and all the countries of the European

Community. The two countries are allies in NATO and

~It can be argued that foreign governments are considered to be ‘ ‘persons’

under sees 302(e) and 304. Sec. 302(e) could be construed as inclusive of possible litigants rather than defining the complete set. Such a construction was

placed on a similarly worded definition under the antitrust laws and thus the

definition in the statute was not a mandate to reverse the longstanding presumption that f’oreign nations are entitled to sue in courts of tbe United States Pfizer,

Inc. v. Government of India 434 U.S. 308 (1978). Accordingly the Court in

Pfizer found that India was a “person” within the meaning of sec. 4 of the

Clayton Act in spite of the fact that the section did not include foreign governments in the list of those authorized to sue.
App. D—Existing Domestic and International Approaches . 305

have a unique military joint command, the North Amer- In practice, however, domestic common law may not,

ican Air Defense Command. and international law does not, provide an effective

means to compel U.S. control efforts. In the case of

RECOURSE UNDER DOMESTIC COMMON LAW domestic common law, recent court decisions as well

AND INTERNATIONAL LAW as problems surrounding proof-of-causation may limit

In theory, domestic common law and international the use of this avenue; in the case of international law,

law also provide a means of legal recourse should Can- there are no effective means to enforce legal doctrines.

ada or others be dissatisfied with U.S. control efforts.

D.2 INTERNATIONAL PROGRAMS FOR

CONTROLLING EMISSIONS OF SULFUR DIOXIDE

As in the United States, air quality laws in Western

Europe, Canada, and Japan focus primarily on ambient

concentrations of air pollutants within the locale of emission sources, rather than on pollutant deposition. However, over the past decade, increasing awareness of acid

deposition as a potential problem has led several countries to develop and adopt further control policies. Working within the existing regulatory framework for controlling sulfur dioxide (S02

), Canada, West Germany,

and the Scandinavian countries have initiated further

S02 emissions limitations and restricted the level of

sulfur in fuel in order to address acid deposition.

European nations have established extensive cooperative monitoring programs to gather information on the

nature and extent of acid deposition and other transported air pollutants. Some accords dealing with transboundary pollution have been reached, and negotiations

are in progress in others.

This appendix describes the international organizations and accords that deal with transboundary pollutants. In addition, it outlines the existing policies of the

countries of Scandinavia, the United Kingdom, West

Germany, Canada, and Japan concerning acid rain and

transboundary air pollution.

International Organizations and

Accords Dealing With Transboundary

Pollution

Considerable international effort has been expended

to address transboundary air pollution and acid rain

over the last decade. At the urging of the Scandinavian

countries, transboundary pollution problems have been

discussed in such international forums as the U.N. Economic Commission for Europe (EC E), the European

Economic Community (EEC), and the Organization for

Economic Cooperation and Development (OECD);

these organizations have also launched research efforts

to study the problem. In March 1984, Environmental

Ministers from nine European nations and Canada

signed an agreement to reduce national sulfur dioxide

emissions at least 30 percent by 1993 in an effort to curb

transboundary air pollution. The countries signing the

agreement—referred to as the ‘‘30 percent Club —

were Canada, Austria, Denmark, West Germany, Finland, France, the Netherlands, Norway, Sweden, and

Switzerland. They also agreed to urge that other

signatories to the Convention on Long Range Transboundary Air Pollution of the UN Economic Commission for Europe (ECE) take similar action.

Economic Commission for Europe (ECE)

and the Convention on Long-Range

Transboundary Air Pollution

The ECE, comprised of all European United Nations

(U. N.) members plus Canada, the United States, and

the U. S. S. R., is one of five regional economic commissions of the U. N. It began to address the transboundary pollution issue as early as 1969, when a working

group on air pollution recommended reducing SO2

emissions. ECE negotiations began in 1977, with Sweden and Norway pressing members to, at a minimum,

hold S02 emissions to current levels, and to lay the

groundwork for abating S02 levels by a fixed percentage.

In 1978, the Committee of Senior Advisors to the

ECE established the Special Group on Long-Range

Transboundary Air Pollution, instructing the group to

draft proposals for the consideration of future senior

advisory sessions. Extensive negotiation produced a convention substantially modified from that originally proposed by the Nordic countries; the modified convention
306 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

was accepted at a high-level meeting of the ECE in

November 1979. The ECE convention was the first multilateral agreement to address specifically the problem

of transboundary air pollution caused by long-range

transport, and was the first major environmental accord

involving the nations of Eastern and Western Europe

and North America.

The accord requires the signing countries to develop

policies and strategies ‘‘as far as possible’ to reduce air

pollution gradually, including long-range transboundary

air pollution, employing “best available technology

which is economically feasible. The convention defines

long-range transboundary pollution as pollution traveling to another nation from such a distance that ‘‘it is

not generally possible to distinguish the contribution of

individual emission sources or groups of sources.

While the convention clearly addresses acid deposition,

it mandates no emission limitations. Since the convention does not establish numerical goals, limits, or timetables, or contain enforcement provisions, the signing

countries do not have to alter their pollution-control policies unless they choose to do so.

However, the convention is important as a basis for

coherent research and international management of

transboundary pollution. The signatories agreed to

cooperate in conducting research on control technologies, monitoring and modeling techniques, and effects

of air pollutants (e. g., sulfur compounds) on human

health and the environment. The ECE countries agreed

to exchange information for advancing international research efforts such as data on emissions and results of

domestic research efforts, and further agreed to support

the ongoing international monitoring program established by the U.N. Environment Program. This program has established monitoring sites to measure S02

and particulate sulfate in the air, and acidity in

precipitation, with stations in some 20 European

countries.

The European Economic Community (EEC)

The EEC was formed in 1957 and presently includes

ten European countries of the Common Market—West

Germany, France, Italy, Belgium, the Netherlands,

Luxembourg, Ireland, the United Kingdom, Greece,

and Denmark. The EEC was formed initially to deal

with economic issues among member countries; however, it has also been used as a forum for discussing international air quality issues. While the EEC has never

directly addressed the long-range transboundary air pollution issue, it has developed and issued directives dealing with S02 emissions generally. A directive on the sulfur content of certain liquid fuels was issued in 1975;

a directive establishing health protection standards for

S02 was submitted to the governing Council of Ministers for approval in 1976 and was finally adopted in

1980. The standards are relatively lenient by comparison

to current World Health Organization and U.S. standards. The directive requires that member countries

adopt measures to meet the standards by April 1983,

but allows nonattainment areas 10 years to achieve compliance.

The directive also requires countries to establish an

air-quality monitoring network, and establishes common procedures for the network and for exchanging data

and information. Although the EEC directive does not

directly address long-range transport and acidic deposition, the resolution accompanying the directive is an

indication of the EEC awareness and concern for these

issues. In language similar to the ECE Convention, the

resolution states that EEC members:

. . . will endeavor, in accordance with objectives of the

above mentioned Directive, and taking due account of

the facts and problems involved, to limit, and, as far as

possible, gradually reduce and prevent transboundary air

pollution . . .

The EEC directive is more significant as a symbol

of commitment to controlling transboundary and domestic air pollution than as a means of implementing

control measures for S02

. Less than 5 percent of EEC’s

land mass will exceed the health standard in 1983, Despite the goals of the EEC directive, it appears to do

little to further the role of either the EEC or its members

in reducing and preventing transboundary air pollution.

The Organization for Economic

Cooperation and Development (OECD)

The OECD was founded in 1961 as a ‘ ‘Western’ alliance for promoting economic growth. Its members include the United States, Japan, Canada, West Germany, the United Kingdom, and the Scandinavian

countries. Although all decisions within the OECD are

nonbinding, the Organization has been highly influential in developing international law and policy concerning transboundary air pollution. The OECD has also

produced some important research on transported air

pollution.

