Catching Our Breath: Next Steps for

Reducing Urban Ozone

July 1989

OTA-O-412

NTIS order #PB90-130451

GPO stock #052-003-01158-1
Recommended Citation:

U.S. Congress, Office of Technology Assessment, Catching Our Breath: Next Steps for

Reducing Urban Ozone, OTA-O-412 (Washington, DC: U.S. Government Printing Office,

July 1989).

Library of Congress Catalog Card Number 89-600715

For sale by the Superintendent of Documents

U.S. Government Printing Office, Washington, DC 20402-9325

(order form can be found in the back of this report)
Foreword

More than a decade has passed since the last major set of amendments to the Clean Air

Act. Deadlines for meeting the health-based air quality standard for ozone, the major

component of urban smog, have come and gone. While some progress has been made, most

metropolitan areas still do not meet the air quality goals first set by Congress in 1970.

This report on urban ozone was requested by the Senate Committee on Environment and

Public Works, the House Committee on Energy and Commerce, and its Subcommittee on

Health and the Environment in anticipation of the upcoming reauthorization of the Clean Air

Act. Of the air pollutants that the Act covers, ozone has been the most difficult to bring under

control; it may well be the most expensive.

One of the key findings of our study is that, once again, we cannot achieve the ozone

standard in all areas with currently available technology. We can make considerable

progress-about two-thirds of the reductions needed, enough to bring about half of the cities

into compliance with the standard-but we cannot get all the way there.

We thus conclude that an effective ozone control strategy must include measures to

achieve both near-term emissions reductions using today’s control methods and, just as

important, measures to ensure that we can continue to make progress post-2000, when many

areas will still exceed the standard. Our report presents options in both categories.

Substantial assistance was received from many organizations and individuals during the

course of this study. We would like to express our thanks to our advisory panel, contractors,

workshop participants, and the many reviewers who provided advice and information

throughout the course of this assessment. Special thanks goes to the many individuals at the

Environmental Protection Agency who answered our numerous requests for data, models, and

technical assistance. OTA, however, remains solely responsible for the contents of this report.

.,. Ill
Catching Our Breath: Next Steps for Reducing Urban Ozone

Advisory Panel

Clifford S. Russell, Chairman

Vanderbilt University

S. William Becker

State and Territorial Air Pollution Program

Administrators/Association of LQcal Air

Pollution Control Officials

Kelly M. Brown

Ford Motor Co.

George D. Carpenter

Procter & Gamble

Kenneth L. Demerjian

State University of New York

Robert Frank

The Johns Hopkins University

Fran Du Melle

American Lung Association/American Thoracic

Association

David Hawkins

Natural Resources Defense Council

Principal Contractors

Beryl Benderly

Sierra Research, Inc.

E.H. Pechan & Associates

Lawrence J. Folinsbee

Additional Contributors

Alliance Technologies Corp.

Richard A. Liroff

The Conservation Foundation

Jennifer Ann Logan

Harvard University

Vincent J. Marchesani

ICI Americas, Inc.

Richard B. Stewart

University of Chicago

William Sylte

California Air Resources Board

Leonard Weinstein

Cornell University

James A. Woodman

North Carolina State University

Stanley L. Zwicker

McClaren Environmental Engineering

(formerly Union Oil)

Raymond J. Kopp

Alan J. Krupnick

Perry J. Sampson

NOTE: OTA appreciates and is grateful for the valuable assistance and thoughtful critiques provided by the advisory panel members.

The panel does not, however, necessarily approve, disapprove, or endorse this report. OTA assumes full responsibility for the

report and the accuracy of its contents.

i v
OTA Project Staff—Catching Our Breath: Next Steps for

Reducing Urban Ozone

John Andelin, Assistant Director, OTA

Science, Information, and Natural Resources Division

Robert W. Niblock, Oceans and Environment Program Manager

Robert M. Friedman, Project Director

Jana B. Milford, Analyst

Richard D. Rapoport, Analyst

Nancy B. Szabo, Analyst

Contributing Staff

Jonathan Chudnoff Theo Colburn Kathryn Harrison

Administrative Staff

Kathleen A. Beil Sally W. Van Aller
Workshop for State and Local Pollution Control Officials

January 13,1987

Bill Becker

State and Territorial Air Pollution Program

Administrators/Association of Local Air

Pollution Control Officials

Eli Bell

Texas Air Quality Board

Mike Bradley

Northeast States for Coordinated Air Use

Management

John Elston

New Jersey Bureau of Air Pollution Control

George Ferreri

Maryland Air Management Administration

James Hambright

Pennylvania Bureau of Air Quality Control

Michael Hayes

Illinois Division of Air Pollution Control

James Lents

South Coast Air Quality Management District,

California

Workshop

Alex Cristofaro

Office of Policy Analysis, EPA

Louis Gitto

Air Management Division, Region 1,

William Hathaway

Air Management Division, Region 6,

David Hawkins

Natural Resources Defense Council

Tom Helms

Bruce Maillet

Massachusetts Division of Air Quality Control

Robert Miller

Michigan Air Quality Division

Donald Moline

Toledo, Ohio, Environment Services Division

Nick Nikkala

Missouri Division of Air Pollution Control

John Paul

Dayton, Ohio, Regional Air Pollution Control

Agency

William W. Sylte

California Air Resources Board

Don Theiler

Wisconsin Bureau of Air Management

for Current and Former EPA Staff

July 16,1987

EPA

EPA

Office of Air Quality Planning and Standards, EPA

David Howekamp

Air Management Division, Region 9, EPA

David Kee

Air Management Division, Region 5, EPA

Joseph Lees

Office of Air and Radiation, EPA

Phil Lorang

Office of Mobile Sources, EPA

William Pedersen

Verner, Liipfert, Bernhard, McPherson, & Hand

John Rasnic

Office of Air Quality Planning and Standards, EPA

Paul Stolpman

Office of Policy Analysis and Review, EPA

John Thillman

Office of Air Quality Planning and Standards, EPA

John Topping

Topping & Swillinger

Michael Walsh

Consultant

Peter Wyckoff

Office of General Counsel, EPA
Workshop for Industry and Government

September 30, 1987

Walter Barber Robert Miller

Chemical Waste, Inc. Michigan Air Quality Division

David Baron Brad Raffle

Arizona Center for Law in the Public Interest Conoco Inc.

Donald Deieso

New Jersey Department of Environmental

Management and Control

Gerald Emison

Office of Air Quality Planning and Standards, EPA

Frank Friedman

Occidental Petroleum

Sam Leonard

General Motors

Phil Reed

Skadden, Arps, Slate, Meagher & Flom

Jim Tozzi

Multinational Business Services

Richard Wilson

Office of Mobile Sources, EPA

Tom Zosel

3M Company

Gladys Meade

American Lung Association of California

vii
Reviewers and Contributors

Gary Agid

California Air Resources Board

Steve Albu

California Air Resources Board

David Aldorfer

General Motors Corp.

Paul Allen

California Air Resources Board

Jeffrey Alson

EPA

Thomas Austin

Sierra Research, Inc.

John Bachmann

EPA

John Bailar

McGill University

Alan Basala

EPA

William Battye

Alliance Technologies Corp.

Keith Baugues

EPA

Eli Bell

Texas Air Control Board

Mark Berger

University of Kentucky

Bruce Bertelsen

Manufacturers of Emission Controls

Association

John Blodgett

Congressional Research Service

Robert Boisselle

Massachusetts Department of

Environmental Quality Engineering

Mike Bradley

Northeast States for Coordinated

Air Use Management

Philip Bromberg

University of North Carolina, Chapel

Hill

Donald Buist

Ford Motor Co.

Frank Bunyard

EPA

Tom Cackette

California Air Resources Board

William Chameides

Georgia Technical University

Raymond Conner

National Paint & Coatings

Association

Greg Cooper

New Jersey Department of

Environmental Protection

Alex Cristofaro

EPA

Greg Dana

Automobile Importers of America

Jan Demmy

Alliance Technologies Corp.

Carmen Difiglio

U.S. Department of Energy

Douglas Dockery

Harvard School of Public Health

Ralph Engel

Chemical Specialties Manufacturers

Association

Lawrence Follinsbee

Combustion Engineering

A. Myrick Freeman III

Resources for the Future

Henry Gong

University of California, Los Angeles

Kenneth Gross

General Motors Corp.

David Gushee

Congressional Research Service

Jack Hackney

University of Southern California

Marcel Halberstadt

Motor Vehicle Manufacturers

Association

Jane Hall

California State University at

Fullerton

James Hambright

Pennsylvania Department of

Environmental Resources

Gary Hawthorn

EPA

Milan Hazucha

University of North Carolina, Chapel

Hill

Walter Heck

Agricultural Research Service

Charles Hudson

Navistar International

Teiji Iida

Toyota Motor Corp.

Michael Jackson

Acurex Corp.

Michael Jackson

Pulmonary Medicine Associates

Jay Jacobson

Boyce Thompson Institute for

Research

Christopher James

Rhode Island Department of

Environmental Management

Arthur Johnson

University of Pennsylvania

Pam Johnson

EPA

Bruce Jordan

EPA

Mario Jorquera

Maryland Air Management

Administration

Patrick Kinney

Health Effects Institute

Erica Laich

E.H. Pechan & Associates

Michael Lebowitz

University of Arizona

Allen Lefohn

A.S.L. & Associates

Sam Leonard

General Motors Corp.

Plant

VIII
Morton Lippman

New York University Medical Center

Phil Lorang

EPA

Matthew Low

TLI Systems

Bruce Madriaga

EPA

Tom McCurdy

EPA

William McDonnell

EPA

Dave McKee

EPA

Barry McNutt

U.S. Department of Energy

Michael Meyer

Georgia Institute of Technology

Ned Meyer

EPA

Ralph Morris

Systems Applications Inc.

Howard Padgham

Chrysler Motors Corp.

James Pasek

General Motors Corp.

John Paul

Dayton Ohio Regional Air Pollution

Control Agency

Norm Possiel

EPA

James Raub

EPA

John Rawlings

North Carolina State University

Glen Reid

Johnson Matthey

Walter Retzsch

American Petroleum Institute

Harvey Richmond

EPA

Molly Ross

U.S. Department of the Interior

Phil Roth

Michael Rusin

American Petroleum Institute

Ted Russell

Carnegie Mellon University

Kenneth Schere

EPA

Sandy Sillman

University of Michigan

John Skelly

The Pennsylvania State University

Mark Smith

Alliance Technologies Corp.

Robert Stricter

American Petroleum Institute

C. Robert Taylor

Auburn University

Michael Walsh

Norman Whittlesey

Washington State University

Jim Wilson

E.H. Pechan & Associates

Richard Wilson

EPA

David Wooley

New York State Attorney General’s

Office

Elaine Wright

General Motors Corp.

Terry Yosie

American Petroleum Institute

Steve Ziman

Chevron

Tom Zosel

3M Company

ix
Contents

Page

Chapter l. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Chapter 2. Ozone and The Clean Air Act . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Chapter 3. Health Effects of Ozone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Chapter 4. Effects of Ozone on Crops and Forests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Chapter 5. LoweringOzone: Effect of Controlling Volatile Organic Compounds and

Nitrogen Oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Chapter 6. Controlling Emissions of Volatile Organic Compounds . . . . . . . . . . . . . . . . . . . . . . . . 113

Chapter 7. New Opportunities for Controlling Ozone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Chapter 8. Policy Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

Appendix A. Parameters Used To Calculate Volatile Organic Compound Emissions Reduction

Potential and Associated Costs of Control for Stationary Sources . . . . . . . . . . . . . . . . . . . . . . 235
Chapter 1

Summary
CONTENTS

Page

INTRODUCTION .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . 3

Why Control Ozone? . . . . . . . ...................... 3

Ozone and Its Precursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ........... 4

HOW RAPIDLY TO PROCEED . . . . . . . . . . . . . . . . . . .. .. .. .. .. .. .. .. ... ... . . 5

Human Health . . . . . . . . . . . . . . . .. .. . . . . . . . . . . . . . . . . . . . . ..7

Setting the Pace for Progress . .. . .. .. .. ... ... ... ... .. .. .. .. .. . 9

CONTROLLING VOLATILE ORGANIC COMPUNDS . . . .. .. .. .. ... ... . . . . . . 11

NEW DIRECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Controlling Nitrogen Oxides .. . . . . . . . . . . . . . . . . . . . . . . . . . . ...... 17

Non-Traditional VOC Controls .. ... . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. ... .. 21

Ozone Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. .. ... 23

Rural Ozone.... .. .. .. . . .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Continuing the Search . .. .. ... .. ....... . . . . . . . . . . . . . . . . . . . . . ........... 25

Figures

Figure Page

l-1. Areas Classified as Nonattainment for Ozone Based on 1983-85 Data . . . . . . . . . . . 6

l-2. Areas Where Ozone Concentrations Exceeded O.12 ppm at Least One Hour Per

Year on Average, From 1983-85. .. .. .. . . . . . . . . . .. ... 7

l-3. Likelihood of Adverse Effects From Ozone While Exercising . . . . . . . . . . . . . . . . . . . 9

l-4. Summary of Estimated Nationwide Volatile Organic Compound (VOC) Emissions

by Source Category, by Year. . . . . . . . . . . . . . . . . . . . . . . . . ... .. . . . . . . . 12

l-5. VOC Emissions in Nonattainment Cities, by Source Category, in 1985 . . . . . . . . . . 13

l-6. Estimates of Possible Shortfalls and Excesses in Emissions Reductions Needed to

Attain the Ozone Standard in 1994 as a Percentage of 1985 Emissions . . . . . . . . . . 14

l-7. VOC Emissions Reductions in 1994 Compared to 1985 Emissions,

by Control Method .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

l-8. Estimated Cost-Effectiveness of VOC Emission Control Methods in 1994 in

Nonattainment Cities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

l-9. Cumulative Annual Cost of, and Percent Emissions Reductions From, VOC

Control Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 18

l-10. Summary of Estimated Nationwide Nitrogen Oxides (NOX) Emissions by

Source Category, by Year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . ... .. . . . . . . . . 19

l-n. NOX Emissions Reductions in 1994 Compared to 1985 Emissions,

by Control Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. .. .. ... .. . . . 20

l-12. Total Solvent Use Covered by Existing Regulations in 1985,

by Source Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

l-13. Estimated Daily 7-hour Average Ozone Concentrations During the

Growing Season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Tables

Table Page

l-1. Options for Amending the Clean Air Act Overall Requirements . . . . . . . . . . . . . . . . . 11

l-2. Options for Amending the Clean Air Act Currently Available Control Methods . . . 16

l-3. Options for Amending the Clean Air Act: New Directions.. . . . . . . . . . . . . . . . . . . . . . 18
Chapter 1

Summary

INTRODUCTION

Within the next year or two, Congress must

reauthorize-and, some believe, rethink-the

Clean Air Act. The mechanism established in

1970 to assure the Nation’s air quality has

notably failed to control a major pollutant,

ozone, in much of the country. Today, almost

two decades after the Act’s original passage,

about 100 urban areas still violate the ozone

standard; indeed, the intense heat of summer

1988 added an estimated 28 new names to the

list of “nonattainment” cities. Currently available control methods are not adequate to bring

all of these cities into compliance. This third

attempt to craft an ozone control program thus

raises several controversial issues: how great a

threat ozone poses to human health, agricultural

production and environmental welfare; what

technical measures to take against this hard-tocontrol pollutant; how to alter deadlines, sanctions, and planning mechanisms; how to deal

with the cities that cannot meet the standard with

any existing or near-term means; and finally,

how to encourage development of new control

methods so that continued progress can be

made. This report aims to assist Congress in

grappling with these issues.

Since 1970, a Federal-State partnership has

been in place to handle ozone control, with the

Environmental Protection Agency (EPA) setting nationally uniform standards and the States,

with the Agency’s help and approval, working

to meet them. Based on ozone’s known health

effects, the standard is currently set at a peak,

l-hour average ozone concentration of 0.12

parts per million (ppm). Any area experiencing

concentrations exceeding the standard more

than once per year, on average, is declared a

‘‘nonattainment” area. EPA updates the nonattainment list annually, as data become available. In

1987, the list included cities housing about half

of the American population; 1988’s number

promises to be substantially higher.

Why Control Ozone?

The 0.12 ppm national standard for ozone

derives from solid evidence of the health effects

of short-term exposure above that level. Excessive ozone is harmful to people. Some healthy

adults and children begin to experience coughing, painful breathing, and temporary loss of

some lung function after about an hour or two of

exercise at the peak concentrations found in

nonattainment cities.

Does the current standard adequately protect

people who are exposed for long periods or at

high exercise levels? Experts are unsure. Several studies over the past 5 years have shown

temporary loss of some lung function after an

hour or two of exposure at concentrations

between 0.12 and 0.16 ppm, among moderately

to heavily exercising children and adults. And

despite the current standard’s emphasis on a

l-hour peak, real-life exposures to near daily

maximum levels can last much longer; ozone

levels can stay high from mid-morning through

late afternoon. With exposure during 6 hours of

heavy exercise, temporary loss of some lung

function can appear with ozone levels as low as

0.08 ppm.

Potentially more troubling and less wellunderstood are the effects of long-term, chronic

exposure to summertime ozone concentrations

found in many cities. Regular out-of-doors work

or play during the hot, sunny summer months in

the most polluted cities might, some medical

experts believe, cause biochemical and structural changes in the lung, paving the way for

chronic respiratory diseases. To date, though,

evidence of a possible connection between

-3-
4 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

irreversible lung damage and repeated exposure

to summertime ozone levels remains inconclusive.

Clear evidence shows that ozone damages

economically, ecologically, and aesthetically

important plants. When exposed to ozone, major

annual crops produce reduced yields. Some tree

species suffer injury to needles or leaves,

lowered productivity, and in severe cases, individual trees can die. Important tree species are

seriously affected in large areas of the country.

In the most heavily affected forested areas, such

as the San Bernardino National Forest in California, ozone has begun altering the natural

ecological balance of species.

How serious are these damages and risks?

What will it cost to avoid them? And how does

the cost compare to the benefits potentially

gained? These are questions that scientists

cannot confidently answer. Deciding how to act

in the absence of full information falls to

Congress and the Nation.

Ozone and Its Precursors

Ozone is produced when its precursors, volatile organic compounds (VOCs) and nitrogen

oxides (NOX

), combine in the presence of

sunlight. VOCs, a broad class of pollutants

encompassing hundreds of specific compounds,

come from manmade sources including automobile and truck exhaust, evaporation of solvents

and gasoline, chemical manufacturing, and petroleum refining. In most urban areas, such

manmade sources account for the great majority

of VOC emissions, but in the summer in some

regions, natural vegetation may produce an

almost equal quantity. NOX arises primarily

from fossil fuel combustion. Major sources

include highway vehicles, and utility and industrial boilers. Ozone control efforts have traditionally focused on reducing local VOC emissions, partly because the relevant technologies

were thought to be cheaper and more readily

available. In addition, under some conditions at

some locations, reducing NOX can have the

counterproductive impact of increasing ozone

concentrations above what they would be if

VOCs were controlled alone.

Through past efforts, the Nation has made

some progress. According to EPA estimates,

while VOC emissions have remained relatively

constant over the last decade, they are about 40

percent lower than they would have been

without existing controls. The major existing

mechanism for regulating air quality is a State

Implementation Plan (SIP). Subject to EPA

review, each State prepares a document analyzing its particular inventory of precursor emissions and establishing the reductions necessary

to meet the ozone standard. SIPS also establish

the programs intended to achieve those reductions, mainly by limiting the amount of precursors that various commercial and industrial

establishments, vehicles and the like are allowed

to discharge into the atmosphere. The process of

developing a SIP is both technically and politically challenging. It not only requires an accurate analysis of the State’s existing and anticipated stationary and mobile source emissions,

but also a broad consensus on the means the

public will accept to reduce them. Changes in

customary practices in industry, manufacturing,

commerce, fuel use, and transportation may be

entailed. Finally, in addition to State-implemented

controls, emissions from new motor vehicles are

regulated by EPA.

Despite these regulatory mechanisms, however, large areas of the country have missed each

of several 5- and 10-year deadlines set by

Congress—first the original deadline of 1975,

and again in 1982 and 1987. Why haven’t past

programs worked?

During a series of workshops held by OTA to

answer this question, many State and local

officials and other participants called the past

deadlines unrealistic. They argued that the

deadlines forced a short-term focus in both

developing plans and implementing programs,

even though the worst nonattaimnent cities
Chapter 1—Summary ● 5

clearly needed decades of concerted effort to

overcome their ozone problems. Inadequate

timeframes, these critics argued, encouraged

States to cheat on their SIPS, and EPA to play

along with them.

Many officials also blamed incomplete or

inadequate inventories of local pollution sources

and overly optimistic forecasts of future emissions for the failure of certain control strategies.

Few regulators, for example, anticipated the

general rise in gasoline volatility, which increased VOC evaporation. Many also underestimated the growth in automobile use that occurred. In addition, some of the mathematical

models used for planning proved inaccurate,

causing miscalculations of the quantities of

controls needed.

Many States also had difficulty enforcing

regulations on stationary emissions sources,

controlling emissions growth, and preventing

ozone or its precursors from blowing in from

neighboring areas. Finally, many of the workshop participants noted a widespread ‘‘lack of

political will” to take steps necessary to meet

the ozone standard, both in EPA and many

States.

Looking ahead, clearly we still do not have all

the answers. If we are willing to use and pay for

currently available technology, we can make

significant advances over the next 5 to 10 years,

achieving about two-thirds of the reductions we

need. This should bring about half of all current

nonattainment areas into compliance. But we

cannot, by the year 2000, get the entire Nation

to the goal that Congress established in 1970.

In facing this reality, Congress will have to

address several major issues, which fill the

remainder of this summary. The next section

considers the question of how hard Congress

should push for ozone reductions. How should

we balance the severity of the health effects

against the difficulty of the task, especially for

those cities with no practical possibility of

achieving the needed reductions with currently

available technology? The third section explores

the currently available means—and costs----of

controlling VOCs. The last section looks into

the technological and regulatory future, examining new directions and long-term efforts toward

VOC reductions as well as approaches that are

largely untried, including NOX controls and

efforts to reduce upwind emissions. Finally, the

last section considers means of reducing ozone

in rural areas.

HOW RAPIDLY TO PROCEED

The central issue facing Congress is how to

balance the urgency of the ozone problem

against the difficulty of the solution. In a number

of areas, meeting the goal will exact substantial

financial and social costs. Though experts disagree about the level of danger that ozone

actually poses to the population, a large portion

of the American people live in places where

ozone concentrations far exceed those known to

be completely safe. Clearly, therefore, the societal goal set by Congress in the Clear Air Act

Amendments of 1970, achieving air quality

necessary ‘‘to protect the public health. . . with

an adequate margin of safety, ” weighs in on the

side of prompt and effective action.

Equally clear, however, is the fact that in the

worst areas, even the most costly and stringent

of available measures will not lower emission

levels sufficiently to meet the standard. Achieving that goal is a long-range project, well beyond

the 5- and 10-year horizons of existing law. It

will require both new technologies and lifestyle

changes in the most affected communities,

including changes in transportation, work, and

housing patterns. In other, less polluted nonattainment areas, the standard can be met with less

cost and disruption.

About 100 nonattainment areas dot the country from coast to coast, with ‘‘design values”—

a measure of peak ozone concentrations—

ranging from 0.13 ppm to as high as 0.36 ppm.

Figure 1-1 summarizes the data for the 3-year

period 1983-85. Generally, the higher the design
6 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 1-1—Areas Classified as Nonattainment for Ozone Based on 1983-85 Data

The shading indicates the fourth highest daily maximum l-hour average ozone concentration, or “design value,” for each area.

SOURCE: U.S. Environmental Protection Agency

value, the stricter the emission controls needed

to meet the standard. Half the areas are fairly

close to attainment, with design values up to

0.14 or 0.15 ppm; for these places, reaching the

standard is probably feasible with existing

technologies. However, the remaining areas,

including the Nation’s worst violator, Los

Angeles, present much more serious and challenging problems, with design values in excess

of 0.16 ppm.

About half of all Americans live in areas that

exceed the standard at least once a year. As

shown in figure 1-2, 130 of the 317 urban and

rural areas for which we have data exceeded

0.12 ppm for at least one hour between 1983 and

1985. Sixty of them had concentrations that high

for at least 6 or more hours per year. A number

of areas topped the standard for 20 or more

hours, with the worst—Los Angeles—

averaging 275 hours per year.

Ozone in a city’s air, however, does not

necessarily equal ozone in people’s lungs.

Concentrations vary with time of day and exact

location. People vary in the amount of time they

spend indoors, where concentrations are lower.

And the more actively someone exercises, the

more ozone he or she inhales. Each year,

nationwide, an estimated 34 million people are

actually exposed to ozone above 0.12 ppm at

low exercise levels, and about 21 million are

exposed during moderate exercise, on average

about 9 hours per year. About 13 million people
Chapter 1—Summary• 7

Figure 1-2—Areas Where Ozone Concentration s Exceeded 0.12 ppm at Least One Hour Per Year on Average,

From 1983-85

6 to 20 v

more than 20

Data from all monitors located in each area were averaged in constructing the map. The shading indicates the number of hours that a

concentration of 0.12 ppm was exceeded. One hundred thirty million people reside in the areas shown.

SOURCE: U.S. Environmental Protection Agency, Storage and Retrieval of Aerometric Data, data base, processed by E.H. Pechan & Assoc., 1987.

are exposed to ozone above 0.12 ppm during

heavy exercise, each of them for about 6 hours

each year, on average. At each exercise level,

one-quarter of these people live in the Los

Angeles area.

It is important to remember that people have

varying lifestyles, not ‘‘average” ones. Those

exposed to high concentrations at high ozone

levels of exercise include some who choose to

be outside and some who have no choice, the

latter including workers doing physical labor

such as construction. About 5 percent of adult

men work outdoors most of the time, and an

additional 10 percent do so part of the time.

Children play outdoors for about 3 to 4 hours

each day, on average, during the summer

months when school is out and ozone concentrations are high.

Human Health

Ozone’s most perceptible short-term effects

on human health are respiratory symptoms such

as coughing and painful deep breathing. It also

reduces people’s ability to inhale and exhale

normally, affecting the most commonly used

measures of lung function (e.g., the maximum

amount of air a person can exhale in one second

or the maximum he or she can exhale after
8 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

taking a deep breath). As the intensity of

exercise rises, so does the amount of air drawn

into the lungs, and thus the dose of ozone. The

more heavily one exercises at a given level of

ozone concentration, and the longer the exercise

lasts, the larger the potential effect on lung

function.

At what point do these short-term effects

become so severe that the public needs protection? The Clean Air Act mandates control of

pollutants that produce “an adverse effect on

public health or welfare,” but scientists differ

on whereto place this threshold. They agree that

permanent respiratory injury or disabling illness

would definitely fall into the ‘‘adverse” category, but not on whether mild to moderate

symptoms and smaller, reversible changes in

lung function that produce no disability should

be considered adverse, as well. Thus, many

Members of Congress and staff have heard

conflicting opinions on the seriousness of the

problem. Some people say it affects only a few

asthmatic joggers who lack the sense to stay

indoors on hot, smoggy summer afternoons.

Others see it as a major public health danger

threatening over 100 million Americans.

Medical concern centers as much-or even

more---on chronic damage as on short-term

effects, although research to date has yielded

only limited understanding of chronic risks.

Some researchers see links between the acute

effects produced by short-term exposure and

certain mechanisms that could produce chronic

effects or lasting injury. Animal studies, for

example, reveal biochemical and structural

changes in lung tissue that could, if duplicated

in humans, produce permanent, irreversible

damage. Ozone exposure appears to reduce, at

least temporarily, the lungs’ ability to ward off

infection, possibly paving the way for disease.

In addition, animal studies have shown a tendency toward ‘stiffening” of the lung, a step in

premature aging. As yet, though, evidence for

chronic effects in humans at concentrations

present in nonattainment cities remains inconclusive.

EPA identifies two subgroups of people who

may be at special risk for adverse effects:

athletes and workers who exercise heavily

outdoors and people with preexisting respiratory problems. Also problematic are children,

who appear to be less susceptible to (or at least

less aware of) acute symptoms and thus may

spend more time outdoors in high ozone concentrations. Most laboratory studies have shown no

special effects in asthmatics, but epidemiologic

evidence suggests that they suffer more frequent

attacks, respiratory symptoms, and hospital

admissions during periods of high ozone. In

addition, about 5 to 20 percent of the healthy

adult population appear to be ‘‘responders, ”

who for no apparent reason are significantly

more sensitive than average to a given dose of

ozone.

Results from a preliminary model developed

for OTA illustrate that at the summertime ozone

levels found in many cities, some people who

engage in moderate exercise for extended periods can experience adverse effects. For example, on a summer day when ozone concentrations average 0.14 ppm, a construction worker

on an 8-hour shift might experience a temporary

decrease in lung function that most scientists

consider harmful. On those same summer days,

children playing outdoors for half the day would

also risk effects on lung function that some

scientists consider adverse. (See figure 1-3.)

And some heavy exercisers, for example runners and bicyclists, would notice adverse effects

in about 2 hours. Even higher levels of ozone,

which prevail in a number of areas, would, of

course, have swifter and more severe impacts on

health.

So what would Americans gain by meeting

the standard nationwide? In terms of acute

effects, the Nation would avoid several hundred
Chapter 1—Summary • 9

Figure 1-3-Likelihood of Adverse Effects From Ozone While Exercising

Construction Work or Children Playing Competitive Sports or Bicycling

some scientists believe adverse effects will occur

I

few adverse effects likely

2

● Current ozone standard

I

Average ozone concentration (ppm) during activity period Average ozone concentration (ppm) during activity period

The likelihood of experiencing adverse effects depends on 1) the ozone concentration, 2) the vigorousness of the activity, and 3) the

number of hours engaged in that activity. The figure on the left shows the number of hours to reach an adverse effect under moderate

exercise conditions (e.g., construction work or children playing). The figure on the right shows that fewer hours are needed under heavy

exercise (e.g., competitive sports or bicycling). The current one-hour ozone standard is shown for comparison.

SOURCE: OTA, based on work for OTA by Lawrence J. Folinsbee, Environmental Monitoring and Services

million episodes of such respiratory symptoms

as coughing, chest pain and shortness of breath.

Some people in the worst areas would experience dozens fewer incidents of respiratory

symptoms each year, while many in other areas

would experience no change. About 8 to 50

million days of restricted activity might also be

eliminated. These are days when someone feels

ill enough to limit the day’s activities, if not

necessarily to stay in bed or home from work.

Most of the benefit would be concentrated in

high ozone areas such as southern California and

the Northeast corridor cities.

The economic value of eliminating those

short-term effects might total between $0.5 and

$4 billion, according to rough estimates that

incorporate assumptions about what people

would be willing to pay to be free of ozone’s

acute symptoms. Unfortunately, we cannot estimate the value of the lowered risk of long-term,

chronic effects, Whether these effects exist, and

what their magnitude may be, is still unknown.

They might be either large or small. This

uncertainty must also be factored into congressional decisions about attainment.

Setting the Pace for Progress

From a policy standpoint the Nation’s nonattainment areas fall along a‘‘continuum of possibility. ” At one end are those that can confidently

expect to achieve the standard within a 5-year

timeframe using existing controls. At the other

extreme are those where attainment is a far-off

prospect, requiring 15 to 20 or more years and

extensive control technology development. In

between fall those that will face differing

degrees of difficulty and need intermediate

amounts of time to meet the Clean Air Act’s

goals.

For the first group, those close to attainment,

both EPA and the State and local air regulators,

STAPPA/ALAPCO (the State and Territorial

Air Pollution Program Administrators and the

Association of heal Air Pollution Control

Officials) suggest 5 years as an appropriate
10 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

planning and implementation period. For the

intermediate group, additional time for planning, modeling, and control technology development and implementation will increase

chances of success. Under the 1977 Clean Air

Act Amendments, Congress permitted these

areas 10 years, 5 more than the original deadline.

Assuming incentives that encourage development of new control methods, a number of these

cities should succeed in meeting the goal within

8 to 10 years after Congress amends the Act. The

worst nonattainment areas, however, especially

Los Angeles, are likely to require 20 years or

more. For these extremely challenging cases,

Congress may wish to set a long-term deadline

such as 20 years, or discard deadlines altogether

and impose interim requirements instead.

Naturally, the areas with the most difficult

control problems are also those with the most

urgent health risks. Thus, even if these worst

areas cannot meet a fixed deadline, they need to

move toward attainment at a reasonable rate. To

monitor progress, Congress may wish to specify

either interim air quality standards, area-wide

emission schedules, source-specific control methods, or some combination of these approaches.

Interim air quality standards are the most

direct way of gauging progress, but have the

disadvantage of requiring averages of several

years of data. Furthermore, they may inappropriately penalize States making sincere efforts

against insurmountable odds. Interim air quality

standards thus are better suited as triggers to

undertake corrective measures, for example,

identifying those plan elements that need improvement or revision. A second option, areawide schedules specifying a rate of progress in

lowering emissions (e.g., reductions of 10 to 15

percent each 3-year period) work well with

market-based approaches and allow States to

choose the most feasible and cost-effective

control methods, which may vary from place to

place. Finally, States lacking the expertise or

political clout to design and enforce new regulations may prefer a third option, a federally

prescribed list of controls that they must carry

out. Source-specific controls remove the burden

of designing control strategies from the States

by outlining exactly what each State must do.

But they also shift the responsibility for finding

new ways to reduce emissions from industry to

the EPA.

Improved data collection and planning will

most benefit the States facing the most difficult

challenges. Better planning techniques, including development of detailed emissions inventory development and air quality modeling, can

help States determine the control measures they

need to impose. At minimum, the modest

planning exercises that EPA has proposed as

basic should benefit all areas. “Enhanced planning” methods such as state-of-the-art modeling and comprehensive evaluation of control

options may be needed in the worst areas. Using

advanced planning techniques could prove expensive, costing the Nation as much as an

additional $100 million per year for the first few

years. Such costs, however, are modest in

comparison to the costs of control. Congress

may wish to assist the States to cover this cost,

either by increasing Federal grants to the States

under the existing program, or by requiring

emission fees that would raise the needed funds

from pollution sources.

Changing the Act’s deadline provisions also

raises the issue of sanctions for failure to

comply. Few people disagree with imposing

sanctions on States that fail to prepare or carry

out reasonable plans. But what should happen to

those fulfilling all the requirements of their

plans and still falling short because of the

uncertainty inherent in predicting air quality or

for other unforeseeable technical reasons? Many

people believe that States should not bear the

brunt of failures beyond their control, whether

due to reasonable scientific and technical errors,

pollution transported into their area from upwind, poor EPA performance, or the inability to

find reductions adequate to maintain a schedule

or meet a deadline. Others argue, however, that
Chapter 1—Summary Ž 11

deadlines or requirements without sanctions

will neither be taken seriously nor provide the

incentive for ‘forcing” the development of new

control technologies.

These ‘overall” policy decisions that Congress must make when amending the Clean Air

Act are summarized in table 1-1.

CONTROLLING VOLATILE

ORGANIC COMPOUNDS

Since 1970, reducing VOC emissions has

been the backbone of our national ozone control

strategy, and even now, additional progress is

still possible in this area. Congress, therefore,

may wish to mandate additional VOC controls

directly, rather than leaving the choice to the

States or the EPA. This section presents an

overview of the possibilities available with

today’s technology.

Total manmade VOC emissions, according to

OTA estimates, will remain about the same for

about a decade. Substantially lower emissions

from cars and trucks should offset sizable

increases from stationary sources, as shown in

figure 1-4. But total emissions will begin rising

again by around 1995 to 2000, assuming that

State and EPA regulations remain unchanged.

Today, as shown in figure 1-5, emissions

from mobile sources, surface coatings such as

paints, and other organic solvent evaporation

Table 1-1-Options for Amending the Clean Air Act: Overall Requirements

Deadlines:

Decision 1: How manyv categories of nonattainment areas, each

with its own deadline and other requirements, should

be established?

Option 1: Two categories-those that can attain the standard

with currently available controls and those that cannot.

Option 2: Three or more categories, including more than one

category of areas that cannot attain with currently available

controls.

Decision 2: What deadline should be set for those areas that can

attain the standard with currently available control

methods’?

. Option 1: Maintain the Act’s current 5-year schedule from start

of planning to attainment.

● Option 2: Require detailed inventories, modeling, and planning

and tallow 5 to 7 years.

Decision 3: What deadline(s) should be set for those areas that

cannot attain the standard with currently available

controli methods?

. Option 1: 8 to 10 years for the “best” of the areas that cannot

attain with currently available control measures; at least 20

years for the “worst” (Los Angeles).

. Option 2: Eliminate deadlines.

interim requirements:

Decision: What interim requirements are needed to ensure

continuing progress towards attainment?

. Option 1: interim air quality targets.

. Option 2: Areawide emission reduction schedules.

. Option 3: Source-specific controls.

● Option 4: Some combination of the above options.

Penalties and corrective actions in the event of failure:

Decision 1: For what kinds of failures should States be penalized?

. Option 1: Sanctions for failing to make “sufficient” efforts.

. Option 2: Sanctions for failing to identify enough controls to

meet a congressionally specified reduction schedule.

● Option 3: Sanctions for failing to attain the standard by the

required date.

Decision 2: What types of sanctions should be adopted?

Option 1: Sanctions that limit growth in nonattainment areas, for

example, a ban on construction of new sources of pollution or

a moratorium on hookups to publicly owned drinking water

distribution systems or sewage treatment systems.

Option 2: Limits on Federal assistance, for example, withholding Federal highway funds (except those for safety, mass

transit, and transportation improvement projects related to air

quailty) or sewage treatment grants.

Decision 3: What types of corrective actions should be adopted?

. Option 1: Planning requirements.

. Option 2: Source-specific controls.

. Option 3: Market-based control programs, for example, emissions fees or marketable emissions permits.

Stats and local planning requirements:

Decision 1: What types of planning should be required and

where?

. Option 1: Minimal requirements for all nonattainment areas.

● Option 2: Enhanced efforts in areas with the worst ozone

problems or a typical conditions.

Decision 2: Who pays for enhanced State and local planning

activities?

. Option 1: Increase funding for section 105 grants or make

special, separate appropriations for ozone nonattainment area

planning.

. Option 2: Develop a nationwide user-fee program (administered by EPA) or a fee requirement (administered by the

States) on nonattainment area emissions.

SOURCE: Office of Technology Aseessment, 1989.
12 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 1-4-Summary of Estimated Nationwide Volatile Organic Compound (VOC) Emissions by Source

Category, by Year

Emissions (million tons/yr)

14.0

12.0

10.0

8.0

6.0

4.0

2.0

0.0

1

11.4

13.1

ge stationary

marine

The numbers directly above the boxes are the total emissions within the source category. For example, emissions from highway vehicles

in 1994 are 8.1 million tons per year, nationwide. Assumes no regulations other than those in place in 1987. The estimates that we present

are representative of the emissions on atypical nonattainment day, multiplied by 365 days per year, rather than estimates of true annual

emissions. For convenience, throughout the report, we refer to these estimates as annual emissions rather than as “nonattainment-dayequivalent-annual-emissions.” Note that the baseline does not include reductions due to the recently promulgated limit on gasoline

volatility of 10.5 psi Reid vapor pressure (RVP). Stationary sources that emit more than 50 tons per year of VOC are included in the large”

Category.

SOURCE: Office of Technology Assessment, 1989.

together account for about two-thirds of all tivities as decreasing metal parts and drycleanmanmade VOCs. Highway vehicles alone con- ing, and products such as insecticides. Next

tribute about 40 to 45 percent of the total, The come surface coatings, which include inks,

next largest category of emissions, evaporation paints, and various similar materials used in

of organic solvents, involves such diverse ac- painting cars, finishing furniture, and other
Chapter 1—Summary • 13

Figure 1-5-VOC Emissions in Nonattainment Cities,

by Source Category, in 1985

Percent of total VOC emissions

0% 10% 20% 30% 40% 50%

Mobile sources

Organic solvent evap

Surface coating

Petroleum industry

Gas marketing

TSDFs

Other industries

Chemical manufact.

Solid waste disposal

Nonresid. fuel comb.

Miscellaneous

Source size

Total emissions = 11 million tons/year

Stationary sources that emit more than 50 tons per year of VOC

are included in the large” categories

SOURCE: OTA, fnxn EPA’s National Emisalons Data System (NEDS) and Natbnal

Md PreoipltaIIon Asae88m ent Program emissions inventories.

products. These sources vary in size from huge

industrial installations to a person painting a

chair. About 45 percent of all VOC emissions

originate in small stationary sources producing

less than 50 tons per year; they include vapors

from solvents and paints, gasoline evaporating

while being pumped, emissions from printers

and autobody repair shops, and the like.

How close can nonattainment cities come to

achieving adequate reductions of these many

different kinds of VOC emissions? We have

analyzed about 60 currently available control

methods that together deal with sources producing about 85 percent of current VOC emissions.

We believe that the potential exists, using these

controls, to lower summertime VOC emissions

in nonattainment cities in the year 1994 by about

35 percent of the 1985 level. A reduction of this

size would equal approximately two-thirds of all

the reductions needed, on average, to allow

nonattainment cities to meet the standard. According to our analysis, if all currently available

controls are applied, total VOC emissions in the

nonattainment cities will fall by about 3.8

million tons per year by 1994; the exact figure

could be as low as 1.5 million tons or as high as

5.0 million tons, depending on the accuracy of

our assumptions.

All cities, however, would not reach the same

level of air quality after implementing these

reductions, as shown in figure 1-6. If those with

current design values (peak ozone concentrations)

of 0.14 ppm were to implement all the VOC

control methods we analyzed, they could

achieve ozone levels at, or even below the

standard. Cities with current design values of

0.16 ppm or higher would still fall short, and in

some cases far short, of the needed reductions.

Each of the 60 control methods analyzed

contributes to the 35-percent reduction from

1985 levels that we foresee happening in nonattainment cities, as shown in figure 1-7. The most

productive method, yielding 12 percent in reductions on a hot summer day, requires changing the composition of the Nation’s motor fuels.

Less volatile gasolinel would curtail evaporation from vehicles’ fuel tanks (including socalled ‘‘running losses” while the vehicle is

moving) and would lower exhaust emissions.

An additional 6 percent in reductions could

come from stricter controls on facilities that

treat, store, and dispose of hazardous wastes

(TSDFs). Another 4 percent could come from

applying all “reasonably available control technology” (RACT-level) controls now found in

any State’s ozone control plan to all nonattainment areas’ sources larger than 25 tons. About

40 types of sources, such as petroleum refineries, chemical manufacturers, print shops, and

drycleaners, would be included.

A 2-percent reduction would come from enhanced programs to inspect cars and trucks and

require maintenance of faulty pollution controls.

This is over and above the reductions achieved

lb Ow ~~ysis, we ~me hat gwl~e vo]atili~ is reduced to 9 pounds per square inch (psi) Reid vapor pre~~ (RVp), nationwide d~f3 ~

5-month summertime period when ozone concentrations most often exceed the standard.
14 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure l-6-Estimates of Possible Shortfalls and

Excesses in Emissions Reductions Needed to Attain

the Ozone Standard in 1994 as a Percentage of

1985 Emissions

As a percentage of 1985 emisslon s

0.14 Shortfalls in

reductions needed

0.15 to meet standard

0.16

0.17

0.18-0.26

> 0.26

\ ,

Excesses in

reductions needed

to meet standard

80% 60% 40% 20% O% 20% 40% 60% 80%

Reduction shortfall Excess reductions

The bars shown above represent ranges of uncertainty associated with our method of estimating the VOC reductions needed to

attain the standard in each city. Because of the uncertainty

associated with estimating the emissions reductions required to

attain the ozone standard, the reduction target we chose for each

city could be too low or too high. Therefore, the adoption of all

additional controls in an individual city may result in either a

shortfall or an excess in the emissions reductions required to meet

the standard. For this reason, we present estimates for both

undercontrol and overcontrol.

SOURCE: Office of Technology Assessment, 1989.

by the inspection and maintenance programs in

operation today. Modifying the nozzles of gas

station pumps to trap escaping vapors (installing

“Stage II gasoline vapor recovery systems”)

would yield another 2-percent reduction. Installing devices to do the same job on individual

vehicles as they fuel up ("onboard technology”) would produce about the same reductions

8 to 10 years later, as newer cars that have the

devices replace older ones that do not. (The two

methods together would yield only slightly

greater reductions than either method alone.)

Adopting new “control technique guidelines”

for smaller categories of stationary sources,

such as autobody refinishing and wood furniture

coating shops, coke oven byproduct plants, and

bakeries, would account for an additional 1

percent. Another 0.5-percent reduction can be

had in the worst nonattainment areas by requiring businesses that operate fleets of 10 or more

vehicles2 in those areas to substitute methanol

for gasoline. Limits on the solvent content in

architectural coatings such as paints and stains

would lower emissions by 0.5 percent. Finally,

more stringent standards for tailpipe emissions

from gasoline-powered cars and light-duty

trucks3 would lower emissions by 1.5 percent by

2004 as new cars and trucks enter the Nation’s

vehicle fleet.

Some of these controls can be implemented

by the States in nonattainment areas alone,

others are better suited to Federal implementation nationwide. The congressional options

mentioned above, as well as several additional

ones discussed in chapter 8, are summarized in

table 1-2.

As we could not identify VOC controls

capable of achieving the final third of the

reductions needed to attain the standard in all

nonattainment cities, we could not estimate the

ultimate price to the Nation of bringing ozone

under control. We can, however, estimate the

cost of bringing about half of the cities into

zwe ~ue hat over tie next ten years, methanol-fueled cars will run on a blend of 85 percent methanol md 15 percent gmline.

3Th~ emi~ion mandw& used in our analysis are as follows: (in grams of pollutant emitted per mile travelled [g/mile] fOr non-methane hydmeadm

[NMHC] and NOX)

Passenger cars- NMHC: 0.25 g/mile; NOX: 0.4 g/mile

Lightduty gasoline trucks (by truck weight)--

(less than 3,750 Ibs) NMHC: 0.34 g/mile; NOX: 0.46 g/mile

(3,750 to 6,000 lbs) NMHC: 0.43 g/mile; NOX: 0.80 g/mile

(6,000 to 8,500 Ibs) NMHC: 0.55 g/mile; NOX: 1.15 g/mile

We assume that these standards can be met during 50,000 miles of controlled tmt driving (certification testing) for passenger cars, and 120,000 miles

for light-duty trucks; however, VOC emission rates after 50,000 miles (for cars) and 120,000 miles (for trucks) of actual use by vehicle owners would

likely exceed these standsrds. We assume that new standards go into effect in 1994 for both passenger cars and light-duty trucks.
Chapter 1-Summary ● 1 5

Figure 1-7—VOC Emissions Reductions in 1994 Compared to 1985 Emissions, by Control Method

● Gasoline volatiIity

TSDFs

RACT

Enhanced l/M

Stage II

New CTG’s

+ Methanol fuels

● Architect. coatings

On board

New mobiIe std’s.

Not effective in 1994

I I

o% 2% 4% 6% 8% 1 o% 1 2% 14%

Percent reductions from 1985 emissions

● Emissions reductions also achieved in attainment areas.

+ Percent reductions onIy in those cities in which it is adopted.

Strategy Descriptions

Gasoline volatility controls which limit the rate of gasoline evaporation.

TSDF = controls on hazardous waste treatment, storage, and disposal facilities.

RACT = “Reasonable Available Control Tehnology” on all existing stationary sources that emit more than 25 tons per year of VOC.

Enhanced inspection and maintenance (i/M) programs for cars and light-duty trucks.

Stage ii control devices on gas pumps to capture gasoline vapor during motor vehicle refueling.

New CTGs = new Control Technique Guidelines for several categories of existing stationary sources for which no current regulations exist.

Methanol fuels as a substitute for gasoline as a motor vehicle fuel.

Federal Controls on architectural surface coatings.

Onboard controls on motor vehicles to capture gasoline vapor during refueling.

New highway-vehicle emission standards for passenger cars and light-duty gasoline trucks.

SOURCE: Office of Technology Assessment, 1989.

compliance, and of substantially improving the nationwide, rather than just in nonattainment

air quality of the rest. Applying all these controls areas, the national price tag would total about

in all nonattainment cities would cost these $8.8 to $13 billion in 2004.

cities between $4.2 and $7.1 billion per year in Some of these controls simultaneously reduce

1994 and between $6.6 and $10 billion annually other air pollutants in addition to VOCs. Enby 2004. Because some controls would apply hanced motor vehicle inspection and mainte-
16 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 1-2-Options for Amending the Clean Air Act:

Currently Available Control Methods

Federally implemented, nationwide control

requirements:

● Option 1: Limits on gasoline volatility.

● option 2: More stringent tailpipe exhaust standards for cars

and trucks.

. Option 3: “Onboard” technology for cars and trucks to control

refueling emissions.

● Option4: Federal solvent relations for example, for architectural

coatings.

Control requirements to be implemented by States

in nonattainment areas:

. Option 1: Lowered source-size cutoff for requiring “reasonably available control technology” (RACT).

● Option 2: Require EPA to define RACT for additional source

categories.

. Option 3: More stringent requirements for motor vehicle

inspection and maintenance programs.

. Option 4: Required use of alternative fuels by centrally

owned fleets.

. Option 5: Transportation control measures.

● Option 6: Tax on gasoline.

Managing growth:

● Option 1: Lower the cutoff for new source control requirements.

. Option 2: Eliminate “netting” out of new source control

requirements.

. Option 3: Areawide emission ceilings.

SOURCE: Office of Technology Assessment, 1989.

nance programs also reduce nitrogen oxides and

carbon monoxide. More stringent highway vehicle standards apply to nitrogen oxides, too.

About $2.5 billion of the total nationwide cost

in 2004 can be assigned to nitrogen oxide

control, the benefit of which will be discussed

later. About $1.5 billion per year can be assigned

to control of carbon monoxide.

Depending on the method used, the cost of

eliminating a ton of VOC emissions varies

considerably. By far the cheapest is limiting

gasoline volatility, at about$120 to $750 per ton

of VOC reduction; by far the most expensive is

replacing gasoline with methanol, at $8,700 to

$51,000 per ton of reductions. (See figure 1-8.)

As shown in figure 1-9, the cheaper methods can

provide reductions equal to about 30 percent of

the 1985 levels. As more reductions are required, though, more and more expensive methods must come into play, and the cost of

additional reductions rises steeply.

Most of the control methods we analyzed cost

between $1,000 and $5,000 per ton of VOC

reductions obtained. We estimate that in 1994,

if controls costing more than $5,000 per ton of

reductions were excluded from consideration,

total annual costs for the nonattainment areas

would drop to about $2.7 to $5.1 billion per year,

a drop of about 30 to 35 percent. There would be

a corresponding loss in reductions of about 2

percent of 1985 emissions.

Were all the analyzed controls applied, the

remaining emissions in nonattainment areas

would come mainly from highway vehicles (25

to 30 percent) and small stationary sources (55

percent), many of which do not lend themselves

to traditional forms of regulation. Solventcontaining consumer and commercial products,

for example, along with architectural surface

coatings, individually emit small amounts of

VOCs, but in aggregate they amount to about 10

percent of the remaining inventory.

NEW DIRECTIONS

Obviously, local controls on VOC emissions

cannot completely solve the Nation’s ozone

problem. New control methods will be needed,

but looking beyond the traditional controls

raises challenging new technical and political

issues. One promising approach for some areas

is controlling NOX

, both locally and in areas

upwind of certain nonattainment cities. Indeed,

some cities will not be able to attain the ozone

standard unless the areas from which they

receive windblown ozone or precursors, which

may themselves comply with the standard,

further reduce their emissions. In addition, rural

areas, many of which are affected by high VOC

emissions from vegetation, transport of pollutants from other areas, or both, call for strategies

different from those used in cities. And finally,

while we can take preliminary steps in each of

these nontraditional approaches over the next
Chapter l-Summary . 17

Figure 1-8-Estimated Cost-Effectiveness of VOC Emission Control Methods in 1994 in Nonattainment Cities

Gasoline volatility

TSDFs

RACT

Enhanced l/M

Stage II

New CTGs

Methanol fuels

Architect. coatings

On board controls

New mobiIe std’s.

Stage II & On board

The cost-effectiveness of enhanced inspection and maintenance (l/M) programs and new mobile standards include only the cost of VOC

control. Since Onboard controls and new mobile standards do not take affect until after 1994, we present the cost-effectiveness in 2004.

The thick horizontal bars represent the average cost-effectiveness in nonattainment cities. The thin horizontal lines for gasoline volatility,

methanol fuels, and l/M programs represent ranges of uncertainty associated with assumptions we used to estimate total annual costs.

The very large uncertainty associated with the methanol fuels is due to the uncertainty of methanol prices relative to gasoline prices. We

were unable to estimate cost-effectiveness uncertainty for other control methods. See figure 7 for a description of control methods.

SOURCE: Office of Technology Assessment, 1989.

decade, additional research will greatly help in

the search for productive new directions for

ozone control after the year 2000. Congressional

options for pursuing these new approaches to

controlling ozone are summarized in table 1-3.

Controlling Nitrogen Oxides

Historically, ozone control efforts have concentrated on VOC emission reductions both because methods were thought to be cheaper and

more available and because in some cases

reducing NOX may actually be counterproductive. The precise local balance of VOCs and

NOX varies from place to place, even within the

same metropolitan area, and from day to day.

Where the concentration of NOX is high relative

to VOCs, for example, in urban or industrial

centers with high NOX emissions, reducing

VOC emissions can effectively cut ozone because production is limited by the quantity of

available VOCs. In these cases, reducing NOX

may actually increase ozone concentrations.

NOX reductions work best where the relative

concentration of VOCs is high and the produc-
18 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 1-9-Cumulative Annual Cost of, and Percent

Emissions Reductions From, VOC Control Methods

Table 1-3-Options for Amending the Clean Air Act:

New Directions

10

200 4

8

6

4

2

0

0 5 10 15 20 25 30 35

Cumulative percent emissions reductions

from 1985 levels

Control methods are ranked by cost-effectiveness, that is, the total

cost of control per ton of VOC reduced. For example, the most

cost-effective controls (e.g., gasoline volatility) are located in the

lower left portion of the curve. In this figure, the costs of enhanced

l/M programs and new highway-vehicle standards include the

VOC control costs and the cost of NOX and carbon monoxide

control (1/M programs, only).

SOURCE: Office of Technology Assessment, 1989.

tion of ozone is thus “NOX-limited.” This

occurs in some cities and in most rural areas. As

an air mass moves away from industrial districts

and out over suburban or rural areas downwind

of pollutant emission centers, conditions tend to

become more NOX-limited because NOX disappears from the air through chemical and physical

processes more rapidly than do VOCs.

Two types of sources, highway vehicles and

electric utility boilers, account for two-thirds of

NOX emissions. Highway vehicles contribute

about a third of the national total, led by

passenger cars with 17 percent and heavy-duty

diesel trucks with 9 percent. In the southern

California cities with design values above 0.26,

highway vehicles account for about two-thirds

of local NOX emissions; in most nonattainment

cities, they contribute about 30 to 45 percent.

Under current regulations, total NOX emissions will increase steadily between 1985 and

2004, rising by about 5 percent by 1994 and by

Controls on emissions of nitrogen oxides in

nonattainment areas:

● Option 1: Congressionally mandated NOX controls.

. Option 2: Presumptive NOX controls on stationary sources, with

EPA authority to exempt areas under specified situations

● Option 3: Requirements to analyze NOX controls under certain

situations.

Long-term control VOC strategies:

. Option 1: Lowering emissions from solvents, either through

traditional “engineering” approaches or through market-based

mechanisms.

● Option 2: Transportation control measures.

● Option 3: Requirements for widespread use of alternative fuels

in nonattainment areas that are far from meeting the standard.

Controls in upwind areas:

● Option 1: Enlarge nonattainment areas to include the entire

extended metropolitan area.

● Option 2: Congressionally specified NOX controls in designated

“transport regions” or nationwide,

● Option 3: Strengthen the interstate transport provisions of the

Clean Air Act.

● Option 4: Provide EPA with clear authority to develop regional

control strategies based on regional-scale modeling.

Reducing ozone in attainment (rural) areas:

. Option 1. Specify a deadline for EPA reconsideration of the

ozone secondary standard and a schedule for Option by the

States.

● Option 2. Congressionally specified NOX controls.

Research:

Decision 1: What areas of research deserve increased funding?

● Improving the planning process, developing new control methods, and further evaluating the risks from ozone.

Decision 2: Who pays for the research?

. Option 1: General revenues.

● Option 2: User fees.

SOURCE: Office of Technology Assessment, 1989.

about 25 percent by 2004. (See figure 1-10.) As

newer, cleaner cars replace older ones, highway

emissions will decline until the mid- 1990s, only

to rise again as miles traveled increase. Stationary sources, however, will increase their emissions steadily.

We analyzed the potential for emissions

reductions and costs of using three currently

available NOX control categories in nonattainment areas. First was placing “reasonably

available” control technology (RACT) on existing stationary sources emitting more than 100

tons per year; these include both electric utility

boilers and other large stationary sources such as
Chapter 1—Summary ● 19

Figure I-l O-Summary of Estimated Nationwide Nitrogen Oxides (NOX) Emissions by Source Category, by Year

Emissions (miIIion tons/yr)

10. 0

8 . 0

6 . 0

4 . 0

2 . 0

0 . 0

1—

8 . 6 —

 large s

stat i o n a r y

iIe source s

tation

198 5 1994 199 9 200 4

Year

The numbers directly above the boxes are the total emissions within the source category. For example, emissions from highway vehicles

in 1994 are 6.0 million tons per year, nationwide. Assumes no new laws or regulations.

SOURCE: OTA, based on work by E.H. Pechan and Associates

stationary engines, gas turbines, industrial boil- could reduce NOX emissions in nonattainment

ers, and process heaters. Second was an en- cities by 1.2 million tons per year in 1994, about

hanced inspection and maintenance (I/M) pro- 17 percent below 1985 levels, and by 2 million

gram for highway vehicles, and third, more tons per year in 2004, about 28 percent below

stringent emission standards for gasoline high- 1985 levels. As shown in figure 1-11, the largest

way vehicles.4 We estimate that these measures reductions would come from controls on electric
20 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 1-11-NOX Emissions Reductions in 1994

Compared to 1985 Emissions, by Control Method

Emissions reductions in 1994

+ Elec utility boiler

+ Other RACT

Enhanced l/M

New mobile std’s.

Percent reductions from 1985 emissions

+ Controls on sources emitting more than 100 tons per year.

Strategy Descriptions:

Elecric utility boiler and other RACT = moderately stringent

controls on all existing stationary sources that emit more than 100

tons per year of NOX. Considered to be “reasonably available

control technologies.”

Enhanced inspection and maintenance (l/M) programs for cars

and light-duty trucks.

New highway-vehicie emission standards for passenger cars

and light-duty gasoline trucks.

SOURCE: OTA, based on work by E.H. Pechan and Associates

utility boilers. In addition to reductions in

nonattainment cities, new highway-vehicle emission standards would eliminate 800,000 tons per

year in attainment areas by 2004.

What would NOX controls cost? Of the three

strategies analyzed, only one, RACT-level controls on large stationary sources, was not included in the cost of “traditional” control

methods presented in the previous section. Over

and above the controls presented there, the NOX

controls would cost about $0.5 billion per year

in 1994 and about $0.7 billion in 2004. About

$2.5 billion of the nonattainment area control

costs in 2004 cited earlier can be assigned to

NOX reductions from enhanced I/M programs

and more stringent highway vehicle standards.

The impacts of controlling NOX emissions in

nonattainment areas will be mixed. The high

degree of local variation complicates the task of

deciding whether or not to mandate controls on

NOX

. Preliminary analyses indicate that in most

southern cities (from Texas east), NOX reductions would help reduce ozone concentrations;

in most isolated Midwestern cities, however,

they might have the opposite effect. Recent

results from EPA’s Regional Oxidant Model

(ROM) simulating ozone formation and transport throughout the Northeast over a 2-week

period, indicate that throughout this region,

results will be mixed. Overall, a one-third cut in

NO, emissions on top of a 50-percent reduction

in regionwide VOC emissions resulted in modest ozone benefits for most nonattainment cities,

compared to a case where VOC emissions were

controlled alone. However, this cut in NOX

emissions increased population exposure to

ozone at concentrations above the standard in

some cities (e.g., Pittsburgh), decreased population exposure in some (e.g., Hartford), and

resulted in negligible changes in others (such as

New York). Further regional and city-by-city

modeling is necessary to verify these conclusions.

Congress might wish to require studies to

determine which areas would indeed benefit

from NOX controls. On the other hand, it may

instead wish to require such controls everywhere, but allow for exemptions in places where

they are useless or counterproductive in reducing ozone.

NO, emissions affect more than just nonattainment area ozone concentrations, further

complicating the decision about whether to

mandate controls. NOX emissions contribute to

acid deposition and are a major determinant of

elevated ozone concentrations in agricultural

and forested regions. Though NOX reductions

can have either a beneficial or detrimental effect

on peak ozone concentrations in nonattainment

areas, they will most likely lower both acid

deposition and regional ozone concentrations.
Chapter I-Summary ● 21

Non-Traditional VOC Controls

Another approach to lowering ozone is developing new methods, both technical and regulatory,

of controlling VOCs. By 1994, between 25 and

30 percent of the VOC emissions remaining

after currently available controls are applied will

come from highway vehicles. About 55 percent

of the remaining total will come from small

stationary sources that individually emit less

than 25 tons per year. Over half of this latter

category will come from surface coatings and

other organic solvent evaporation. Efforts

further reduce VOC emissions must focus

these sources.

Solvents

Solvents are used in a wide variety

to

on

of

industrial, commercial, and home uses, from

cleaning and decreasing heavy equipment to

washing paintbrushes and removing spots from

garments. They appear in thousands of commercial and consumer products such as personalcare products, adhesives, paints, and cleaners

used daily throughout the country. They are

used by manufacturers to paint or otherwise coat

cars, appliances, furniture, and many other

products in facilities that range from the huge to

the tiny.

At present, only about one-quarter of total

solvent use is covered by regulations, mostly in

industrial applications. Currently available control methods could be applied to about an

additional quarter of the total, mainly by controlling solvent and coating use by small to

mid-sized industrial and commercial sources.

As indicated in figure 1-12, however, all existing regulations, whether applied or not, cover

less than half of solvent use. In trying to further

reduce solvent emissions, regulators face the

challenge of encouraging development of an

enormous variety of new products, manufacturing processes and control methods. For that

reason, alternative, innovative approaches must

be seriously considered.

One more traditional approach to controlling

these ubiquitous emissions is applying existing

controls to smaller-sized commercial and industrial sources. This is no easy task for regulators,

however, because hundreds of thousands of

firms in nonattainment areas individually use

small quantities of solvents. Another approach

is to place limits on the permissible VOC

content of certain products and processes; those

that exceed the limit after a specified date would

be banned from sale. These two strategies are

variations on established ‘‘engineering” techniques of regulating users.

Also possible are so-called market-based

approaches that do not directly regulate the user

but make the polluting products or processes

either more expensive or unobtainable, thus

harnessing producers’ and users’ self-interest in

the cause of finding substitutes. This would

encourage manufacturers to reformulate solvents and users to seek non-solvent alternatives.

Either emission fees or marketable emission

permits could be established to discourage use

of products high in VOCs by making it more

profitable to use substitutes.

Transportation Control Measures

Reducing solvent emissions will pose technological challenges. In contrast, a technologically

simple, if politically difficult, way to lower

VOC emissions now exists: cutting the use of

motor vehicles, especially private cars. The

1977 Amendments to the Clean Air Act required

urban areas to implement transportation control

measures (TCMs) necessary to meet ozone and

carbon monoxide standards. Experience shows,

though, that TCMs require considerable local

initiative and political will because they aim to

change the everyday habits and private decisions of hundreds of thousands of people.

Involuntary TCMs have proven politically infeasible and voluntary ones difficult to sustain.

Success requires long lead times, high priority

given to air quality concerns in urban transportation and land-use planning, a high degree of
22 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

Figure 1-12—Total Solvent Use Covered by Existing Regulations in 1985, by Source Category

Solvent use (million tons/year)

architectural coating

identifiable

industrial r“- architecturaI coating I

Covered Regs not applied

consumer and

commercial products

miscelIaneous

surface coating

N o regs exist

— 0.0

We show solvent use that is (1 ) covered by existing regulations in place as of 1985, (2) not covered in a particular nonattainment area, but

for which regulations do exist in other areas, and (3) not covered and for which no regulations exist as of 1985. The identifiable industrial

category includes solvent use by 14 major industrial users, including rubber and plastics manufacturing, paper coating, printing, metal

decreasing, and auto refinishing.

SOURCE: OTA, baaed on the National Acid Precipitation Assessment Program 1985 emission inventory and Environmental Protection Agency, Summary of State VOC Regulatons,

EPA450/2-S5-003.

public support and participation and, in some places; and encouraging employers to locate

cases such as mass transit development, major closer to residential areas, which would cut

capital expenditures. Possible tactics include distances workers have to travel.

requiring staggered work hours; encouraging During the 1984 Olympics, Los Angeles carpools through inducements like priority park- demonstrated that some TCMs, such as ining places, dedicated highway lanes and reduced creased transit service and modified work and

tolls; constructing attractive and economical delivery schedules, can yield worthwhile benemass transit systems; limiting available parking fits with little lead time. But the real payoff from
Chapter 1—Summary . 23

a TCM strategy comes in the long term. The

transportation and land use control measures

outlined in the 1988 Los Angeles area Air

Quality Management Plan are expected to reduce vehicle VOC emissions by a few percent in

the mid- 1990s, but with additional legal authority and highway funding, Los Angeles hopes to

achieve reductions of about 30 percent by 2010,

compared to projected levels without TCMs.

Growth management measures aimed at matching new jobs with nearby housing account for

almost half the reductions projected for 2010,

but will have only negligible impact before

2000. An additional 15 percent of the reductions

by 2010 will come from new freeway construction intended to reduce congestion.

Neither of these measures will be easy:

growth management will require coordination

of zoning laws and other development policies

among dozens of municipalities. The proposed

freeway construction will require additional

revenue, and, if it were to encourage vehicle use

more than anticipated, would be less effective

than planned.

Alternative Motor Vehicle Fuels

Fueling vehicles that now use gasoline with

either methanol or compressed natural gas

(CNG) is another technically feasible option that

would produce only modest reductions in the

near term but that could, with advances in

automotive technology and an infrastructure to

support delivery of fuels, ultimately result in

quite substantial air quality benefits. Methanol

cars likely to be available over the next 10 years

will run on a blend of 85 percent methanol and

15 percent gasoline (or straight gasoline if

necessary). VOC emissions from these vehicles

would be about 30 percent lower in ozoneproducing potential than comparable use of

low-volatility gasoline.

Over the long term, assuming advances in

vehicle technology and widespread availability

of methanol so that straight (100 percent)

methanol can be exclusively used, the ozoneproducing potential of dedicated methanol vehicles may be up to 90 percent lower than current

gasoline vehicles. Several technical problems

must first be addressed, however, including

difficulty starting vehicles on straight methanol

in cold weather and safety concerns related to

the fuel’s acute toxicity and invisible flame.

The ozone-producing potential of dedicated

CNG vehicles would also be up to 90 percent

lower than current gasoline vehicles. The distance they can travel before they must be

refueled is about half that of gasoline, however,

even with a considerably larger fuel tank.

Moreover as we have seen, use of alternative

fuels, especially methanol, is potentially a very

expensive control measure. The actual marginal

cost over gasoline depends, of course, on future

fuel prices, which are notoriously difficult to

predict. Widespread use of alternative fuels

would require development of both commercially available vehicles and a considerable

supply infrastructure, neither of which now

exist. Requiring use of CNG or methanol in

selected cities, and only in commercial fleets of

vehicles that are fueled at a central location,

would be a way of gaining some experience with

alternative fuels and beginning to reap some air

quality benefits, while holding down infrastructure costs.

Ozone Transport

In many places, even those with good control

of their local emissions, reducing ozone is

complicated by the ‘‘transport” of pollutants, as

ozone or precursors originating elsewhere are

carried in by the wind. ‘‘Plumes” of elevated

ozone have been tracked 100 miles or more

downwind of some cities: New York’s, for

example, can extend all the way to Boston. Over

half of the metropolitan areas that failed to attain

the ozone standard between 1983 and 1985 lie

within 100 miles downwind of other nonattainment cities. In such cases, VOC (and sometimes

N OX) reductions in the upwind cities could

probably improve air quality in their downwind
24 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

neighbors. Indeed, reductions in certain areas

that are themselves already meeting the standard

might also aid certain downwind nonattainment

areas.

The significance of transported pollutants

varies substantially from region to region and

day to day. During severe pollution episodes

lasting for several days, for example, industrial

or urban NOX or ozone pollution can contribute

to high ozone levels hundreds of miles away. In

certain heavily populated parts of the country,

pollution transport is a significant, and a very

complex, problem. The northeast corridor, from

Maine to Virginia, contains 21 nonattainment

areas in close proximity; California, 8; the gulf

coast of Texas and Louisiana, 7; and the Lake

Michigan area, 5. Over the next 2 to 5 years

proposed or ongoing modeling studies in these

four major transport regions could provide

information about the quantities of pollutants

that are transported and the potential effectiveness of different control strategies.

Congress may wish to mandate direct controls on transported pollutants, possibly by

enlarging nonattainment areas to include entire

consolidated metropolitan areas or even larger

regions. Designing effective strategies, however, requires very detailed information. As an

alternative, Congress might wish to provide

EPA the clear authority to develop regional

control strategies based on regional modeling.

Rural Ozone

Excessive ozone and precursor pollutant transport affect more than just cities and suburbs.

Both crops and trees in rural areas are sensitive

to ozone concentrations well below the human

health-based standard.

Light flecks, dark stipples, yellow spots,

premature aging, and leaf loss mark annual

crops injured by ozone; reduced growth rates

and yields may occur even without visible

injury. Crop losses increase as ozone concentrations rise. At concentrations found in rural areas

throughout much of the United States, ozone

depresses yields of economically important

crops such as soybeans and cotton by between

a few and 20 percent. Ozone concentrations

during the day, averaged over the entire growingseason, exceed 0.04 ppm in California, parts of

the Midwest, throughout the South, and up the

east coast. (See figure 1-13.) We estimate that

the Nation could realize between $0.5 billion

and $1 billion in benefits from a nationwide

drop in ozone concentrations amounting to 25

percent of the difference between current levels

and estimated background levels.

In the forests of the San Bernardino Mountains east of Los Angeles, and throughout the

Eastern United States, sensitive strains of trees

are seriously affected by ozone. However, the

impacts of ozone on trees and forest ecosystems

are not yet well enough understood to allow us

to estimate the economic benefits from a reduction of ozone damage to trees in National and

State parks, forests, and commercial timberlands.

Strong evidence links ozone to damage of

ponderosa and Jeffrey pines in the San Bemar-

.dino National Forest. Incense cedar and white fir

may replace these ozone-sensitive trees as the

dominant species. Sensitive strains of eastern

white pines in the Great Smoky Mountains and

Acadia National Parks show symptoms of ozone

injury. Scientists are concerned that ozone may

be contributing to declines of red spruce in some

high-elevation Appalachian forests and to reduced growth rates of yellow pines in some

southern forests.

Congress may wish to specify a deadline for

EPA reconsideration of revising the “secondary” standard, which protects vegetation, and

a schedule for subsequent adoption by the

States. Currently, the secondary standard is

identical to the health-based standard and is

generally thought to be poorly designed for

protecting vegetation. Another option is for

Congress to directly specify regional or national
Chapter 1—Summary • 25

Figure 1-13-Estimated Daily 7-hour Average Ozone Concentrations During the Growing Season

Location of Rural Ozone Monitors

N Ox controls, for example, stricter vehicle Continuing the Search

emission standards, in order to help lower ozone Ozone is probably the least understood of the

in rural areas. Theory suggests that NOX controls six ‘‘criteria” pollutants that the Clean Air Act

in southern and eastern rural areas will produce seeks to control and, not surprisingly, the most

greater benefits than VOC controls. intractable to date. A modest investment in
26 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

research today will pay off in better decisions

and better results 10 years from now. Research

should focus on improving the planning process,

developing new control methods, and further

evaluating the magnitude of the risks from

ozone.

Planning-related research would provide better VOC emissions inventories and air quality

models, which would permit more accurate

plans and effective programs. Current VOC

emissions inventories are quite poor. Emissions

are not actually measured, but are estimated

using models. Today’s VOC models are far less

accurate than, for example, those used for sulfur

dioxide or NOX. Only the 10 percent of emissions from large stationary sources such as

refineries and chemical plants are individually

surveyed and their emissions estimates reasonably accurate. The 40 to 45 percent from

highway vehicles are estimated from a recently

updated model that some still believe to be

inadequate. Another 25 to 30 percent of emissions, those from diverse uses like solvents,

drycleaning, and surface coatings, can be estimated nationally from sales figures; in any

given nonattainment area, however, they can

only be crudely guessed. Emissions from vegetation, which may figure crucially in the inventories of some nonattainment areas, are also very

poorly understood. The air quality models used

by most States to prepare their control plans are

a good deal less accurate than the very best

‘‘state-of-the-art” versions now available. More

EPA attention to the operational aspects of

modeling—developing tools for the average

State agency, rather than for the expert modeller—

could improve most States’ ability to understand

the effectiveness of alternative emissions controls.

Developing solvent substitutes, cleaner fuels

and methods of trapping and destroying VOCs

from small sources also deserve high priority. At

present, though, EPA’s annual budget for new

and cheaper VOC control measures is less than

one-tenth of one percent of the projected cost of

control. In fiscal year 1989, EPA spent about

$3.8 million on methods to lower mobile source

emissions, the vast majority on one program,

methanol-fueled vehicles. EPA spent only $0.4

million on research to develop new control

methods for stationary sources of VOC.

This level of funding does not seem well

matched to the magnitude of the shortfall in

reductions needed to attain the standard after

applying all currently available technology.

Moreover, putting the majority of the research

emphasis on but one new control strategy-use

of methanol fuels—seems very risky.

And finally, an intelligent approach to ozone

requires a broader understanding of its effects.

Regulatory efforts now focus primarily on one

category of effects, temporary loss of some lung

function resulting from exposure to short-term

peaks. We cannot evaluate ozone’s true risks,

however, without knowing much more about the

chronic effects of long-term exposure. We also

need to know the full nature and extent of

ozone’s ‘‘welfare” effects, especially those on

forests.
Chapter 2

Ozone and The Clean Air Act
CONTENTS

Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. ... ... .....29

EVOLUTION OF OZONE CONTROL UNDER THE CLEAN AIR ACT... . . . . . . . . . . 29

STATE IMPLEMENTATION PLAN DEVELOPMENT AND

IMPLEMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

FAILURE TO MEET THE OZONE STANDARD FOLLOWING THE

1977 AMENDMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Incomplete and Inadequate Emissions Inventories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Underestimates of the Extent of Control Required To Attain the Standard . . . . . . . . . . . 33

States Had Difficulty Issuing Stationary Source Regulations . . . . . . . . . . . . . . . . . . . . . . . 34

Poor Control Over Emissions Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Inability To Control “Transported” Ozone and Precursors . . . . . . . . . . . . . . . . . . . . . . . . . 35

Lack of Leadership and Political Will To Solve the Problem . . . . . . . . . . . . . . . . . . . . . . . 35

Unreasonable Deadlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

REFERENCES FOR CHAPTER 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Chapter 2

Ozone and The Clean Air Act

INTRODUCTION

The goal of the Clean Air Act is to “protect and

enhance the quality of the Nation’s air resources. ”

To implement that goal, the 1970 Clean Air Act

Amendments required EPA to establish National

Ambient Air Quality Standards (NAAQS) to define

the level of air quality that is expected to be

maintained throughout the Nation. Of the six ‘criteria” pollutants for which standards have been

established, we have been least successful in our

efforts to attain the standard for ozone. Nationwide,

about 100 areas still violate the ozone standard.