In 1972, the OECD established the “Cooperative

Technical Program to Measure the Long-Range Transport of Air Pollutants. The program measured S02

emissions in 11 European countries, as well as air concentrations of S02

, particulate sulfate, and sulfate in

precipitation. Computer models were used to estimate

domestic and foreign contributions to each country’s

sulfur deposition. The effort, coordinated by the Norwegian Institute for Air Research, was among the first

to rely extensively on long-range transport models; re-
App. D—Existing Domestic and International Approaches . 307

suits were published initially in 1977 and in an expanded

version in 1979. The study concluded that more than

half of the deposition in five countries was caused by

transboundary pollution.

The OECD has also produced reports on the legal

aspects of transboundary pollution. By adopting the

Principles Concerning Transfrontier Pollution the

OECD Council urged member countries to follow

guidelines in developing international law to deal with

transfrontier pollution. Specifically, the Principles recommend: 1 ) a country in which transboundary pollution originates should address the problem as it would

if the pollution occurred within its borders; 2) equal

rights should be granted to foreigners in administrative

and judicial proceedings; and 3) other nations should

be informed of actions that a country believes might increase transboundary pollution. In addition, the Council

also espoused the principle that the producers of pollution should pay for its control even when effects are felt

outside the country of origin.

The Nordic Environmental

Protection Convention

In 1974, Finland, Denmark, Norway, and Sweden

signed the Nordic Environmental Protection Convention. The convention essentially eliminates international

boundaries with respect to controlling pollution from

stationary sources, and can be construed to deal with

acid deposition from transboundary pollution. In many

respects the Nordic Convention resembles the principles

on transboundary pollution approved by the Council

of OECD. It provides that permit decisions for pollution sources should weigh any adverse effects the source

might have on a foreign country as though such effects

would occur domestically. The Convention also adopts

the principle that a foreigner has a right to institute proceedings in the country of emission concerning the permissibility of the emissions and to seek compensation

for damages.

Multilateral European Monitoring Efforts

international research efforts in Europe began over

a decade ago. Three monitoring networks have provided

information on air and precipitation chemistry on longrange transport of air pollutants: the European Atmospheric Chemistry Network (EACN), the Organization

for Economic Cooperation and Development Study on

Long Range Transport of Air Pollutants (OECD /

LRTAP), and the Economic Commission for Europe’s

cooperative program for monitoring and evaluating

transported air pollutants in Europe (EC E-EMEP).

The EACN, begun in 1950 by Swedish scientists,

consisted at its peak of 120 stations in 12 countries

analyzing air quality and wet deposition monthly. Data

from this network showed an expanding area with highly

acidic precipitation and led to the creation of OECD/

LRTAP, operating from 1972 to 1977.5

Results of OECD/LRTAP suggested that future studies should include all European countries. EMEP, organized under ECE, in cooperation with the United Nations Environment Program (UNEP) and the World

Meteorological Organization (WMO), was begun in

1977. Its main objective is to ‘ ‘provide governments

with information on the deposition and concentration

of air pollutants, as well as on the quantity and significance of long-range transmission of pollutants and

transboundary fluxes. 6

About 65 stations in 20 European countries are currently in operation. The monitoring sites have been

selected primarily to represent rural areas. The EMEP

sampling network relies principally on 24-hour sampling

of S02 and particulate sulfate in air, and sulfate and

acidity in precipitation. In addition, nitrate and ammonium in precipitation are measured in more than half

the countries. The EMEP program is projected to issue

semiannual reports for several years.

Approaches to SO2 Control in Canada,

Scandinavia, West Germany, the

United Kingdom, and Japan

CANADA

Acid rain has become a major public policy issue in

Canada. Particularly in the Eastern Provinces, there is

deep and widespread concern over the possible damage to Canadian lakes and forests, and to the extensive

tourist, recreational, and forestry industries they support. Due to transboundary transport of pollutants between the United States and Canada, acid rain has become a major issue in relations between the two

countries.

Total S02 emissions in Canada in 1980 were about

5.3 million tons a year, approximately one-fifth the

amount emitted by the United States. Most of these

emissions come from two source categories: nonferrous

smelters and coal-fired utilities. Although utilities contribute much less to Canada’s total S02 emissions than

smelters, Canadian powerplants could have a disproportionate effect on transboundary pollution because the

majority of plants are located close to the U.S. border.

Canada and the United States are formally committed

to developing a bilateral strategy to control transbound5

1. Granat, ‘‘Sulphate m Preclpltatkn as Obsen,ed by the European Atmospbcrlc Cbemmtry Network, ” Atmosphem- Ent,ronmenr 12, 413-424, 1978

‘H. Douland, ‘ ‘European Networks—Operation and Results, Sulfur /n (he

Atmosphere, Proceedings of an Intcrnatlonal S},mposlum In Dubrovnik, Yugoslavla$ Sept 7-14, 1977
308 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

ary air pollution. In August 1980, the two nations signed

a Memorandum of Intent (MOI) establishing five scientific and technological workgroups and pledging both

countries to formal treaty negotiations. Three of the five

workgroups under the MOI have completed their work

and released their results on February 22, 1983.

Canadian air pollution control programs tend to be

undertaken flexibly, with minimum use of formal legal

measures, emphasizing government/industry cooperation instead. The legal basis for controlling air pollution in Canada lies in its Clean Air Act, most recently

“amended in December 1980. Although the act now provides the Canadian Federal Government with the authority to control transboundary pollution originating

in Canada, the Federal role is mainly one of guidance

and demonstration to the relatively autonomous

Provinces.

The Canadian Clean Air Act of 1980 exhibits distinctive differences from, but important similarities to, the

U.S. Clean Air Act:7

●

●

●

●

●

●

The national ambient air quality objectives contained in Canada’s Clean Air Act, like those of the

United States, are concerned primarily with local,

ground-level effects, rather than regional or longrange transport impacts.

As in the United States, the act does not directly

address sulfates and nitrates (the main components

of acid deposition), because they are largely formed

in the air, rather than being emitted directly.

Unlike those of the U.S. Clean Air Act, Canada’s

Federal standards are only guidelines and are not

binding on Provinces. The Provinces have absolute discretion in the Canadian regulatory process.

The Provincial governments often negotiate with

industry to attain emissions reductions. Canadian

courts are not involved in this process.

Not all Provinces of Canada have adopted ambient

standards. Standards for those that have—Alberta,

Manitoba, New Brunswick, Ontario, and Saskatchewan—are far more stringent than the comparable U.S. primary standards.

Cost effectiveness is a major consideration in developing most Provincial air pollution control programs. Less costly measures, such as the use of lowsulfur coal, and dispersion techniques such as tall

stacks and siting, are the major means used to avoid

excessively high ambient concentrations from powerplants. No scrubbers are in use in Canada today.

The Canadian Clean Air Act empowers the Federal Government to set national guidelines only for

7

.—

G. Wetstone, “Review of Approaches to Long-Range Transport Control

m the United States, Canada, Europe, and Japan, report prepared by the

Environmental Law Institute for the OTA, March 1981

new sources and pollutants determined to have

health effects. These guidelines are not mandatory.

● In 1981, Canada passed a program for coal-fired

powerplants analogous to U.S. New Source Performance Standards. Other new sources are not as

stringently controlled; emphasis has focused on

controlling existing sources.

The Canadian Parliament, in December 1980,

amended the Canadian Clean Air Act to grant the Minister of the Environment authority to recommend sitespecific standards for sources ‘‘that may reasonably be

anticipated to constitute a significant danger to the

health, safety, or welfare of persons in another country . Provinces are given the first opportunity to enforce standards to “eliminate or significantly reduce”

transboundary pollution. The Government-in-Council

(essentially, the Federal Cabinet) may implement the

standards if the provinces have not acted expeditiously.8

In March 1984, federal and provincial Ministers of

the Environment agreed to reduce S02 emissions by 50

percent in eastern Canada by 1994, using 1980 as a base

case year.

Formerly, Canada had been committed to a 25 percent emissions reduction east of Saskatchewan by 1990

to be achieved primarily by controlling Ontario Hydro

and the International Nickel Co. (INCO) smelters.

Ontario Hydro, the provincially controlled utility system and largest aggregate source of utility emissions in

Canada, was to reduce total S02 and NOX emissions

43 percent from 1982 levels.

Ontario’s Government-in-Council (i.e., the Provincial Cabinet) restricted emissions from the largest single

source of Canada’s S02

, INCO’s massive smelters at

Sudbury, Ontario, to 1,950 tons/day in 1983. This represented a decrease from a maximum of 7,200 tons per

day in the late 1960’s.9

The control measures imposed on INCO, and Ontario Hydro may be changed when implementation

plans for the recent decision to reduce emissions 50 percent in eastern Canada are developed.

SWEDEN

Swedish authorities consider acidification to be the

most serious environmental problem of the decade, and

are continuing their efforts both in Sweden and internationally, to reduce acid deposition. Of about 85,000

Swedish lakes classified as medium to large in size, more

than 18,000 are currently acidified. About 4,000 of them

are very seriously acidified and have suffered extensive

biological damage. In about 9,000 lakes, mainly in

‘Clean Air Act 522.1, House of Commons 1st Session, 32d Parliament, 29

Elizabeth II, 1980, Bill 151.

‘Written communications from Bruce Jutzi, First Secretary, Embassy of Canada, Mar. 10, 1983, and Sept 13, 1983.
App. D—Existing Domestic and International Approaches ● 309

southern and central Sweden, damage to fish stocks

range from minor upsets in lifecycles to extinction of

trout and crayfish species. 10 Swedish scientists believe

that several thousand more lakes will be threatened if

acid deposition continues at present rates.

Sweden has decided to control its own S02 emissions

stringently, although it is estimated that 70 percent of

Sweden’s pollutant deposition originates from sources

outside the country. Since the early 1970’s, when the

problems of acidification first attracted notice, Sweden

has introduced emission controls that have lowered

emissions substantially in recent years. In 1970, S02

emissions in Sweden totaled about 450,000 metric

tons (tonnes). Currently, Sweden is emitting about

250,000 tonnes of S02 a year. New control limits for

powerplants effective October 1, 1984, will set maximum emissions of 0.24 gram of sulfur/megajoule of

fuel—about 1.1 lb SO2

/million Btu fuel burned. Nineteen of twenty-four Provinces in Sweden currently meet

that standard.

In the spring of 1981, the Swedish Parliament adopted

an interim measure limiting maximum emissions of sulfur from any installation to 1,600 tonnes/day. This emissions cap has required two flue-gas desulfurization

(FGD) units to be installed on a 400-megawatt (MW)

and 700-MW powerplant. The Swedish Parliament has

set a goal of reducing industrial sulfur discharges from

200,000 tonnes of S02 a year to half that amount by

1985. According to Sweden’s National Environmental

Protection Board, emissions probably will be reduced

to about 85,000 tonnes by 1985. A special committee

on coal, health, and the environment is currently preparing a report expected to lead to new proposals for

a much lower industrial emissions standard in the spring

of 1984.

Sweden has also embarked on an ambitious liming

program to restore acidified lakes. A total of 3,000 lakes,

3,000 kilometers of streams, and 500 watersheds have

been limed from the program’s inception through July

1983. Total program costs have reached $17 million to

date, including approximately $4 million to lime 500

lakes in fiscal year 1983. The program is financed by

a tax on fuel oil. Although liming has been shown to

be successful in temporarily preventing acidification and

restoring natural acidity to surface waters, the Swedish

Government has adopted the policy that liming is a stopgap measure and cannot substitute for controlling acidifying emissions at their source.11

NORWAY

Norwegian officials currently consider acid deposition

to be their single most significant pollution problem. Extensive acid-deposition damage has been found in

Southern Norway, where recent studies of 5,000 lakes

have shown losses of fish populations in 1,750 lakes, with

another 900 lakes projected to undergo serious acidification. As much as 90 percent of Norway’s acidic deposition has been estimated to originate from sources outside its borders—the highest estimated percentage of

pollution import of any European country.12

Overall emissions of S02 have been reduced in Norway following the enactment of new fuel-sulfur limitations in the late 1970’s. Under the Neighbor Act of 1961,

air pollution sources are required to use fuel oil with

a maximum sulfur content of 2.5 percent (about 2.7 lb

SO2

/million Btu). Amendments to the act in 1977 and

1979 imposed a maximum sulfur content of 1 percent

(about 1.1 lb S02

/million Btu) for all fuel oils used by

new sources or by expansions of existing sources. In addition, existing sources were required to reduce annual

S02 emissions by 20 percent from 1977 emissions levels.13 These more stringent requirements apply only to

the nine southern and most populated counties of Norway. Further reductions in S02 emissions are expected

over the next 5 years; however, Norwegians assert that

no national-level controls will be sufficient to rectify the

damage to their environment caused by acid deposition.

Norwegian concern over the effects of acid precipitation prompted major government-sponsored research

beginning in 1972. The multidisciplinary research project, entitled ‘‘Acid Precipitation—Effects on Forests and

Fish , culminated in an International Scientific Conference in March 1980 in Sandefjord, Norway. Norwegian officials believe that reports from this conference

conclusively link emissions of S02 to environmental

damage.

Over the past 10 years, the Norwegian Government

has worked to achieve a gradual reduction of total sulfur

emissions from the member countries of the ECE. This

goal was most recently articulated at the Stockholm 1982

Conference by Wenche Frogn Sellaeg, Norwegian Minister of the Environment, who called for: 1) reducing

sulfur emissions in the countries of Europe and North

America, and 2) ensuring that no new powerplant or

industrial source is constructed without effective controls on sulfur emissions.

12w~r,tt(.n ‘Ommunlca[lon from Stein Seeberg, Counselor, ROY~ No~egian

‘0’ ‘Acldlficatmn I“oday and Tomorrow, Swedish Ministry of Agriculture, Embassy, Sept 7, 1983

En\lronment 1982 Committee, 1982, pp. 50 and 130. ‘

3

’ Norwegian Strategies and Policles for the Abatement of Air PoHutmn

11~’rltten ~ommunication from Car] Johan Llden, Counselor, Embass) of Caused by Sulphur Compounds, .4 fajor Government Review of 1982, Oslo,

Swecien, Jan 7, 1983 June 1982
310 . Acid Rain and Transported Air Pollutants: Implications for Public Policy

DENMARK

Unlike other Scandinavian countries, Denmark contains large areas with soils capable of buffering the high

levels of acid deposition it receives. However, Danish

researchers have found evidence of lake acidification in

some poorly buffered areas. Acting on this evidence,

Federal and local government officials, along with power

company executives, have formed a task force to examine ways to reduce emissions of S02 and NOx

.

Denmark emits about 450,000 tonnes of S02 annually. Two-thirds of these emissions come from oilfired powerplants and oil-heated homes. Half of all

sulfur deposition in Denmark is thought to originate in

other countries, principally West Germany and the

United Kingdom.