This upcoming reauthorization of the Clean Air

Act will be the third time that Congress will specify

a mechanism to achieve the goal specified in 1970.

To provide context for the remainder of the report,

in this chapter we first review the Framework for

meeting the ozone standard that was established in

the 1970 and 1977 Clean Air Act Amendments and

then briefly discuss the State implementation planning (SIP) process. The last section presents some of

the reasons why efforts to meet the standard

following the 1977 Amendments failed.

EVOLUTION OF OZONE CONTROL

UNDER THE CLEAN AIR ACT

The 1970 and 1977 Clean Air Act Amendments

established a partnership between the States and the

Federal Government. EPA sets nationally uniform

air quality standards; and the States, with the

Agency’s assistance, are responsible for meeting

them. The requirement that the States develop

“State Implementation Plans” (SIPS) and submit

them to EPA for review allows for Federal oversight

of the States’ efforts to achieve and maintain the

required level of air quality. In addition to the SIP

process, the 1970 Clean Air Act Amendments

established two mandatory control programs, one

applying to new motor vehicles and the other to new

stationary sources. EPA is responsible for setting

standards for new motor vehicles. EPA also issues

regulations for new stationary sources, but the

program is implemented by the States. The 1977

Amendments added three additional control programs, requiring ozone and carbon monoxide nonattainment areas to apply retrofit controls on existing

stationary sources and more stringent emissions

limits on new stationary sources, and to develop

motor vehicle inspection and maintenance programs.

As defined in the Clean Air Act, “primary” air

quality standards represent the maximum allowable

concentration of each criteria pollutant that protects

against adverse health effects. The primary standards are required to be set at a level that ‘protects the

public health” with an “adequate margin of safety,”

without regard to the economic or technical feasibility of attainment. Secondary standards are established to protect against adverse impacts on human

comfort and welfare, including impacts on visibility,

vegetation, animals, wildlife, materials, and property. The States, together with EPA, are responsible

for ensuring that the primary air quality standards are

met “as expeditiously as practicable,” within the

deadlines specified in the Act. The secondary

standards are to be attained in a‘ ‘reasonable” period

of time.

Primary and secondary standards for oxidants2

were first set by EPA in 1971. In 1979, EPA revised

the standards to the current definition. Both the

primary and secondary standards for ozone are

currently defined as a daily maximum, l-hour

average concentration of 0.12 parts per million

(ppm). not to be exceeded more than once per year,

on average.

In the Clean Air Act Amendments of 1970,

Congress set 1975 as the deadline for meeting the

primary air quality standards. The States were

required to develop and carry out SIPS, estimating

the emissions reductions required to attain the

NAAQS, and establishing control programs to

achieve the required reductions. In addition, EPA

IThe Slx ‘tcnte~a” @lutat~ for which the Environmental protection Agency has been explicitly req~re(t to establish NAAQs are ozone, lead,

sulfur dioxide, particulate, nitrogen dioxide, and carbon monoxide.

zphotwhemic~ Oxldmts ~e ~ ~oup of chemically related pollutants. From tie standpoint of he~th and welf~e eff~ts, ozone is the IIIOSt important

of these pollutants. Ozone typically comprises over 90 percent of the total mass of” photochemical oxidants measured in urban air.

–29–
30 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

President Richard M. Nixon signs the Clean Air Act

Amendments of 1970.

was required to develop New Source Performance

Standards (NSPS) that would be imposed on new or

modified stationary sources with the potential to

emit more than 100 tons per year of any of the

criteria pollutants or of volatile organic compounds

(VOCs), one of the two principal precursors of

ozone. To enforce the NSPS, the States were

required to include construction permit programs in

their SIPS. EPA was also required to enforce a

specified schedule for reducing emissions from

motor vehicles.

By 1977, 2 years after the original deadline, 78

areas were still violating the ozone standard then in

place (no more than one exceedance per year of a

l-hour average oxidant concentration of 0.08 ppm).

The widespread failure to attain the ozone standard

by 1977 has been attributed to the fact that mobile

source emissions reductions that the States and EPA

were counting on to reduce ozone were not fully

realized [3], and that few controls were required on

existing stationary sources of VOCs [1]. Due to

waivers granted by the EPA Administrator and an

extension given by Congress, the schedule specified

in the Clean Air Act for tightening motor vehicle

emissions limits had not been met. For example,

while new car VOC emissions rates were about 60

percent lower in 1977 than in 1970, according to the

schedule specified in the Act, a 90-percent reduction

should have been achieved. Transportation control

measures such as gas rationing, restricted parking,

and restricted freeway lanes generally met with

strong resistance; and in 1974 Congress enacted

legislation that prohibited EPA from requiring many

types of transportation control measures.

In 1977, the deadline for meeting the ozone

standard was moved back to 1982. Severe nonattainment areas that did not expect to be able to meet the

1982 deadline could obtain an extension to 1987.

Responding to the failure to meet the goals of the

1970 Clean Air Act, the 1977 Amendments included

a new and more aggressive control program. New

SIPS were to be developed and submitted to EPA in

1979, and again in 1982, for areas seeking extensions of the attainment deadline to 1987. A new

schedule was established for imposing emissions

limits for new motor vehicles. Existing stationary

sources in nonattainment areas would have to be

retrofit with emissions controls. A new source could

only be constructed in a nonattainment area if it

would operate at the ‘‘lowest achievable emissions

rate” and if emissions reductions could be obtained

from other sources to offset the emissions from the

proposed source. Transportation control measures

would have to be considered. Severe nonattainment

areas would have to implement automobile inspection and maintenance programs.

By 1983, 17 areas that had not asked for extensions to 1987 were still violating the ozone standard

(which had by that time been revised to its current

definition, a daily peak l-hour average concentration of 0.12 ppm not to be exceeded more than once

per year, on average). Following its interpretation of

the Act, EPA proposed to ban construction of major

stationary sources in these areas. However, Congress then prohibited the Agency from using appropriated funds to impose construction moratoriums in

areas with approved SIPS. Consequently, the areas

that had not met the 1982 deadline were simply

required to submit revised SIPS demonstrating how

they would attain the standard by 1987. By the end

of 1987, no final action had been taken to approve or

disapprove any of these SIPs. Since 1983, the

Agency’s policy on sanctions has been to restrict

their imposition to areas with deficient SIPs or areas

that have failed to carry out their SIP commitments

in good faith.
Chapter 5—Lowering Ozone: Effect of Volatile Organic Compound and Nitrogen Oxides Controls ● 31

In addition to the 17 areas that were supposed

to meet the 1982 deadline but failed to do so,

approximately 40 ozone nonattainment areas had

obtained deadline extensions prior to 1982. These

areas were to have submitted SIPS in 1982 that

would demonstrate attainment by 1987. EPA promulgated approvals and disapprovals for most of these

SIPS in 1983 or 1984. Sanctions were imposed in

some areas to spur correction of SIP deficiencies. In

July of 1987, EPA proposed construction bans for 11

ozone nonattainment areas that still did not have

adequate SIPS.

Some progress has been made since 1977 in

reducing emissions of VOCs, one of the two

principal sets of precursors of ozone. EPA estimates

that nationwide, emissions of VOCs have decreased

by about 10 percent over the last decade. The decline

in VOC emissions is due primarily to a 30-percent

decline in mobile source emissions, which has

occurred because of significant reductions in vehicle

emissions rates, despite a 25-percent increase in

vehicle-miles traveled [4]. Stationary source VOC

emissions have increased by about 3 percent since

1977.

Emissions of nitrogen oxides (NOX, the other

principal set of precursors of ozone) are estimated to

have declined by less than 2 percent [4].

Despite the progress that has been made in

reducing VOC emissions, more than 60 areas still

violate the current ozone standard. In November of

1987, EPA proposed a “post-1987” policy for

addressing ozone and carbon monoxide nonattainment. Then, on December 11, 1987, Congress

extended the deadline for attainment once again, this

time to August 1988. The legislation precluded the

imposition of the construction bans EPA had proposed in July.

STATE IMPLEMENTATION PLAN

DEVELOPMENT AND

IMPLEMENTATION

The principal regulatory mechanism by which the

air quality standards are to be met and maintained is

the State-level process of developing and implementing State Implementation Plans (SIPS).

Through the SIP process, the States determine the

emissions reductions required to meet the air quality

standard and then set up programs to achieve the

required reductions. EPA is responsible for reviewing the SIPS to ensure that they will lead to

attainment, and also provides guidance to the States

on several aspects of SIP development. In addition

to deadlines for attainment of the standards, Congress has also specified deadlines for SIP development.

Developing and implementing a State Implementation Plan for ozone involves a series of steps that

are carried out primarily at the State and local levels:

●

●

●

●

First, the extent and severity of the local air

quality problem is determined by monitoring

ambient ozone concentrations. An area is

classified “nonattainment” for ozone if peak

1-hour average concentrations measured at any

monitor exceed 0.12 ppm more than 1 day per

year, averaged over 3 years.

A critical piece of information required to

develop a strategy for meeting the ozone

standard is an inventory of VOC and NOX

emissions that covers both stationary and

mobile sources. The first step is to estimate

current emissions of both precursors. The

second is to forecast the changes in emissions

that are anticipated to occur in the future

without additional local control efforts. Such

changes include increases or decreases due to

anticipated changes in population, motor vehicle use and industrial activity, and also reductions due to control programs which will be

implemented at the Federal level.

The next step is to use a mathematical model to

predict how much emissions will have to be

reduced (in addition to the reductions that will

be achieved through federally implemented

control programs) to meet the ozone standard

by the congressionally specified deadline. The

predicted control requirement becomes the

emissions reduction target for the area.

The three preceding steps are technically challenging. The fourth step is difficult not only

from a technical standpoint, but also from a

political standpoint. Each nonattainment area

must develop a control strategy that allocates

the required emissions reductions among

sources in the area, and then design programs to

carry out the strategy. A control strategy

typically includes imposition of emission lim-
32 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

●

●

●

●

its or control technology requirements on

stationary sources, with permitting and source

inspection and monitoring programs to ensure

compliance. Control strategies may include

measures to encourage people to cut back on

driving. Retrofit controls on some categories of

stationary sources, new source construction

permitting programs and motor vehicle inspection and maintenance programs have been

specified by Congress as mandatory components of SIP control strategies for ozone.

Once an ozone control strategy has been

developed, the regulations contained in the SIP

must be approved through the State regulatory

process, and in some cases, by the State

legislature. This step alone can be timeconsuming. State rulemaking processes typically take from 6 to 11 months [2].

Once a SIP has been approved at the State level,

it is sent to EPA for review. The Agency

ensures that the SIP has made the required

“attainment demonstration,” i.e., that the control measures the State has committed to

implementing will provide the level of emissions reductions predicted to be required to

meet the standard. The Agency also ensures

that the SIP includes all of the control programs

that Congress requires. If the States are delinquent in their submittals or submit deficient

SIPS, the Agency is required to impose specified sanctions and may impose others at its

discretion.

The first six steps can be regarded as SIP

development. What remains is to carry out the

regulatory programs contained in the SIP. This

includes operating inspection, monitoring, and

enforcement programs for both stationary and

mobile sources. As SIP implementation progresses, the impact of the SIP is assessed by

tracking emissions, and ultimately through

monitoring ambient ozone concentrations.

Finally, the control strategy is revised, if

necessary, to resolve problems identified by

EPA during its review process, or to compensate for inaccurate predictions of emissions

trends or of the efficacy of control measures, or,

finally, if the ozone standard is not attained.

EPA participates in SIP development by providing guidance to the States on monitoring, emissions

inventory development, modeling, and on the cost

and reduction potential of alternative control measures. Most States rely heavily on EPA as a source of

this information. For ozone, the “control technique

guidelines” (CTGs) issued by EPA on retrofit

control strategies for existing sources of VOCs have

been particularly critical. States have not only relied

on the CTGs to help identify potential VOC control

measures but also to facilitate promulgation of

State-level regulations. For example, the existence

of a CTG for a particular source can provide leverage

in convincing State legislators that the source ought

to be controlled.

EPA is responsible for reviewing the SIPs to

ensure that they will lead to attainment by the

specified deadline and that they contain the required

control programs. This process involves repeated

interaction between EPA, its Regional offices, and

the States.

FAILURE TO MEET THE OZONE

STANDARD FOLLOWING THE

1977 AMENDMENTS

More than 10 years have now gone by since the

passage of the last major set of amendments to the

Clean Air Act, which called for a new and more

aggressive control program to attain the ozone

standard throughout the country by 1987. While

ozone concentrations have been lowered in many

nonattainment areas, about 100 areas still exceed the

standard. OTA sponsored two workshops involving

State and local air pollution control agency officials

and current and former EPA staff, respectively, to

explore the reasons why this decade-long effort has

not resulted in more areas attaining the standard.

Before each of the workshops, participants were

asked to complete a questionnaire that suggested

possible problems associated with the development

and implementation of the ozone control strategy

pursued since the late 1970s. The results of the

questionnaires formed the basis for further discussion.

Participants at each workshop tended to agree on

a few problems that they saw as most significant.

However, the problems emphasized by EPA and

State regulators were quite different. State and local

respondents emphasized the problems of transport of
Chapter 5-Lowering Ozone: Effect of Volatile Organic Compound and Nitrogen Oxides Controls ● 33

ozone and ozone precursors, inadequate air quality

models, States’ inability to promulgate regulations

without EPA support, and inadequate EPA performance. EPA respondents most often cited emissions

growth, inaccurate emissions inventories, unreasonable deadlines in the Act, and “lack of political

will” to solve the ozone problem.

Many of the key problems identified in the OTA

workshops were similar to those discussed in a

recent General Accounting Office (GAO) report [5].

The GAO investigators also identified problems

stemming from inaccurate emissions inventories,

flawed modeling, and ineffective EPA oversight. In

addition, they found that some control measures

planned by States were not implemented or were

poorly enforced.

In this section, we will summarize the reasons for

continued nonattainment most often suggested by

participants in the OTA workshops and in the GAO

report. Our discussion begins with “planning”

problems, such as inadequate inventories and poor

modeling, and continues with the more difficult

administrative and political problems, such as the

slow pace of issuing control regulations and poor

control over emissions growth.

Incomplete and Inadequate Emissions

Inventories

An early and extremely important step in developing an ozone control strategy is to estimate current

emissions of ozone precursors and to project future

emissions in the absence of additional controls. Both

EPA and State participants at the OTA workshops

suggested that incomplete or inaccurate emissions

inventories were a very serious problem. Respondents were particularly concerned that emissions

projections made in the past have been too low, thus

leading to underestimation of the reductions needed

to ensure attainment by 1987. State respondents

emphasized that when current SIPs were developed,

regulators did not anticipate the gradual increase in

gasoline volatility and hence evaporative emissions

that has since occurred. EPA participants stressed

that in many areas, growth in automobile use has

been much higher than originally expected, and as a

result automobile emissions have exceeded expectations.

The GAO investigators agreed that the ozone

plans they reviewed often understated VOC emissions. For example, they found that ‘the plan for the

Los Angeles area estimated that vehicle mileage

would increase 14 percent for the planning period,

but the mileage actually increased during the 1979

to 1985 period by 26 percent” [5].

Underestimates of the Extent of Control

Required To Attain the Standard

The next step in devising a control strategy is to

estimate the extent of emissions reductions necessary. Ozone is formed by a complex series of

reactions involving volatile organic compounds

(VOCs) and nitrogen oxides (NOX) in the presence

of sunlight. In order to control ozone formation, one

must decide how much to reduce emissions of VOCs

or NOX, or both. To do so, regulators have relied on

atmospheric models that describe the relationship

between VOC and NOX emissions and ambient

ozone levels. Since each nonattainment area is

unique due to a different mix of sources and different

meteorological conditions, relying on computer

models to predict control requirements allowed

regulators to tailor control programs to each area’s

local circumstances.

State and local participants at the OTA workshops

suggested that inaccuracy and misuse of atmospheric models were among the most significant

problems that contributed to continued nonattainment.

They suggested that, due to incomplete scientific

understanding of ozone formation, available atmospheric models were (and still are) too inaccurate

to derive accurate estimates of the emissions reductions needed to ensure attainment. State participants

suggested that state-of-the-art models, which they

believe are accurate to within 30 percent at best, are

not sufficient to ensure compliance with a standard

that allows only 3 exceedances over a 3-year period.

State participants suggested that a second problem with models was that delegation of responsibility for applying models to the States provided them

with ample opportunities to cheat in developing their

implementation plans, a practice known as “gaming. ” States were able to choose favorable model

assumptions and inputs to arrive at the least stringent

predictions of emission reduction requirements.
34 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Many State participants were also concerned

that available models do not adequately account for

transport of ozone and its precursors. Finally, State

workshop participants questioned whether NOX

emission reductions may have been needed in

addition to the VOC reductions, which EPA has

exclusively encouraged.

In contrast to State and local workshop participants, EPA participants were relatively comfortable

with available air quality models. They suggested

that uncertainties in modeling are no greater than the

uncertainties associated with many other steps of

devising and enforcing an ozone control strategy.

EPA respondents were also much less concerned

than their State and local counterparts with whether

NOX reductions were needed, although they did

suggest that NOX controls might be beneficial in a

few areas. However, some EPA participants, 1ike

their State counterparts, were concerned that available models do not adequately account for transport.

The GAO investigators pointed out the problems

that resulted from the use of modeling with incorrect

or inadequate data when preparing SIPS. For example, they pointed out that Houston’s 1982 SIP

indicated that they needed a 41-percent reduction to

attain the standard, but that the analysis relied on

some poor quality atmospheric data. When the same

analysis was performed by EPA with more accurate

data, a 71-percent reduction was predicted to be

required [5].

States Had Difficulty Issuing Stationary

Source Regulations

Once the magnitude of overall reductions needed

has been established, State regulators must decide

which sources or source categories will be required

to lower emissions, and by how much. EPA provides

States with technical guidance concerning the availability and cost of various control measures for new

and existing sources. For 29 categories of existing

sources of VOCs, the agency issued CTGs that

presumptively define the level of controls that EPA

considers “reasonably available” (the level of

control required for existing sources under the Act).

The actual regulations limiting emissions from both

new and existing sources were issued by the States.

States were required to include regulations corresponding to the CTGs in their SIPS, plus any

additional regulations needed to achieve the standard.

State workshop participants pointed out that in

many cases reductions due to CTGs alone were not

sufficient to attain the standard. They argued that

they were unable to promulgate the additional

regulations necessary to achieve the requisite VOC

emission reductions. First, they suggested that many

State regulators face legislative prohibitions or

political pressure not to adopt particular control

measures unless they are clearly forced to do so by

EPA. Second, they suggested that State agencies

often do not have the resources or technical expertise

needed to develop new regulations on their own.

State participants complained that EPA stopped

issuing CTGs in recent years, leaving them without

a clear Federal directive to issue particular regulations and without the resources to develop their own

regulations. They also argued that it is more resource

efficient for EPA to develop regulations or CTGs

once than for each State to duplicate the activity.

In their own defense, some EPA participants

suggested that the Agency stopped issuing CTGs in

the face of resistance from the Office of Management and Budget (OMB). One participant suggested

that after OMB reviewed them, the most recent

group of CTGs were “so watered down that it may

have been better not to issue them.” Other EPA

participants argued that budget limitations were

much more significant than OMB review.

The GAO report provides some specific examples

of areas that did not implement all of the measures

they needed to attain the standard. The report states

that in Los Angeles, about half of the stationary

source control measures committed to in their SIP

were not implemented as of 1986. GAO concludes

that “in general, the measures had not been implemented either because the control technology was

not fully developed or the local air quality board

considered the measures too costly given the expected reductions” [5].

Poor Control Over Emissions Growth

In order to meet the air quality standard, nonattainment areas needed to both reduce existing

emissions and ensure that new sources of emissions

were offset by additional reductions from existing
Chapter S---Lowering Ozone: Effect of Volatile Organic Compound and Nitrogen Oxides Controls ● 35

sources. EPA respondents most often cited emissions growth as the most important reason for the

widespread failure to attain the ozone standard. As

suggested above, growth in automobile use was seen

as particularly problematic. Although many areas

experienced a net decrease in mobile source emissions as a result of more stringent tailpipe emission

standards, the reductions were often less than

anticipated due to higher than expected automobile

use. Workshop participants also stressed that the

increasing number of automobiles will eventually

reverse the downward trend in mobile source emissions nationwide unless more stringent tailpipe

standards are adopted.

EPA respondents were sharply divided over the

effectiveness of regulatory measures intended to

offset new stationary source emissions. Only ‘major”

new sources, those that emit more than 100 tons per

year, have been subject to new source review, which

requires them to obtain emissions reductions from

existing sources to offset their emissions, and to

install the most stringent control technology available. New sources larger than 100 tons per year can

avoid new source review by obtaining offsetting

reductions to limit the net emissions increase to less

than that of a “major” source, a practice called

“netting.” About half of EPA respondents felt that

too many sources have been exempt from new

source review. However, others suggested that

current new source review adequately counteracts

emissions growth or results in only insignificant

emissions increases.

Most State and local workshop participants were

dissatisfied with new stationary source controls.

They distrust emissions trading, since they feel that

most emissions reductions used in “netting” or

offsets would have occurred anyway. State participants argued that such reductions should have been

“credited toward cleaner air” rather than used to

facilitate new emissions.

Inability To Control “Transported” Ozone

and Precursors

State and local participants complained about the

difficulty of achieving adequate emissions reductions when the geographic characteristics of the

problem do not correspond to State boundaries. State

and local respondents suggested that many nonattainment areas monitor high levels of ozone precursors and even nonattainment levels of ozone in

air masses entering their areas. They argued that

emissions in upwind attainment and nonattainment

areas contribute significantly to some cities’ air

quality problems and to elevated ozone levels in

rural areas. EPA respondents also ranked transport

as a serious problem, although they did not rank it as

highly as did State respondents.

Lack of Leadership and Political Will

To Solve the Problem

State and local workshop participants complained

that EPA has not demonstrated sufficient leadership

and commitment to solve the problem. They suggested that EPA “dragged its feet” on decisions to

issue Federal regulations for fuel volatility, automobile refueling emission controls, and more stringent

tailpipe standards. Participants suggested that EPA’s

indecision discouraged States from developing their

own regulations for those particular sources or for

other categories that would deliver small benefits in

comparison. As discussed above, the States argued

that they were often unable to promulgate additional

stationary source regulations because EPA stopped

issuing CTGs.

In response to these criticisms, EPA respondents

suggested several areas in which the States did not

require the measures that they should have, citing

inadequate automobile inspection and maintenance

programs and incomplete SIP implementation as

examples. Although they acknowledged that some

Federal regulations have been delayed, most EPA

respondents suggested that earlier issuance of those

regulations would not have had a large effect on the

overall nonattainment problem.

The GAO report concluded that both State implementation and enforcement of control programs

and EPA oversight have not been as effective as they

should have been. From their discussions with State

and local officials, the GAO investigators concluded

that at the local level there has been “a general

reluctance to implement control measures that will

have a negative impact on economic development or

change lifestyles” [5]. Agreeing with comments

made by EPA participants at our workshops, GAO
36 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

pointed out a number of specific examples of weak

implementation, inspection, and enforcement at the

State and local level.

Although the Act delegates primary responsibility

for developing SIPS and promulgating the necessary

regulations to the States, EPA is responsible for

reviewing SIPS and overseeing their implementation.

The GAO report was critical of EPA’s oversight

role. In two of the three urban areas they studied,

EPA did not enforce requirements that the States

stick to their declared schedules of annual emissions

reductions. All three areas had problems with their

SIPS. Even though EPA was aware of deficiencies,

it did not call for SIP revisions in two of the areas and

waited until July 1987 to disapprove the SIP

submitted by the third area.

EPA participants at our workshops agreed with

many of the criticisms of EPA’s performance, but

stated that they faced serious constraints on their

ability to administer the Act. Questionnaire respondents cited inadequate budgets, OMB interference,

and lack of political support. Some suggested that

there was never really the ‘political will” to take the

steps necessary to solve the ozone problem. Although many EPA participants cited “lack of

political will” as a problem, they disagreed over

whose will was lacking. Some suggested that there

was an implicit understanding between the States

and EPA not to push for more aggressive control

measures since they felt that they had reached the

limits of public acceptability. Others suggested that

past efforts were not at all aggressive; administrative

will, not public support, was lacking. Some argued

that the change in Administration in 1981 lead to

weaker EPA implementation of the Clean Air Act.

Unreasonable Deadlines

Finally, many EPA respondents suggested that

the deadlines Congress specified in the 1977 Amendments were simply unreasonable. They argued that

widespread failure to attain the standard by December 31, 1987, does not reflect insufficient progress as

much as unrealistic expectations. While some suggested that the deadline was only unreasonable for

Los Angeles, others felt that it was unrealistic for

many areas. Participants at both workshops argued

that unreasonable deadlines were counterproductive. They suggested that overly stringent deadlines

encouraged States to cheat on their SIPS and EPA to

play along with them.

REFERENCES FOR CHAPTER 2

1.

2.

3.

4.

5.

Hawkins, D., Natural Resources Defense Council,

personal communication, March 1988.

Pacific Environmental Services, Inc., Study of the

1979 State Implementation Plan Submittals, prepared

for the National Commission on Air Quality (Elmhurst, IL: December 1980).

Stewart, R. B., and Krier, J. E., Environmental Law and

Policy, 2nd ed. (Indianapolis, IN: Bobbs-Merrill Co.,

Inc., 1978).

U.S. Environmental Protection Agency, National Air

Quality and Emissions Trends Report, 1985, EPA-4501

4-87-001 (Research Triangle Park, NC: 1987).

U.S. General Accounting Office, Air Pollution: Ozone

Attainment Requires Long-Term Solutions To Solve

ComplexProblems, GAO/RCED-88-40(Gaithersburg,

MD: Jan. 26, 1988).
Chapter 3

Health Effects of Ozone
CONTENTS

Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . 39

A PRIMER ON THE HEALTH EFFECTS

OF OZONE . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

Major Issues . . . . . . . . . . . . .. . . ... ... ...... 40

The Acute Effects of Ozone .. ... ... ...... 43

Chromic Effects: The Development of

Respiratory Disease .. .. .. .. ... ... ...... 44

The Possibie Link Between Acute and

Chronic Effects . . . . . . . . . . . . . . . . . . . . . . . . 48

Potentially Susceptible Members of

the Population . . . . . . . . . . .+ ... .. 4......9. 49

Possible Synergistic Effects of Ozone

and Acid Aerosols . .. . . . . ........ ..... 50

EXPOSURE TO OZONE . . . . . . . . . . . . . . . . . . . 52

Areas Failing To Meet the Standard . . . . . . . . 52

Frequency and Magnitude of Exceedances. . 53

Factors Influencing Exposure to Ozone . . . . . 55

Population Exposure Estimates . . . . . . . . . . . . . 58

EXTRAPOLATION OF EFFECTS OF

MULTIPLE-HOUR EXPOSURES

TO OZONE . . . . . . . . . . . . . . . . . .. . . . . . . . . . 60

SELECTED NATIONWIDE HEALTH

BENEFITSFROM CONTROLLING

OZONE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

How the Estimates Are Calculated . . . . . . . . . 65

Selected Health Benefits of Lowered

Ozone Concentrations . . . . . . . . . . . . . . . . . . . 66

Assigning a Dollar Value to Health

Improvements From Lowered Ozone

Levels .. .. .. .. .. .. .. .. ... ... . . . . . . . . . . 68

REFERENCES FOR CHAPTER . . . . . . . . . . . 70

Figures

Figure Page

3-1. Acute Effects of Ozone Exposure . . . . . . . . 44

3-2. Percent Decreases in Group Mean Lung

Function During 2-hr Ozone Exposures

With Different Levels of Intermittent

Exercise .. ...................... . . . . . . 45

3-3. Areas Classified as Nonattainment for

Ozone Based on 1983-85 Data .... ..... 53

3-4. Areas Where Ozone Concentrations

Exceeded O.12 ppm at Least One Hour Per

Year on Average, From 1983-85 . . . . . . . . . 55

Page

3-5. Areas Where Ozone Concentrations

Exceeded O.14 ppm at Least One Hour Per

Year on Average, From 1983-85 . . . . . . . . . 56

3-6. Areas Where Ozone Concentrations

Exceeded O.18 ppm at Least One Hour Per

Year on Average, From 1983-85 . . . . . . . . 57

3-7. Profile of Ozone Concentrations as They

Change Over the Day at a Single Monitoring

Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

3-8. Contour Map of the Variation in Daily Peak

Ozone Concentrations Predicted for the

New York City Area . . . . . . . . . . . . . . . . . . . . 58

3-9. Likelihood of Adverse Effects From Ozone

While Exercising .. .. . .. .. .. .. . . . . . . . . . 62

Tables

Table Page

3-i. Gradation of Individual Physiological

Response to Acute Ozone Exposure. . . . 43

3-2. Areas Classified as Nonattainment for

Ozone Based on 1983-85 and 1985-87

Data . . . . . . . . . . . . . . . . . . . . . . . . . . . ...... 54

3-3. Estimated Exposures to Ozone

Concentrations Above O.12 ppm . . . . . . . . 59

3-4. Population Residing in Areas Where the

Indicated Concentration is Exceeded at Least

One Period Per Year, for Each Averaging

Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

3-5. Number of Cities Where Ozone

Concentrattions Exceed O.14 ppm for 2-, 4-,

and 8-hr Periods for the Specified Number of

Days Per Year, on Average, and Population

Residing in Those Cities . . . . . . . . . . . . . . . 64

3-6. Avoided Episodes of Respiratory

Symptoms .. . . . . .. ........ . . . . . . . . . . . . 67

3-7. Avoided Episodes of Respiratory

Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

3-8. Avoided Days of Adverse Consequences. 68

3-9. Avoided Days of Adverse Consequences . 69

3-10. Dollar Value of Selected Health Benefits. 69
Chapter 3

Health Effects of Ozone

INTRODUCTION

Ozone has been shown to cause immediate,

short-term changes in lung function and increased

respiratory symptoms among healthy adults and

children who exercise moderately or heavily during

periods of elevated ozone concentrations. Decreases

in lung function and pronounced symptoms such as

coughing and pain when breathing deeply have been

experienced by people exposed to ozone for 1 to 2

hours at ozone levels comparable to peak levels

found in many nonattainment cities. Short-term

effects have also been observed at concentrations

lower than the l-hour ozone standard (0.12 parts per

million (ppm)) when exposures last for longer

periods (about 6 hours). The implications of these

effects are unclear at this time.

In addition to short-ten-n effects, ozone has been

suspected of playing a role in the development of

chronic lung diseases and in increasing the rate at

which the adult lung ages. While not dismissing the

short-term effects of ozone, many health professionals appear more concerned that repeated exposure to

ozone over a lifetime may result in permanent

impairment of the lungs. Some studies suggest that

there may be some persistent effects associated with

long-term exposure to ozone, although our understanding of such effects is currently limited. Some

new research provides evidence that exposure to

ozone for several hours at concentrations equal to or

below 0.12 ppm is associated with inflammation of

the lungs, a suspected intermediary step in the

progression from acute to chronic health effects.

In this chapter, we present four different perspectives on the effects of ozone on human health. First,

we present a descriptive summary of the acute and

chronic effects that ozone is known or suspected to

cause. The second section presents nationwide

estimates of population exposure to ozone at concentrations that exceed the standard. About 35

million people-one-quarter of the people who live

in nonattainment areas-are exposed to ozone

concentrations above the standard, on average, about

9 hours per year. About 13 million people are

exposed to concentrations above the standard while

exercising at moderate levels of exertion.

Next, we present an assessment of the lung

function effects that may be occurring in exercising

populations exposed for several hours at concentrations common on days when the ozone standard is

exceeded. For example, on a summer day when the

ozone level averages 0.14 ppm, a construction

worker on an 8-hour shift or a child who plays

outdoors for about 4 hours would be at risk of

adverse effects on lung function. People exercising

more vigorously—e.g., athletes engaged in competitive sports-could expect to experience potentially

adverse effects after about 2 hours.

Finally, we attempt to quantify some of the health

improvements that would result from lowering

ozone concentrations. If ozone concentrations were

lowered enough to meet the standard in all areas,

several hundred million incidents of respiratory

symptoms, such as coughing or pain on deep

breathing, might be avoided each year. Some people

living in the worst nonattainment areas would

experience dozens fewer incidents of respiratory

symptoms each year, while many people living in

other nonattainment areas would experience no

change. Also eliminated would be about 8 million to

50 million days each year when someone’s activities

are restricted because they are feeling ill from

exposure to ozone. By asking people what they

would be willing to pay to avoid a day of coughing

or restricted activity, for example, it is possible to get

a rough feel for the economic value of the health

improvements listed above. The uncertainties are

quite large due to the many assumptions that must be

made, but about $0.5 billion to $4 billion per year is

a reasonable range for the portion of health benefits

that we were able to evaluate. We could not estimate

benefits associated with changes in lung function, or

the effect of repeated exposure to ozone over a

lifetime (e.g., possible premature aging of the lungs

or permanent lung impairment).

-39-

89-146 0 - 89 - 2
40 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

A PRIMER ON THE HEALTH

EFFECTS OF OZONE1

Human exposure to ozone primarily affects the

lungs. Ozone has been shown to cause immediate,

short-term changes in lung function and increased

respiratory symptoms, and has been suspected of

playing a role in the long-term development of

chronic lung diseases. The immediate or ‘‘acute”

effects may include some breathing difficulty and

coughing, but such effects appear to be reversible,

usually disappearing after a few hours. Ozone has

also been suspected of playing a role in initiating

asthma attacks.

Although the short-term effects are important,

many health professionals are more concerned that

repeated exposure to ozone over a lifetime may

result in permanent impairment of the lung. Since

ozone damages the tissues lining the airways of the

lung, it has been hypothesized that ozone exposure

could contribute to the accelerated aging of the lung,

retardation of lung development in children, or the

development of pulmonary fibrosis, a chronic lung

disease. However, research is just beginning to shed

light on questions about the possible long-term

effects of ozone exposure. We are not yet able to

confirm or dismiss many of the concerns about these

effects.

Major Issues

The debate over health effects from ozone has

centered around four major issues:

1. what are the lowest ozone concentrations at

which health effects are observed?

2. what constitutes an “adverse health effect”

from ozone exposure?

3. what are the effects of exposure to ozone over

a long period of time? and

4. who appears to be most susceptible to ozone’s

ill effects?

All of these issues play an important role in the

standard-setting process. 2 Determining the lowest

level at which health effects are observed is a crucial

frost step. Studies conducted both in the laboratory

and in the ambient environment generate data which

help scientists define the lowest observable effects

level. Once this level has been determined, a margin

of safety is built into the standard to protect the

groups most sensitive to the pollutant. The margin of

safety is designed to protect these populations

against health effects that research has not yet

identified. Deciding which effects are to be considered "adverse” and determining which populations

may be most sensitive to ozone are essential to

setting an “adequate” margin of safety. Information

about adverse effects helps policymakers define an

upper bound on this margin; information on sensitive populations assists in defining a lower bound.

Finally, studies of the long-term effects of exposure

to a pollutant also provide input to the standardsetting process. These four major issues are discussed briefly below.

ISSUE 1: What are the lowest ozone concentrations at which health effects are observed?

The lowest concentration at which effects from

ozone have been observed has been revised downward during the last 15 years, as more information

has become available. In the early 1970s the

threshold for responses to oxidants3 was presumed

to be 0.25 ppm. This was based on limited data,

however [87]. In 1977, new ozone studies showed

lung function effects to heavily exercising people at

concentrations as low as 0.15 ppm [16]. During the

last 5 years or so, the health effects database for

ozone has greatly expanded. Scientists now believe

that the duration of exposure to ozone and the

intensity of exercise during exposure play a major

role in determining responses at lower levels of

ozone. A number of new human studies show that

temporary loss of some lung function occurs in

moderately to heavily exercising children and young

adults exposed for 1 to 2 hours to ozone concentrations between 0.12 and 0.16 ppm [60,5,70,71].

Significant acute effects have been observed during

prolonged periods of exposure (6.6 hours) at moderate exercise levels, at concentrations as low as 0.08

l’rhe fo]lo~ng s~mW of tie health effects of ozone is based on a report prepared by Lawrence J. Folinsbee for the Office of Mhnology

Assessment (see ref. [25a]).

Z’r’he ~r q~ity Standard for ozone is currently under review by the Environmental PHMcXtiOn Agency.

sphotochemic~ oxidants are a group of chemically related pollutants, From the standpoint of health and welfare effects, ozone 1S the mOSt importmt

photochemical oxidant. Ozone typically comprises over 90 percent of the total mass of photochemical oxidants measured in urban air.
Chapter 3-Health Effects of Ozone ● 41

Photo credit: South Coast Air Quality Management District

Much of our understanding of the short-term effects of ozone comes from laboratory studies such as the one shown here. Volunteers

breathe filtered air with known concentrations of ozone added, typically for an hour or two while exercising. Both before the

experiment begins and after it is over, this volunteer’s lung function was measured by having him exhale as rapidly as possible into

a test device. Some healthy adults experience some temporary loss of lung function after an hour or two of heavy exercise at ozone

concentrations about equal to the standard.

ppm [28,39]. This information is of crucial importance as EPA considers revising the ozone standard

from its current level of 0.12 ppm for a l-hour

averaging time. Consideration of both the concentration and averaging time are considered by EPA as

it reviews the standard. Some argue that the averaging time of the standard should be extended to more

accurately reflect atmospheric evidence that ozone

concentrations may remain elevated for up to 8

hours, not just rise and fall rapidly around a sharp

peak concentration. In addition, others argue that

lowering the concentration level of the l-hour

standard to below 0.12 ppm should provide some

protection from prolonged exposure effects observed below that level.

ISSUE 2: What is an adverse health effect?