Denmark is presently in the midst of major switches

from oil to coal use, but this fuel change is expected to

cause S02 emissions levels to decline. Oil containing up

to 2.5 percent sulfur has met over 80 percent of Denmark’s energy needs since the early 1970’s. The imported coal replacing the oil will have a much lower

sulfur content. However, maximum allowable sulfur

levels for coals have not yet been established.14

Denmark’s air pollution is regulated by the Environmental Protection Act of 1973. The act sets standards

for maximum sulfur levels for oils at 0.8 percent for light

oil and 2.5 percent for heavy oil (about 0.9 and 2.7 lb

SO2

/million Btu, respectively). A stricter limit of 1.0

percent for all oil was established in the metropolitan

area of Copenhagen. The act is implemented by municipal and county authorities under the guidelines of

the National Agency for Environmental Protection. The

act required major polluters to receive permits from the

municipal or county officials.

Although Denmark is mainly concerned with reducing emissions to levels that do not contribute to adverse

health conditions in the country, it is actively participating in developing international-level controls. Denmark cosponsored the draft proposal that led to the ECE

Convention on Long-Range Air Pollution in November

1979.15

THE FEDERAL REPUBLIC OF GERMANY

West Germany is the second largest producer of S02

in Western Europe, and is believed to be a substantial

contributor to acid deposition in Scandinavia. West Germany has established an ambitious air pollution control program. It is currently the only country in Europe

to rely on scrubbers to abate sulfur pollution from new

sources and presently operates eight FGD units.

I+ Written communication with Evy Jordan, Vice Consul, ROYd Danish Embassy, Oct. 1, 1982,

151bld

Air pollution in West Germany is regulated under the

Federal Emission Protection Act of 1974 (FIPA). Embodied in the Act are detailed nonbinding guidelines entitled ‘ ‘Technical Instructions for Air’ or TA-Luft. The

responsibility for meeting these requirements rests with

each State or “Lander.” Legislative proposals are under

consideration to make the TA-Luft legally binding on

the Landers.

The first phase of planned revisions to FIPA was approved by the Bundesrat on February 4, 1983. In particular, the new regulations reduce S02 emissions limits

for new sources by about 35 to 40 percent. It is estimated that this will reduce West Germany’s emissions

from electricity generation by 1 million tonnes by 1988.

West Germany emitted about 3.9 million tonnes of

S02 in 1982, primarily from coal-fired powerplants and

from industries burning oil and coal. West Germany

is also believed to receive substantial amounts of pollution from other nations: about half of the sulfur deposited in West Germany is estimated to be of non-domestic

origin.16

In recent years, environmental officials and the general public have become increasingly concerned about

the possible effects of acid deposition on German forests. 17 Because forestry is one of the country’s leading

industries, recent reports that air pollution—both local

and transported—is severely damaging the nation’s

pine, fir, and spruce trees have aroused major concern.

In response to this new evidence, the Federal Government has recently passed (July 1983) an ordinance on

large firing installations to reduce total S02 emissions

by 50 percent over the next 10 years. Additionally, West

Germany has recently shifted its position from opposing international accords to promote control of transboundary air pollution to willing participation in international efforts.

UNITED KINGDOM

The United Kingdom is the largest emitter of S02

in Western Europe and is believed by some scientists

to be the largest contributor to acid deposition in Scandinavia. An OECD study concluded that the United

Kingdom is a significant exporter of pollutants to downwind nations, and calculates that it is the largest contributor of acid deposition to Norway, as well as the

second-largest outside contributor of acid deposition to

Sweden, after West Germany.

Instatement by the Feder~ Republlc of Germany’s Interior Minister at the

“Conference on Acidification, ” Stockholm, June 27, 1982.

ITWrltten communication with Dedef Boldt, Aug. 23, 1982

16 Elam, “Present and Future Levels of Sulfur Dioxide Emissions in Northern Europe, prepared for the Swedish Ministry of Agriculture, June 1979,
App. D—Existing Domestic and International Approaches ● 3 1 1

Air pollution regulations in the United Kingdom date

back to the Alkali Act of 1863, and are based on the

concept of regulating emissions via the ‘ ‘best practicable’ means of control. The approach is designed to

allow flexibility and evolving standards as control technologies improve—a wide range of emission standards

are enforced by a central government inspectorate.

However, for SO2 and NOX emissions, Britain’s principal control strategy is dispersion. Backup strategies

include regional use of low-sulfur fuel, coal washing,

siting industrial plants in nonurban areas, and developing nuclear power. FGD is not used to control S02 in

the United Kingdom at the present time.

Britain relies on coal to produce almost 70 percent

of its electric power, and powerplants account for almost

60 percent of its total S02 emissions. Total S02 emissions in the United Kingdom have already declined during the past 10 years from 6 million to 4.5 million

tonnes; they are estimated to remain about constant or

possibly decrease slightly in the future.

The British Government takes the position that significant uncertainties exist about the atmospheric processes leading to acid rain formation and about its

reported effects. It asserts that more research is needed

before a firm case can be established for policies to further reduce S02 emissions. However, international action within the UNECE convention, the Stockholm 1982

Conference, and the EEC may influence future U.K.

policy with regard to transported air pollutants.19

JAPAN

Although Japan is not typically a focus of discussion

for long-range transported air pollutants, its stringent

control program and success in reducing ambient concentrations make it worth noting. Japan has the most

rigorous S02 control policies in the world. Control requirements are geared to an ambient standard of 100

μg/m3 for a daily averaging time, compared to the U.S.

standard of 365 μg/m3

. In 1981, 98 percent of the

monitoring stations in Japan met that standard. In 1974,

i ~~~,~,[(~n ~fl~~Un,c ~cl”~ from Mike Norton, F’mst Secretary, Embassyof

(jreat Britain, Aug ?0, 1982

Japan instituted an emissions fee for large S02 sources

in polluted areas. The proceeds are used in designated

areas for the medical care of patients affected by air pollution.

About 1,362 FGD units were in operation in Japan

during 1982. Most are small units installed primarily

on industrial plants producing chemicals or pulp and

paper products. Sixty-three of the units are installed on

powerplants, accounting for 40,000 MW of electrical

generating capacity. Unlike the United States and West

Germany, where coal-fired plants are the focus of FGD

controls, 29 of the Japanese units have been installed

on coal-fired boilers and 34 on oil-fired plants. 20

According to the Japanese Government, these FGD

units have not created a sludge disposal problem,

because such materials as gypsum produced by scrubbers have been highly salable in Japan. The use of FGD

was in fact promoted by the short supply of sulfur materials, creating a favorable market for these products.

However, rapid expansion in the production of these

goods has recently outstripped the market demand,

which may make scrubber-byproduct disposal a landuse problem. Other countries are now beginning to

follow Japanese techniques for regenerating FGD

sludge.

Government subsidies and the expansion of the Japanese economy have contributed to the rapid increase

of FGD use. The Government provides low-interest

loans and allows accelerated depreciation for facilities

that install control devices. The total investment in S02

control, including FGD and hydro desulfurization of oil,

was about $3.7 billion in 1977 U.S. dollars.

Ambient S02 concentrations have declined substantially in major urban areas as a result of the abatement

program. From a 1965 level of about 150 μg/m3

, the

1978 annual ambient average on a 24-hour basis

dropped to about 40 μg/m3

,

21 a figure comparable to

the 1978 urban ambient average in the United States.

20’ ‘Envlronrnent in Japan 1981 ,‘ Envlronmenl Agen{ y, (hJ\ernnlent t)f]apan, December 1981

21wrltten ~ommunlcatlon ~lth s~.ill Ikkatal, Se{ t)ncl Se( retary, F.mbass} ~jf

Japan, Feb 23, 1983
312 Acid Rain and Transported Air Pollutants: Implications for Public Policy

D.3 MITIGATING THE EFFECTS OF

ACID DEPOSITION ON AQUATIC ECOSYSTEMS

Introduction

Available strategies for controlling acid deposition and

its ecological consequences include both further controlling pollutant emissions at their source and mitigating

effects on sensitive resources—in particular, reducing

the acidity of sensitive lakes and streams. Ameliorative

measures such as liming affected lakes, streams, and watersheds have been proposed in several bills introduced

during the 97th and 98th Congresses. Research is also

underway on developing acid-tolerant strains of fish and

aquatic plant life.

Proposed emissions control strategies are likely to require several years from enactment to implementation.

“ Likewise, biological experimentation to develop acid-resistant aquatic life will require many years. Thus, few

prospects exist for a short-term solution to the acid deposition problem. Alleviating the symptoms of the problem—decreasing the acidity of soil or water and restoring normal buffering capacity by adding lime or

limestone— may save or restore many important recreational and commercial fisheries while long-term solutions are developed and implemented.

Important biological or chemical effects of acid deposition on water quality or fish populations have been

reported in New York, Massachusetts, New Hampshire,

Maine, Pennsylvania, West Virginia, North Carolina,

and Tennessee, as well as in Ontario, Quebec, and

Nova Scotia. Almost all States and Provinces in the

Eastern United States and Canada are thought to contain some sensitive surface waters, based on analyses

of their soils and geology.

The most sensitive lakes and streams generally are

located in areas that receive high levels of acid deposition, have steep topography, and are covered with thin

and poorly buffered soils. If these soils are depleted of

their limited capacity to neutralize incoming acidity,

acid accumulates in lakes and streams within the watershed, and, in turn, mobilizes toxic metals. Eventually

the water body becomes unable to support its normal

range of plant and animal life. Temporarily restoring

the buffering capacity of a lake or stream by applying

lime or limestone can often allow aquatic life to be

restored. For most mitigation efforts to date, the primary objective has been to improve water quality sufficiently to maintain reproducing fisheries.

Liming has been effective in counteracting surface water acidification in parts of Scandinavia, Canada, and

the United States. Although its effects are only tempora

ry, the material is inexpensive, the dosage required

fairly well known, and the technology of applying lime

simple.

However, not all lakes and streams respond sufficiently to liming to reestablish aquatic life. In particular, lakes with rapid water flow in comparison to their

volume (i. e., with water ‘ ‘retention time’ of less than

a year), and running waters with great variation in flow,

are very difficult to lime effectively. Moreover, it is impossible to determine the effectiveness of a liming application without extensive monitoring of the chemical

and biological changes that follow. The results of individual applications will remain uncertain until more is

known about how liming affects various types of water

bodies. On the average, however, the buffering capacity

that a single application of lime restores to a lake or

stream will be depleted over a period of 3 to 5 years,

after which the effectiveness of the application must be

reconsidered, and a decision made whether to continue

mitigation efforts.

Possibly of greater concern with regard to establishing

a wide-scale liming program is that scientists do not

know how periodic realterations of water body chemistry

through liming will affect aquatic ecosystems over the

long term. For example, a number of substances that

normally are found in a biologically inert form in neutral

waters become unbound, or soluble, in acidified waters.

If, several years after liming, the lake again begins to

acidify, accumulated metals that have been rendered insoluble over a period of time may again become soluble and create a serious toxic condition. In addition, little is known about the effects of periodic or even single

applications of liming on other living organisms in the

water body. While liming has enhanced fish survival in

a number of lakes and streams, its long-term implications for the food chain on which fish depend are uncertain.

Though it is neither possible nor desirable to lime all

acid-sensitive aquatic ecosystems in the Eastern United

States, liming can be an effective stopgap measure to

restore or preserve water bodies of particular value from

the effects of acid deposition. Some characteristics to

consider in choosing which water bodies to lime are:

●

●

●

the current or historic ability of the system to support a viable and important fishery;

recreational importance and public access to the

waters;

present chemical condition, i.e., pH, alkalinity,

acid loadings, watershed buffering capacity;
App. D—Existing Domestic and International Approaches . 313

c physical factors—water retention time, geographic

location; and

● economic constraints—costs of material, application, and frequency of reapplication.

Such characteristics must be assessed on a site-specific

basis before the feasibility of liming can be determined.

Figure D-1 presents a series of criteria suggested by a

report to U.S. Fish and Wildlife Service for evaluating

the appropriateness of liming a water body. All of these

criteria must be met for liming to be an appropriate mitigating strategy.

Liming Materials

Many alkaline materials can be used to neutralize

acidified surface waters. These include lye, soda ash,

olivine, and lime compounds, as well as several byproducts and wastes of industries such as cement dust and

sludge from water treatment plants. However, while industrial byproducts are low in price, they frequently

have a high level of such impurities as heavy metals,

which may exacerbate the already-elevated metal concentrations typically present in acidified waters. Lime

compounds are much more chemical] y uniform and

have been the neutralizing material of choice for the majority of water bodies.

The term ‘ ‘lime’ is generally applied to several compounds of calcium and magnesium that are highly capable of neutralizing acid. The three most often used

calcium compounds are limestone (calcium carbonate),

quicklime (calcium oxide), and hydrated or slaked lime

(calcium hydroxide). Available magnesium-based compounds include dolomite, dolomite lime, and dolomite

hydrated lime. Calcium lime is used more commonly

than dolomite. Dolomites have a slightly higher neutralizing value by weight than the nonmagnesium lime,

but if their magnesium carbonate content is greater than

10 percent, they may dissolve too slowly to be of value

in neutralizing acidified lakes and streams.

Crushed limestone, or “aglime, ’ is currently the primary alkaline material used in experimental liming programs in the United States and Canada and in more

wide-scale programs in Scandinavia. The more acidic

the water, and the finer the limestone is ground, the

more quickly it will dissolve. Limestone is a relatively

inexpensive natural material and is less caustic than

quicklime or hydrated lime. In general, limestone goes

into solution more slowly than either quicklime or hydrated lime, but remains effective longer. The differences between lime and limestone are shown in figure

D-2.

Response to Liming

Chemical Changes

Adding a liming agent causes the pH of the water

body to rise and restores alkalinity —i.e., the ability to

neutralize further acid inputs. If a very soluble base such

as quicklime is added, pH rises sharply, and the highest

pH is reached shortly after the treatment. In a New York

State lake, for example, adding lime initially raised pH

from 5 to 9—a ten-thousandfold decrease in acidity before the water body reached equilibrium at a lower pH

value. The shock from such chemical changes, if too

rapid, can be lethal to a variety of aquatic life, especially fish. When a less soluble agent such as limestone

is added to a water body, the rise in pH is less dramatic.

The pH generally will not exceed 7, even during the

initial period after limestone is added. Applied as a

powder or finely crushed stone, it will settle readily to

the bottom and dissolve slowly.

Aluminum, manganese, and zinc frequently are

found in elevated concentrations in acidified waters.