The Clean Air Act directs EPA to set air quality

standards for pollutants that may produce ‘‘an

adverse effect on public health or welfare. ” A great

deal of discussion has been conducted within the

scientific and medical community as to what constitutes an “adverse health effect,” especially with

regard to the effect on lung function of inhaling
42 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

ozone at levels equal to or below the National

Ambient Air Quality Standard. There is general

agreement that permanent respiratory injury or

episodes of pollutant-induced respiratory illness that

interfere with normal activity would be considered

“adverse” [23]. However, it is less clear that acute,

reversible changes in lung function or increases in

the incidence of respiratory symptoms, neither of

which may be associated with disability, constitute

an adverse health effect.

The broad continuum of effects and the diversity

of scientific opinion make it difficult to precisely

define what is and is not an adverse health effect.

Moreover, perceptions of what is a medically

significant health effect can vary greatly among

physicians and patients.

The EPA staff recommends, and most members of

EPA’s Clean Air Science Advisory Committee

(CASAC) agree, that the threshold for an individual’s adverse respiratory response to acute ozone

exposure should include all of the following “moderate” responses: (See also table 3-l.)

●

●

●

10 to 20 percent decrement in FEV1 (i.e., loss

of lung function) in individuals (with complete

recovery after 6 hours);

mild-moderate cough, shortness of breath, pain

when inhaling deeply; and

a few individuals (i.e., some with preexisting

respiratory disease or heavily exercising

healthy individuals) choose to discontinue

activity.

Most members of the medical community would

consider a 10 percent or greater group mean loss in

lung function to be sufficient to warrant concern

about damage to the lung, especially if one considers

that some individuals in these groups are likely to

experience greater than average decrements in lung

function. In addition, lung function losses which

may not be harmful for people with normal, healthy

lungs may be more significant for individuals with

preexisting lung disease. Certainly effects that could

be incapacitating and could interfere with normal

activity (e.g., asthma attacks) should be considered

adverse.

ISSUE 3: What are the implications of long-term

human exposure to ambient ozone levels?

Perhaps the most important health concern with

respect to ozone is the potential for irreversible

damage to the lung from repeated exposure to ozone

over a long period of time. This is especially critical

when one considers that a significant percentage of

the U.S. population is living in areas that may

experience recurrent episodes of ozone concentrations at or near the national standard. (For further

discussion of population exposure to ozone in

nonattainment areas, see the following section in

this chapter.)

Ozone can cause temporary loss of some lung

function and increased respiratory symptoms in

healthy individuals exercising heavily (e.g., competitive sports) at concentrations as low as 0.12 ppm.

However, while the effects of short-term exposure to

this level of ozone appear to be reversible, it is not

known if repeated exposure to ozone levels in the

range of 0.08 to 0.20 ppm results in extended or,

possibly, permanent changes in lung function, structure, state of growth or aging of the lung.

Both animal and human repeated-exposure studies as well as some epidemiologic studies have

attempted to address concerns about the implications of long-term (“chronic”) exposure to these

low concentrations of ozone. Together, these studies

have yielded preliminary evidence that there may, in

fact, be some persistent effects associated with

chronic exposure. To date, the most compelling

evidence suggesting that ozone plays a role in the

initiation or triggering of respiratory disease processes has come primarily from animal toxicology

studies and human epidemiology studies. This

research has also provided scientists with some

initial clues about the possible link between acute

reversible effects and chronic irreversible effects.

ISSUE 4: Are there any subpopulations which

are particularly susceptible to ozone’s ill

effects?

In response to the Clean Air Act’s mandate that

EPA set air quality standards for pollutants, “allowing an adequate margin of safety . . . to protect the

4~v1_ the “~1~~ of ~ e~h~e.d in tie first s~ond of a forced expiration-is oneme~~e of pu~on~ f~ction that may IIldiCi+te drWay

obstruction in the lungs.
Chapter 5—Health Effects of Ozone ● 43

Table 3-l-Gradation of Individual Physiological Response to Acute Ozone Exposure

Gradation of

response Mild Moderate Severe Incapaciting

Change in lung function

(FEV1

, FVC) . . . . . . . . . .5-10°10 10-20”/0 20-40% >40%

Duration of effect . . . . , .Complete recovery Complete recovery Complete recovery Recovery in

in <30 min in <6 hr in 24 hr >24 hr

Symptoms . . . . . . . . . . . Mild to moderate Mild to moderate Repeated cough, Severe cough,

cough, pain on moderate to severe pain on deep

deep inspiration, pain on deep inspiration inspiration, and

shortness of breath and shortness of breath; shortness of breath;

breathing distress obvious distress

Limitation of activity . . . .None Few individuals Some individuals choose 1 Many individuals

choose to discontinue to discontinue activity choose to discontinue

activity activity

NOTE: EPA staff recommend that Uw moderate, swam, and incapacitating categories should be considered “adverse” respirato~ heafth effects. All four types of effects within a

category must be present tir a rvsponse to Iw called “adverse.”

SOURCE: U.S. Environmental Protection Agency, Offioe of Ah Ouality Planning and Standards, “Review of the National Ambient M Ouality Standards for Ozone-Assessment of

Scientific and T*nical Information,” draft staff paper, November 1968, p. VII-46.

public health,” the EPA has sought to identify those

subpopulations, if any, which are shown to be more

sensitive to ozone exposure than the general population.

EPA has identified two major groups at increased

risk of developing adverse health effects from

exposure to ozone: 1) a subgroup of the general

population with preexisting disease (e.g., asthma,

chronic obstructive pulmonary disease); and 2)

those individuals who exercise or work outdoors

[98]. The first group is of concern because their

respiratory systems are already compromised, placing them at greater risk than individuals without

preexisting disease exposed to the same ozone dose.

The second group is at risk because by exercising or

working in an outdoor environment, they are increasing the dose of ozone to their lungs. To date,

neither of these groups as a whole has been clearly

shown to be more sensitive to ozone than the rest of

the population, although some individuals within

these groups appear to be more sensitive. In general,

people with pre-existing respiratory disease have not

been studied at ozone concentrations and exercise

levels as high as those used for healthy subjects. The

strongest evidence for a population “at-risk” exists

for healthy, heavily exercising individuals.

Studies have also shown that there is a subpopulation of otherwise healthy individuals who consistently respond more significantly to the same dose of

ozone than do their cohorts. These ozone-sensitive

individuals are called “responders.” The EPA

estimates that from 5 to 20 percent of the healthy

population may represent a subgroup of responders

who are at abnormally high risk for the acute effects

of ozone exposure [98]. The factors that would

account for such individual variability in sensitivity

are unknown at this time. Whether these susceptible

individuals are also at increased risk for the development of chronic, irreversible effects from ozone is

also unknown. (Susceptible populations are discussed at greater length towards the end of this

section. )

The Acute Effects of Ozone

A great deal of research has been conducted on the

acute or short-term health effects from ozone exposure. The primary acute effects investigated are:

impairment of lung function, inflammation of the

deep lung, respiratory symptoms, and limitations on

activity. These acute effects of ozone exposure are

summarized in figure 3-1, along with the ozone level

at which they begin. The figure is divided into two

sections: the upper section describes effects that

occur with 1- to 3-hour exposures, the lower section

those that occur with 4-to 8-hour exposures. The tail

of the arrow indicates the concentration at which an

effect may begin. At the lowest concentrations at

which effects are seen, the exposures are typically

accompanied by very heavy exercise for 3 hours or
44 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 3-l—Acute Effects of Ozone Exposure

Increased airway resistance

Increased airway reactivity

Exercise performance decline

> 10% drop in mean FEV1

I

1-3 hr acute

ozone exposure I

Increased symptoms

> 10% drop in individual FEV1

* . -

Ozone (ppm)

0.08 - 0.10 -

0.20 0.30 0.40 0.50

0.08 0.12

> 10% drop in individual FEV1

Lung cellular injury

in animals

Effects above the ozone concentration line are from 1 to 3 hour exposures to ozone. Effects below the line are from 4 to 8 hour exposures.

FEV1 (forced expiatory volume in 1 second) is a measure of lung function. The bolder arrows indicate the range of concentrations at which

effects occur from exposure while exercising heavily; the lighter arrows indicate the concentrations at which effects occur while exercising

moderately. Effects begin at the concentration indicated by the tail (left side) of the arrow.

SOURCE: L.J. Folinsbee, “A Summary of the Health Effects of Ozone,” contractor report for OTA, June 30, 1988.

less. With moderate exercise, effects occur at low

concentrations if exposures are prolonged (6 or more

hours). The more adverse responses, such as cell

damage shown in laboratory animal studies, occur at

the higher concentrations.

Lung Function Effects

Ozone has well-documented, short-term, reversible effects on lung function. In studies of people

exposed to ozone, the most commonly measured

lung function effects are changes in “one-second

forced expiatory volume” (FEVl) and ‘forced vital

capacity” (FVC).5 Ozone can cause decreases in

both of these measures of lung function.

Changes in lung function depend on the dose of

ozone which is ultimately delivered to the lung. A

number of factors influence dose, including the

concentration of ozone in the air, duration of

exposure, and the average volume of air breathed per

minute, referred to as the ventilation rate. The

ventilation rate increases with exercise. Figure 3-2

describes the dose-response relationship between

ozone and FEV1. As this diagram shows, an increase

in exercise intensity at any given ozone concentration results in a decrease in group mean FEV1

. It is

important to point out that this figure illustrates the

average effect of exercise on groups, and that a great

deal of variability in response exists among individual. Many studies have, in fact, shown that there
Chapter 3—Health Effects of Ozone ● 45

Figure 3-2—Percent Decreases in Group Mean Lung

Function During 2-hr Ozone Exposures With Different

Levels of Intermittent Exercise

Light exercise

Heavy

exercise

Very heavy

exercise

\

0.1 0.2 0.3 0.4

Ozone concentration (ppm)

An increase in exercise intensity at any given ozone concentration

results in a larger group average loss of lung function (FEV1,

forced expiatory volume in 1 second). The lung function changes

shown in the graph are for 1- to 2-hour exposures. Note that some

individuals may experience decreases as much as three times

greater than the group average.

SOURCE: U.S. Environmental Protection Agency, office of Air Quality Planning and

Sfmdards, Review of the Natfonal Am&”ent Ai?Ouelity Standards for Ozone

ReJrnhary Aasasamenf of Sc&ntific and Technieal Information, Draff staff

Fapar (Weahlngton, DC: November 1988).

can be a large difference between the average change

in lung function for a group and changes experienced

by some individuals within a group.6

Prior to 1980, there was very little information on

lung function changes from controlled exposures to

ozone concentrations below 0.30 ppm. This was

mainly because under the conditions of rest or mild

exercise employed in most of these studies, there

was little, if any effect observed from 11 to 2-hour

exposures to ozone levels less than 0.30 ppm.

However, a number of studies, using higher exercise

levels, have since shown clear responses to ozone

levels between 0.12 to 0.24 ppm [70,26,3,35].

Average decreases in group mean FEVl ranged from

6 to 22 percent. For comparison, the range of lung

function decrease due to the normal aging of the lung

ranges from about 0.5 to 1 percent per year in adult

males between the ages of about 30 to 70 years old

[19]. While the lung function changes due to acute

ozone exposure appear to be temporary, the changes

due to normal lung aging are permanent. Furthermore, the mechanism initiating these permanent

changes in aging lungs is quite different from that at

work in lungs acutely exposed to ozone.

At ozone concentrations equal to or exceeding the

current ambient air quality standard for ozone, some

investigators have seen small (4 to 6 percent) but

statistically significant group mean decreases in

FVC and FEV1 under conditions of heavy exercise

[70,35], while others have not [85,52,60]. Because

of the variability in observed changes in lung

function among different studies, it is difficult to

draw any definite conclusions about changes in lung

function in the range of 0.08 to 0.16 ppm ozone for

1- or 2-hour exposure periods. The most substantial

responses in this range of ozone concentration occur

under conditions of moderate or heavier exercise and

durations of exposure longer than 1 or 2 hours. For

example, Folinsbee and coworkers recently observed 7- to 13-percent decreases in group mean

FEVl in subjects performing moderate exercise for

6.6 hours at ozone levels of between 0.08 and 0.12

ppm [28,39]. Folinsbee, under contract to OTA, used

these and other laboratory data to extrapolate the

effects of multiple-hour exposures to ozone at

concentrations typical of summertime conditions

present in a number of U.S. cities [25 b]. A discussion of this analysis, including the lung function

impacts one could expect from “typical” exercise

scenarios, is presented in the third section of this

chapter.

All of the lung function effects mentioned above

were observed in human chamber studies. Some

scientists believe, however, that chamber studies

underestimate the effects from ozone exposure that

may occur in populations exposed to ozone in the

ambient air while engaged in normal recreational

activity. The effects of ozone on lung function have

also been evaluated in the ambient environment

through field studies. Many of these studies have

been of children in summer camp, but some have

been of healthy adults engaged in outdoor exercise

[89,63]. The decreases in lung function observed in

these studies have been greater than those seen in

% a smdy by FolinsIxx et al. [28], the average group change in FEVI at 0.12 ppm of ozone was 13 percent, with individual Chmges ringing from

-47.6% to +3.5 percent. Gong et al. [35] showed an average change in lung fbnction of –5.6 percent in a group exposed to 0.12 ppm of ozone, with

individual responses varying from –30 percent to +1O percent. In a study by McDonnell et al, [70], while the average group decrease in FEVl was @

percent, individual responses ranged from a 17-percent decrease in FEVI to no change in this measure of lung function.
46 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

human chamber studies in controlled indoor environments. Some scientists have postulated that the

presence of other pollutants in the ambient environment, as well as other cofactors such as temperature

and humidity, have contributed to this increased

effect. With regard to the more significant lung

function effects observed in summer camp children,

some have proposed that this is the result of their

greater cumulative daily exposure to ozone. These

children may be exposed to ozone outdoors practically all day long, as opposed to children in

chambers who may be exposed to ozone for 1 to 2

hours, with periods in clean air both before and after

ozone exposure.

A current controversy surrounding impairment of

lung function from ozone exposure involves the

definition of an “adverse” loss in lung function.

Group mean decreases in either FEVl or FVC of

greater than 10 percent are clearly significant

enough to be considered adverse, especially in light

of the fact that some individual within these groups

experience decrements in lung function greater than

the average. There is less consensus, however, as to

whether or not temporary and infrequently occurring

changes of less than 10 percent, in and of themselves, represent an adverse health effect for a

healthy young adult. Some health professionals

would consider such changes to be adverse if they

restrict activity or limit performance [23]. Shortterm, reversible loss of lung function could have

adverse effects in individuals whose lung capacity is

already reduced. However, there is no universal

agreement among scientists as to the implications of

such “small” changes.

Symptom Responses

Symptoms experienced by people exposed to

ozone are also important markers of the effects of

ozone. The major respiratory symptoms-coughing

and pain when breathing deeply—typically are

observed at about the same ozone exposure levels as

are changes in lung function indices; heavy exercise

for 1 to 3 hours at concentrations as low as 0.12 ppm

have been shown to cause such symptoms in healthy

young adults [70,3,52]. Pronounced symptoms such

as repeated coughing or pain when taking a deep

breath will almost always be associated with substantial (greater than 10 percent) lung function

changes. Folinsbee and coworkers’ recent study [28]

demonstrated a significant correlation at 0.12 ppm

between discomfort on deep breathing and changes

in lung function (FVC) within individuals. However, most other studies that have looked for such an

association have not seen it at this concentration.

Adults perceive symptoms of ozone exposure at

low concentrations (0.12 ppm) [70] but children

apparently do not [71,4,5]. While children are

certainly capable of sensing breathing discomfort,

their lack of response from these low-level exposures could be the result of a higher “threshold” of

perception for symptoms. It has been suggested that

the weak symptom responses of children may put

them at greater risk from ozone exposure because

they may not try to avoid being exposed if they are

unable to perceive the effects. Further research is

needed on the sensitivity of children to the symptoms of ozone exposure.

The last section of this chapter presents the results

of a health benefits study conducted for OTA [49].

This study estimates the benefits of controlling

ozone with respect to symptoms avoided and restricted activity. The benefits of reducing lung

function effects and the risk of developing chronic

respiratory diseases were not estimated.

Chronic Effects: The Development of

Respiratory Disease

In understanding how ozone may contribute to the

development of respiratory disease, information

about the mechanism of effect is vital. Because such

effects are difficult to observe in humans, however,

scientists often turn to animal studies for this

information. Until very recently, little information

has been available on the underlying changes (e.g.,

biochemical and structural effects) occurring in the

lungs that may mark the beginnings of respiratory

disease. Because scientists cannot easily observe the

changes induced by ozone exposure that may be

occurring at the cellular level in the human lung,

they have tended to investigate other types of

responses. Both human chamber and epidemiology

studies have been used to examine some of these

responses, including: symptoms produced by exposure, the magnitude of decline in lung function, and

the related disability or peformance decreases that

may occur in exposed individuals. These responses,
Chapter 5—Health Effects of Ozone ● 47

while important in their own right, may also reflect

changes at the cellular level that contribute to the

development of chronic respiratory disease.

Animal Studies

Animal studies serve two distinct purposes: 1)

providing information on the basic mechanism at

work in the lungs in response to ozone exposure, and

2) providing a better understanding of the possible

effects of chronic exposure to ozone.

Animal studies have shown that ozone exposure

can cause biochemical and structural changes in the

lung. Some of these changes are suspected of

playing a role in the development of chronic lung

diseases (e.g., pulmonary fibrosis), although there is

no scientific consensus regarding the significance of

these observed effects. Studies of animals exposed

repeatedly to relatively high levels of ozone (0.50

ppm) have revealed that it may be responsible for at

least temporarily reducing the ability of the lungs to

clear foreign material and thus ward off infection

[29], and for causing lung inflammation [104].

Generally speaking, extended exposure to either

high or low concentrations of ozone will tend to

retard lung clearance. There is some evidence that

acute exposure to low concentrations of ozone may

actually enhance clearance.7 Several studies, however, have shown an increased response to bacterial

infection in animals exposed to ozone levels as low

as 0.08 to 0.10 ppm for several hours [73,22].

Continuous exposure to ozone (at 0.50 ppm) has also

been shown to alter the course of viral infection in

mice by leading to structural changes in the lungs

that increase the likelihood that fibrosis8 will occur

[41].

One type of structural change in the lungs that

some scientists believe may be linked to the

development of lung fibrosis is the deposition of

collagen-a structural protein that contributes to

“stiffening” of the lungs [53,11].9 Repeated, intermittent exposure of monkeys to ozone concentrations as low as 0.25 ppm has been shown to result in

increased lung collagen content [91], although it is

not certain whether such increases alone are great

enough to cause fibrosis. Injury to the periphery of

the lungs has been demonstrated in rats exposed to

ozone at the current standard level of 0.12 ppm [15].

Ozone has also been shown to damage certain lung

cells in animals at levels as low as 0.25 ppm [14].

However, the long-term health consequences of this

cell damage are not known.

While many of these studies offer important

insights about the effects of exposure to ozone, the

inherent uncertainties in extrapolating from animal

data make it difficult to assess risk to humans from

these studies. For example, uncertainties about: 1)

how the distribution of dose within the respiratory

system compares among animals and humans, and

2) whether, for a specified dose to a target site,

responses in the two species would be quantitatively

and qualitatively equivalent, make dose-response

comparisons a difficult task.

Epidemiologic Studies

Epidemiologic studies have also been used to

investigate the potential link between ozone exposure and respiratory disease. These studies involve

large groups of people who are exposed to oxidant

air pollution (mostly ozone) in their daily life and

who may experience a variety of adverse responses

from this exposure. One question that has received

considerable attention is whether regular exposure

to oxidant air pollution causes an increased rate of

loss of lung function with age. Part of the normal

aging process of the lung involves loss of “usable

lung volume,” perhaps related to the changes in

elasticity of the lung known to occur with aging. If

breathing ozone over along period of time causes an

acceleration of the lung aging process, we would

expect to see a more rapid age-related decline in lung

volume in people who reside continuously in oxidantpolluted areas. One epidemiologic study of populations living in southern California suggests that

TSome ~jentjsts ~ljeve hat short-term exposure to ozone does not allow enough time for the cilia (a defense mechanism of the lungs against fOreiW

material) to be damaged, which tends to occur when the lungs are exposed to ozone for a prolonged period. Cilia normally act to clear out foreign material

in the lungs, and some suspect that short-term exposure to ozone may increase the liquid flow of mucus in the lungs, stimulating the cilia to react to clear

the lungs.

8MOW fibrosis res~~ from the formation of excessive amounts of protein fibers that stiffen the hmg. If this Stiffening is severe enou@~ it cm

produce debilitating disease.

9~ ~ltion t. its s~wt~ role in tie development of fibrosis, l~g stiffening is msociat~ ~~ breafi~g ~fficulty md subsequent limitation of

work petfotmance,
48 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

respiratory function is affected by chronic exposure

to ozone. The study showed an association between

an accelerated loss of lung function over an extended

period of time (5 years) and residing in a high

oxidant community [17].10 The evidence is far from

conclusive, however, and the question of what

impact ozone may have on lung function over a

lifetime requires further evaluation before a definitive answer can be reached.

Susceptibility and Adaptation From

Repeated Exposure to Ozone

Chamber studies of humans show two notable

responses to repeated ozone exposure: 1) when an

individual is exposed to ozone on two consecutive

occasions separated by less than 48 hours, the

second exposure generally causes greater lung

function effects than the first one [27,10]; and 2)

with continued exposure, these effects begin to

diminish in intensity and after 4 or 5 days the

pulmonary function effects are undetectable [40,50,58].

This gradual loss of functional response has been

called ‘‘adaptation. ”

The adaptive responses of individuals who live in

areas with high ozone levels, however, might be

different from the responses of subjects exposed to

ozone for only a few consecutive days in a laboratory

setting. Recent preliminary evidence indicates that

people who live in Los Angeles may become less

sensitive to ozone during the “smog season” but

regain their sensitivity during the relatively smogfree winter season [61]. In this study, “adaptation”

did not disappear rapidly, as in the chamber exposures, but appeared to persist for at least 2 to 3

months after the end of the smog season. Although

this suggests that processes other than those observed in a chamber may be involved in long-term

adaptation to ozone exposure, further evaluation is

needed.

Though measurable lung function changes and

symptom responses may lessen for a period during

repeated exposure, other changes within the lungs

may still be ongoing. For example, research on

animals shows that some lung injury, in the form of

effects on host defense systems [33], increased

susceptibility to disease [34], and lung inflammation

[46], may continue during an “adaptive” period

when lung function changes and symptom responses

are reduced. Therefore, individuals who, through

adaptation, experience fewer or less severe symptoms, may be at increased risk for longer-term

damage because of these other, ongoing effects.

Since these individuals may believe that they are

able to tolerate exercise outdoors during peak ozone

episodes because they experience fewer symptoms,

they may receive potentially greater tissue damage

over the long-term.

The Possible Link Between Acute

and Chronic Effects

New research examining the effects from prolonged exposure to ozone at levels equal to or below

the standard are providing scientists with preliminary information on the possible links between acute

and chronic effects. Prolonged exposure to ozone at

concentrations equal to or below the ozone standard

can be associated with inflammation of the lungs, a

suspected intermediary step in the progression from

acute to chronic health effects [46,21]. However,

questions about the degree of tissue injury occurring,

and, if it occurs repeatedly, whether this injury leads

to chronic health effects, remain unanswered. Not

only has tissue injury in the lungs been demonstrated

at 0.12 ppm, but the elasticity of the lungs also

appears to have been affected. This latter effect is

believed to accelerate the normal aging process of

the lungs [13,6].

Human Chamber Studies

Prolonged acute exposures (up to 6.6 hours) of

humans in controlled laboratory settings to ozone

concentrations similar to those found in many

nonattainment cities (0.12 to 0.18 ppm) have produced several effects, including: progressively larger changes in respiratory function and symptoms

with time [28], increased responsiveness of the

airways of individuals to inhaled substances [72],

and increased membrane permeability [43,46]. The

relationship between these changes in the lung and

the progressive development of chronic structural

and functional damage is not known. Some health

professionals postulate that the link between acute

and chronic effects is the lung inflammation obl~]e the ~tels et ~, smdy [17] does not provide scientists with quantitative dose-response data, its results showing an ~~ciation between living

in a high oxidant area and increased lung function losses, contribute to our understanding of the potential long-term effects of ozone exposure.
Chapter 3-Health Effects of Ozone ● 49

served in the animal and human subjects of shortterm ozone studies. Before this inflammatory response disappears, some suggest that it may induce

other, persistent changes in the lung or, with

additional exposure or a concurrent infection, might

culminate in chronic degenerative respiratory effects. Airway inflammation occurs during the development of a number of respiratory diseases, most

notably asthma and chronic bronchitis.

Potentially Susceptible Members

of the Population

Implicit in the Clean Air Act’s directive that EPA

set air quality standards with an “adequate margin

of safety” is the desire to protect the most sensitive

groups in the population. This desire has been

echoed more explicitly in the legislative history of

the Act [94].

At present, scientists postulate that about 5 to 20

percent of the healthy population may represent a

subgroup of “responders” [98] who may be significantly more responsive than the general population

to the same dose of ozone. Some also consider

people with pre-existing respiratory disease (e.g.,

asthma, chronic bronchitis), individuals who exercise heavily or work outdoors, and children as

potential “at-risk” groups.

The strongest evidence for increased responsiveness exists for people who exercise intensively

outdoors, since the dose of ozone they receive is

much higher than average due to their increased

breathing rate. Because individuals with preexisting

lung disease already have compromised respiratory

systems, there is concern that lung function changes

and other respiratory effects may be more serious for

these people than for the normal, healthy population.

However, limited data make it difficult to confirm

the susceptibility of people with preexisting respiratory disease.

Athletes and Outdoor Workers

Both epidemiologic and chamber studies have

indicated that athletes may be at substantial risk of

experiencing decreases in work performance and

temporary loss of some lung function when exercising for approximately 1 hour at ozone concentrations

as low as 0.20 ppm [26,35,85]. Outdoor workers

exposed to ozone for prolonged periods may also be

at increased risk. New research shows that volunteers performing the equivalent of a day of heavy

manual labor while exposed to 0.12 ppm ozone

experience significant loss in lung function (13

percent group mean decrease in FEV1

) and pronounced symptoms (e.g., cough, pain when inhaling

deeply) [28]. This research suggests that extended

periods of heavy exercise while exposed to ozone

may be harmful to respiratory health and physical

performance, not only during periods of high ozone

concentrations (greater than 0.20 ppm), but also at

levels found in many nonattainment cities (0.12 to

0.18 ppm).

Asthmatics

Results of studies on asthmatics are mixed. A

number of epidemiologic studies of asthmatics have

suggested that ozone exposure may be associated

with increased asthma attacks, hospital admissions

for asthma, temporary loss of some lung function,

and symptoms (See ref. [103,9,38,36]. Asthmatics

have also participated in studies in which lung

function and symptoms were assessed before and

after breathing ozone in a controlled laboratory

environment. These studies have typically shown

that the lung function and symptom responses of

asthmatics to a specific low concentration level of

ozone do not differ from the responses of healthy

non-asthmatics [44,62,57] .11

It is unclear why asthmatics have generally failed

to exhibit increased sensitivity to many of the effects

of ozone in chamber studies. However, these have

been group analyses; there may be a subpopulation

of asthmatics more sensitive than a subgroup of

“normals” to ozone inhalation. For example, moderate to severe asthmatics have not been studied in

these controlled environments. Chamber studies of

asthmatics have only recently been conducted at the

higher exercise and ozone concentration levels that

have yielded the most significant responses in

non-asthmatics. The discrepancy between results in

epidemiologic and chamber studies may also be due

to interaction between ozone and other environllwhile tie wej@t of tie evidence su=ests that asthmatics are no more sensitive to ozone than healthy, non-asthmatics, one recent clinical smdy

suggests that asthmatics may be slightly more sensitive to the effects of ozone on airway narrowing, which occurs at somewhat higher ozone

concentrations than the changes in FEV1 [47].
50 . Catching Our Breath: Next Steps for Reducing Urban Ozone

mental factors (i.e., other pollutants, high temperatures, and humidity) in the field. Factors operating in

the ambient environment may not have been replicated in clinical studies. The question of whether

asthmatics may be somewhat more adversely affected by ozone inhalation is not yet resolved.

People With Chronic Obstructive

Pulmonary Disease

People with chronic obstructive pulmonary disease (COPD) (e.g., chronic bronchitis, emphysema),

many of whom are former smokers, are also of

concern as an “at-risk” subgroup because they

already have poor lung function. Like asthmatics,

relatively small decrements in lung function could

be adverse for them, compared to healthy individuals, who may not be affected by such changes.

Several different laboratory studies have been conducted on COPD patients exposed to ozone

[51,58,59,88,42], but none have found them to

experience significant reductions in lung function

measures (FVC, FEV1) even at concentrations as

high as 0.30 ppm for 1 to 2 hours. It would be

necessary to study these individuals over longer

periods of exposure and at higher exercise levels

(unobtainable by many COPD patients) in order to

adequately evaluate their risk from ozone exposure.

Out of concern for their health, studies of patients

with COPD, like those with asthma, have not been

performed under such conditions to date.

Children

Concern for children as a potentially susceptible

subgroup has been raised for several reasons:

1.

2.

3.

their lungs are not fully developed until

adulthood, increasing their risk for damage

from ozone exposure;

they are more likely than the average adult to

be exercising outdoors when ozone levels are

high (summertime); and

their higher metabolic rates tend to lead to

higher ventilation rates during exercise, which

may give them a greater dose of ozone than

exercising adults.

The critical question regarding children exposed

to ozone is whether repeated exposure will influence

their lung maturation. Relatively low concentrations

of ozone (at or around the standard) do appear to

have an adverse impact on the lung function of

active children [71,63]. On the basis of both

controlled exposure studies and field studies of

ambient pollutant exposure, however, children do

not appear to have lung function effects that are

different than those experienced by adults. However,

children appear to experience fewer symptoms than

adults when exposed to concentrations as low as

0.12 ppm [71,3,52]. It is unclear at this time why

children have weaker symptom responses. Some

scientists have suggested that this lack of significant

symptom response may put them at greater risk

because it would fail to deter them from future ozone

exposure.

The Elderly

Concern over the elderly as a possible “ozonesensitive” subgroup has been largely because of a

general belief that the most frail members of any

population may be at an overall greater risk from

numerous environmental stresses than the population at large. However, it is commonly accepted that

these individuals are the least likely to be exercising

outdoors where they might be exposed to ozone. A

subgroup of healthy, older adults may be at risk

because they may participate in outdoor activities

where they might be exposed to ozone. The limited

evidence available at this time, however, does not

indicate that age plays a significant role in their

response to ozone. While lung function effects have

been observed in this subpopulation, several studies

suggest that healthy older adults may, in fact, be less

susceptible to the acute lung function effects of

ozone than healthy young adults [20,82]. The extent

to which pulmonary function changes reflect other

events occurring in the lungs of older adults who are

exposed to ozone is unknown.

Possible Synergistic Effects of

Ozone and Acid Aerosols12

Some scientists are concerned that ozone and acid

particulate and vapors may interact to affect human

health. This has been prompted by research indicating that both pollutants affect a similar target in the

lungs, may be enhanced by exercise, and reach peak

concentrations at the same time of the year. Some

laboratory findings suggest that the response of

lz~s ~tion is b~ largely on EPA’s “Acid Aerosols Issue paper” [99].
Chapter 3-Health Effects of Ozone ● 51

Photo credit: Steve Delaney

Many health scientists are worried about the effects of ozone on children at play during high ozone episodes found in many

nonattainment cities. The critical unknown is whether repeated exposure will influence their lung maturation.

subjects exposed to ozone in conjunction with acid Possible interaction between ozone and some acid

aerosols is greater than when exposed to ozone alone aerosols is believed by some scientists to affect lung

[75]. clearance mechanisms, lung function, and acute

The two types of acid particulate that are

receiving the most attention are ammonium bisulfate

and sulfuric acid. There is evidence to suggest that

both acids are respiratory irritants and that their

‘‘target zone,” owing to their small size, is the

periphery of the lungs, similar to that for ozone. In

addition, exercise seems to exacerbate the effects of

inhaled sulfuric acid [100], as has been shown to be

the case with the impact of ozone exposure. Moreover, on the east coast, airborne sulfates are most

acidic in the summertime, the time of year when

peak ozone levels tend to occur.13

respiratory hospital admissions. Recent studies of

animals exposed to sulfuric acid show persistent

impairment of lung clearance, as does research

currently underway with ozone [86].14 Disturbance

of lung clearance mechanisms is believed by some

scientists to promote the inception or progression of

chronic respiratory disease, but there is no proven

connection at this time. Given the recent concern

about chronic health effects from exposure to ozone

alone, and the possibility of synergism between

ozone and certain acid aerosols, this new information is of particular concern.

13011 the west COast, nitric acid, which is in vapor form under most ambient conditions, has shown a correspondence with ozotIe COncenWatiOm.

Idwork on 4., 8-, and 12-month exposures is in progress M thk the.
52 ● Catching our Breath: Next Steps for Reducing Urban Ozone

Short-term loss of some lung function in

children exposed to ozone (0.12 to 0.18 ppm) in the

ambient environment has led some researchers to

postulate that other pollutants, in particular, acid

sulfates, may have contributed to this enhanced

effect [62]. One epidemiologic study has shown a

significant correlation between ozone, sulfates, temperature, and respiratory disease admissions to the

hospital during the summer months [9].

Research suggests that the acidity of an aerosol is

related to its toxicological potency, and is an

important factor in determining whether the aerosol

will interact synergistically with ozone [99,54].

There is some evidence that much lower concentrations of sulfuric acid—the more acidic aerosol—

than ammonium sulfate (0.04 mg/m3 v. 5.0 mg/m3,

respectively) [102,101] are needed to produce a

synergistic effect. Evidence from field studies shows

temporary effects on lung function of summer camp

children from elevated levels of sulfuric acid (>0.04

mg/m3) and ozone (>0.13 ppm) [79,80]. Concentrations of sulfuric acid up to 0.04 mg/m3 have been

observed in urban areas in the United States [99].

Preliminary evidence from animal studies, however,

indicates effects only at much higher levels than the

human studies. Effects on the rat lung do not appear

until sulfuric acid concentrations reach 0.5 mg/m3,

in combination with 0.12 ppm of ozone [102].

While our understanding of the relationship

between ozone and acid aerosols is limited at this

time, the apparent correlation between atmospheric

concentrations of ozone and acid particulate and

their respective health effects, as well as the general

lack of data on acids in the ambient environment,

indicate a need for additional research on pollutant

mixtures.

EXPOSURE TO OZONE

As discussed above, ozone has been shown to

cause short-term decreases in lung function and

increased respiratory symptoms in people engaged

in moderate to heavy exercise when ozone concentrations exceed the standard. There is also concern

about persistent health effects associated with longterm exposure to ozone. This section presents

information on the number of areas throughout the

United States where the ozone standard is not met,

and the population that lives in those areas. To get a

sense of the frequency with which people may be

exposed to elevated ozone levels and the magnitude

of these exceedances, the number of times that areas

fail to meet the standard is also presented. Because

living in an area where ozone levels have been

measured above the standard does not guarantee that

a person will actually be exposed at those levels, we

look at the various factors that influence exposure to

ozone.

Areas Failing To Meet the Standard

An area is designated “nonattainment” for ozone

if concentrations exceeding 0.125 ppm (l-hour

average) are measured on more than 3 days over a

3-year period at any monitoring site in the area (i.e.,

the area has an “expected exceedance” rate greater

than once per year, averaged over 3 years).

Figure 3-3 shows the metropolitan statistical areas

(MSAs) and grouped or “consolidated” metropolitan statistical areas (CMSAs) that were classified as

ozone nonattainment areas based on 1983-85 monitoring data. Areas that were designated nonattainment for the 1983-85 period, as well as the 1985-87

period, are listed in table 3-2. As indicated in the

table, several non-MSA areas were also designated

nonattainment but are not shown on the map.15

EPA updates the list of nonattainment areas every

year as data for a new season become available.

Based on the 1983-85 data, 76 urban areas (encompassing 104 individual MSAs plus the 10 non-MSA

areas) were designated nonattainment. In contrast,

70 areas were designated nonattainment based on

the 1985-87 period (18 areas were dropped in and 12

areas were added). The difference is partially

attributable to differences in weather between the

two periods. We focus on the nonattainment list

from the 1983-85 period for consistency with other

parts of our assessment. The list for the most recent

3-year period at the time of publication (1986-88) is

not yet available.

The shading in figure 3-3 indicates the 1983-85

“design value” for each area. The design value is a

lsme non-MsA areas me Dover, DE; seaford, DE; Iberville Parish, LA; Pointe Coupee Parish, LA; St. James Parish, LA; Acadia National park, ME;

Gardiner County, ME; Hartcoek County, ME; York County, ME; and Northampton County, VA.
Chapter 3-Health Effects of Ozone ● 53

Figure 3-3-Areas Classified as Nonattainment for Ozons Based on 1083-85 Data

I

measure of the highest l-hour average ozone concentrations in the area and is the fourth highest of all

of the daily peak l-hour average ozone concentrations observed within the area over the most recent

3-year period. Areas with design values of 0.13 ppm

or higher are violating the ozone standard. On

average, the higher the design value, the greater the

level of emissions control required to prevent

violations of the standard. For the 1983-85 period,

39 areas had design values of 0.13 or 0.14 ppm, 27

areas had design values of 0.15 to 0.17 ppm, and 10

areas had design values of 0.18 ppm or more. The

highest design value for any area was 0.36 ppm, for

Los Angeles, CA.

Frequency and Magnitude of Exceedances

Figures 3-4 through 3-6 show the areas throughout the contiguous United States where ozone

concentrations exceeded 0.12, 0.14, and 0.18 ppm,

respectively, at least 1 hour per year, averaged over

the years 1983 to 1985. By averaging data from all

of the monitors in each area, the maps indicate the

number of hours each concentration level was

typically exceeded.l6 The data shown were obtained

from EPA [84]. The all-monitor average statistics

are assumed to be more representative of air quality

throughout each area than data for the peak monitor

(the monitor where the highest concentrations were

recorded) would be. Note that more areas would be

l~e n~~r of moni~rs in Mch ~ea rmges from 1 to 18 (in Los Angeles). me average number of monitors in each mea is tiw.
54 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 3-2-Areas Classified as Nonattainment for Ozone Based on 1983-85 and 1985-87 Data

Design value (ppm) Design value (ppm)

Area name 1983-85 1985-87 Area name 1983-85 1985-87

1983-85 design value of 0.13 to 0.14 ppm Tulsa, OK . . . . . . . . . . . . . . . . . . . . .....0.13 0.12

Acadia National Park, ME* . . .. . . .....0.13 ----

Allentown-Bethlehem, PA .. . .. . ... ...0.14 0.13

Birmingham, AL** . . . . . . . . . . . . . .....0.13 0.15

Charleston, WV . . . . . . . . . . . . . . . . . . . . 0.13 ----

Charlotte-Gastonia-Rock Hill, NC-SC .. .0.13 0.13

Cleveland, OH** . . . . . . . . . . . . . . . . . . . . 0.14 0.13

Dayton-Springfield, OH . . .. . ..... ....0.13 ----

Denver-Boulder, CO** . . . . . . . . . . .....0.13 ----

Detroit, Ml** .. . . . . . . . . . . . . . . .. .....0.13 0.13

Dover, DE* . . . . . . . . . . . . . . . . . . . . .. ..0.14 ----

Erie, PA . . . . . . . . . . . . . . . . . . . . . .. ....0.13 ----

Gardiner, ME* . . . . . . . . . . . . . . . . . . . . . . 0.14 ----

Grand Rapids, Ml . . . . . . . .. . . . . .. ....0.13 0.13

Hancock County, ME* . . . . . . . . . . .0.13.... 0.13

Harrisburg-Lebanon-Carlisle, PA .. ....0.13 ----

Huntington-Ashland, WV-KY-OH . .....0.14 0.14

Iberville Parish, LA* . . . . . . . . . . . . .....0.13 0.13

Indianapolis, IN . . . . . . . . . . . . . . . . . . . . 0.13 0.13

Jacksonville, FL . . . . . . . . . . . . . . . . . . . . 0.14 0.16

Janesville-Beloit, WI . . . . . . . . . . . .....0.13 ----

Jefferson County, NY* . . . . . . . . . . . . . . . ---- 0.13

Kansas City, MO-KS . . .. .. .. .. .. ....0.14 ----

Kennebec County, ME* . . . . . . . . . . . . . . ---- 0.12

Kent County, DE* . . . . . . . . . . . . . . . . . . . ---- 0.13

Kewaunee County, WI* . . . . . . . . . . . . . . ---- 0.13

Kings County, CA* . . . . . . . . . . . . . . . . . . ---- 0.13

Lake Charles, LA. . . . . . . . . . . . . . .....0.14 ----

Lancaster, PA . . . . . . . . . . . . . . . . .....0.13 ----

Lexington, KY . . . . . . . . . . . . . . . . . . . . . ---- 0.13

Lincoln County, ME* . . . . . . . . . . . . . . . . ---- 0.13

Miami-Hialeah, FL** .... .. ... ... .....0.13 0.15

Montgomery, AL . . . . . . . . . . . . . . . . . . . ---- 0.14

Muskegon, Ml . . . . . . . . . . . . . . . . . .....0.14 0.17

Nashville, TN . . . . . . . . . . . . . . . . . . . . . . 0.14 0.14

Norfolk, VA . . . . . . . . . . . . . . . . . . . . . . . . ---- 0.13

Northampton County, VA* . . . . . . .....0.14 ----

Parkersburg, WV-OH . . . . . . . . . . . . . . . ---- 0.13

Pittsburgh, PA** . . . . . . . . . . . . . . . . . . . . 0.13 0.13

Pointe Coupee Parish, LA* . . . . . . .....0.13 ----

Portland, OR-WA** . . . . ... .. . . . .....0.13 0.15

Portsmouth-Dover-Rochester, NH-ME ..0.13 0.13

Raleigh-Durham, NC . . . . . . . . . . . . . . . . ---- 0.13

Reading, PA . . . . . . . . . . . . . . . . . . . . .. .0.13 ----

Richmond-Petersburg VA . . . . . . . .....0.13 0.13

St. James Parish, LA* . . . . . . . . . . .....0.13 ----

Tampa-St. Petersburg-Clearwater, FL** .0.13 0.13

“non-MSA area. ““ multi-MSA consolidated area. ----in attainment.

SOURCE: U.S. Environmental Protection Agency.

Visalia-Tulare-Porterville, CA . . . . .....0.13

York, PA . . . . . . . . . . . . . . . . . . . . . .....0.13

Yuba City, CA . . . . . . . . . . . . . . . . . . . . .0.13

1983-&J design value of 0.15 to 0.17 ppm

Atlanta, GA . . . . . . . . . . . . . . . . . . . . .. ..0.16

Bakersfield, CA . . . . . . . . . . . . . . . . . . . . 0.16

Baltimore, MD . . . . . . . . . . . . . . . . . . . . ..0.17

Baton Rouge, LA . ..................0.1 6

Beaumont-Pod Arthur, TX . . . . . . .....0.16

Boston, MA** . . . . . . . . . . . . . . . . . . . . ..0.16

Cincinnati, OH-KY-IN** .. .. . .. . .. ....0.17

Dallas-Ft. Worth, TX** . . . . . . . . . . .....0.16

El Paso, TX . . . . . . . . . . . . . . . . . . . . .. .0.16

Fresno, CA . . . . . . . . . . . . . . . . . . . . .. ..0.17

Longview-Marshall, TX . . . . . . . . . ..0.15...

Louisville, KY-IN . . . . . . . . . . . . . . . . . . . . 0.15

Knox County, ME* . . . . . . . . . . . . . . . . . . ----

Memphis, TN-AR-MS .. . . . . . . . . . .....0.15

Milwaukee, WI** . . . . . . . . . . . . . . . . . . . . 0.17

Modesto, CA . . . . . . . . . . . . . . . . . . . . . ..0-15

New Bedford, MA. . . . . . . . . . .. . . .....0.16

Phoenix, AZ . . . . . . . . . . . . . . . . . . . . .. .0.16

Portland, ME . . . . . . . . . . . . . . . . . . . . . ..0.16

Salt Lake City-Ogden, UT. . . . . . . .....0.15

Santa Barbara-Santa Maria-Lompoc, CA.. 0.16

Seaford, DE* . . . . . . . . . . . . . . . . . . . . ..0.15

St. Louis, MO-IL** . . . . . . . . .. . .. .....0.16

Stockton, CA . . . . . . . . . . . . . . . . . .....0.15

Washington, DC-MD-VA . . . .. . . . .....0.16

Worcester, MA . . . . . . . . . . . . . . . . . . . . . 0.15

York County, ME* . . . . . . . .. . . . . . .....0.15

San Francisco, CA** . . . . . . . . . . . .....0.17

1983-65 design value 0.18 to 0.26 ppm

Atlantic City, NJ . . . . . . . . . . . . . . . . . . . . 0.19

Chicago, IL** . . . . . . . . . . . . . . . . . . . . ..0.20

Greater Connecticut** . . . . . . . . . . .....0.23

Houston, TX** . . . . . . . . . . . . . . . . . . . . .0.25

New York, NY-NJ-CT* . . . . . . . . . .....0.22

Philadelphia, PA-NJ** . . . . . . . . . . .....0.18

Providence, RI* . . . . . . . . . . . . . . .....0.18

Sacramento, CA . . . . . . . . . . . . . . . . . ..0.18

San Diego, CA.... . . . . . . . . . . . . .....0.21

1983-85design value 0.27 ppm or higher

Los Angeles-Long Beach, CA** . . .....0.36

0.15

----

----

0.17

0.16

0.17

0.14

0.13

0.14

0.14

0.16

0.16

0.17

----

0.16

0.15

0.13

0.17

0.15

0.14

0.14

0.14

0.15

0.14

----

0.16

0.14

0.15

0.13

0.15

0.14

0.14

0.17

0.17

0.20

0.19

0.16

0.16

0.17

0.18

0.35

expected to show exceedances of the specified where a concentration ofO.12 ppm was exceeded at

concentrations if data for the peak monitor in each least l hour per year, on average, between 1983 and

area were used. 1985.17 Sixty of those are a shad concentrations equal

Of the 317(urbanandnonurban) areas for which to or greater than 0.12 ppm for60r more hours per

we have ozone data, figure 3-4 shows the 130 areas year, The Dallas, Houston, and Atlanta areas and

ITIfdatafor~eW&mofi~r ine~hareah~b~n~~ insteadof~e~l monitor average statistics, 146 ~easwould beindicated ashavingozone

concentrations greater than orequalto O.12ppm atleastl hourper year.
Chapter 3—Health Effects of Ozone ● 55

Figure 3-4-Areas Where Ozone Concentrations Exceeded 0.12 ppm at Least One Hour Per Year on Average,

From 1983-85

1 to 5

u

Data from all monitors located in each area were averaged in constructing the map. The shading indicates the number of hours that a

concentration of 0.12 ppm was exceeded. One hundred thirty million people reside in the areas shown.

SOURCE: U.S. Environmental Protection Agency, Storage and Retrieval of Aerometric Data, database, processed by E.H. Pechan & Associates, 1987.

parts of California, New York, New Jersey, and

Connecticut all recorded concentrations greater than

or equal to 0.12 ppm more than 20 hours per year.

The maximum number of hours that monitored

ozone concentrations exceeded 0.12 ppm in any one

area was 275 hours per year.

Figure 3-5 shows the 60 areas where the allmonitor average statistics indicate that ozone concentrations reached 0.14 ppm at least 1 hour per year

between 1983 and 1985. Twenty-four of these areas

recorded ozone concentrations of at least 0.14 ppm

for 6 or more hours per year. Seven areas, namely the

Houston area and parts of Connecticut and southern

California, recorded concentrations of 0.14 ppm or

higher more than 20 hours per year.

Figure 3-6 shows the 18 areas where concentrations were as high as 0.18 ppm for 1 or more hours

per year between 1983 and 1985. The all-monitor

average statistics indicate that concentrations exceeded 0.18 ppm 6 or more hours per year in

Houston and in two areas in Connecticut. Concentrations reached 0.18 ppm more than 20 hours per year

in three areas in southern California.

Factors Influencing Exposure to Ozone

Just because an individual lives in an area where

ozone concentrations of 0.14 ppm (for example)

have been measured does not mean that he or she has

been exposed to ozone concentrations at that level,

or that if exposed, he or she would experience
56 ● Catching our Breath: Next Steps for Reducing Urban Ozone

Figure 3-5-Areas Where Ozone Concentrations Exceeded 0.14 ppm at Least One Hour Per Year on Average,

From 1983-85

more than 20

Data from all monitors located in each area were averaged in constructing the map. The shading indicates the number of hours that a

concentration of 0.14 ppm was exceeded. Eighty-six million people reside in the areas shown.

SOURCE: U.S. Environmental Protection Agency, Storage and Retrieval of Aerometric Data, database, processed by E.H. Pechan & Associates, 1987.

adverse health effects. This section discusses some 4. person-to-person variability in how sensitive

of the factors that determine what a specified people are to ozone.

measured ozone concentration means for human

health. The factors that need to be kept in mind . At urban locations, ozone concentrations usually include: peak during the early to mid-afternoon, after build1.

2.

3.

how outdoor ozone concentrations vary over

time and location within a city;

where people are and for how long—

especially how much time they spend outdoors

v. indoors, where concentrations are lower;

people’s activity levels—which determine their

breathing rate and the depth of the breaths they

take, and thus the amount of ozone they

inhaled over a given period of time; and

ing up throughout the morning. At suburban and

rural locations, the peak concentrations usually

occur later in the afternoon or early evening. Figure

3-7 shows a profile of ozone concentrations as they

change over the day at a single monitoring site. The

profile is typical of a suburban area downwind of the

center of a major city. Especially at suburban and

rural locations, ozone concentrations often stay

within 10 to 20 percent of the peak l-hour average

concentration for several hours.
Chapter 3—Health Effects of Ozone ● 57

Figure 3-6-Areas Where Ozone Concentrations Exceeded 0.18 ppm at Least One Hour Per Year on Average,

From 1983-85

more than 20

Data from all monitors located in each area were averaged in constructing the map. The shading indicates the number of hours that a

concentration of 0.18 ppm was exceeded. Twenty-five million people reside in the areas shown.

SOURCE: U.S. Environmental Protection Agency, Storage and Retrieval of Aerometric Data, database, processed by E.H. Pechan & Associates, 1987.

The first step in relating measured ozone

concentrations to potential health effects is to

estimate from the monitor readings the pollutant

concentrations to which people have actually been

exposed. Figure 3-8 shows a contour map of how

peak ozone concentrations on a given day vary

across the New York City metropolitan area. The

diagram shows ozone concentrations predicted using

a model, with meteorological conditions and emissions of July 16, 1980 as inputs. As shown in the

example, at any one time, outdoor ozone concentrations can vary by a factor of two or more across an

urban area. However, as shown in figure 3-8, ozone

concentrations tend to vary smoothly over large

areas, and not to show sharp, localized peaks.18

People who are outdoors during the afternoon

when ozone concentrations reach their peak are apt

to be exposed to higher ozone concentrations than

people who are indoors. In air-conditioned buildings, indoor ozone concentrations are typically

about 30 percent of those measured outdoors at the

same location [76]. Ozone concentrations inside

buildings with open windows instead of airconditioning are estimated to be about 60 percent of

Igone exception to this gener~ rule is that in the plumes of large NOX sources, up to about a mile downwind of the source, ozone cOncenwtiOnS cm

be much lower than in the surrounding air. This is txxause extremely high concentrations of NOX without comparably high VOC concentrations destroy

ozone faster than it is produced. However, as the N% plume disperses, VOC and NOX levels come into balance and net ozone production results,
58 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 3-7-Profile of Ozone Concentrations as They

Change Over the Day at a Single Monitoring Site

0.12

0.10

0.08

0.06

0.04

0.02

I 1 I I 1

12 6 12 6 12

a.m. p.m.

Hour of day

Figure 3-8—Contour Map of the Variation in Daily Peak

Ozone Concentrations Predicted for the

New York City Area

The profile is typical of a suburban area downwind of a strong

source area or city center.

SOURCE: Maptad from U.S. Environmental Protection Agency, Environmental Criteria and Aaaassmerrt Offioe, Air CXIafify Criteria for Ozone and Other

RWochembsl Oxi&rnts, vol. I (Washington, DC: August 1966).

outdoor concentrations [76]. Most people spend 80

to 90 percent of their time indoors. Note, however,

that some people work or recreate outdoors most of

the day. About 5 percent of adult men work mostly

outdoors. An additional 10 percent work outside part

of the time. The proportion of women who work

outside is thought to be somewhat lower [77].

Two factors determine the total amount of ozone

an individual inhales over a given period of time: 1)

the ozone concentrations to which the person is

exposed; and 2) the depth and rate at which the

individual is breathing. The depth and rate at which

someone breathes is determined by the level of

exercise he or she is performing. Since the amount

of air and thus the amount of ozone inhaled increases

with increasing physical exertion, people who are

exercising or doing vigorous labor outdoors are

more likely to experience health effects due to

elevated ozone concentrations than people who are

sitting, standing, or walking at a leisurely pace. As

examples, recreational jogging, swimming and bicy -

The map was prepared with results from an urban-scale ozone

model, with meteorological conditions and emissions of July 16,

1980. As shown, ozone concentrations typically vary smoothly

over a large area and do not show localized peaks. Ozone

concentrations in parts per million.

SOURCE: Adapted from S.T. Rae, A#ication of the Urban AWted Model to the New

York Matropdltan Area, EPA 450/4-67-011 (Research Tnangie Park, NC:

U.S. Envkmmerrtal Protection Agency, May 1987).

cling can constitute heavy exercise. Those who

compete in these sports are likely to be attaining very

heavy exercise levels.19

As discussed in the section on health effects,

clinical and epidemiologic studies have shown that

different people respond differently to ozone even

when they are exposed to the same concentrations

over the same time period and are breathing at the

same rate. From 5 to 20 percent of the population of

healthy adults are thought to be very sensitive to

ozone. The reasons for their heightened sensitivity

have not been established.

Population Exposure Estimates

Based on 1984 census estimates [92] and the data

presented in figures 3-4 to 3-6, approximately 130

million people live in areas where ozone concentrations are expected to equal or exceed 0.12 ppm at

least 1 hour per year.20 Eighty-six million people

live in areas where concentrations reach at least 0.14

ppm at least 1 hour per year; 25 million where

19A low G~lup -eyindica~ hat ~~ut 18 ~rcentof ~u]t ~eric~s jog at le~ once yr w~k [31 ]. FOU out of every 1,000” adults (().4 ~rCtHlt)

run more than 6 miles at least once per wmk [32].

20EPA defines non~~ent ~em ~ ~W where o~ne ~oncen~ations wud or exc~ (). ]25 ppm ~ le~t 1 how per ye=. OVer 12 milliOn PtX)ple

live in areas that are included in Figure 24, with the 0.12 ppm cutoff, but are excluded with EPA’s 0.125 ppm cutoff.
Chapter 3—Health Effects of Ozone ● 59

Table 3-3-Estimated Exposures to Ozone Concentrations Above 0.12 ppm

People exposed Percent of people living Hours of exposure per

Exercise level per year in areas exceeding 0,12 ppm person exposed per year

Nationwide:

Low . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 million 26% 8.8 hr

Moderate . . . . . . . . . . . . . . . . . . . . . . . . 21 million 16% 8.6 hr

Heavy . . . . . . . . . . . . . . . . . . . . . . . . . . 13 million 10% 5.7 hr

Very heavy . . . . . . . . . . . . . . . . . . . . . . 80 thousand <0.1% 4.1 hr

Nationwide except Los Angeles:

Low . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Moderate . . . . . . . . . . . . . . . . . . . . . . . .

Heavy . . . . . . . . . . . . . . . . . . . . . . . . . .

Very heavy . . . . . . . . . . . . . . . . . . . . . .

LosAngeles:

Low . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Moderate . . . . . . . . . . . . . . . . . . . . . . . .

Heavy . . . . . . . . . . . . . . . . . . . . . . . . . .

Very heavy . . . . . . . . . . . . . . . . . . . . . .

24 million

16 million

IO million

60 thousand

9.7 miilion

4.6 million

3.0 miilion

20 thousand

20%

13%

8%

<0.1%

97%

46%

30%

0.2%

3.7hr

4.6 hr

3.2 hr

2.1 hr

22 hr

24 hr

14 hr

IO hr

These estimates are based on hourly ozone data for the period 1983-85, and take into account people’s activity patterns (e.g. time

commuting, time indoors at work, etc.) and Iocation throughout the day. The estimates are broken down according to people’s exercise

levels. Those exercising at the higher levels are most apt to be susceptible to health impacts. The total number of people residing in areas

where ozone concentrations exceeded 0.12 ppm at least 1 hour per year, on average during 1983-85, was approximately 130 million.

SOURCE: OTA, using data from T.R McCurdy, Offb of Air Ouaiity Planning and Standards, U.S. Environmental Protection Agency, Natione/ Estimates of Exposure to Ozone Un&v

Alftwnatib&NatiorW StanaWds (R&arch Triangle Park, NC: ~mber 1986).

concentrations reach at least 0.18 ppm; and 10

million live in the Los Angeles and Anaheim, CA

MSAs where ozone concentrations reach or exceed

0.25 ppm.

Of the 130 million people who live in areas where

ozone concentrations reach or exceed 0.12 ppm, 43

percent (62 million) live in areas where concentrations reach 0.12 ppm 6 or more hours per year; 34

percent (44 million) in areas where concentrations

reach 0.12 ppm at least 20 hours per year, and almost

10 percent (12 million) in areas (Los Angeles,

Riverside and Anaheim, CA) where ozone concentrations reach 0.12 ppm more than 100 hours each

year. As with the maps presented above, it is

important to note that the preceding estimates are

based on the average of all of the monitors in each

area, not the ‘‘peak” monitor.

The population statistics presented above might

be considered the number of people “potentially”

exposed to ozone—people who, if they were outside

at the “right” time and location, would be exposed

to ozone concentrations above the level at which the

current ozone standard is set. Table 3-3 presents

estimates of actual exposures: the number of people

who do happen to be in the right place at the right

time to be exposed to concentrations above 0.12 ppm

for at least an hour; and for each person who is

exposed, the average number of times each year that

exposures occur. The numbers given in table 3-3

were calculated by combining EPA’s exposure

estimates [69] with the number of people that we

have estimated live in areas where ozone concentrations are expected to exceed 0.12 ppm more than 1

hour per year.

The numbers given in table 3-3 are broken down by

the exercise levels at which the exposures were

estimated to have occurred. Recall that people

exercising at higher levels are expected to be more

susceptible to health impacts, Nationwide, 34 million people are estimated to be exposed each year at

low exercise levels; 21 million at moderate exercise

levels; 13 million at heavy exercise levels; and

approximately 80,000 during very heavy exercise.21

In each exercise category, these numbers represent

about 25 percent of the people who achieve that

exercise level some time during the year. Thus, since

everyone is exercising at a low level at some time

(e.g., when they are walking leisurely on a flat

surface), about 25 percent of the people who live in

zlThe coneswn~ng Ventilatim ra~s for tie= exerci~ levels are: low = 225 liters~inute (I/rein); moderate = 26 to 43 l/rein; high = W to 63 Umti;

and very high = 264 t/rein [68].
60 ● Catching our Breath: Next Steps for Reducing Urban Ozone

areas where ozone concentrations exceed 0.12 ppm

are estimated to be exposed to concentrations at or

above this level. By far the most people are exposed

at low or moderate exercise levels. Fewer people are

exposed at the highest exercise level, because

relatively few people engage in very heavy exercise.

Of the nationwide totals, 9.7 million, 4.6 million, 3

million, and 20,000 of the people exposed at low,

moderate, heavy, and very heavy levels, respectively, are residents of the Los Angeles area.

On a nationwide basis, people who are exposed to

ozone concentrations of 0.12 ppm at moderate

exercise levels are estimated to be exposed an

average of about 9 hours per year; people exposed at

heavy levels an average of 5.7 hours per year; and

people exposed at very heavy exercise levels an

average of 4.1 hours per year. However, the national

averages mask considerable variability among urban

areas. In particular, the national figures are skewed

by the high incidence of exposures in the Los

Angeles area. In Los Angeles, the average numbers

of hours people are exposed at low, moderate, heavy,

and very heavy exercise levels are estimated to be

22,24,14, and 10 hours per year per person exposed,

respectively. For the rest of the country, with the Los

Angeles estimates subtracted out, the estimated

numbers of hours of exposure are, respectively, 3.7,

4.6, 3.2, and 2.1 hours per year for people exposed

at low, moderate, heavy, and very heavy exercise

levels.

EXTRAPOLATION OF EFFECTS

OF MULTIPLE-HOUR EXPOSURES

TO OZONE

A carpenter spends the day hauling lumber and

hammering away at the frame of a two-story house.

A group of elementary school children are packed

off to spend the summer at camp, where they will

swim, hike, and compete in games of basketball,

tennis, and the like. A high school cross-country

track team begins practicing in August for their

upcoming fall season, engaging in vigorous, daily

routines of sprinting and long runs around the school

track. Are these people at risk for adverse health

effects from exposure to ozone? What conditions

would make them at risk? Could their lung function

be harmed by exercising outdoors when the ozone

level is high? How many people like them might be

harmed by working or playing in ozone contaminated environments?

In this next section we take a closer look at the

effects of ozone on people performing various

activities, examining the role that exercise and ozone

concentration play in the time it takes for an

“adverse” health effect to occur.

While data exist on the lung function effects

expected from exposure to ozone above the current

l-hour standard of 0.12 ppm, there is little information available on effects for longer periods of

exposure and at lower ozone levels. Information

about the health effects that might be experienced

under such conditions is needed to assist scientists

and policy makers in determining the adequacy of

the current standard for protecting public health and

in determining how quickly areas should be required

to meet the ozone standard.

To begin to address these issues, an OTA contractor22 developed a model to extrapolate the results of

1- to 2-hour exposure studies to conditions of

multiple-hour exposures (up to 8 hours) at ozone

concentrations typically measured during summertime in many U.S. cities (0.08 to 0.16 ppm). This

extrapolation model predicts the average changes in

lung function (measured by FEV1 and FVC)23 for

people exercising at different intensities under these

conditions. Data were selected nom a number of

exposure studies24 and applied to a regression model

that expresses the dose of ozone that an exposed

individual would receive, and then predicts a response in terms of lung function changes. Dose is

assumed to be affected by: the ozone concentration

in the air one is breathing, the effect of exercise

intensity on one’s inhalation rate, how long one is

exposed to ozone, and how much of the exposure

zzThis ~tion is based on an OTA contractor report by Lawrence J. Folinsbee [25bl.

23Forc~exp~ato~ Volwe in I s~~nd(mV,) and forctivital capacity (FVC) are common measures of lung f~ction tiatcan ~ aff~ted by exPOS~e

to ozone. FEVl is the maximum amount of air that can be exhaled from the lungs in 1 second; FVC is the maximum amount of air that can be exhaled

from the lungs after taking a full deep breath.

zdM~el p~meters ~ereest~at~ fiomexPWe st~ies conduct~ at low ozone concen~ations.me primary cfi~rion for selecthg studies to include

was that the exposures occurred at ozone concentrations that were wilhin or close to the ozone concentration region of interest (i.e., 4).20 ppm).
Chapter 3— Health Effects of Ozone ● 61

period one is exercising. This model can be used to

predict changes in lung function in exercising

populations. 25 It is important to note that the predicted losses in lung function in the model are group

mean changes, and that some individuals may

experience FEV1 or FVC losses greater or less than

the average changes for the whole group.26

Given the limited time available to develop this

model and the number of simplifying assumptions

that had to be made,27 the model results must be

considered approximate. When more data applicable

to multi-hour exposures at low ozone concentrations

become available, such a model can be improved.

Two alternative activity scenarios illustrate how

exercise can affect lung function, given various

ozone concentrations. The first scenario—

representing a moderate level of exercise—

corresponds to activity intensities and patterns of

typical construction workers, and children playing

outdoors on a summer day. The second scenario

corresponds to a more vigorous activity level, for

example, people engaged in active sports or biking.28Figure 3-9 illustrates how the level of outdoor

activity could affect the time it takes before an

‘‘adverse” change in lung function might occur,

given average ozone concentrations of 0.08 to 0.16

ppm.

29With respect to “adverse” effects, we

assumed that most scientists would not consider

group mean decreases in FEV1 of less than 5 percent

to be an adverse effect; some scientists would call

group mean decreases of 5 to 10 percent an adverse

effect; and most scientists would call decreases of 10

percent or greater an adverse effect. The lower line

on these figures represents a 5 percent cutoff; the

upper line represents a 10 percent cutoff. These

ranges apply to healthy people rather than to persons

with preexisting respiratory disease. This definition

of ‘‘adverse” is consistent with the definition

presented by EPA in its most recent review of the

ozone standard.30

Figure 3-9 shows that as one undertakes more

vigorous exercise, fewer hours of ozone exposure

are required to produce an adverse effect on lung

function, given the same ozone concentration. For

example, in the graph to the right in figure 3-9, when

average ozone concentrations are 0.14 ppm, a

5-percent loss of lung function would be anticipated

2SFor ~Xmple, ~der Fol~S~’S m~el, the % ch~ge in FEV1 = 03 X SVE X ExpDur X ActRat X -0.0367, where o~ is ozone concen~ation~ SVE

is specific ventilation (ratio of ventilation to vital capacity, or IJmin/L of forced vital capacity), ExpDur is exposure duration, and ActRat is activity

ratio (fraction of total exposure duration during which individual is exercising). The last number is the slope of the relationship between dose rate

and rate of change of FEVI. SW Table 4 in [25b] for the complete range of predicted lung function changes.

~For exmple, in a study by Fol~s~ [28], ~ average d~re~e of 13 percent in =Vl W* expefienc~ by a ~oup exposed to 0.12 ppm Of OZOne

over a 6.6-hour period; individual variability rangwi from losses as high as 47.6 percent to positive changes of 3.5 ~rcent.

27~ ~der t. m~e gener~~~ ex~wlations ~ross d~a rages for which minim~ info~ation exists, the following fisumptions were made: 1)

changes in lung function area linear function of exposure duration; 2) the influence of ozone concentration on function changes over the concentration

range of interest is approximately linear; 3) there is no threshold concenuation for response; 4) the influence of ozone at low concentrations on people

breathing at rest cannot be demonstrated and thus only the ozone exposure accompanied by exercise is relevant; 5) the effects of ozone on the lungs are

a function of the size of the lungs, and more specifically, the surface area of the lungs affected by ozone; and 6) within the concentration range of interest,

ozone’s effects are proportional to the estimated dose of ozone breathed during exercise.

28For ~~ of &ese exerci~ sccn~os, we @the following fom~a, b~d on Fo]ins~’s ~~ysis, to dete~ine tie ho~s to reach ~ adverse effCCt:

number of hrs to reach adverse effect= 100/60 X FEV1decr/(03 X SVE X ActRat X -0.0367). At the moderate exercise level, we assigned an SVE,

or specific ventilation rate, of “6” (about 33 liter#min) to be consistent with EPA’s definition of a typical ventilation rate experienced at a moderate

(or “medium”) level of exercise (26to434rnin). h activity ratio of 0.66 was applied, because it was assumed that a typic~ cons~ction worker would

be working about 40 minutes of every hour, with 20 minutes of rest time interspersed. At the heavy exercise level, the SVE was ‘‘ 10” (about 55 l/rein),

which is in line with EPA’s definition of heavy exercise (44 to 63 l/rein). At heavy exercise levels, we assumed an activity ratio of 0.84, or 10 minutes

of rest for every 50 minutes of exercise.

z91t is fip~t t. ~~t out hat the= ozone levels we not ~~concen~ations, but represent wh~ ~ average ozone level would be during the period

of exposure.

sWpA s~frecomends tie fo]]owing &finition for an ‘‘adverse” response [98]: tndividuul lung function loss of 10 to 20 percent for Up to 6 hews.

with accompanying symptoms and curtailment of some activity. We use group mean lung function losses of 5 to 10 percent as a surrogate for indivliiuaf

losses on the order of 10 to 20 percent, i.e., the most sensitive members of the population. Studies have shown that when groups experience losses of

between about 5 percent and 10 percent, a number of individuals within these groups maybe experiencing hmg function losses up to two and three times

this much. Using data presented in a risk assessment prepared for EPA [37], we compared group mean lung fmction changes to the EPA estimates of

the percent of the population with lung function losses of greater than 10 and 20 percent. A 5 percent group mean decrease in FEV1, which in our analysis

we consider a response that ‘‘some scientists would consider adverse”, is roughly equivalent to 10 to 20 percent of the population (the most sensitive

individuals) experiencing equal to or greater than a 10 percent decrease in FEV1, according to EPA’s risk assesment. Furthermore, a 10 percent group

mean loss in FEVI, which we describe as a response that ‘most scientists would consider adverse”, is about the same as 20 percent of the population

(most sensitive members) experiencing lung function losses of equal to or greater than 20 percent,
62 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

.08 .09 .10 .11 .12 .13 .14 .15 .16 .08 .09 .10 .11 .12 .13 .14 .15 .16

Average ozone concentration (ppm) during activity period Average ozone concentration (ppm) during activity period

The likelihood of experiencing adverse effects depends on 1) the ozone concentration, 2) the vigorousness of the activity, and 3) the

number of hours engaged in that activity. The figure on the left shows the number of hours to reach an adverse effect under moderate

exercise conditions (e.g., construction work or children playing). The figure on the right shows that fewer hours are needed under heavy

exercise (e.g., competitive sports or bicycling). The current one-hour ozone standard is shown for comparison.

SOURCE: OTA, based on work for OTA by Lawrence J. Folinsbee, Environmental Monitoring and Services.

for groups engaged in strenuous exercise-such as

biking or playing tennis—for 2 hours. At the same

ozone concentration (0.14 ppm), a 10 percent lung

function loss would be expected to occur after about

4 hours of strenuous exercise. Looking at a more

moderate level of exercise, e.g. construction work as

shown in the graph to the left in figure 3-9, we see

that it takes about twice as much time-or 4

hours-to reach lung function losses of 5 percent at

0.14 ppm than with more rigorous exercise. On a

typical summer day, one might expect children to be

outside playing for about 4 hours, the time it takes to

experience what some scientists believe would be

adverse lung function effects (5 percent average

decreases). After about 8 hours-not an unlikely

workday for construction workers-people exercising at a moderate level when ozone concentrations

are 0.14 ppm may, on the average, have as great as

10 percent lung function losses.

Note also on these two figures that the level where

adverse effects appear likely to occur (e.g., where

some or most scientists become concerned about

adverse effects) gets closer to the NAAQS for ozone

as exercise intensity increases from moderate to

heavy levels. In other words, the ozone standard is

less protective of people who choose to work

outdoors or exercise more vigorously than people

who lead less active lifestyles.

Not only is it important to realize how one’s

activity level might affect the amount of time it

would take to produce an ‘‘adverse” health effect,

but also, within a given activity level, how ozone

concentration affects the number of hours until

adverse effects occur. At a moderate level of

activity-construction work or the equivalent in

outdoor exercise-we see that at 0.16 ppm of ozone,

it takes about 3 1⁄2 hours to produce FEV1 decreases

of 5 percent; at 0.13 ppm it takes about 4 1/2 hours;

and at 0.10 ppm, approximately 5 1/2 hours. For a

group of construction workers to average 10 percent

decreases in lung function-the point at which few

scientists disagree that the effects are adverse-it

would take about 7 hours at 0.16 ppm and 9 hours at

0.13 ppm.

Table 3-4 indicates the population residing in

areas where ozone levels equal or exceed average

concentrations ranging from 0.08 to 0.16 ppm for
Chapter 3—Health Effects of Ozone . 63

between 1 to 8 hours, on at least 1 day per year.31

Table 3-5 presents the number of cities and population living in those cities where the ozone concentration exceeds 0.14 ppm for 2-,4-, and 8-hour periods

for at least 1,2,5, and 10 days a year. The estimates

given in tables 3-4 and 3-5 represent “potentially”

exposed people—they would not actually have been

exposed unless they were outside when the recorded

ozone episodes occurred. (And they would probably

not be affected by their exposure unless engaged in

some kind of exercise.) While we do not have

precise data on the number of exercising people

actually exposed, we can make some general statements about the percentage of individuals living in

these areas who may be exposed to these ozone

conditions while working or exercising outdoors.

First of all, we know that a significant portion of

the U.S. population is living in areas where ozone

levels are within the ranges discussed so far. For

example, table 3-5 shows that 45 million people live

in 24 cities where the 4-hour average ozone concentrations exceed 0.14 ppm for at least once per year.

About one-third of this population lives in 14 cities

where these conditions occur at least five times a

year; one-quarter live in areas where these conditions occur at least 10 times a year. About 18 million

people live in 10 cities in which 8-hour average

ozone levels exceed 0.14 ppm at least once per year.

Second, we know that within these potentially

exposed populations, some portion will actually be

exposed because of their outdoor activity. One

subpopulation that has been defined as potentially

‘‘at risk” for adverse effects from exposure to ozone

is peopIe who work outdoors. Looking at construction workers, we see that they could experience

adverse health effects under conditions found in

many areas around the United States. As mentioned

above, a moderate level of exercise like construction

work in areas where 7-hour average ozone concentrations exceeded 0.16 ppm would produce what

most scientists would consider to be an adverse

effect (10 percent group mean decrease in FEV1).

We estimate that a few percent, or about 0.4 million

of the 18 million people residing in areas in which

these ozone conditions occur, would be exposed at

Table 34-Population Residing in Areas Where the

Indicated Concentration is Exceeded at least One

Period Per Year, for Each Averaging Time

Population (millions) in areas

exceeding concentrations of

Averaging .08 .10 .12 .14 .16 .18 .20

time (hours) ppm ppm ppm ppm ppm ppm ppm

1 . . . . . . . . . . . . 160 150 110 65 41 21 17

2 . . . . . . . . . . . . 160 140 98 54 22 18 15

4 . . . . . . . . . . . . 160 130 75 45 18 16 12

6 . . . . . . . . . . . . 160 120 60 23 17 12 9.7

8 . . . . . . . . . . . . 150 93 45 18 12 9.7 1.8

SOURCE: OTA, treed on EPA Storage and Retrieval of Aerometric Data (SARDAD)

198345 monitoring data.

least once per year while engaged in construction

work. 32 Average lung function decreases of 5 percent—

a change of concern to some scientists-might be

seen in people exercising at moderate levels when

ozone concentrations exceed 0.14 ppm for four

hours. We estimate that a few percent of the 45

million people living in the 24 cities where these

conditions occur-or about one million people—

would be exposed at least once per year while

engaged in construction work. About one-third of

this population would be exposed at least five times

a year in the six cities where these conditions occur.

Active children exposed to ozone under comparable conditions might also experience adverse lung

function effects. For example, kids exercising moderately (at approximately the same relative intensity

as construction workers) for 4 hours when the ozone

concentration is 0.14 ppm would be expected to

average about a 5-percent decrease in their lung

function. As mentioned above, this is the point at

which some scientists become concerned about

adverse health effects. Since children between 5 and

14 years of age constitute about 14 percent of the

total U.S. population, [93] about 6 million kids 1ive

in the 24 cities where ozone concentrations exceed

0.14 ppm at least once a year. About 2 million

children live in the six cities where similar ozone

levels occur at least five times a year.

Finally, it is important to reemphasize that under

any of the above-mentioned scenarios, some portion

of the population will be more sensitive to ozone

slDa~ MC for the petiod 1983-85.