High levels of copper, mercury, nickel, and iron may

also be present due to leaching from surrounding soils

or industrial wastes. These trace-metal concentrations

generally decrease after acidified waters are limed. After

experimental liming at four lakes near Sudbury, Ontario, decreases in metal concentrations ranged from 66

to 91 percent for aluminum, 23 to 73 percent for zinc,

15 to 79 percent for manganese, 32 to 95 percent for

copper, 23 to 81 percent for nickel, and 15 to 89 percent for iron. Such metals will precipitate out of solution most quickly in small shallow lakes where liming

agents mix thoroughly in a short time .22 Dissolved

organic material, which usually gives water a brownish

tint, also will be removed as the metals precipitate out

of solution. This causes the water to appear more transparent following liming. *

The chief agent responsible for fish mortality in acidified water bodies is aluminum released by acid percolating through watershed soils. Although aluminum is

the most prevalent metal in the Earth’s crust, the concentrations of soluble aluminum compounds are low in

surface waters with moderate acidity levels (above pH

5.5). As surface-water pH drops to about 5, aluminum

“J. E. Fraser and D L Britt, Liming of AcidIfied }$’arcrs A Retmw of

,Methods and Effects on Aquatic Ecos,vstems, L’ S Fish and Wddilfe Service,

Diwsion of Biological Services, Eastern Energy and Land Use Team, FWS/OBS

80/40. 13, 1982

“Acidlficatirm of water bodies also mav make them clearer as phytoplankton

(tiny plan[ life) die off
314 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

Figure D-1.— Criteria for Evaluating a Water Body for Suitability of Liming

Yes
App. D—Existing Domestic and International Approaches ● 315

Figure D-2.—Comparison of Lime and Limestone

Lime I Limestone (CaC03) I

becomes much more soluble and more toxic to fish. Below pH 4.5, aluminum appears to have less effect on

fish, but acidity levels themselves are so high that few

species can survive. If a water body of less than pH 5

is limed, it will pass again through the critical pH range

at which aluminum is especially toxic—and for a brief

time fish mortality will be of concern. As the pH increases beyond this range, the aluminum will precipitate

out of solution and settle to the bottom.

The pH of surface waters will gradually decrease if

significant acidic inputs continue from precipitation,

streamflow, ground water infiltration, or perhaps even

from the lake sediments as they use up the buffering capacity of the water above them. Liming will generally

prevent acidity from increasing for about 3 to 5 years.

However, once acidity increases again, aluminum and

other soluble metals that have been precipitated out of

the water are again ‘ ‘mobilized. The water may contain greater concentrations of metals following reacidification than in its original acidified state several years

earlier. This is because the sediments will release both

those metals initially precipitated out of solution by adding lime as well as those that entered the lake or stream

and settled to the bottom while the lime provided buffering capacity. Continued liming must be timed carefully to prevent such toxicity from recurring. Table D1 displays water quality changes in an acidified Ontario

lake immediately prior to, and for 6 years following, the

addition of lime.

Biological Changes

Acidification of aquatic ecosystems reduces the diversity of the normally present biological community. The

total number of plant and animal species often decreases

significantly. Species sensitive to acidic conditions are

eliminated while tolerant species proliferate. Acidification inhibits the bacteria normally responsible for decomposition, thereby slowing the rate of nutrient cy -

Table D-1 .—Changes in Chemistry of Lohi Lake, Ontario, Canada, Following

Addition of Neutralizing Agents in 1973 (hydrated lime), 1974 (hydrated lime and limestone)

Parameters 1973 1974 1975 1976 1977 1978 1979

pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.39 6.04 6.09 6.09 5.27 4.79 4.76

Copper (mg/m3) . . . . . . . . . . . . . . . . . , , , 84 44 43 37 44 71 —

Aluminum (mg/m3). . . . . . . . . . . . . . . . . . — 140 110 120 100 160 —

Water transparency (Secchi disk, m) . . 8.8 5.6 5.7 5.7 6.9 9.3 7.6

Alkalinity μeq/l) . . . . . . . . . . . . . . . . . . . . O 46 102 44 0 0 0

SOURCE: National Research Council Canada, “Acidification in the Canadian Aquatic Environment: Scientific Criteria for Assessing the Effects of Acidic Deposition on Aquatic Ecosystems, ” Ottawa, Canadian Environmental Secretariat, 1981,
316 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

cling. Aluminum toxicity associated with acidification

eliminates various fish species.

Liming drastically decreases the density of acid-tolerant phytoplankton (e. g., algae). Normal populations

generally will be established within about a year. Normal zooplankton populations (animals that feed on the

phytoplankton) may take much longer to recover. Fish

populations, in turn, feed on the zooplankton; thus, several years may be required to reestablish a viable fishery. Liming experiments so far have shown enhanced

survival of natural populations of brook trout in Adirondack lakes; lake trout, brook trout, and smallmouth bass

in an Ontario lake; and Atlantic salmon in a Nova Scotia

stream.

Biological diversity in limed water bodies might be

enhanced by adding organic carbon and/or phosphorus

in nutrients (organic humus or perhaps biologically

treated wastewater). Phosphorus, an important element

in phytoplankton nutrition, is often in short supply in

acidic waters. Limited success has been reported when

phosphorus was added following liming in Canadian

lakes. The effect of adding organic carbon is highly speculative. If these nutrient additions prove effective in

enhancing recover-y of limed acidified water bodies, they

could be applied at little cost.

Costs and Methods of Applying

Liming Materials23

The techniques available for liming aquatic systems

depend on the type of neutralizing material used, the

availability of dispersal equipment, and the target area

being limed. The major application methods used to

date in the United States, Canada, and Scandinavia are

outlined in figure D-3.

The accessibility of the water body may determine

the appropriate liming method. For example, a remote

lake can be limed only by aircraft, while an accessible

water body can be limed by truck or boat. Directly liming the water body appears to be the most economically

efficient technique. It is currently the most commonly

used method for lakes, and is appropriate as long as the

water retention time (a measure of how rapidly the lake

is replenished) is longer than 1 year. If the water retention time is short, the added alkalinity will quickly leave

the system (although it may neutralize water bodies

downstream). Liming tributary streams might provide

downstream lakes and rivers with longer term buffering capacity, and enhance fish spawning.

Researchers have yet to determine whether acidified

aquatic resources may be restored more effectively by

liming watersheds or lakes and streams themselves.

—-

zs”rhl~ ~cctlon IS based In part on Fraser and Britt, op. cit. , 1982.

However, to achieve comparable acid-neutralizing capacities in surface water, 100 times more lime must be

applied to a watershed than directly to a water body.

Despite this, Sweden has applied 40 percent of its total

tonnage of lime on land.

For maximum effect, lime should be added shortly

before critical periods of peak acidity and biological activity, i.e., during early spring, for surface waters that

still support fish populations. Spring snowmelts often

flow directly into water bodies without experiencing the

potential neutralizing effects of soils. In much of the

Eastern United States and Canada, this snowmelt has

a pH of less than 4.5. The acidity that has been stored

in snows throughout the winter reaches water bodies

when sensitive embryos and fish fry are developing. Alternatively, liming lakes slightly later in the season, during the spring overturn, takes advantage of lake circulation patterns to enhance mixing and distribution of

neutralizing agents.

Table D-2 outlines costs of limestone materials, transport, and application in Sweden in 1981. Normally, 1

to 2 tons of limestone are added per acre of surface water. The Government of Sweden has undertaken the

most extensive liming program to date—3,000 lakes,

3,000 kilometers of streams, and 500 watersheds from

the program’s inception through July 1983. Total program costs have reached $17 million to date, including

approximately $4 million to lime 500 lakes in fiscal year

1983.

Several waterway deacidification experiments have

taken place in North America. Since 1973, the Ontario

Ministry of the Environment has limed four acidified

lakes in the Sudbury region. The treatments have been

successful in returning pH to normal levels.

The most extensive program in the United States was

begun by the New York State Department of Environmental Conservation in 1959. It initially targeted small,

naturally acidic ponds in heavily used recreational areas,

and expanded to treating selected acidified lakes with

significant potential to support recreational fishing during the mid-1970’s. The program is quite small in scope;

only about 60 lakes in total (covering approximately

1,000 acres) have been treated to date. It has significantly improved water quality at a number of lakes and

ponds, and permitted self-propagating sport fishing populations to be maintained and/or reintroduced. Costs

for liming ponds and lakes under the program have

ranged from approximately $50 to $300/acre for each

application, depending on the size and accessibility of

the water body. Between 1 and 2.2 tons of lime are normally added per acre of surface water to be treated—

costs for transporting the material to the lake site constitute a significant portion of overall expenses.

Currently, only Massachusetts and New York have

formal surface water mitigation projects. Since 1957,
App. D—Existing Domestic and International Approaches ● 3 1 7

Technique

Boats

Sediment

Injecti on

Figure D-3.—General Comparison of the Various Liming Application Techniques

Table D-2.—Range of Costs for Limestone Materials,

Transport, and Application in Sweden 1981

Liming parameters costs

Materials:

Bulk limestone . . . . . . . . . . . . . . . . . . . . . . . . $20-$30/ton

Bagged limestone . . . . . . . . . . . . . . . . . . . . . $40/ton

Transport of limestone . . . . . . . . . . . . . . . . . . . $10-$20/ton

Application techniques:

Truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $4-$6/ton

Pontoon boat with blower . . . . . . . . . . . . . . $10-$ 16/ton

Helicopter . . . . . . . . . . . . . . . . . . . . . . . . . . . . $30-$40/ton

By hand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $20-$60/ton

SOURCE National Fisheries Board of Sweden, Rad och Riktinijer for Kalkning

av Sjoar OCh Vattendrag, Report No. 1, 1982

Massachusetts has limed about 40 small ponds covering 2,000 acres. Funded for liming is quite limited, however, and future projects are uncertain. New York has

developed a 6-year liming plan. During this time, 33

lakes will receive aglime treatments, and extensive chemical and biological monitoring will be conducted. A recent study of liming requirements in the Adirondack region of New York estimated that a 5-year program for

liming all the known acidified lakes in the region would

cost from $2 to $4 million per year, depending on the

targeted buffering level .24 This estimate represents

14F ~ ~~~nz ~nd C. T Drisc 011 , “An Estmate of the (;OSIS of Limlrrg [o

N“eutrallze ,ACICIIC ,Acliron(fa( k Surfa( e i$raters, ( ontrlhutmn # 1 ‘f. Upstate

~“reshwdter [nstltutc, June 1983
318 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

materials and labor only; it does not include costs for

fish restocking or continued monitoring which can be

considerable. Particularly in the initial stages of a liming program, frequent monitoring for chemical and biological changes in treated water bodies is necessary. Annual costs may range from $3,000 to $20,000 per lake.

When a sufficient data base exists to develop a generic

treatment protocol for various aquatic ecosystems—

water bodies of differing geological, chemical, and biological characteristics—monitoring costs may be reduced

significantly.

No direct Federal support is currently being provided

to States, localities, or other organizations that undertake to treat acidified surface waters. Federal involvement in mitigation research began in 1982 under the

direction of the Fish and Wildlife Service (FWS), as provided for in the National Acid Precipitation Assessment

Plan. * To date, the Federal research effort has produced

a technical report on liming25 and an agenda of further

“~;hapter 6 discusses the National Acid Precipitation Assessment Program

and Federal research on mitigation techniques in greater detail

Z~Fraser and Britt, 1982.

research needs determined by participants in an international mitigation conference. Current plans for field

research include monitoring the effects of liming on fish

populations in several lakes in the Adirondack Mountains, as part of the research program on water chemistry sponsored privately by the Electric Power Research

Institute. FWS is also supporting a pilot scale liming

project on 10 acidified lakes in the Adirondack region

in an attempt to understand the variation in response

of fish populations and to evaluate the success of restocking strategies. Total Federal funding for such efforts in

fiscal year 1983 amounted to about $225,000. The administration recently proposed about $.5 million for liming research for fiscal year 1985. Such funding increases

would permit researchers to study the effects of liming

on water bodies with differing geological, chemical, and

biological characteristics throughout the Eastern United

States, and to investigate the effectiveness of alternative

mitigation measures.
Index
a( id deposition, 3, 5, 9, 10, 11, 12, 13, 15, 16, 27, 28,

42, 49, 80, 81, 85, 87, 106-110, 124, 212

Adirondacks, .5, 13, 44, 81, 82, 112, 213, 230

,Ad\anced Statistical ‘1’rajectory Regional Air Pollution

Model (ASTRAP), 280

agricultural prmductivit), ad~’erse effects, 12, 90, 217

Air Qualit) (;ontrol Reqions (AQRs), 136

Alabama, 63, 85, 90, 98, 125, 126

.4ppala[ h ians, 50, 51, 85, WI, 127, 141, 196, 226

Arkansas, 52, 90

atmospheric processes, 265-299

chemistry, 26.5-273

altering emissions of primary pollutants, 269

deposition of sulfur and nitrogen, 265

oxides of nitrogen, 267

oxides of sulfur. 266

ozone, 268

source-receptor rclatiortships, 274-299

acid-producing substances, 274

t ont ribut ions to acidic deposition, 279

cffecti~encss of cmissions reductions for achieving

deposition reductions, 286

rclat ionsh ip between current emissions and

deposit ion, 279

‘‘target cieposition rates, 289

13rookha\en National I.aboratory, 255

Business Roundtablc, 29

Canada, 3, 5, 13, 29, 30, 31, 43, 47, 48, 119, 120, 125,

213, 302-305, 307

Center for Air Pollution Impact and Trend Analysis, 253

Con$ress:

House Committee on Energy and Commerce, 27

Senate Cotnmittec on Environment and Public Wrorks,

27

cf)n,grcssiona] interest, 41-48, 80-90, 105-120, 123, 146

Connecticut, 52

(;ounci] on Environmental Quality (CEQJ, 117

domestic and international approaches, 300-318

Clean Air Act, 300

control of transboundar> pollution, U. S .-Canada,

302-305

intc’rstatc pollution control and the Clean Air Act,

300

international programs, 305

Canada, 307

Denmark, 310

Europe”, 30.5, 306, 307

Japan, 311

Norwa}r, 309

Sweden, 308

Uni[cd Kingdom, 310

\Vest Germany, 310

mitigating the effects of ac id deposition on aquatic

resources, 312

liming materials, 313-318

Index

——._——

Edison Electric Institute. 192

effects of transported pollutants, 207-264

aquatic rtsourrcs, 207-216

effects of acid deposition, 212

economic sectors, 261

health risks, 255-261

acid precipitation, 259

nitrogen oxides, 258

materials, 239-244

terrestrial resources, 217

agricultural product i~’it?’, 217

effects of acid deposition, 228

effects of acid rain, 218

effkcts of multiple pollu tan ts on forests, 224

effects of ozone on forest product itit}r, 227

\’isibilit)’, 244

factors affecting, 244-248

key studies, 253

measurement techniques, 252

mechanisms of degradation, 248

Electric Power Research Institute, 279

emissions, 57-63, 106-111, 149-206

control technologies 153-167

n itrogcn oxides, 166-167

flue-gas treatment, 167

sulfur dioxide, 157

cost

coal clean ing, 158

dr) processes of FGD, 165

flue-gas desulfurization, 164

fluidized bed combustion, 164

fuel-switching, 157

limestone injection multistage burner (LIMB), 16:3

oil desulfurization, 163

regenerable processes, 166

wet scrubbers, 164

of control, 149, 167-180

o~erview of model used in cost analyses, 178

state-b?’-state reductions, 170-178

current and historical, 57, 58

future, 59

hydrocarbon, 61

nitrogen oxides, 59

sulfur dioxide, 59

utility sulfur dioxide, 61, 62

industrial and commercial boilers, 183

industrial processes, 183-185

mobile sources, 185

trends in highway \’chicle emissions, 187

legislating, 123-146

secondary economic effects of programs, 190-206

coal production and related employment, 190

employment forecasts, 194

methods of’ projecting production, 192

patterns of change, 195

reser~.es and current production, 190

elect ricity-intcnsi~’c industries, 199-201

utilities in the eastern 31 states, 201-206

321
322 ● Acid Rain and Transported Air Pollutants: Implications for Public Policy