3zTMs es~ate (’‘a few percent”) of adversely affected construction workers is based on the foIlowing information. First, an estimated 5 percent of

adult men work outdoors full-time, and another 10 percent work outdoors part of the time [77]. We assume that a smaller fraction of women work outdoors

and that about 1.5 percent of the U.S. population (mostly men) are employed in nonsupexvisory cxmstruction jobs [92].
64 Ž Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 3-5-Number of Cities Where Ozone Concentrations Exceed

0.14 ppm for 2-,4-, and 8-hr Periods for the Specified Number of

Days Per Year, on Average, and Population Residing in Those Cities

2-hr 4-hr 8-hr

Population Population Population

Days per year (millions) Cities (millions) Cities (millions) Cities

>1 . . . . . . . . . . . . . . . . . . . . . . . . . . 54 33 45 24 18 10

>2 . . . . . . . . . . . . . . . . . . . . . . . . . 34 21 21 12 13 5

>5 . . . . . . . . . . . . . . . . . . . . . . . . . 19 9 14 10 2

>10 . . . . . . . . . . . . . . . . . . . . . . . . . 13 4 12 3 10 2

SOURCE: OTA, baaed on EPA SARDAD 1983-85 monitoring data.

than indicated by the group mean responses we have

considered. EPA has labeled these people as “responders,” and estimates that from 5 to 20 percent

of the healthy population in the United States are in

this more sensitive group. Therefore, while Folinsbee’s model has allowed us to predict group

mean lung function decreases, about 5 to 20 percent

of the exposed population discussed above would

experience significantly larger lung function

changes under the ozone exposure conditions considered here.

SELECTED NATIONWIDE

HEALTH BENEFITS FROM

CONTROLLING OZONE

This section looks at expected nationwide reductions in some types of health effects from reducing

ozone levels in all nonattainment areas.33 Estimates

are made of the number of incidents of various

respiratory symptoms and days when ozone exposure may limit a person’s activity, under three

scenarios: 1) current ozone levels, 2) ozone levels

after all reasonably available volatile organic compound (VOC) control methods are applied, and 3)

ozone levels assuming that the standard is attained

in all areas. The “benefit” of control is the

difference between the nationwide health effects

from current ozone levels and the health effects after

control. A rough approximation of the economic

value of these health improvements is also given.

We estimate that if ozone concentrations were

lowered enough to meet the standard in all areas,

several hundred million incidents of respiratory

symptoms, such as coughing or pain on deep

breathing, might be avoided each year. Among the

approximately 115 million people 1iving in nonattainment areas, some in the worst areas would

experience dozens fewer incidents of respiratory

symptoms each year while many in other areas

would experience no change. About 8 million to 50

million “restricted activity days” might also be

eliminated. These are days when someone feels ill

enough to limit a day’s worth of activitiesdisrupting most of the day’s activities, but generally

not spending the day in bed or staying home from

work.

By asking people what they would be willing to

pay to avoid a day of coughing or a day of restricted

activity, it is also possible to get a rough feel for the

economic value to individuals of the health improvements listed above. As will be discussed below, the

uncertainties are quite large due to the many

assumptions that must be made, but about $0.5

billion to $4 billion per year is a reasonable range for

the portion of health benefits that we were able to

evaluate. Under some assumptions, benefits are less

than $0.1 billion per year and under others, up to

about $10 billion per year.

Keep in mind, however, that we could only

quantitatively estimate some of the benefits. We did

estimate such acute health effects as the number of

times per year when people experience respiratory

symptoms, such as coughing or pain on deep

breathing; days when someone’s daily activities are

restricted; and days with asthma attacks. We did not

estimate benefits associated with changes in lung

function because we had no method for assigning a

value to this effect. (We did, however, include

shortness of breath, a symptom of lung function

changes perceptible by people without medical

33~s ~tion is b- on results presented in an OTA contractor report by Alan J. Ihpnick iind Raymond J. KoPP [49].
Chapter 3—Health Effects of Ozone ● 65

measuring devices.) And, even though many health

professionals are concerned that repeated exposure

to ozone over a lifetime may result in premature

aging of the lungs, along with the possibility of

permanent lung impairment, current understanding

does not allow us to quantity the lowered risk of

chronic effects.

We also did not include health benefits of

lowering VOC emissions that are not related to

lowered ozone concentrations. Probably the most

significant omission in this regard is that some

VOCs are carcinogenic. A preliminary EPA assessment estimated that nationwide, about 2,000 cancers

per year might result from exposure to toxic air

pollutants [97]. About half of the risk from the 20

chemicals considered in the study, about 1,000

cancers per year, comes from VOCs. The specific

chemicals or groups of chemicals posing the greatest

aggregate risk include benzene, butadiene, formaldehyde, gasoline vapors, and emissions from hazardous waste treatment, storage, and disposal facilities. Another EPA study concluded that about 250 to

400 deaths per year might be due to exposure to three

VOCs from mobile sources: benzene, butadiene, and

formaldehyde [12,67,74]. These estimates of cancer

risks from exposure to VOC should be regarded as

rough estimates due to uncertainties about how

carcinogenic these chemicals truly are, and to the

simplistic method of estimating human exposure.

Nonetheless, reducing VOC emissions to lower

ozone concentrations will also lead to lower risks of

cancer from exposure to these chemicals.

How the Estimates Are Calculated

To calculate the aggregate benefits from lowering

ozone concentrations in nonattainment areas, several steps are followed. First “concentrationresponse” relationships are developed, that is,

equations that describe the “response” (e.g., cough

incidents or days of restricted activity days) from

exposure to ozone at different concentrations. Next

data are obtained on ozone levels in nonattainment

areas. For this analysis we obtained 3 years of data

on daily maximum hourly ozone concentrations

measured at each of several hundred monitors in

EPA’s nationwide data base. Using the concentrationresponse relationships, we then calculate the effects

of ozone on the population of each nonattainment

county from the concentrations measured each day

during the ozone seasons of 1983 through 1985.34

Then, using a simplified air quality model (called

EKMA and discussed in chapter 4), we estimated

ozone concentrations after controls have been

adopted. We modeled two control scenarios: 1) air

quality levels after sufficient controls have been

adopted to meet the ozone standard in all areas, and

2) air quality levels after VOC emissions in nonattainment areas have been lowered by 35 percent—

controls about equivalent to adopting all currently

available control measures. (The emissions control

aspect of this scenario is discussed in chapter 6.) We

then calculate the effects of ozone—again county-by -

county and day-by-day—at these lower ozone concentrations. The diference between the before and

after estimates (either avoided episodes of respiratory symptoms or avoided days of selected adverse

consequences) are displayed in a series of tables.

If desired, one can take the aggregate estimates of

effects and assign dollar values to the avoided

symptom incidents and restricted activity days.

These values are taken from interviews where

people are asked what they would be willing to pay

to avoid such effects as a day of coughing or an

asthma attack. As one might imagine, the range of

responses is quite large, thus the dollar values must

be treated as more uncertain than the estimates of

adverse effects avoided.

Two types of studies are used to estimate the

concentration-response relationships: clinical and

epidemiologic. In clinical studies, people are exposed in laboratories to carefully monitored ozone

concentrations, typically while exercising on a

stationary cycle or treadmill. Researchers measure

changes in lung function as well as ask the volunteers to describe any respiratory symptoms they may

be experiencing. In the epidemiologic studies used

in this analysis, volunteers fill out daily or biweekly

diaries of their health status. These are later compared to concentrations measured at nearby ozone

monitors, after controlling for many other factors

such as age, sex, smoking status, occupation, daily

temperatures, and concentrations of other air pollutants.

34 For counties with more than one ozone monitor, we averaged the readings from all monitors. For counties with no ozone monitors, we averaged

the readings from all monitors operating within the metropolitan area.
66 ● Catching our Breath: Next Steps for Reducing Urban Ozone

Each type of study has advantages and disadvantages for estimating the health benefits from lowering ozone concentrations. The clinical studies provide excellent data on how individuals respond to

very specific exposure conditions (typically 1 to 2

hours of exposure while exercising vigorously).

However, one is left with the difficult task of

extrapolating the effects of ozone under typical daily

routines-adults exercising and walking to work,

children playing, and so on.

The epidemiologic studies directly produce data

on effects of interest—respiratory symptoms and

restricted activity—while engaged in typical day-today activities, but the relationship to ozone exposure

is more difficult to establish. First, the effects data

must be statistically compared to ozone levels that

are often only rough indicators of actual exposure.

Second, because several other factors that affect

respiratory health must be considered simultaneously (e.g., smoking status, temperature) it is quite

difficult to isolate the effect of ozone alone.

Keep in mind that none of the studies we used

estimate the risks of chronic effects from longer term

exposure to ozone. Whether there are chronic effects

from exposure over many years and, if so, the

magnitude, is still uncertain.

Selected Health Benefits of Lowered

Ozone Concentrations

As mentioned above, we used two types of studies

to estimate the effects from exposure to ozone:

clinical studies and epidemiologic studies. Using a

clinical study, we estimated three types of symptoms: the number of incidents of coughing, shortness

of breath, and chest discomfort (i.e., pain on deep

breathing) [70]. From the epidemiologic studies, we

estimated the number of days when respiratory

illness restricted normal activities [78], days with

any type of respiratory-related symptom (e.g., coughing, wheezing, chest discomfort, sore throat, etc.)

[49], and days of asthma attacks [38].

Table 3-6 presents our estimates of the total

number of incidents of respiratory symptoms

avoided from adopting the two control scenarios

mentioned above. Two sets of estimates based on

clinical studies are shown. The lower estimates

assume that the only people who might be affected

by ozone are those who engage in heavy exercise

outdoors. The higher estimates assume that people

exercising at light and moderate exercise levels can

also be affected by ozone, but with proportionally

lower effects at the lower exercise levels .35 The time

spent outdoors at each exercise level is estimated

from EPA data [76].

Taking into consideration uncertainty about who

will be affected, we estimate that meeting the

standard in all areas would eliminate about 110 to

350 million cough incidents each year, and about 60

to 200 million incidents each of shortness of breath

and chest pain. Our scenario that reduces VOC

emissions by 35 percent would eliminate about 40 to

130 million coughing episodes per year and about 20

to 70 million incidents each of shortness of breath

and chest pain. As shown in the table, the range is

even greater when one considers possible errors due

statistical estimation of the concentration-response

function from clinical data.

These health benefits may be easier to conceptualize when expressed on a per-person basis, or more

accurately, the type of response one might expect

within a group of 100 people. Among every 100

people, averaged across all nonattainment areas,

meeting the standard would eliminate about 100 to

300 cough episodes per year. The improvement,

averaging about one to three fewer cough episodes

per person per year, can be compared to an average

of about eight cough days per person per year [24].

The number of symptom episodes avoided would

vary from individual to individual, of course, for

several reasons. First, not everyone is active outdoors. Second, among every 100 people, about 5 to

20 are much more sensitive than the average for

unknown reasons. In addition, the average improvement varies considerably from nonattainment area to

nonattainment area, depending on the severity of the

ozone problem.

In table 3-7, we report the per-person improvement in areas by a measure of peak ozone concentralisM~~ ~l~ic~ ~~die~ have show ~ver~ effW~ from ozone ~der heavy and very heavy exerci~ conditions. At least one has show effects under

moderate exercise over muhi-hour time periods, supporting the hypothesis that the effects of ozone are due as much to “dose’ ’-the total amount of

ozone inhaled-as to concentration and exercise level. Limiting our analysis to only heavy exercisers is a fairly conservative assumption; extrapolating

effects to all exercise levels (including light) is a reasonable extrapolation, but no clinical data exist to support it.
Chapter 3—Health Effects of Ozone . 67

Table 3-6-Avoided Episodes of Respiratory Symptoms (millions of episodes per year)

From meeting the standard From a 350/. VOC reduction

Midpoint Range Midpoint Range

Cough:

Affecting heavy exercisers only . . . . . . . . . . . . . . . . . 110 (78-130) 39 (29-49)

Affecting all exercisers . . . . . . . . . . . . . . . . . . . . . . . 350 (250-440) 130 (100-160)

Shortness of breath:

Affecting heavy exercisers only . . . . . . . . . . . . . . . . . 61 (43-77) 22 (16-27)

Affecting all exercisers . . . . . . . . . . . . . . . . . . . . . . . 200 (140-250) 72 (51-89)

Pain on deep breathing:

Affecting heavy exercisers only . . . . . . . . . . . . . . . . . 60 (42-78) 22 (15-28)

Affecting all exercisers . . . . . . . . . . . . . . . . . . . . . . . 200 (140-260) 72 (51-93)

SOURCE: OTA, modified from A.J. Krupnick and R.J. Kopp, The Health and Agricultural Benefits of Reductions in Ambient Ozone in the LMed SWes, cmtractor reporl prepared for

fha Offioa of Technology Assessment, June 1988.

Tabie 3-7-Avoided Episodes of Respiratory Symptoms (episodes per 100 people per year)

From meeting the standard From a 35% VOC reduction

Heavy All Heavy All

exercisers only exercisers exercisers only exercisers

Cough:

All area average . . . . . . . . . . . . . . . . . . 96 310 36 120

Peak <0.14 ppm . . . . . . . . . . . . . . . . . 17 55 12 39

Peak 0.14 to 0.18 . . . . . . . . . . . . . . . . . 63 210 24 79

Peak 0.18 to 0.27 . . . . . . . . . . . . . . . . . 150 490 50 170

Peak >0.27 . . . . . . . . . . . . . . . . . . . . . 430 1410 140 470

Shortness of breath:

All area average . . . . . . . . . . . . . . . . . . 55 180 20 65

Peak <0.14 ppm . . . . . . . . . . . . . . . . . 10 33 7 24

Peak 0.14 to 0.18 . . . . . . . . . . . . . . . . . 38 120 14 46

Peak 0.18 to 0.27 . . . . . . . . . . . . . . . . . 88 290 29 95

Peak >0.27 . . . . . . . . . . . . . . . . . . . . . 240 780 74 240

Pain on deep breathing:

All area average . . . . . . . . . . . . . . . . . . 54 189 20 65

Peak <0.14 ppm . . . . . . . . . . . . . . . . . 10 32 7 23

Peak 0.14 to 0.18 . . . . . . . . . . . . . . . . . 36 120 14 45

Peak 0.18 to 0.27 . . . . . . . . . . . . . . . . . 85 280 28 93

Peak >0.27 . . . . . . . . . . . . . . . . . . . . . 240 790 79 260

SOURCE: OTA, modified from A.J. Krupnick and R.J. Kopp, The /+sa/fh and A@cultura/ Benefits of Raducticm in Arnb&nt Ozone in the Unifed States, contracbr reporl prepared for

the office of Technology Assessment, June 1988.

tions, We use the fourth highest concentration Table 3-8 presents the benefits estimated using

observed over the 3-year period in each county (i.e., the epidemiologic studies. Meeting the standard in

the equivalent of a county-level “design value”) all areas would eliminate about 25 million days per

rather than characterize an entire metropolitan area year of restricted activity and about 50 million days

by a single concentration. In those areas where peak with respiratory-related symptoms. About 2 million

ozone concentrations are close to the standard days of asthma attacks would also be eliminated.

(between 0.12 and 0.14 ppm), meeting the standard Our scenario that reduces VOC emissions by 35

would eliminate about 15 to 55 cough episodes per percent would eliminate about 8 million restricted

activity days per year, about 18 million symptom year among every 100 people. In those areas with the days, and about 0.6 million asthma attack days. worst ozone problems, meeting the standard would

eliminate 400 to 1,400 cough episodes per year Note that in the tables we have disaggregate

among every 100 people. restricted activity days and symptom days into
68 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 3-8-Avoided Days of Adverse Consequences (millions of days per year)

From meeting the standard From a 35% VOC reduction

Midpoint Range Midpoint Range

Restricted activity days:

Adults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 (5.3-34) 5.9 (1.9-10)

Children . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7 (2.3-15) 2.5 (0.8-4.4)

Days with any respiratory symptom:

Adults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 (22-46) 12.6 (8.2-17)

Children . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 (10-20) 5.4 (3.5-73)

Asthma-attack days:

All . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9 (1.0-3.0) 0.6 (0.4-09)

SOURCE: OTA. modifiedfrom A.J. KruonickandR.J. Kooo, The HdthandAgicultural Sensfits ofReductionsinAm/kWOzone intblJnitedStates, contractorreporl preparedfor

fheOfficeofTschrmlogyAa~sement,June 19~.

improvements among adults and improvements

among children. The epidemiologic studies that we

relied on found effects in adults only. his might be

because children are less likely to perceive symptoms than adults, or might only indicate that children

are less likely to report symptoms. The estimates

given in the text assume that children and adults are

affected in similar ways.

In table 3-9, we once again express these improvements on a per-person basis. Among every 100

people (adults and children), averaged across all

nonattainment areas, meeting the standard would

eliminate about 45 days with respiratory symptoms

each year. About half (25 days) would also be days

of restricted activity. Among every 100 asthmatics,

meeting the standard would eliminate about 60

asthma-attack days each year. Improvements from

lowering VOC emissions by 35 percent would

average about 8 fewer restricted activity days and 15

fewer days with respiratory symptoms among every

100 people. Among every 100 asthmatics, we would

expect to see 20 fewer asthma-attack days. These

improvements can be compared to a current total of

about 130 respiratory-related restricted activity days

[95] and 800 cough days each year among every 100

people [24]. Among 100 asthmatics, one would

expect about 1000 asthma-attack days each year

[49]. Each of these totals is the number of days of

poor respiratory health from all causes, not just air

pollution.

Again, there is considerable variation from area to

area. For example, in those areas where peak ozone

concentrations are close to the standard (between

0.12 and 0.14 ppm), meeting the standard would

eliminate about 8 days with respiratory symptoms

each year, and 3 days of restricted activity, among

every 100 people. In those areas with the worst

ozone problems, meeting the standard would eliminate about 200 days with respiratory symptoms, and

120 days of restricted activity, among every 100

people.

Note that the epidemiologic studies predict lower

benefits than the clinical studies, that is, the epidemiologic studies predict fewer health effects from

exposure to ozone than the clinical studies. Several

reasons are possible. First, people may be less likely

to exercise outdoors on days with high ozone

concentrations due to both the pollution and high

temperatures. If so, one would expect that fewer

people would actually be affected than the number

predicted from laboratory studies. Second, there is

considerable variation among similar types of studies. For example, EPA compares data from the

McDonnell study (which we used) to a similar study

by Kulle and concludes that the McDonnell study

predicts about twice as many people would experience at least mild cough after exercising heavily for

two hours at ozone concentrations in the range of

0.12 to 0.20 ppm [98]. There are too few epidemiologic studies to be able to get a feel for how variable

they might be. All we can conclude is that the

difference between the results predicted by the

clinical and epidemiologic studies falls within the

range of uncertainty of this type of analysis.

Assigning a Dollar Value to Health

Improvements From Lowered Ozone Levels

Although it is extremely difficult to assign a dollar

value to the health improvements described above,

table 3-10 presents our best guesses, based on the

limited information available in the economic literature. These are derived by simply multiplying our
Chapter 3—Health Effects of Ozone . 69

Table 3-9-Avoided Days of Adverse Consequences (days per 100 people per year)

From meeting the standard From a 35% VOC reduction

Midpoint Range Midpoint Range

Restricted activity days:

All area average . . . . . . . . . . . . . . . . . . 23 (7-44) (2-13)

Peak <0.14 ppm . . . . . . . . . . . . . . . . . 3 (l-6) 2

Peak 0.14 to 0.18 . . . . . . . . . . . . . . . . . 13 (4-23) 5 (2-8)

Peak 0.18 to 0.27 . . . . . . . . . . . . . . . . . 34 (11-61) 11 (4-19)

Peak >0.27 . . . . . . . . . . . . . . . . . . . . . 120 (32-240) 32 (lo-57)

Days with any respiratory symptom:

All area average . . . . . . . . . . . . . . . . . . 44 (29-60) 16 (1 1-22)

Peak <0.14 ppm . . . . . . . . . . . . . . . . . 8 (5-1 1) 6 (4-8)

Peak 0.14 to 0.18 . . . . . . . . . . . . . . . . . 30 (19-40) 11 (7-1 5)

Peak 0.18 to 0.27 . . . . . . . . . . . . . . . . . 69 (45-94) 23 (15-31)

Peak >0.27 . . . . . . . . . . . . . . . . . . . . . 195 (130-260) 64 (42-87)

Asthma-attack days (per 100 asthmatics):

All area average . . . . . . . . . . . . . . . . . . 58 (31-89) 19 (11 -28)

Peak <0.14 ppm . . . . . . . . . . . . . . . . . (5-1 3) 6 (4-9)

Peak 0.14 to 0.18 . . . . . . . . . . . . . . . . . 35 (20-51 ) 13 (7-1 8)

Peak 0.18 to 0.27 . . . . . . . . . . . . . . . . . 86 (48-130) 27 (15-39)

Peak >0.27 . . . . . . . . . . . . . . . . . . . . . 280 (145-449) 78 (44-1 10)

SOURCE: OTA, modified from A.J. Krupnick and RJ. I@p, The Health and A@uttural BeneHts of Reductions h Amh&t Ozone in the Untied States, contractor report prepared for

Uw Offke of Technology Aaaessment, June 1968.

Table 3-10-Dollar Value of Selected Health Benefits (millions of dollars par year)

From meeting the standard From a 35% VOC reduction

Midpoint Range Midpoint Range

Based on epidemiologic studies: 550 (150-1 ,500) 190 (54-500)

Based on clinical studies:

Heavy exercisers only affected:

Two episodes per symptom day . . . . . . . . . . . . . . . . . 570 (200-1 ,400) 210 (75-520)

One episode per symptom day . . . . . . . . . . . . . . . . . . 1,100 (400-2,900) 420 (150-1,000)

All exercisers affected:

Two episodes per symptom day . . . . . . . . . . . . . . . . . 1,900 (670-4,700) 680 (250-1,700)

One episode per symptom day . . . . . . . . . . . . . . . . . . 3,700 (1 ,300-9,500) 1,400 (500-3,400)

SOURCE: OTA, modlflad from A.J. Krupnkk and RJ. Kopp, The Mahh and A@cu/tura/ 6enetits of %ductbns /n Ambient Ozone in fha Un/ted SYates, contractor report prepared for

the office of Ttinoiogy Assessment, June 1988.

estimates of the number of days of improved

respiratory health by a dollar value for each day of

adverse health effects. A range of dollar values are

available from four studies where people were

directly asked how much they would be willing to

pay to avoid a day of respiratory symptoms [90,18,83,66].

The estimates in table 3-10 assume the following

dollar value of each health effect: People would be

willing to pay $5 to avoid each day of respiratory

symptoms, with a range of $2.50 to $10. People

would be willing to pay $18 to avoid each day of

restricted activity, ranging from $11 to $30. And

people would be willing to pay $25 to avoid each day

of asthma attacks, with a range of $9 to $41. These

were chosen as reasonably representative estimates

of the “typical” responses found in the available

studies, but keep in mind that the range of individual

responses in the studies was enormous.

For example, in one of the studies [18], the

arithmetic average response for the value of a cough

day was about $11. However, half the survey

respondents replied $1 or lower. For shortness of

breath, the average response was about $8, but over

half of the respondents replied that they would be

willing to pay nothing. In addition, these average

values do not include very high responses (e.g., one

respondent valued a cough day at $10,000).

With these limitations in mind, let us turn to table

3-10. From epidemiologic studies, we were able to

quantify the following health benefits from lowering
70 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

ozone concentrations: avoided days with respiratory

symptoms, avoided days of restricted activity, and

avoided days of asthma attack. We estimate that the

economic value of these health improvements from

meeting the standard would be about $550 million

per year, ranging from about $150 million to $1.5

billion per year. 36 The economic value of these

health improvements from a 35-percent reduction in

VOC emissions would be about $190 million per

year, ranging up to about $500 million per year.

From the clinical studies, we are able to estimate

the number of avoided episodes of three types of

respiratory symptoms: coughing, shortness of

breath, and pain on deep breathing. Dollar benefits

based on these studies range from values about equal

to those stated above, to several times as much.

Our “best” estimates from the clinical studies of

the economic value of the respiratory symptoms

avoided from meeting the standard range from about

$570 million to $3.7 billion per year. Under alternative reasonable assumptions, benefits range from

about $200 million per year to about $9.5 billion per

year. The higher estimate assumes: 1) a somewhat

higher probability of experiencing respiratory symptoms from exposure to ozone, and 2) that people

would be willing to pay $10 to avoid a day of

respiratory symptoms.

Our “best” estimates of the value of respiratory

symptoms avoided from a 35-percent reduction in

VOC emissions range from about $210 million per

year to about $1.4 billion per year. Under alternative

assumptions, our estimates range from $50 million

to $3.4 billion per year. Again, the higher estimate

assumes a somewhat higher responsiveness to ozone

and that people would be willing to pay $30 to avoid

a day of restricted activity.

We have no way of judging which of the estimates

presented in the table are more likely. Neither

approach—using epidemiologic studies or clinical

studies—seems clearly superior for this type of

benefits assessment. For meeting the standard, about

$0.5 billion to $3.7 billion per year is the range of our

“best” estimates for the portion of health benefits

that we were able to evaluate. From lowering VOC

emissions by 35 percent, about $0.2 billion to $1.4

billion per year is a reasonable range for the portion

of health benefits that we were able to evaluate. In

either case, the benefits could reasonably be lower or

about 21⁄2 times greater, depending primarily on the

value one assigns to a day of respiratory illness.

Again, none of the studies we used estimate the

risks of chronic effects from longer term exposure to

ozone. As discussed in an earlier section, many

health professionals appear to be particularly concerned over the possibility of permanent damage to

the lung from exposure to ozone over many years.

We were not able to quantify these risks and include

them in our benefits estimates.

REFERENCES FOR CHAPTER 3

1.

7-.

3,

4.

5.

6.

7.

Abraham, W. M., Januszkiewicz, A. J., Mingle, M.,

Welker, M., Wanner, A., and Sackner, M. A.,

‘‘Sensitivity of Bronchoprovocation and Tracheal

mucous Velocity in Detecting Airway Responses

to Oj,” J. Appl. Physiol., 1980, 48:789-793.

American Thoracic Society, “Guidelines as to

What Constitutes an Adverse Respiratory Health

Effect, with Special Reference to Epidemiologic

Studies of Air Pollution,” Am. Rev. Respir. Dis.,

1985, 131:666-668.

Avol, E. L., Linn, W. S., Venet, T. G., Shamoo,

D. A., and Hackney, J. D., “Comparative Respiratory Effects of Ozone and Ambient Oxidant

Pollution Exposure During Heavy Exercise, ”

JAPCA, 1984, 34:804-809.

Avol, E. L., Linn, W. S., Shamoo, D. A., Valencia,

L. M., Anzar, U.T, Venet, T. G., and Hackney, J. D.,

“Respiratory effects of Photochemical Oxidant

Air Pollution in Exercising Adolescents, ” Am.

Rev Respir. Dis., 1985, 132:619-622.

Avol, E. L., Linn, W. S., Sharnoo, D. A., Va.lencia,

L. M., Venet, T. G., Trim, S. C., and Hackney, J. D.,

‘‘Short-term respiratory Effects of Photochemical

Oxidant in Exercising Children, ” JAPC’A, 1987,

37: 158-162.

Bdet~ D. Jr, Faulkner, C.S. II, and cook, K.,

“Effect of Chronic Ozone Exposure on Lung

Elasticity in Young Rats,” J. Appl. Physiol., 1974,

37; 92-96.

Bates, D. V., and Sizto, R,, ‘‘Relationship Between

Air Pollutant l&vels and Hospital Admissions in

Southern Ontario,” Can. J. Pub. Health, 1983,

74: 117-122.

36~ow ~~ysls, we ~s~e that on days of resmict~ Wtivity, respiratory symptoms will zdso be feh. We therefore assume hat tie estimate hat ~ple

are willing to pay to avoid a day of restricted activity includes the amount they are will to pay to avoid a day of respiratory symptoms. Our estimates

of economic value have been adjusted to refleet this overlap.
Chapter 3-Health Effects of Ozone . 71

8.

9.

10.

11

12.

13.

14.

15.

16.

Bates, D. V., and Sizto, R., “A Study of Hospital

Admissions and Air Pollutants in Southern Ontario, ” 1986, In: Lee, S. D., Schneider, T., Grant,

L. D., Verkerk, P. J., (eds.), Aerosols: Research,

Risk Assessment, and Control Strategies: Proceedings of the 2nd US-Dutch tnternationul Symposium (Williamsburgh, VA, Chelsea, MI: J.zwis

Publishers, Inc., May 1985), pp. 767-777.

Bates, D. V,, and Sizto, R., “Air Pollution and

Hospital Admissions in Southern Ontario: The

Acid Summer Haze Effect, ” Environ. Res., 1987,

43:317-331.

Bedi, J. F., Dreschsler-Parks, D. M., and Horvath,

S. M., ‘Duration of Increased Pulmonary Function

Sensitivity to an Initial Ozone Exposure, ” Am.

Ind. Hyg. Assoc. J., 1985, 46:731-734.

Bhatnagar, R. S., Hussain, M. Z., Sorense, K. R.,

Mustafa, M.G., von Dohlen, F. M., and Ise, S. D.,

“Effect of Ozone on Lung Collagen Biosynthesis, “ in be, S. D., Mustafa, M. G., and Mehlman,

M.A. (eds.), an international symposium on the

biomedical effects of ozone and related photochemical oxidants, Advances in modern epidemiological toxicology: vol. 5 (Pinehurst, NC., Princeton, NJ: Princeton Scientific Publishers, Inc.,

March 1982), pp. 311-321.

Carey, P. M., Air Toxics Emissions From Motor

Vehicles, Tecnical Report EPA-AA-TSS-PA-86-

5, Office of Mobile Sources, Environmental Protection Agency, September 1987.

Costa, D. L., Kutzman, R. S., bhmann, J. R., Popehoe, E. A., and Drew, R. T., ‘‘A Subchronic

Multi-dose Ozone Study in Rats,” (1983) In: be

SD, Mustafa MG, Mehlman MA, Eds. International Symposium on the Biomedical Effects of

Ozone and Related Photochemical Oxidants; (Pinehurst, NC, Princeton, NJ: Princeton Scientific

Publishers Inc. March 1982), pp. 369-393. (Advances in Modem Environmental Toxicology: V.

5).

Crapo, J. D., Barry, B. E., Chang, L-Y., and Mercer,

R.R., “Alterations in Lung Structure Caused by

Inhalation of Oxidants,” J. Toxicol. Environ.

Health, 1984, 13:301-321.

Crapo, J, D., Ying, H., Chang, L-Y., and Mercer,

R. M., “Assessment of Lung Injury Caused by

Oxidant Air Pollutants Using Electron Microscopic Morphometric Techniques, ” presented at

80th Annual Meeting of APCA, New York, NY,

June 21-26, 1986; Session 99, “Extrapolation of

animal toxicological data to man, ” pp. 1-10.

Delucia, A.J., and Adams, W. C., “Effects of

Ozone Inhalation During Exercise on Pulmonary

17.

18.

19.

20.

21.

22.

23.

~4,

25a.

25b.

26.

Function and Blood Biochernisv, ” J. APP1.

Physiol. Respir. Environ. Exercise Physiol., 1977,

43:75-81.

Detels, R., Tashkin, D. P., Sayre, J. W., Rokaw,

S. N., Coulson, A. H., Massey, F. J., and Wegman,

D. H., “The UCLA Population Studies of Chronic

Obstructive Respiratory Disease, ” Chest, October

1987, 92:594-603.

Dlckie, M., Gerking, S., Brookshire, D., Coursey,

D., Schulze, W., Coulson, A., and Tashkin, D.,

“Reconciling Averting Behavior and Contingent

Value Benefit Estimates of Reducing Symptoms

of Ozone Exposure” Improving Accuracy and

Reducing Costs of Environmental Benefi”ts Assessments (Washington DC: EPA 1987).

Dockery, D. W., Ware, J. H., Ferris, B. G., Glicksberg, D. S., Fay, M. E., Spiro, A., and Speizer,

F. E., “Distribution of Forced Expiatory Volume

in One Second and Forced Vital Capacity in Healty

White Adult Never-smokers in Six U.S. Cities, ”

Am. Rev. Resp. Dis., 1985, 131:51 1-520.

Drechsler-Parks, D. M., Bedi, J, F., and Horvath,

S. M., “Pulmonary Function Response of Older

Men and Women to Ozone Exposure, ” Exp.

Gerontology, 1987, 22:91-101.

Driscoll, K. E., Yollmuth, T. A., and Schlesinger,

R. B., “Acute and SubChronic Ozone Inhalation in

the Rabbit: Responses to Aveolar Macrophages, ”

J. Tox. and Environ., 1987, 12;27-43.

Ehrlich, R., Findlay, J. C., Feners, J. D., and Gardner, D. E., ‘‘Health Effects of Short-term Inhalation

of Nitrogen Dioxide and Ozone Mixtures, ” Environ. Res., 1977, 14:223-231.

Ferris, B.G. et al., “Guidelines as to What

Constitutes an Adverse Respiratory Health Effect,

With Special Reference to Epidemiologic Studies

of Air Pollution, ” Am. Rev. Respir. Dis., 1985,

131 :666-668.

Flesh, R. D., Riha, M, L., and Miller, M. F,, “Effects

of Short-term Intermittent Air Pollutants on Incidence and Severity of Acute Respiratory Disease:

Data Collection and Quality Assurance. Project

Summary, ” U.S. Environmental Protection

Agency, EPA-600/S l-81-065.

Folinsbee, L. J., “A Summary of the Health Effects

of Ozone, ” contractor report for OTA, June 30,

1988.

Folinsbee, L. J., “Extrapolation of the Effects of

Exposure to Ozone for Durations Up to Eight

Hours and Ozone Concentrations Up to 0.16

ppm, ” contractor report for OTA, June 20, 1988.

Folinsbee, L.J., Bedi, J. F., and Horvath, S. M.,

‘‘Pulmonary Function Changes After 1 h Continu-
72 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

ous Heavy Exercise in 0.21 ppm Ozone, ” J. App/.

Physiol., 1984, 57:984-988.

27. Folinsbee, L.J., and Horvath, S.M., “Persistence

of the Acute Effects of Ozone Exposure, ” Aviat.

Space Environ. Med., 1986, 57:1136-1143.

28. Folinsbee, L. J., McDonnell, W. F., and Horstman,

D. H., “Pulmonary Function and Symptom Responses After 6.6 Hour Exposure to 0.12 ppm

Ozone With Moderate Exercise, ” JAPCA, 1988,

38:28-35.

29. Foster, W.M., Costa, D.L., and Langenback, E. G.,

‘‘Ozone Exposure Alters Tracheobranchial Mucociliary Function in Humans, ” J. AppZ. Physical.,

1987, 63:996-1002.

30. Friedman, Robert D., Sensitive Populations and

EnvironrnentalStandarddn Issue Report (Washington, DC: The Conservation Foundation, 1981).

31. Gallup Poll,“Percentage of Americans Who

Exercise Daily Up 12 Points Since 1982/

Popularity of Jogging Continues to Increase,” The

Gallup Opinion Index, vol. 226, July, 1984,

pp.9-l 1.

32. Gallup Po~I, “As Runners Extend Distances,

Percent Reporting They Jog bvels Off; Half of

Americans Exercise Regularly, ” The Gallup Opinion Index, 1983.

33. Gardner, D.E., Lewis, T.R., AlperL S. M., Hurst,

D. J., and Coffin, D. L., “The Role of Tolerance in

Pulmonary Defense Mechanisms, ” Arch. Environ.

Health, 1972, 25;432-438.

34. Gardner, D. E., and Graham, J.A., “Increased

Pulmonary Disease Mediated Through Altered

Bacterial Defenses,” 1977. In: Sanders, C. L.,

Schneider, R.P., Dagle, G. E., and Ragen, H.A.

(eds.), Pulmonary Microphage and Epithelial

Cells: Proceedings of the Sixteenth Annual Hanford Biology Symposium (Richland, VA, Washington, DC: Energy Research and Development

Administration, September 1976), pp. 1-21.

35. Gong, H., Bradley, M. S., Simmons, D. P., and

Tashkin, “Impaired Exercise Performance and

Pulmonary Function in Elite Cyclists During

Imw-level Ozone Exposure in a Hot Environmerit, ” Am. Rev. Respir. Dis., 1986, 134:726-733.

36. Gong, H., ‘‘Relationship Between Air Quality and

the Respiratory Status of Asthmatics in an Area of

High Oxidant Pollution in Los Angeles County, ”

Cal#ornia Air Resources Board Find Report,

April 1987.

37. Hayes, S.R., Rosenbaum, A. S., Wallsten, T. S.,

Whitfield, R. G., and Winkler, R. L., Assessment of

Lung Fuction and Symptom Health Risks AssociatedwithAttainment ofAlternative Ozone NMQ$-

Draft Final Report, EPA 68-02-4313 (Washington, DC: U.S. Environmental Protection Agency,

Sept. 18, 1987).

38. Holguin, A.H., Butller, P. A., Contant, C.F., Stock,

T. H., Kotchmar, D., Hsi, B.P., Jenkins, D. E.,

Gehan, B.M., Noel, L. M., and Mei, M., “The

Effects of Ozone on Asthmatics in the Houston

Area,” Air Pollution Control Association Transactions on Ozone/Oxidants Standards, Houston, TX,

November 1984, pp. 262-280.

39. Horstman, D. H., McDonnell, W. F., AbdulSalaam, S., Folinsbee, L.J., and Ives, P.J., “Current U.S. EPA Research Concerning More Prolonged Exposure of Humans to Imw Ozone

Concentrations, ” presented at the 81st annual

meeting of APCA, Dallas, TX, June 19-24, 1988..

40. Horvath, S.M., Gliner, J. A., and Folinsbee, L.J.,

“Adaptation to Ozone: Duration of Effec4° Am.

Rev. Respir. Dis., 1981, 123:496-499.

41. Jakab, G. J., “InfluenzaVirus, OzoneandFibrogenesis, ” Part 2 of two parts (abstract), Amer. Rev.

Respir. Dis. 137:4:166, April 1988.