state regulatory policies, 203

tax strategies, 180-182

Energy & Resource Consultants, Inc., 183

European Economic Community (EEC), 306

Federal Aviation Administration, 244

Federal concern, 29

Florida, 49, 52, 126

Ford, 189

forest productivity, 12, 89

General Electric, 163

General Motors, 189

geographical patterns of deposition and air concentrations

for transformed pollutants, 63

Georgia, 63, 83, 85, 125, 126

Great Smoky Mountain National Park, 213

Harvard School of Public Health, 256

ICF, Inc., 192, 193

Illinois, 12, 49-50, 82, 90, 142, 195, 242

Indiana, 12, 49, 50, 64, 82, 90, 142

Interagency Task Force, 105, 114, 118

interstate coal shipment, 142

Iowa, 82, 90

Kentucky, 46, 49, 50, 81, 82, 98, 142, 190, 195

legislating emissions reductions, 123, 146

By what time should reductions be required?, 130

How should emissions reductions be allocated?, 133

How widespread should a control program be?, 125-126

What approach to control should be adopted?, 131

What can be done to mitigate employment and

economic effects of a control policy?, 140

What level of pollution control should be required?, 126

Which pollutants should be further controlled?, 123-125

Who should pay the costs of emissions reductions?, 138

legislation:

Acid Precipitation Act of 1980, 21, 23, 105, 114, 115,

117, 118

Airline Deregulation Act of 1978, 143

Clean Air Act, 3, 5, 15, 23, 24, 27, 29, 35, 36, 48, 59,

105, 106, 109, 118, 1 ~9, 120, 132, 139, 141, 142,

145, 189, 199, 244, 255, 300, 301, 302, 308

Dingell-Johnson Act, 112, 13, 114

Economic Recovery Tax Ac of 1981, 144, 145

Trade Act of 1974, 143

liming lakes and streams, 19, 1 ~, 111-114

Limestone Injection Multistage , ~rners (LIMB), 144

Louisiana, 126

Maine, 52, 82, 90, 119

Memorandum of Intent, 48, 119

Michigan, 52, 142

Minnesota, 48, 82, 209

Mississippi, 63, 90, 107, 125, 126

Missouri, 49, 90, 126, 142

National Academy of Sciences, 29, 53, 117, 289

National Acid Precipitation Assessment Program

(NAPAP), 21, 23, 108, 115, 116, 117, 207

National Ambient Air Quality Standards (NAAQS), 23,

24, 105, 118, 119, 120, 131, 132, 133, 268, 300

National Clean Air Coalition, 192

National Commission on Air Quality, 28

National Crop Loss Assessment Network (NCLAN), 217

National Governors’ Association, 28

National Wildlife Federation, 192

New England, 5, 12, 13, 48, 53, 80, 83, 125, 127, 224,

231

New Hampshire, 82, 90, 114

New Jersey, 44, 81

New Source Performance Standards, 61, 129, 131, 195

New York, 48, 82, 112, 119, 125, 183, 214, 231, 242

New York State Department of Environmental

Conservation, 112, 113

North Carolina, 17, 64, 81, 82, 90, 107, 126

Norway, 82, 230

Nova Scotia, 82, 214

Oak Ridge National Laboratory, 208, 230

Ohio, 5, 12, 49, 50, 63, 82, 111, 143, 195

Ontario, Canada, 82, 125, 213, 214

Ozark Mountains, 85

ozone, 4, 7, 11, 12, 13, 27, 33, 34, 85, 86, 227, 228, 268

Pennsylvania, 5, 49, 50, 52, 63, 82, 98, 111, 114, 119,

127, 183, 278

policy debate, characteristics of, 30-31

policy options, 15-24, 105-120

current law and recent proposals, 105

liming lakes and streams, 18, 106, 111-114

mandatory emissions reductions, 16, 106-111

modifying existing provisions of the Clean Air Act, 23,

106, 118-120

modifying the current research program (NAPAP) to

provide mom timely guidance to Congress, 21

modifying the Federal acid deposition research

program, 115-118

pollutants of concern, 4-9, 57-75

hydrocarbons, 4, 27, 57-75, 123-146

nitrogen oxides, 4, 5, 7, 8, 12, 27, 49, 57-75, 93, 95,

105, 106, 123, 146, 149-167

sulfur dioxide, 4, 5, 7, 8, 9, 12, 15, 16, 27, 49, 57-75,

92, 95, 96, 97, 105, 107, 123-146, 149-180

precipitation acidity (pH), 5, 6, 9, 42, 125, 126, 213,

224, 225, 266

public concerns, 28

Redwoods National Park, 143

regional distribution of risks, 79-101

aquatic ecosystems, 80

health effects, 94

materials, 91

rates of pollutant emissions, 94

shifts in coal production, 97-101

terrestrial ecosystems, 82
Index ● 3 2 3

utility industry, 95

visibility, 91

risk and uncertainty, 31-32

regional patterns of sulfur oxides transport, 64-75

San Bernardino Mountain Study, 228

scientific uncertainties, 32-37

current damages, 32

effectiveness of reducing emissions, 36

future damages, 33

origin of observed levels of transported pollutants, 34

research program, 36

State Implementation Plans (SIP), 61, 118, 120, 167, 178,

301

Stockholm Conference on the Acidification of the

Environment, 1982, 29, 53

South Carolina, 64, 85

Sweden, 82

Tennessee, 12, 17, 44, 49, 50, 81, 107, 126

Tennessee Valley Authority (TVA), 164, ~65

The Institute of Ecology (TIE), 207, 209

transported air pollutants, 41-54

effects on utility and industrial financial health, 51

effects on U.S. coal market, 50

resources at risk, 41

aquatic ecosystems, 41

terrestrial ecosystems, 43

risks of health effects, 47

risk of strained international relations, 48

utility control costs, 49

United Mine Workers, 142, 198, 199

University of Illinois, 256

U.S.-Canada Memorandum of Intent on Transboundarv

U s .

U s .

U s .

U s .

Us.

U s .

Us.

Us.

Air Pollution, 53, 120, 149, 181, 242, 279, 289

Census Bureau, 199

Chamber of Commerce, 29

Department of Agriculture (USDA), 218

Department of Energy, 29, 149, 161, 183, 192

Environmental Protection Agency (EPA), 18, 19,

23, 24, 29, 35, 46, 48, 105, 106, 108, 110, 117,

118, 119, 120, 126, 128, 129, 131, 143, 144, 149,

161, 178, 185, 189, 192, 217, 259, 300, 301

Fish and Wildlife Service (FWS), 113, 114

Forest Service, 85

Geological Surve), 208

Vermont, 12, 44, 4!3, 52, 82, 90, 114

Virginia, 44, 47, 52, 81, 98

West Germany, 44, 118, 230

West Virginia, 5, 49, 56, 63, 81, 82, 98, 127, 143, 161,

190, 195, 278

Wisconsin, 48, 82

0