42. Kehrl, H.R., Hazucha, M. J., Solic, J. J., and Bromberg, P. A., “Responses of Subjects with Chronic

Obstructive Pulmonary Disease After Exposures

to 0.30 ppm Ozone,” Am. Rev. Respir. Dis., 1985,

131 :719-724.

43. Kehrl, H.R., Vincent, L. M., Kowalsky, R.J., Horstman, A. H., O’Neil, J. J., McCartney, W. H., and

Bromberg, P.A., “OzoneExposure Increases Respiratory Epitheilial Permeability in Humans, ” Am.

Review of Respir. Dis., 1987, 135: 1124-1128.

44. Koenig, J. Q., Covert, D. S., Marshall, S. G., Belle,

G. V., and Pierson, W. E., “The Effects of Ozone

and Nitrogen Dioxide on Pulmonary Function in

Healthy and in Asthmatic Adolescents,” Am. Rev.

Respir. Dis., 1987, 136:1 152-1157.

45. Koren, H, S., Devlin, R. B., Graham, D. E., Mann,

R., Horstman, D. H., Kozumbo, W. J., Becker, S.,

McDomell, W. F., and Bromberg, P.A., “OzoneInduced Inflammation in the Lower Airways of

Human Subjects,” Am. Rev. Respir. Dis., 1989,

139:407-415.

46. Koren, H. S., Graham, D., Becker, S., and Devlin,

R., “Modulation of the Inflammatory Response in

Human Lung Exposed to Ambient hvels of

Ozone, ” in Atmospheric Ozone Research and Its

Policy Implications (cd.) Schneider, T., he, S.D.,

Welters, G.J.R., and Grant, L.D. (Amsterdam:

Elsevier, 1989), pp. 745-753.

47. Kreit, J. W., Gross, K. B., Moore, T. B,, Lorenzen,

T.J., D’Arch, J., and Eschenbacher, W. L., “Ozone-
Chapter 3-Health Effects of Ozone . 73

Induced Changes in Pulmonary Function and

Bronchial Responsiveness in Asthmatics,” J. App/.

Physiol., 1989, 66(1):217-222.

48. Krupnick, A., Barrington, W., and Ostro, B.,

“Ambient Ozone and Acute Health Effects: Evidence From Daily Data,” Discussion Paper 89-01,

Resources for the Future, Washington, DC, 1989.

49. Krupnick, A.J. and Kopp, R. J., “The Health and

Agricultural Benefits of Reductions in Ambient

Ozone in the United States, ” contractor report for

OTA, June 1988.

50. Kulle, T.J., Sauder, L. R., Kern, H. D., Farrell, B.P.,

Bermel, M. S., and Smith, D. M., “Duration of

pulmonary Function Adaptation to Ozone in

Humans,” Am. Ind. Hyg. Assoc. J., 1982, 43:832-

837.

51. Kulle, T.J., Milman, J.H., Sauder, L.R., Kerr, H. D.,

Farrell, B.P., and Miller, W. R., ‘Pulmonary Function Adaptation to Ozone in Subjects With Chronic Bronchitis, ” Environ. Res., 1984, 34:55-63.

52. Kulle, T. J., Sauder, L.R., Hebel, J. R., and Chatharn, M. D., “Ozone Response Relationships in

Healthy Non-Smokers, ” Am. Rev. Respir. Dis.,

1985, 132:36-41.

53. Las4 J. A., Greenberg, D. B., and Castleman, W. L.,

‘‘Ozone-Induced Alterations in Collagen Metabolism of Rat Lungs,” Toxicol. Appl. Pharmacol.,

1979, 51:247-258.

54, LasL J. A., Hyde, D.M., and Chang, D.P.Y., “A

Mechanism of Synergistic Lung Damange by

Ozone and Respirable Aerosol,” Exp. Lung Res.,

1984, 7:223-235.

55. Las6 J. A., and Warren, D. L., ‘‘Synergistic Interaction of Ozone and Respirable Aerosols on Rat

Lungs; III. Ozone and Sulfuric Acid Aerosol, ”

Toxicol. Appl. Pharmacol., 1987, 88:203-216.

56. Linn, W. S., Buckley, R., Speir, C., Blessey, R.,

Jones, M., Fischer, D., and Hackney, J.D., “Health

Effects of Ozone Exposure in Asthmatics,” Am.

Rev. Respir. Dis., 1978, 117:835-843.

57. Linn, W. S., Jones, M.P., Bachmayer, E.A., et al.,

“Short Term Respiratory Effects of Polluted Air:

A Laboratory Study of Volunteers in a High

Oxidant Community,” Am. Rev. Respir. Dis.,

1980, 121:243-252.

58. Linn, W. S., Fischer, D. A., Medway, D.A., Anzar,

U.T., Spier, C.E., Valencia, L. M., Venet, T.G., and

Hackney, J. D., “Short Term Respiratory Effects

OS Exposure in Volunteers With Chronic Obstructive Pulmonary Disease, ” Am. Rev. Respir. Dis.

125:658-663, 1982.

59. Linn, W. S., Shamoo, D. A., Venet, T. G., Spier,

C.E,, Valencia, L, M., Anzar, U.’E, and Hackney,

J.D., “Response to Ozone in Volunteers With

Chronic Obstructive Pulmonary Disease, ” Arch.

Environ. Health 38:278-283, 1983.

60. Linn, W. S., Avol, E.L., Shamoo, C. E., Speir, L. M.,

Valenci~ TG., Venet, D.A., Fischer, J.D., and

Hackney, J., ‘‘A Dose Response Study of Healthy,

Heavily Exercising Men Exposed to Ozone at

Concentrations Near the Ambient Air Quality

Standard, ” Toxicol. Indust. Health 2:99-

112, 1986.

61. Linn, W. S., Avol, E.L., Shamoo, D.A., Peng, R-C,

Valencia, L. M., Little, D.E., and Hackney, J.D.,

‘‘Repeated Laboratory Ozone Exposures of Volunteer hs Angeles Residents: An Apparent Seasonal

Variation in Response,” Toxicol. Indust. Health

4:505-520, 1988.

62, Lioy, P, J., Vollmuth, T. A., and Lippmann, M.,

‘‘Persistence of Peak Flow Decrement in Children

Following Ozone Exposures Exceeding the National Ambient Air Quality Standard,” J. Air

Pollut. Control Assoc., 1985, 35:1068-1071.

63. Lippmann, M., Lioy, D.J., tiikauf, G., Green,

K. B,, Baxter, D., Morandi, M., Pasternack, B.,

Fife, D., and Speizer, F.E., Adv. in Modern

Environ, Toxicol. 5:423-446, 1983.

64. Lippmann, M., Lioy, P. J., IAlcauf, G., Green,

K. B., Baxter, D., Morandi, M., and Pasternack,

B. S., “Effects of Ozone on the Pulmonary Function of Children,” In: he, S. D., Mustafa, M. G.,

and Mehlman, M.A. (eds.), International Symposium on the Biomedical Eflects of Ozone and

Related Photochemical Oxidants (Princeton, NJ:

Princeton Scientific Publishers, Inc., March 1982),

pp. 423-446.

65. Lippmann, M., “Health Significance of Pulmonary Function Tests, ” Presented at the 80th

Annual Meeting of APCA. New York, NY, June

21-26, 1987.

66. Lmehman, E.T., et al., “Distributional Analysis of

Regional Benefits and Air Quality Control, ”

Journal of Environmental and Economic Management 6:222-243, 1979.

67. Mathtech, Inc., “Methodology for Estimating

Costs of Carcinogenic Emissions From Mobile

Sources,” report prepared for U.S. Environmental

Protection Agency, Office of Air Quality Planning

and Standards, September 1988.

68. McCurdy, TR., Office of Air Quality Planning and

Standards, U.S. Environmental Protection

Agency, Nationul Estimates of Exposure to Ozone

Under Alternative National Standards (Research

Triangle Park, NC: December 1986).

69. McCurdy, TR., OffIce of Air Quality Planning and

Standards, U.S. Environmental Protection
74 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Agency, Research Triangle Park, NC, personal

communication, February 1988.

70. McDonnell, W.F., Horseman, D. H., Hazucha, M. J.,

Seal, E., Haak, E. D., Sallam, S. A., and House,

D.E., “pulmonary Effects of Ozone Exposure

During Exercise: Dose Response Characteristics,”

J. Appl. Physiol. 54, 5:1345-1352, 1983.

71. McDonnell, W.F., Chapman, R. S., bigh, M. W.,

Strope, G.L., and Collier, A. M., “Respiratory

Responses of Vigorously Exercising Children to

0.12 ppm Ozone Exposure,” Am. Rev. Respir. Dis.

132:875-879, 1985.

72. McDonnell, W. F., Hortsman, D. H., AbdulSalaam, S., Raggio, L.J., and Green, J.A., “The

Respiratory Responses of Subjects With Allergic

Rhinitis to Ozone Exposure and Their Relationship to Nonspecific Airway Reactivity, ” Toxicol.

j~utr. Health 3:507-517, 1987.

73. Miller, F.J., Illing, J.W., and Gardner, D. E.,

“Effect of Urban Ozone hvels on LaboratoryInduced Respiratory Infections,” Toxicol. Lett.

2:163-169, 1978.

74. Morton, B., “Addendum to ‘Methodology for

Estimating Costs of Carcinogenic Emissions From

Mobile Sources,’” U.S. Environmental Protection

Agency, Office of Air Quality Planning and

Standards, Apr. 5, 1989.

75. Osebold, J. W., Gershwin, L.J., and Ace, Y. C.,

“Studies on the Enhancement of Allergic Lung

Sensitization by Inhalation of Ozone and Sulfuric

Acid Aerosol,” J. Environ. Pathol. Toxicol. 3:221-

234, 1980.

76, Paul, R. A., Johnson, T., Pope, A., Ferdo, A., and

Biller, W. F., National Estimates of Exposure to

Ozone Under Alternative Natio(nal Standards,

drail report to U.S. Environmental Protection

Agency by PEI Associates, Inc. (Research Triangle Park, NC: December 1986).

77. Pope, A., Development of Activity Patterns To

Determine Population Exposure to Ozone, EPA

68-02-4309 (Research Triangle Park, NC: U.S.

Environmental Protection Agency, May 1986).

78. Portney, P.R., and Mullahy, J., “UrbanAirQuality

and Acute Respiratory Illness, ” Journal of Urban

Economics 20:21-38, 1986.

79. Raizenne, M. E., Hargreave, F., Sears, M., Spengler, J., Stern, B., and Burnett, R., “Exercise and

Lung Function Responses During an Air Pollution

Episode in Young Females With Airway Hypemxponsiveness to Methacholine, ” Am, Rev. Respir. Dis.

135:A343, 1987.

80. Raizenne, M, E., Stem, B., Burnett, R., Franklin,

C.A., and Spengler, J. D., “Acute Lung Function

Reponses to Ambient Aerosol Exposures in Children,” In: International Symposium on Health

Effects of Acid Aerosols: Addressing Obstacles in

the Emerging Data Base (Research Triangle Park,

NC: October 1987, also Environ. Health Perspect.,

in press.

81. Rae, S.T., Application of the Urban Airshed Model

to the New York Metropolitan Area, EpA 45 W4-87-

011 (Research Triangle Park, NC: U.S. Environmental Protection Agency, May 1987).

82. Reisenauer, C. S., Koenig, J. Q., McManus, M. S.,

Smith, M. S., Kusic, G., and Pierson, W.E., “Pulmonary Response to Ozone Exposures in Healthy

Individuals Aged 55 Years or Greater,” JAPCA

38:51-55, January 1988.

83. Rowe, R. D., and Chestnu4 L. G., Energy and

Resource Consultants, Inc., Report to EPA, Oxidants and Asthmatics in Los Angeles: A Benefits

Ana/ysLs, EPA-23 O-O7-85-O1O (Washington, DC:

1985).

84. SAROAD, Storage and Retrieval of Aerometric

Data, database, data files for 1983, 1984 and 1985

(Research Triangle Park, NC: U.S. Environmental

Protection Agency, 1987).

85. Schlegle, E. S., and Adams, W. C., “Reduced

Exercise Time in Competitive Simulations Consequent to Low hvel Ozone Exposure, ” Med. Sci.

Sports Exercise 18:408-414, 1986.

86, Schlesinger, R.B., Naumann, B. D., and Chen,

L. C., “Physiological and Histological Alterations

in the Bronchial Mucociliary Clearance System of

Rabbits Following Intermittent Oral or Nasal

Inhalation of Sulfuric Acid Mist,” J. of Toxicol.

and Environ. Health 12441-465, 1983.

87. Schoettlin, C. E., and Landau, E., “Air Pollution

and Asthmatic Attacks in the Ims Angeles Area, ”

Public Health Rep. 76:545-548, 1961.

88. Solic, J.J., Hazucka, M.J., and Bromberg, P.A.,

‘‘Acute Effects of 0.2 ppm Ozone in Patients With

Chronic Obstructive Pulmonary Disease, ” Am.

Rev. Respir. Dis. 125:664-669, 1982.

89. Specktor, D. M., Lippmann, M., Lioy, P. J., Thurston, G. D., Citak, K., James, D. J., Bock, N.,

Speizer, F. E., and Hayes, C., Am. Rev. Respir. Dis.

137:313-320, 1988.

90. Tolley, G. S., et al., “Valuation of Reductions in

Human Health Symptoms and Risk,” final report

to EPA, Grant #CR-81053-01-0, 1986.

91. Tyler, W. S., Tyler, N. K., Last, J. A., Gillespie,

M.J., and Barstow, T.J., “Comparison of Daily

and Seasonal Exposures of Young Monkeys to

Ozone,” Toxicology 50:131-144, 1988.

92. U.S. Department of Commerce, Bureau of the

Census, DetaiiedPopulation Characteristics, Uni-
Chapter 3— Health Effects of Ozone ● 75

ted States Summary, 1980 Census of Population

(Washington, DC: March 1984).

93. U.S. Department of Commerce, State andMetropolitan Area Data Book, 1986, Files on Diskette

(Washington, DC: 1986).

94. U. S. Congress, Senate Committee onPublic Works,

Senate Report No. 91-1196, 91st Cong., 2d sess.

11 (1970), reprinted in A Legislative History of the

Clean Air Act Amendments of 1970, Ser. No.

93-18, 93d Cong., 2d sess. 411 (1974).

95. U.S. Department of Health and Human Services,

National Center for Health Statistics, “National

Health Interview Survey: United States 1979,”

April 1981, table 3, p. 15.

96. U.S. Environmental Protection Agency, Environmental Criteria and Assessment Office, Air @zZity Criteria for Ozone and Other Photochemical

Oxidants, Vol. I of V (Washington, DC: August

1986).

97. U.S. Environmental Protection Agency, Office of

Policy, Planning, and Analysis, Unfinished Business: A Comparative Assessment of Environmental Problems, Appendix 1, Report of the

Cancer Risk Work Group, (Washington, DC:

February 1987).

98. U.S. Environmental Protection Agency, Office of

Air Quality Planning and Standards, Review of the

National Anbient Air Quality Standards for Ozone

Preliminary Assessment of Scientific and Technical Information, Draft Staff Paper (Washington,

DC: November 1988).

99. U.S. Environmental Protection Agency, Office of

Health and Environmental Assessment, Acid AeroSOIS Issue Paper, Review Draft (Washington, DC:

Febrwuy 1988).

100. Utell, M.J., Momow, P. E., Bauer, M.A., Hyde,

R. W,, and Schrek, R. M., “Modifiers of Responses

to Sulfuric Acid Aerosols in Asthmatics, ” Aerosols: Formation and Reactivity (London: Pergamon Press, 1986).

101. Warren, D.L., Guth, D,J., and Las4 J. A., “Synergistic Interaction of Ozone and Respirable Aerosols

on Rat Lungs; II. Synergy Between Ammonium

Sulfate Aerosol and Various Concentrations of

Ozone,” Toxicol. Appl. Pharmacoi. 84:470-479,

1986.

102. Warren, D.L., and Las~ J.A., ‘‘Synergistic Interaction of Ozone and Respirable Aerosols on Rat

Lungs: III. Ozone and Sulfuric Acid Aerosol, ”

Toxicol. Appl. Pharmacol. 88:203-216, 1988.

103. Whittemore, A. S., and Kom, E. L., “Asthma and

Air Pollution in the I-m Angeles Area, ” Am. J.

Public Health 70:687-696, 1980.

104. Wright, E. S., Kehrer, J.P., White, D. M., and

Smiler, K. L., “Effects of Chronic Exposures to

Ozone on Collagen in Rat Lung, ” ToxicoZ. Appl.

Pharmacol, 92:445-452, 1988.
Chapter 4

Effects of Ozone on

Crops and Forests
CONTENTS

Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

CONCENTRATIONS OF OZONE IN RURAL AREAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

POTENTIAL EFFECTS OF OZONE ON FORESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Ponderosa and Jeffrey Pine Trees in the San Bernardino National Forest and

Other Locations in California....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Sensitive Strains of White Pine Trees in the Eastern United States . . . . . . . . . . . . . . . . . . 82

Red Spruce Trees at High-Elevation Sites in the Eastern United States . . . . . . . . . . . . . . 82

Yellow Pine Trees in the Southeastern United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Sugar Maple Trees in Pennsylvania, New York, New England, and

Southeastern Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ....................+.. 84

European Forests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

EFFECTS OF OZONE ON CROPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Economic Estimates of Agricultural Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Agricultural Benefits of Reducing Ozone By 10 to 50 Percent. . . . . . . . . . . . . . . . . . . . . 88

REFERENCES FOR CHAPTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Figures

Figure Page

4-l. Estimated Daily 7-hour Average Ozone Concentrations During the

Growing Season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

4-2. Major Forested Areas and Dominant Tree Types of the United States . . . . . . . . . . . . 82

4-3. 1984 Crop Production at the State Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

4-4. Dose-Response Functions for Corn Used in the Two Agricultural Benefits

Analyses Performed for OTA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Tables

Table Page

4-1. Yield Losses Predicted to Occur for Seasonal Average 7-hour Mean

Ozone Concentrations of 0.04 and 0.06 ppm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

4-2. Estimates of Agricultural Benefits That Would Result Under Market Conditions,

If Ozone Concentrations Were To Be Reduced Nationwide by the Indicated

Amounts Relative to a Background Concentration of 0.03 ppm, . . . . . . . . . . . . . . . . 89
Chapter 4

Effects of Ozone on Crops and Forests

INTRODUCTION

At concentrations that occur in rural areas throughout the southern and eastern halves of the United

States, ozone reduces yields of economically important crops by from 1 to 20 percent, compared to

yields that would be expected if natural background

concentrations were not exceeded [10]. Analyses

performed for OTA show that annual agricultural

benefits in the range of $500 million to $1 billion

(1986$) would be expected to result from increased

productivity of major crops, if ozone concentrations

throughout the country were reduced by 25 percent

of the difference between current and background

levels [1,21]. These benefits include lower prices for

consumers, and increased profits for crop producers

in at least some parts of the country. Crop producers

in California, the South, and the Northeast would be

most apt to benefit from nationwide reductions in

ozone, as current concentrations are highest in these

areas.

Severe damage to ponderosa and Jeffrey pines in

southern California forests, and foliar injury and

growth reductions in sensitive strains of eastern

white pine, have been clearly linked to exposure to

ozone. Ozone has been hypothesized as partially

responsible for declines of other tree species that

have been observed in the Eastern United States,

southern Canada, and Europe. In several cases, the

location and timing of the declines suggest that air

pollutants might have played a role. In controlled

experiments, ozone has been shown to produce

foliar injury and/or reduce growth rates in young

trees of numerous species.

The forest-related benefits of reducing ozone

concentrations cannot currently be estimated. Exposureresponse information for major annual crops was

developed through research coordinated by an 8-

year program, the National Crop Loss Assessment

Network. Research on exposure-response relationships for trees is being conducted under the National

Acid Precipitation Assessment Program, and a new

10-year effort was established by the Forest Ecosystems and Atmospheric Pollution Research Act of the

100th Congress. However, developing exposureresponse information for trees is more difficult and

takes longer than for crops, due to the comparatively

slow growth and long lifetimes of trees, and to

complicating factors in their natural settings.

This chapter first shows the magnitude of ozone

concentrations at rural locations across the United

States. Then, current understanding of the effects of

ozone on trees is reviewed, and the major cases in

which ozone has been suggested as a cause of

decline are discussed. Finally, the effects of ozone

on crops are reviewed, and new estimates of the

agricultural benefits of reducing ozone presented.

CONCENTRATIONS OF OZONE IN

RURAL AREAS

Figure 4-1 shows estimated daily 7-hour average

(9 a.m. to 4 p.m.) ozone concentrations averaged

over the months April to October and the years

1978-82 [28].1 For comparison, the natural background value of the statistic shown is estimated to be

on the order of 0.030 parts per million (ppm),

although this value is highly uncertain [23]. Figure

4-1 was prepared by interpolating data from over

300 selected monitors, generally including suburban

monitors but excluding those at urban sites. Because

this chapter addresses the effect of ozone on crops

and forests, figure 4-1 also shows where rural

monitors are located [26]. There are fewer than 100

ozone monitors located at rural sites across the

United States, and a number of States do not have

any. Because the reliability of a concentration

estimate is extremely sensitive to the density of

monitoring sites in the area, no estimates are shown

for most Western States,

Ozone concentrations vary from one growing

season to another as a consequence of year-to-year

differences in weather patterns. An analysis of ozone

data from the years 1978-83, for forested subregions

of the Eastern United States, gives an indication of

IR~ent studies have suggested that for many crops, a measure of cumulative exposure to ozone would be a better measure of exposure dl~ t.hc 7-hour

seasonal average ozone concentration [44]. However, the 7-hour seasonal average concentration has been reported most often.

–79–
80 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 4-1-Estimated Daily 7-hour Average Ozone Concentrations During the Growing Season

Location of Rural Ozone Monitors

how much April to October, daily 7-hour average

concentrations change from one year to the next

[32]. Data from major cities were excluded from the

analysis. As examples, during the 6-year period

concentrations averaged over sites in the upper Great

Lakes region (northeastern Minnesota, northern

Wisconsin, and northern Michigan) ranged year to

Parts per million (ppm)

Daily 7-hour daytime ozone concentrations are average over the

months April through October and the years 1978-82. The lower

map shows the location of rural ozone monitors in 1984.

SOURCE: a) Adapted from R.J. Olson, L.J. Allison, and I.L. McCullough, Addnet

Notebook: Documentation of the Acid Deposition Data Network (ADDNET)

Data Base Supporting the National Add Precipitation Assessment Program,

Environmental Sciences Division publication no. 2755 (Oak Ridge, TN: Oak

Ridge National Laboratory, August 1987). b) Adapted from National Acid

Precipation Assessment Program, Interim Assessment: The Causes and

Effects of Acidic Deposition, vol. Ill (Washington, DC: October 1987).

year from 0.035 to 0.043 ppm; and concentrations

averaged over sites in Pennsylvania, New York and

western Maryland ranged year to year from 0.036 to

0.042 ppm. Concentrations for individual sites

varied more than these multi-state averages: concentrations at Whiteface Mountain, NY, ranged from

0.037 to 0.049 ppm, for example.
Chapter 4—Effects of Ozone on Crops and Forests ● 81

POTENTIAL EFFECTS OF OZONE

ON FORESTS

Exposure to ozone has been suggested as a factor

in several confirmed or reported cases of tree species

decline in the United States, Canada, and Europe. In

two cases-the decline of ponderosa and Jeffrey

pines in the San Bernardino Mountains east of Los

Angeles, and the decline of sensitive strains of

eastern white pine trees throughout the Eastern

United States-exposure to ozone has been established as a primary cause.

Ozone-induced injury in trees shows up primarily

as foliar injury, including leaf or needle discoloration and premature loss. In advanced cases, needles

or leaves and then branches of injured trees die back.

For example, ozone injury to eastern white pine

needles appears as a “chlorotic” or yellow mottle,

with needles ultimately dying back from the tips.

Reduced growth rates may precede or follow foliar

injury. Increased susceptibility to diseases and other

stresses may result from reduced photosynthesis and

decreased allocation of carbohydrates to tree roots

[34]. Ultimately trees may die prematurely. All of

these effects have been observed in forests of the San

Bernardino Mountains as a result of exposure to high

concentrations of ozone originating from NOX and

VOC emissions in the Los Angeles basin. In

addition to trees, ozone injures a variety of other

plants that occur in forest ecosystems. Examples

include wild grape, blackberry, milkweed and poison ivy [30,42].

Some of the symptoms of exposure to ozone can

also have other causes. And inmost cases of decline,

it is likely that multiple stresses contribute, so it is

difficult to sort out primary causes and even tougher

to predict the gains that might be made if one stress

is mitigated. Controlled exposure studies indicate

that seedlings of many species are sensitive to ozone.

However, the responses observed in studies conducted to isolate the effects of ozone do not always

match symptoms observed in natural environments.

Moreover, for the most part, programs to monitor air

pollution levels at forest sites where injury has been

observed, and controlled studies of the effects of

ozone on mature trees, are only now being initiated.

So, although exposure to ozone has been suggested

as an explanation for several declines, in most of

these cases scientists have not yet established

whether or not ozone is in fact, an important

contributor.

Figure 4-2 shows the major forested areas of the

United States, and identifies the dominant types of

trees in each area. Comparing figure 4-2 with figure

4-1 indicates that elevated ozone concentrations are

generally present in the western conifer region of

California, and the eastern hardwood and southeastern yellow pine regions. Below, we discuss whether

ozone is contributing to major declines in each of

these areas of the United States, as well as to

widespread damage in Central European forests.

Ponderosa and Jeffrey Pine Trees in

the San Bernardino National Forest and

Other Locations in California

Ozone is generally held to be the principal cause

of visible injury and accelerated mortality of ponderosa and Jeffrey pine trees in the San Bernardino and

San Gabriel Mountains of southern California.

White fir, incense cedar, and California black oak

trees have also been affected, but are less sensitive

than the pines. The symptoms observed in the forests

have been duplicated in controlled exposure studies.

At some sites in the San Bernardino National Forest

east of Los Angeles, daytime (14 hour) average

ozone concentrations of 0.10 ppm are typical during

June, July, and August [26]. The decline of ponderosa and Jeffrey pine there has been so severe that if

current trends persist, incense cedar and white fir are

expected to replace them as dominant species [25].

The National Park Service has reported extensive

ozone injury in national parks in California [42].

Average summer, daytime ozone concentrations at

some sites along the western slopes of the Sierra

Nevada, including a site in western Sequoia National

Park, range from 0.060 to 0.085 ppm [31]. Over 75

percent of the ponderosa and Jeffrey pine trees

surveyed at the western border of Sequoia National

Park in 1984 showed foliar injury attributed to ozone

[42], with associated growth reductions in Jeffrey

pine trees [31]. Foliar symptoms that match symptoms of ozone exposure have been observed on giant

sequoia seedlings in Sequoia National Park, as well

[41]. Injury to ponderosa and Jeffrey pines has also

been documented in Yosemite National Park [42].
82 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 4-2-Major Forested Areas and Dominant Tree Types of the United States

Western conifer

SOURCE: National AcM Preolpkatlon Assessment P~am, Irrrerlm Assessment: T/m Causes arrd Effecfs of Ao/c#c Depos/tkzn, wt. IV (Washlrqkm, DC: Ootober 1987).

Sensitive Strains of White Pine Trees in the

Eastern United States

Foliar injury, reduced growth rates, and increased

mortality due to exposure to ozone are apparent in

some eastern white pine trees throughout the Eastern

United States.* Symptoms of ozone injury have been

observed in some eastern white pine trees in Acadia

and Great Smoky Mountains National Parks [42].

Controlled exposure studies and field studies support the hypothesis that concentrations of ozone

observed throughout the East are high enough to

injure the most sensitive white pine trees (as with

other species of trees, not all strains of white pine are

equally sensitive to ozone) [45]. Reductions in

growth rates have been shown to be positively

correlated with the degree of foliar injury in individual trees [5]. Preliminary evidence in Great Smoky

Mountains National Park suggests that the most

sensitive strains of eastern white pine may be

disappearing [42]. However, considering all eastern

white pines, not just sensitive strains, regionwide

reductions in productivity have not been observed

[4].

Red Spruce Trees at High-Elevation Sites in

the Eastern United States

Reductions in radial growth rates, dieback, and

increased mortality have been observed in red spruce

trees at high-elevation sites in the northern Appalachian Mountains of New York and New England and

the southern Appalachians of North Carolina, Tennessee, Virginia, and West Virginia [26].3 The

populations of red spruce trees in some highelevation forests in the Northeast have declined by

40 percent to over 70 percent since the mid 1960s,

and the decline is continuing [16]. Red spruce

mortality in the southern Appalachians is much

lower, within normal limits for high-elevation forests [9]. Different foliar symptoms are observed in

northern and southern trees, suggesting that different

factors must be involved. Less severe foliar injury,

zThe e~tem white pine ~osystern mtnpri~s about 10 percent of the forested area in the Northeast, and less thm 1 Pereent in tie Scuthem [s9].

3< CHi@+levati~” refers t. si~s above ~ut 2,500 f~t in the Northeast ad above about 5,800 fat in the Southemt.
Chapter 4—Effects of Ozone on Crops and Forests . 83

Photo credit: U.S. Depertmenf of Agriculture

Above photograph shows a stand of ponderosa pine trees. Ozone is generally held to be the principal cause of visible injury and

accelerated mortality of ponderosa and Jeffrey pine trees in the San Bernardino and San Gabriel Mountains of southern California.

mortality, and growth reductions have also been creased pollution levels, winter damage and/or

observed in red spruce trees at low elevations in the drought that have occurred since the 1960s could be

Northeast [26]. The growth reductions observed at pushing the trees into decline [16].

most low-elevation sites are thought by some

scientists to be consistent with natural-trends associ- Heavy mortality from pest infestation (by the ated with aging [12]. balsam woolly adelgid) and unexplained reductions

It is not clear which stresses are responsible for the in growth rates have occurred in Fraser fir trees that

decline of high-elevation red spruce, and it is likely are mixed with red spruce at high-elevation sites in

that more than one factor is involved. Scientists have the southern Appalachians [12,9]. Although the

noted that soil and climate conditions at high balsam woolly adelgid does not affect red spruce

elevations are often marginal for red spruce. They directly, it has been suggested that heavy Fraser fir

suggest that under these marginal conditions, im- mortality leaves co-occurring red spruce more ex-
84 . Catching Our Breath: Next Steps for Reducing Urban Ozone

posed to harsh climatic conditions at high elevations

[9]. Balsam woolly adelgid infestation is not a

particularly severe problem in the Northeast.

Air pollution has been considered as a possible

cause of red spruce decline in high-elevation forests

because no insects and diseases are ubiquitous

(although various pathogens are present at different

sites), and because the affected forests are exposed

to high concentrations of ozone and other gaseous

air pollutants, and to strongly acidic cloud water.

However, the question of whether exposure to high

pollutant levels has actually damaged red spruce is

still under study. In the Eastern United States, water

carried by the clouds intercepted by high-elevation

forests is up to 100 times more acidic than “clean”

rainwater, and some high-elevation sites are

shrouded in clouds up to 40 percent of the time [26].

For two reasons, forests at high elevations are also

likely to be exposed to more ozone than nearby

low-elevation forests. First, nighttime and early

morning ozone concentrations are often much greater at high-elevation sites in rural or remote areas

than concentrations measured at adjacent sites at

lower elevations.4 Second, the frequent presence of

clouds and consequent high humidity enhances

ozone uptake through leaves and needles [26].

Yellow Pine Trees in the

Southeastern United States

The southeastern part of the United States is a

major timber-producing region, containing 20 percent of the Nation’s commercial softwood. More

importantly, the region typically contributes about

half of the Nation’s annual growth in softwood

stocks [40]. To illustrate the importance of southern

softwood, hypothetical simulations have been performed with a model used by the U.S. Forest Service

to project future timber resources. The simulations

suggest that a 15-percent reduction in growth rates

throughout the Southeast would reduce softwood

stocks in the contiguous United States by almost 10

percent after 25 years, and by about 15 percent in 45

years, compared to a base case with no growth rate

reductions [8]. The study estimated that a 15-percent

reduction in growth rates of eastern softwoods

would cost the Nation about $500 million per year.

(The Southeast accounts for about 60 percent of the

softwood trees grown in the East.)

Southern softwood production is dominated by

yellow pine varieties such as loblolly and shortleaf.

In Florida, Georgia, North Carolina, South Carolina,

and Virginia, radial growth rates of yellow pine trees

in natural stands (which comprise about 70 percent

of the yellow pine forests in these States) have been

reduced by up to 50 percent compared to rates

observed in the late 1950s [38]. The causes of the

widespread growth reductions, which have occurred

without visible injury, have not been definitely

established. However, drought, the natural aging of

the stands, and increased competition from hardwoods, are all thought to be involved. Root rot

pathogens have been shown to cause growth reductions in loblolly pine [7], in some cases without

apparent symptoms. Exposure to air pollution may

be a contributing stress. Recent studies using controlled exposures have shown that ozone injures

needles and reduces growth of loblolly pine seedlings [11,35,19,36,37]. However, additional research

is needed to determine whether ozone is involved in

the reductions in growth rates that have been

observed in mature trees in the field.

Sugar Maple Trees in Pennsylvania,

New York, New England, and

Southeastern Canada

Dieback of tree crowns and elevated mortality

rates became apparent in stands of sugar maple and

associated hardwoods at some locations in southeastern Canada in the late 1970s. A 1985 survey

indicated that 40 percent of the area of the sugar

maple forests in Quebec had some foliar injury, with

associated growth reductions in cases of moderate to

severe injury [26]. Injury to sugar maples has been

noticed more recently in the Northeastern United

States. Pest infestation or disease are apparent

causes in all of the cases in this country, although

some of the cases in Canada have not been explained

[26]. Air pollution has been suggested as a contributing factor. Recent experiments conducted in chambers have indicated that exposure to ozone reduced

growth rates of sugar maple seedlings without

dA~r suxt, when Omne ~~uction ce~es, groud-level ozone concentrations fall off as the pollutant is deposited onto vegetation or he ~omd.

In layers of air hundreds of yards above the ground, however, deposition is not a factor, and ozone concentrations can remain high. Where ridges or

hill tops intercept pollution carried aloft, high-elevation forests can be exposed to high concentrations of ozone at night.
Chapter 4—Effects of Ozone on Crops and Forests ● 85

observable foliar injury [15]. However, no reduction

in regionwide average growth rates of sugar maples

has been observed in the United States [13].

European Forests

Forest survey data indicate that 15 percent of the

conifers in 17 European countries have lost more

needles than normal (i.e., more than 25 percent), and

that 17 percent of the deciduous trees have lost more

leaves than normal (i.e., more than 10 percent) [27].

Although damage to trees in Europe is popularly

attributed to air pollution, other factors are understood to contribute, including climate, soil conditions, and stand aging.

At least in West Germany, the country with the

longest forest survey record, the extent of damage

appears to have stabilized. Since 1984, the overall

percentage of trees in West Germany with more than

25 percent foliar loss has held constant at about 18

percent. In fact, the condition of some species, and

of trees in some regions, has improved [6].

The most significantly affected species in central

Europe is Norway spruce, which comprises about 40

percent of central European forests. Needle chlorosis

associated with magnesium deficiency in foliage

and soils is the most prominent symptom observed

in Nonway spruce growing at high elevations, while

thinning of tree crowns is the main symptom

observed at lower elevations [33]. Poor soil conditions and magnesium deficiency have also been

observed in association with chlorosis in Norway

spruce at some sites in the United States [17].
86 ● Catching Our Breath; Next Steps for Reducing Urban Ozone

Photo credit: Grady Neely, Environmental Research Laboratory, US. Environmental Protection Agency, Corvallis, OR

Outdoor exposure chambers are used to study the effects of ozone on various crop and tree species under controlled experimental

conditions.

One hypothesis that has been suggested to explain

the chlorotic symptoms of high-elevation Norway

spruce was that chronic exposure to ozone might

damage cell membranes, exacerbating nutrient

losses, which might also be occurring due to the

leaching action of acidic deposition. If uptake from

the soil was inadequate to replenish essential nutrients, damage might result [33]. However, laboratory

studies testing this hypothesis have not reproduced

the symptoms observed in the field, and some

scientists now discount it [6].

EFFECTS OF OZONE ON CROPS

In annual crops, visible symptoms of exposure to

ozone typically include light flecks, dark stipples,

and yellow spots or patches on leaves. Chronic

exposure to ozone can induce premature aging and

loss of foliage. The minimum concentrations of

ozone that produce acute foliar injury in susceptible

plants exposed for 4 hours range from 0.04 to 0.09

ppmn, depending on the plant species [14]. Among

other environmental factors, light conditions, temperature, relative humidity, and soil water content

affect how plants respond to ozone exposures.

For field and cash crops, the most important

responses to ozone are reduced growth rates and

yields. These effects may occur without the visible

injury usually associated with exposure to ozone,

but they are often accompanied by premature loss of

foliage. Reduced growth and yields result primarily

from reduced photosynthesis and transport of carbohydrates within plants. Table 4-1 displays reductions in yields predicted to occur for various crops

exposed over the growing season to average daily

7-hour mean ozone concentrations of 0.04 and 0.06

ppm [43]. The predictions are from the National

Crop Loss Assessment Network (NCLAN), an

8-year study in which crops were grown in the field
Chapter 4-Effects of Ozone on Crops and Forests ● 87

either in ambient air, air that had been filtered to

remove ozone, or air to which extra ozone had been

added. The reductions shown in the table are relative

to the yields obtained for crops exposed to assumed

background ozone concentrations. The range of

reductions given for each crop indicates differences

among varieties. In addition to the major crops listed

in table 4-1, yield reductions have been seen with a

wide variety of other crops including alfalfa, clover,

sorghum, barley, dry bean, root crops, tomatoes,

spinach, lettuce, and other produce.

Figure 4-3 shows State-level production of each

of the four crops listed in table 4-1. As shown in

figure 4-1, daytime, growing-season average concentrations of 0.04 ppm were widely exceeded over

the 1978-82 period, and a few locations saw

concentrations higher than 0.06 ppm. Due to year-toyear variability in weather, concentrations at a given

site would be higher in some years and lower in

others, if data for individual years were shown [32].

Elevated ozone concentrations throughout the South

may damage cotton. The major soybean-producing

regions of the Mississippi and Ohio River valleys

and corn-producing regions throughout the eastern

half of the United States are also exposed. Unfortunately, only scant ozone data are available for most

areas where wheat is grown.

Table 4-l-Yield Losses Predicted to Occur for

Seasonal Average 7-hour Mean Ozone

Concentrations of 0.04 and 0.06 ppm

0.04 ppm ozone 0.06 ppm ozone

Crop percent yield reduction percent yield reduction

Cotton . . . . . . . . 4.6 to 16 16 to 35

Wheat . . . . . . . . 0.0 to 29 0.9 to 51

Soybeans . . . . . 1.7 to 15 5.3 to 24

Corn . . . . . . . . . . 0.0 to 1.4 0.3 to 5.1

NOTE: As shown in figure 4-1, the 0.04 ppm level exceeded overlarge portions of the

southern and Eastern United States. The 0.06 ppm level is more extreme, with

few areas having multi-year averages that reach it.

SOURCE: U.S. Environmental Protection Agency, Office of Air Quality Planning and

Assessment “Review of the National Ambient Air Quality Standards for

Ozone Preliminary Assessment of Scientific and Technical Information,”

draft staff paper (Research Triangle Park, NC: November 1987).

Economic Estimates of Agricultural Benefits

By using relationships between ozone levels and

crop yields estimated from the NCLAN experiments, together with models of the Nation’s agricultural economy, it is possible to estimate how much

crop producers and consumers would benefit from

reducing ozone. If ozone concentrations were reduced, crop yields would increase and prices fall,

benefiting consumers (and some livestock producers). Crop producers’ profits could either rise or fall,

depending on whether local yield increases reduced

their unit production costs enough to offset the lower

prices they would receive. Crop producers in areas

where ozone concentrations are currently highest

would benefit the most from nationwide reductions,

or conversely continue to incur the largest losses if

concentrations are not reduced.

In this section we present estimates of the

agricultural benefits of a range of plausible reductions in ozone, based on models developed by two

different groups of researchers (21,1). At present, it

is not possible to reliably predict the impact that

VOC and NOx control measures would have on

ozone concentrations in rural areas. So, for the

purposes of this analysis, we assume that currently

available control measures could reduce rural ozone

concentrations by some amount between 10 and 50

percent of the way to an estimated background

concentration of 0.030 ppm.5

The two models used to estimate agricultural

benefits for this report use different exposuresT&s e~a~is b- on s~ace memuements at rural cites in Canada [23]. The appropriate concentration to use for background is very mCertti,

so calculations were performed to investigate the sensitivity of the benefits estimates to this parameter.
88 . Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 4-3-1984 Crop Production at the State Level

SOURCE: U.S. Department of Agriculture, Agricultural Statistics 1965 (Washington, DC: U.S. Government Printing Office, January 1980).

response functions (mathematical expressions of the Agricultural Benefits of Reducing Ozone

relationship between ozone concentrations and crop By 10 to 50 Percent

yields) and economic parameters, and base case

ozone concentrations from different years. They also Estimates of agricultural benefits associated with

adopt different assumptions about how farmers will reductions in ozone of 10, 25, and 50 percent of the

change the number of acres of each crop that they difference between base levels and background, are

plant in order to optimize their operations, as crop given in table 4-2. Both sets of estimates include

prices decline in response to higher yields and benefits associated with corn, soybean, wheat,

increased production. cotton, barley, alfalfa, and sorghum production and
Chapter 4+’fleets of Ozone on Crops and Forests ● 89

Table 4-2-Estimates of Agricultural Benefits That

Would Result Under Market Conditions, if Ozone

Concentrations Ware To Be Reduced Nationwide by

the indicated Amounts Relative to a Background

Concentration of 0.03 ppm

Ozone Krupnick and Kopp Adams and Glyer

reduction ($ millions [19861) ($ millions [19861)

10% . . . . . . . . . . . . . . . . . 230 390

25% . . . . . . . . . . . . . . . . . 540 990

50% . . . . . . . . . . . . . . . . . 10% 1910

SOURCES: A.J. Krupnick and R.J. Kopp, The We/th arrd Agticuftural Senefits of

Reductions in Amb”ent Ozone in fhe United States, contractor reporl

PPfI~ for h - of Ttinobgy Assessment, June 1988. R.M.

Adams and J.D. Glyer, An Assessment of f% Agriculfurel 8enefifs of

Tmpo@eric Ozone Reductions Using Of/ice of T~hnology Assessment

(OTA) Assumptions, contractor report papered for the Office of Technology Assessment, August 1988.

consumption. Krupnick and Kopp’s estimates also

include benefits for oats and peanuts. Adams and

Glyer’s estimates additionally include benefits for

grass-legume hay and rice. Crops that are important

in limited areas, like citrus fruit and produce grown

in Florida and California, were not included.6

As shown in table 4-2, the estimates of total

benefits range from $230 million per year for a 10

percent reduction in ozone to about $1.9 billion per

year for a 50 percent reduction.7 In all cases, corn,

soybeans, wheat, and cotton account for over 90

percent of the total benefits. At each reduction level,

Adams and Glyer’s estimates of total benefits are

almost double Krupnick and Kopp’s estimates. An

important result predicted by Krupnick and Kopp is

that on a nationwide basis, crop producers might

suffer a net loss due to lower prices, if ozone

concentrations are reduced. Adams and Glyer’s

model lumps livestock producers (who benefit from

reduced feed prices) together with crop producers,

and predicts that together they would benefit. It is

not possible to separate crop producers from livestock producers, in Adams and Glyer’s model.

Underlying the nationwide estimates are benefits

to crop producers that vary by region. The largest

improvements in yields in both analyses occur in

California, the South, and the Northeast, where

ozone concentrations in agricultural areas are currently highest. Accordingly, crop producers in these

areas would benefit the most from reducing ozone.

For the 25-percent reduction scenario, for example,

in Adams and Glyer’s analysis, corn yields increase

by about 3 percent or more in California and in some

Northeastern States, whereas in some Midwestern

States, corn yields increase by half a percent or less.

The first reason for the discrepancy between

Adams and Glyer’s and Krupnick and Kopp’s results

is the different changes in yields that are predicted in

the two analyses, due to their use of different

baseline ozone concentrations and different exposureresponse functions. Comparing them on a State-byState basis, for the 25-percent reduction scenario, the

yield changes for corn tend to be about 3 times

larger, for cotton and wheat about 2 times larger, and

for soybeans about 2.5 times larger, in Adams and

Glyer’s analysis than in Krupnick and Kopp’s.

Baseline ozone concentrations were generally higher (uncertainties in the baseline ozone concentrations are discussed in a subsequent section), and crop

yields more sensitive to ozone (as shown for corn in

figure 4-4), in Adams and Glyer’s analysis than in

Krupnick and Kopp’s.

The exposure-response functions used by

Krupnick and Kopp were estimated by averaging

results from NCLAN experiments conducted

through 1982. Additional experiments conducted by

NCLAN through 1986 were also averaged into the

exposure-response functions used by Adams and

Glyer. Some of the crop varieties used in the later

experiments were apparently more sensitive to

changes in ozone concentrations than those tested

earlier [20]. Incorporating the more recent data, the

exposure-response functions used by Adams and

Glyer represent a broader sample of the crop

varieties grown in the United States than those used

by Krupnick and Kopp. However, it is not clear how

Cyield losses due to ozone atc~ent levels may be significant for some of these crops. For example, yield reductions of almost Zopercent m estimati

for California oranges, grapes, and lemons, compared to yields with 12-hour seasonal average ozone concentrations of 0.025 ppm [29].

T~evioW ~y=s have estim~d hat if ozone concentrations in rural areas were reduced by a st@ht 25 percent, without ~J~ting for b~k~otmd

ozone, total benefits would be on the order of $2 billion per year [3,18,2]. The estimates of the benefits of reductions above a 0.030 ppm background

given here are roughly consistent with previous estimates, since ozone is reduced by smaller absolute amounts in our scenarios. For example, for an initial

ozone concentration of 0.045 ppm, the change in the ozone concentration corresponding to a straight 25-percent reduction would be three times larger

than that corresponding to a reduetion of 25 percent of the way to a background concentration of 0.030 ppm.

8~ms ad Glyer [1] u~ b= c= oneconcen~ations avera~ over tie period 19 fJ1-83. ~pNck md Kopp [21] M concentrations aVera@d

over the period 1979-82.
90 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60

Average daytime ozone (ppb)

The dose-response function used by Krupnick and Kopp was

estimated from experiments conducted by the National Crop Loss

Assessment Network through 1981. The function used by Adams

and Glyer was estimated from experiments conducted through

1986.

SOURCE: A.J. Krupnick and R.J. Kopp, The Health and Agriwltural Senefits of

R6@Otbn6 In AmHent Ozons In th@ Ud- @9f@6 COmcbr rWfl

mwa for IfIS Offios of TeohnobgY Aaaassrnent, June 19S8; and R.M.

Marns and J.D. Glyer, An Assessment of the @riwlturel BenMs of

Trqws@aric Ozone Recfucfkms (JWW Of)?oe of T-bgy Assesenrent

(OTA) Assumptions, contractor report prepared for the office of Technobgy

Assessment August 19SS.

well the exposure-response functions used by either

group represent the average responses of the actual

mix of varieties planted by farmers.

The structure and assumptions of the economic

components of their models is also a reason for

discrepancy between Adams and Glyer’s and Kopp

and Krupnick’s results. First, Adams and Glyer’s

model is based on economic conditions for the

1981-83 period, whereas Krupnick and Kopp’s

model reflects the target price provisions established

by the Food Security Act of 1985 for crops grown in

1986.9 Incorporating 1986 target prices into Adams

and Glyer’s analysis reduces their total benefits by

about 10 percent, to $880 million.

Finally, as ozone concentrations are reduced and

crop prices tend to decline in response to higher

yields, Adams and Glyer assume that farmers would

change the number of acres sown with each crop to

maximize their profits under the new conditions.

Krupnick and Kopp assume that planted acreage

would stay constant at 1986 (base case) levels.

Krupnick and Kopp’s assumption seems reasonable

in the short term, before a steady trend in market

prices is observable. So the prediction that producers

would not gain from reducing ozone seems to be

reasonable for the first few years after ozone

concentrations are reduced. Adams and Glyer’s

assumption that farmers will eventually adjust their

acreage seems more reasonable as a prediction of

what would occur after several years if ozone

concentrations remain low.

Agricultural Benefits Under Current

Price Support Programs

In order to stabilize supplies and prices, and to

supplement farmers’ incomes, the Federal Government currently pays farmers the difference between

the price they obtain on the market and a higher

‘‘target” price established by law, for several major

crops. The target prices encourage surplus production, at some expense to society because the cost of

producing the surplus exceeds its value. Increased

yields due to reduced ozone can be viewed as adding

to the surplus, and some economists argue that the

benefits estimates presented in the previous section

need to be adjusted for this effect. Given 1986 target

prices, and adjusting the benefits estimates to

account for the loss to society associated with

surplus production, Krupnick and Kopp estimate

that for corn, cotton, soybeans, and wheat, the

benefits of the 25-percent reduction scenario would

be $380 million, about 20 percent lower than the

benefits associated with those four crops when the

cost of the surplus is not taken into account.

However, others argue that subsidy programs could

be adjusted to reflect the yield changes, so that

surpluses would not necessarily increase above

desirable levels [24].

Sensitivity of Benefits to Uncertainty in Ozone

Concentrations in Agricultural Areas

An important source of uncertainty in agricultural

benefits is the estimation of current ozone concentrations in areas across the country where crop production takes place. Baseline ozone concentrations are

estimated by extrapolating from both suburban and

rural monitors to agricultural areas. Unfortunately,

9~ ~rdcr tO ~tabili~ ~ppliesadpri~s,~dto supplement f~ers’ incomes, tie F~er~ Government currendy pays f~ersthe difference ktW&ll

the price they obtain on the market and a higher ‘target” price established by law, for several major crops.
Chapter 4—Effects of Ozone on Crops and Forests ● 91

in many States, appropriate data are only available

from one or two monitors, and significant errors are

apt to be introduced by extrapolating from these data

[22]. The natural background concentration of ozone

is also uncertain, because it cannot be measured

anywhere—areas that are similar to the continental

United States are invariably affected by human

activity. When the benefits of a 25-percent reduction

in ozone were recalculated with 0.005 ppm either

uniformly added to or subtracted from the baseline

concentrations, the total benefits were correspondingly increased or reduced by about 50 percent. A

similar degree of sensitivity to the assumed background ozone concentration was found.

REFERENCES FOR CHAPTER 4

1.

2.

3.

4.

5.

6.

7.

8.

Adams, R. M., and Glyer, J. D., An Assessment of the

Agricultural Benefits of Tropospheric Ozone Reductions Using Office of Technology Assessment (OTA)

Assumptions, contractor report prepared for the

(Xl’& of Technology Assessmen~ August 1988.

Adams, R.M., Glyer, J.D., Johnson, S.L., and McCarl, 13. A., A Reassessment of the Economic Eflects

of Ozone on U.S. Agriculture (Corvallis, OR: Oregon

State University, 1988).

Adams, R. M., Hamilton, S. A., and McCarl, B. A., The

Economic E#ects of Ozone on Agriculture, EPA

report No. EPA-600/3-84-090 (Corvallis, OR: U.S.

Environmental Protection Agency, 1984).

BennetQ J. F., Status of Eastern White Pine Project:

A Progress Report (Research Triangle Park, NC:

U.S. Department of Agriculture, 1987), as cited in

NAPAP, 1987.

Benoi~ L. F., Skelly, J. M., Moore, L. D., and Dochinger, L. S., “Radial Growth Reductions of Pinus

Strobus L. Correlated With Foliar Ozone Sensitivity

as an Indicator of Ozone-Induced Losses in Eastern

Forests,” Canadian J. Forest Research 12:673-678,

1982.

Blank, L. W., Roberts, IM., and Skeffigton, R.A.,

“Commentary: New Perspectives on Forest Decline, ” Nature 336:27-30, 1988.

Bradford, B., Alexander, S.A., and Skelly, J. M.,

“Determination of Growth Imss of Pinus Taeda L.

Caused by Heterobasidion Annosus (Fr.) Bref.,”

European J. Forest Pathology 8:129-134, 1978.

Darwin, R. F., Nesse, R.J., and Callaway, J. M.,

Economic E#ects of Hypothetical Reduction in Tree

Growth in the Northeastern and Southeastern United

States (Richland, WA: Pacific Northwest Laboratory, August 1986).

9.

10,

11.

12.

13.

14.

15.

16.

17.

18.

19.

Dull, C. W., Ward, J. D., Brown, H. D., Ryan, G. W.,

Clerke, W. H., and Uhler, R. J., Evaluation of Spruce

and Fir Mortality in the Southern Appalachian

Mountains, Protection Report R8-PR13 (U.S. Department of Agriculture, Forest Service Southern

Region, October 1988).

Heck, W. W., Cure, W.W., Rawlings, J. O., Zaragoza,

L.J., Heagle, A. S., Heggestad, H. E., KohuL R.J.,

Kress, L. W., and Temple, P.J., “Assessing Mpacts

of Ozone on Agricultural Crops: II. Crop Yield

Functions and Alternative Exposure Statistics,” J.

Air Pollution Control Association 34;810-817, 1984.

Heck, W. W., U.S. Department of Agriculture, personal communication, March 25, 1988.

Hertel, G.D., Spruce-Fir Research Cooperative Technical Report (U.S. Department of Agriculture, March

1988).

Hombeck, J. W., Smith, R. S., and Federer, C. A.,

“Extended Growth Decreases in New England Are

Limited to Red Spruce and Balsam Fir,” Proceedings, International Symposium on Ecological Aspects of Tree-Ring Analysis (Palisades, NY: LamontDoherty Geological observatory, 1987), as cited in

NAPAP, 1987.

Jacobson, J. S., “The Effects of Photochemical Oxidants on Vegetation,” Ozon und Begleitsubstanzen

irn Photochemishen Smog, VDI colloquium (Dusseldorf, West Germany: Verein deutscher Ingenieure

(VDI) GmbH, 1976), pp. 163-173, as cited in U.S.

EPA, 1987.

Jensen, K. F., and Dochinger, L. S., “Response of

Eastern Hardwood Species to Ozone, Sulfur Dioxide

and Acid Precipitation, ” paper 88-70.3, presented at

the 81st Meeting of the Air Pollution Control

Association (Dallas, TX: June 1988).

Johnson, A. H., and McLaughlin, S. B., “The Nature

and Timing of the Deterioration of Red Spruce in the

Northern Appalachian Mountains,” Acid Deposition: Long-term Trends (Washington, DC: National

Academy Press, 1986).

Ke, J., and Skelly, J.M., “An Evaluation of Norway

Spruce in the Northeastern United States, ” presented

at the International Union of Forest Research Organizations Symposium (Interlaken, Switzerland: Oct.

20-21, 1988).

Kopp, R.J., Vaughan, W.J., and Hazilla, M., Agricultural Sector Benefits Analysis for Ozone: Methods

Evaluation and Demonstration, EPA report No.

EPA-450/5-84-O03 (Research Triangle Park, NC:

U.S. Environmental Protection Agency, 1984).

Kress, L.W., Allen, H. L., Mudano, J. E., and Heck,

W. W., “Response of Imblolly Pine to Acidic Pre-
92 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

cipitation and Ozone, ” paper 88-70.5, presented at

the 81st Meeting of the Air Pollution Control

Association (Dallas, TX: June 1988).

Kress, Lance, U.S. Department of Agriculture, personal communication, December 1988.

Krupnick, A.J., and Kopp, R.J., The Health and

Agricultural Benefits of Reductions in Ambient

Ozone in the United States, contractor report prepared

for the Office of Technology Assessment, June 1988.

Mfohn, A. S., Knudsen, H. P., Imgan, J. A., Simpson

J., and Bhumralkar, C., “An Evaluation of the

Kriging Method to Predict 7-h Seasonal Mean Ozone

Concentrations for Estimating Crop Losses,” J. Air

Pollution Control Association 37:595-602, 1987,

Imgan, J. A., “Tropospheric Ozone: Seasonal Behavior, Trends, and Anthropogenic Influence, ” J. Geophysical Research 90:10463-10482, 1985.

Madriaga, B., “Ambient Air Quality Standards for

U.S. Agriculture: The Correct Welfare Measure

Revisited,” J. Environmental Management 27:421-

427, 1988.

McBride, J. R., MiI1er, P.R., and Laven, R. D., “Effects of Oxidant Air Pollutants on Forest Succession

in the Mixed Conifer Forest T~ of Southern

California%” Proceedings of the Symposium on Air

Pollutants E#ects on Forest Ecosystems (St. Paul,

MN: Acid Rain Foundation, 1985), as cited in

NAPAP, 1987.

National Acid Precipitation Assessment Program,

Interim Assessment: The Causes and Effects of Acidic

Deposition, vols. III and IV (Washington, DC:

October 1987).

Nilsson, S., and Duinker, P., “The Extent of Forest

Decline in Europe, “ Environment 29:4-9 and 30-31,

1987.

Olson, R.J., Allison, L.J., and McCullough, I.L.,

Addnet Notebook: Documentation of the Acid Deposition Data Network (ADDNET) Data Base Supporting the National Acid Precipitation Assessment

Program, Environmental Sciences Division publication No. 2755 (Oak Ridge, TN: Oak Ridge National

Laboratory, August 1987),

Olszyk, D.M., Cabrera, H., and Thompson, C.R.,

“California Statewide Assessment of the Effects of

Ozone on Crop Productivity,” J. Air Pollution

Control Association 38:928-931, 1988.

The Pennsylvania State University, Department of

Plant Pathology,

Diagnosing Injury to Eastern Forest Trees (University Park, PA: 1987).

Peterson, D. L., Arbaugh, M.J., Wakefield, V. A,, and

Miller, P.R., “Evidence of Growth Reduction in

Ozone-Stressed Jeffrey Pine (Pinus Jeffreyi Grev.

32.

33.

34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

and Balf.) in Sequoia and Kings Canyon National

Parks,” J. Air Pollution Control Association 37:906-

912, 1987.

Pinkerton, J. E., and Ufohn, A. S., “The Characterization of Ozone Data for Sites Imcated in Forested

Areas of the Eastern United States,” J. Air Pollution

Control Association 37:1005-1010, 1987.

Prinz, B., “Causes of Forest Darnage in Europe, ”

Environment 29:1 1-15 and 32-37, 1987.

Reich, P, B., and Arnundson, R. G., “Ambient Wvels

of Ozone Reduce Net Photosynthesis in Tree and

Crop Species,” Science 230:566-570, 1985.

Reinert, R. A., Shafer, S.R., Eason, G., Horton, S.J.,

Schoeneberger, M.M., and Wells, C., “Responses of

~blolly Pine Half-Sib Families to Ozone,” paper

88-125.2, presented at the 81st Meeting of the Air

Pollution Control Association (Dallas, TX: June

1988).

Slutfer, S. A., Heagle, A. S., and Camberato, D. M.,

‘‘Effects of Chronic Doses of Ozone on Field-grown

kblolly Pine: Seedlings Response in the First

year,” J. Air Pollution Control Association 37:1 179-

1184, 1987.

Shafer, S. A., and Heagle, A. S., “Responses of Field

Grown lmblolly Pine to Chronic Ozone During

Multiple Growing Seasons,” Canadian J. Forest

Research, in press, 1989.

Sheflield, R. M., Cost, N. D., Bechtold, W.A., and

McClure, J. P., Pine Growth Reductions in the

Southeast, Research Bulletin SE-83 (U.S. Department of Agriculture, Forest Service Southeast Forest

Experiment Station, 1985), as cited in NAPAP, 1987.

U.S. Department of Agriculture, An Assessment of

the Forest and Range Lund Situation in the United

States (Washington, DC: U.S. Government Printing

Office, January 1980).

U.S. Department of Agriculture, Agricultural Statistics 1985 (Washington, DC: U.S. Government Printing Office, 1985).

U.S. Department of the Interior, testimony, Impacts

of Air Pollution on National Park Units: Hearings

Before the Subcommittee on National Parks and

Recreation of the House Committee on Interior and

Insular Affairs, 99th Cong., 1st sess., 535-538, 1985.

U.S. Department of the Interior, National Park

Service, Air Quality in the National Parks, Natural

Resources Report 88-1 (Denver, CO: July 1988).

U.S. Environmental Protection Agency, Office of Air

Quality Planning and Assessment, Review of the

National Ambient Air Quality Standards for Ozone

Preliminaq Assessment of Scient@ and Technical

[formation, draft staff paper (Research Triangle

Park, NC: November 1987).
Chapter4—Effects of Ozone on Crops and Forests ● 93

44. U.S. Environmental Protection Agency, Ofilce of 45. Woodman, J.N., and Cowling, E. B., “Airborne

Health and Environmental Assessment, Sumrna~ of Chemicals and Forest Health,” Environrnenlal SciSelected New Information on Effects of Ozone on ence and Technology 21 :120-126, 1987.

Health and Vegetation: Draft Supplement to Air

Quality Criteria for Ozone and Other Photochernical

Oxidants, EPA report No. EPA/600/8-88-105A (Washington, DC: November 1988).
Chapter 5

Lowering Ozone: Effect of

Controlling

Compounds and Nitrogen

Volatile Organic

Oxides
CONTENTS

Page

INTRODUCTION .., ... ... ... . .... . 97

THE RELATIONSHIPS OF VOLATILE ORGANIC COMPOUND AND

NITROGEN OXIDE EMISSIONS TO OZONE . . . . . . . . . . . . . . . . . . . . . . . . . . ● . . . 97

EFFECT OF CONTROLLING VOLATILE ORGANIC COMPOUNDS . . . . . . . ● . . . . . 99

Local Volatile Organic Compound Reductions Required To Meet the Standard . . . . . 99

The Effect of Lowering Volatile Organic Compound Emissions by 35 Percent . . . . . 100

Sensitivity to Emissions From Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

EFFECT OF CONTROLLING NITROGEN OXIDES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Balance of Volatile Organic Compounds and Nitrogen oxides . . . . . . . . . . . ● ..... . 101

The Effects of Nitrogen Oxide Controls in Urban Areas . . . . . . . . . . . . . ... 102

Combined Volatile Organic Compound and Nitrogen Oxide Control in the

Northeast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 102

RURAL OZONE, TRANSPORTED OZONE AND PRECURSORS . . . . . . . . . . . . . 106

Transported Ozone and precursors . . .. . . . . . . . . . . . . . . . . . . . .......106

Regional Episodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Reducing Rural Ozone .. .. ... . . . . . . . . .. .. . . .. . . . . . . . . . .. . . .. .. . . 107

REFERENCES FOR CHAPTER 5 .. .. .. ... ... ..... .. .. ... .. .. .. ... . ... 108

Figures

Figure Page

5-1. VOC Emissions Reductions Estimated To Be Required to Reduce Ozone From the

Initial Peak Concentrations or ’’Design Values” Show, Down to 0.12 ppm......100

5-2. Ozone Concentrations Predicted To Result When VOC Emissions Are Reduced

by 35 Percent with No Change in NOX Emissions Levels... .. . .. .. . . . . . . . . . . 101

5-3. Change in Peak Ozone Concentrations in the Los Angeles Basin, Predicted

to Result From Reducing NOX Emissions by 35 Percent Below 1982 Levels . . . . . 103

5-4. Region Covered by the U. S. Environmental Protection Agency’s Regional

Oxidant Model (ROM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................. 104

Tables

Table Page

5-1. Predicted Effect of VOC-Alone and Combined VOC and NOX Control Strategies

in Northeaster Cities, Over a 16-Day Period in July 1980 . . . . . . . . . . . . . . . . . . . . . . 105

5-2. Predicted Effects of VOC-Alone and Combined VOC and NOX Controls in the

Hartford, New York City, and Pittsburgh Areas, Over a 16-DayPeriodin

July 1980 . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . .. .. .. .. .. .. ... .. . ... 105

5-3, Predicted Effect of V0C-Alone and Combined VOC and NOX Control Strategies

in Nonurban Areas of the Northeast, Over a 16-Day Period in July 1980 ........ 108
Lowering Ozone: Effect of Controlling

Compounds and

Chapter 5

Volatile Organic

Nitrogen Oxides

INTRODUCTION’

Ozone is not emitted; rather it is produced in the

atmosphere from reactions involving two ‘ ‘precursor” pollutants: volatile organic compounds (VOCs)

and nitrogen oxides (NOX). To develop effective

strategies for reducing ozone, an understanding of

the complex relationship between ozone concentrations and VOC and NOX emission levels is needed.

Unfortunately, our ability to predict the effectiveness of control strategies is limited by uncertainties

in emissions inventories, especially for VOCs (see

chapter 6); lack of atmospheric concentration data

for VOCs, NOX, and rural ozone; and deficiencies in

air quality models that have been applied to most

cities. Moreover, generalizations are difficult to

make because of the fact that the relationship

depends strongly on local conditions such as topography, and spatial distributions and types of emission sources, which vary from one city to another,

and on meteorological conditions that vary from

day-to-day.

The focus of efforts to reduce urban ozone has

historically been on controlling local VOC emissions. We assume that this focus will be continued.

However, as discussed in chapter 6, we project that

in many cities, currently available VOC control

measures will fall short of providing the reductions

needed to meet the ozone standard. In some cases,

controlling NOX emissions in addition to VOCs

might reduce ozone more than controlling VOC

emissions alone. In other situations, however, a

combined strategy of NOX and VOC controls might

actually reduce peak ozone less than reducing VOCs

alone. For many cities, the modeling and data

gathering needed to reliably predict whether NOx

controls would be helpful have yet to be done.

Reducing emissions in upwind areas as well as

locally might also help reduce peak ozone concentrations in some nonattainment cities. Some studies

have indicated where controls in upwind areas might

be important, but we cannot yet quantify how much

they would help.

To date, no control efforts have been undertaken

expressly to reduce ozone concentrations in rural

areas. However, a few recent modeling studies have

attempted to simulate rural conditions. The studies

suggest preliminarily that outside of pollution

plumes downwind of urban and industrial areas,

reducing NOX emissions will generally be a more

effective strategy for lowering ozone than reducing

VOC emissions.

In this chapter, we first present an overview of the

relationship between ozone levels and VOC and

NOX emissions. We then present estimates of the

amounts that VOC emissions need to be reduced to

enable cities with different design values to meet the

ozone standard, and the amount that ozone concentrations could be reduced in these cities using

available VOC control measures. The question of

whether reducing NOX emissions in addition to

VOCs is likely to be beneficial or not is considered

next. After that we look at the role of transported

ozone and precursors. Finally, we discuss how VOC

and NOX emission reductions might affect ozone in

rural areas, where it can damage trees and annual

crops.

THE RELATIONSHIP OF

VOLATILE ORGANIC

COMPOUND AND NITROGEN

OXIDE EMISSIONS TO OZONE

Ozone is produced through chemical reactions

involving nitrogen oxides and volatile organic

compounds. 1 Ozone concentrations tend to be highest on hot, sunny days for three reasons: 1) the

chemical reactions depend on sunlight and temperature; 2) emissions from some sources increase with

outdoor temperatures; and 3) stagnant air that tends

to limit pollutant dispersal is often associated with

high temperatures. Ozone concentrations exceeding

the standard occur almost exclusively between May

and September in most areas of the United States,

although California and the gulf coast have longer

seasons with high ozone [32]. The highest concenIQrbon monoxide and me~~e We also involved in ozone production. However, NOX and VOCS are most import~t in wbm weas.

-97-
98 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

trations are often observed after more than 1 day of

hot, sunny conditions. Multi-day episodes can lead

to concentrations that approach or even exceed the

ozone standard over large areas of the Eastern

United States, encompassing rural areas as well as

cities [35,36,37]. Ozone levels observed at a given

location can be influenced significantly by transported pollutants as well as local emissions. Plumes

of elevated ozone concentrations have been observed 200 or more miles downwind of urban areas,

under some circumstances [21 ,8,30].

Nitrogen oxides are products of fossil fuel combustion. On a nationwide basis, approximately 35

percent of NOX emissions are from highway vehicles, another 35 percent are from utilities, and 12

percent are from industrial fuel combustion. NOX

emissions from natural sources are negligible [16].

About 60 percent of the NOx in the Northeastern

United States is emitted in nonattainment cities. In

the South and Midwest, however, most of the NOx

originates in rural areas or small cities, with only

about 30 percent coming from nonattainment areas.

NOX has an atmospheric lifetime in summer of about

6 to 10 hours [28] and thus is unlikely to be

transported more than about 100 miles.

VOCs are a broad class of organic gases such as

vapors from solvents and gasoline. In urban areas,

approximately 45 percent of manmade VOCS are

emitted from highway vehicles, about 25 percent

from surface coatings and other organic solvent use,

and smaller fractions from other categories including gasoline evaporation from gas stations, solid

waste disposal, chemical manufacturing, and petroleum processing. The proportion of manmade VOC

emissions originating in nonattainment cities rather

than attainment areas varies from 60 percent in the

Northeast to about 30 percent in the South. Evaporative emissions of VOCs tend to be especially high ins

hot weather.

Individual VOCs differ substantially in how

quickly they react in the atmosphere. In summer, the

atmospheric lifetimes of common organic gases

range from less than an hour to several days [1], and

correspondingly, transport distances for various

VOCs range from a few to hundreds of miles. The

fastest reacting VOCs tend to produce the most

ozone, however, so VOCs from distant sources tend

to be less important than “fresh” emissions.

Along with manmade sources, trees and other

plants also produce VOCs, with especially high

emissions in hot weather. Estimates of VOC emissions from vegetation are extremely uncertain-a

recent study suggests they might be either high or

low by a factor of 3 or more due to questions about

emission rate measurements and land use estimates

[11]. If current estimates of vegetative emissions are

correct, though, totaled over the contiguous 48

States, peak summertime emissions from vegetation

exceed manmade VOC emissions by about a factor

of 2 [11]. The national totals reflect the vast amount

of rural area in the United States where, in summertime, vegetation is the dominant source of VOCs.

Vegetative emissions are generally highest in the

rural Southeast, but are also high in forested parts of

the Southwest, Northwest, and Northeast. In summer in nonattainment areas, we estimate that ratios

of manmade-to-vegetative VOC emissions range

from about 1 to 1, in wooded suburbs, to more than

20 to 1, in densely developed urban cores [11,20]..

A useful way of thinking about how effective

VOC and/or NOX reductions are likely to be in a

given area is to look at the balance in concentrations

of VOCs and NOX found in the ambient air, given

existing emissions levels and pollutant transport

from upwind. Generally, VOC reductions are effective and NO, reductions ineffective where the

concentration of NOX is relatively high compared to

the concentration of VOCs (i.e., ozone production is

‘‘VOC-limited”). Under such conditions, which are

most likely to occur in high emissions areas such as

urban or industrial centers, reducing NOX can

actually increase ozone concentrations. Conversely,

NOX reductions are most effective and VOC reductions least effective where the concentration of

VOCs is relatively high compared to the concentration of NO, (ozone production is NOX

-limited).

Conditions tend to be increasingly NOX-limited as a

polluted air mass is transported out over suburban

and rural areas downwind of high emissions regions,

because chemical and physical processes tend to

remove NOX more rapidly than VOCs. Although

measurements are sparse, conditions in rural areas

tend to be NOX

-limited [1,31,10].

The relationship between ozone and its precursors

is actually much more complicated than implied by

the simple description of VOC-limited v. NOX-

limited conditions. Atmospheric concentrations of
Chapter 5--Lowering Ozone: Effect of Controlling Volatile Organic Compounds and Nitrogen Oxides ● 99

ozone, VOCs and NOX, vary from place-to-place and

day-to-day, making it difficult to reliably predict the

impact of VOC and/or NOX reductions in a given

city. Computer models used to predict the effect of

emissions changes on ozone levels usually include

mathematical representations of VOC, NOx, and

carbon monoxide emissions; chemical reactions

among 30 or more chemical compounds; meteorological conditions including wind speed and direction, temperature, humidity, cloud cover, and atmospheric mixing; and pollutant concentrations at the

start of the simulations and along the boundaries of

the region being modeled. Various models differ

greatly in how detailed their inputs are (e.g., whether

they use emissions totaled over an urban area or

require them to be “gridded,” i.e., broken out for

small subdivisions of the area).

The most detailed urban models perform reasonably well in replicating observed ozone concentrations over episodes lasting 1 to 3 days, provided that

adequate emissions inventories, boundary and initial

pollutant concentration data, and meteorological

data are available [26]. Unfortunately, application of

these models is time-consuming and expensive

(costing on the order of $500,000), and their use has

been limited. To date, most cities have used EPA’s

Empirical Kinetic Modeling Approach (EKMA)

model instead.2 EKMA was designed to minimize

input requirements, and allows use of default values

for many parameters. Consequently, it often oversimplifies the relationship between precursor emissions and ozone.

EPA has historically encouraged exclusive reliance on VOC emission controls to ensure compliance with the air quality standard for ozone. NOX

emission controls have mostly been used only to the

extent necessary to comply with the standard for

nitrogen dioxide. Part of the reason for the emphasis

on VOC controls is that laboratory (smog chamber)

experiments and computer modeling studies have

shown that reducing NOX emissions could increase

ozone concentrations under some conditions found

in urban areas. (See ref. [17,9,2] for reviews of some

of these studies.) However, recent measurements of

VOC and NOX concentrations in a number of areas,

new modeling analyses, and new estimates of the

impact of VOC emissions from vegetation have

elicited speculation that in rural areas [27,31] and in

some cities [3,7,5], NOX controls may be more

effective in reducing photochemical pollution than

previously thought. In short, the issue of whether

reducing NOX emissions would generally help lower

ozone is still controversial.

EFFECT OF CONTROLLING

VOLATILE ORGANIC

COMPOUNDS

Local Volatile Organic Compound Reductions

Required To Meet the Standard

This section presents estimates of local VOC

emission reductions needed to reduce local peak

l-hour average ozone concentrations or “design

values” down to 0.12 parts per million (ppm), the

maximum concentration allowed under the ozone

standard. For areas with design values up to 0.20

ppm, the control requirements presented in figure

5-1 were estimated using EPA’s EKMA model, with

the Agency’s default set of “typical” meteorological, emissions, and transport conditions [18]. A

moderate amount of ozone (0.07 ppm) is assumed to

be transported from upwind, and VOC emissions

from vegetation are assumed to be negligible. NO,

emissions were assumed to be unchanged from 1985

levels.

A key parameter in an EKMA calculation is a ratio

of the VOC and NOX concentrations measured at a

central location in a given city, and averaged over

the period from 6 to 9 a.m. on the day when the city’s

highest ozone concentration occurred. This VOC-toNOX ratio is assumed to be a measure of the

precursor balance that initially exists in the parcel of

air that produces the peak ozone concentration later

in the day. In figure 5-1, the range of VOC control

requirements shown for each design value corresponds to the range of VOC-to-NOX ratios expected

to prevail on most days, in most cities-from about

8:1 (8 ppb carbon to 1 ppb NO.) to 15:1 [3]. For two

2’r’he EKW ~~el consists of a single cell, or ~x, ~ which chemic~ reactions take place, and which is moved in a straight line at a constant velocity

during the course of a day, The box leaves the center of a city at 8 a.m. and arrives in the afternoon at the location where the peak ozone concentration

was observed. En route, the contents of the box are diluted with comparatively clean air, and emissions are added as the box moves over sources. Problems

with the model include its unrealistic treatment of the horizontal movement of the box and the mixing of freshly emitted pollutants into it; lack of spatial

resolution; and sensitivity to difficult-to-measure starting concentrations of VOCS and NOX.
100 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 5-1-VOC Emissions Reductions Estimated To

Be Required To Reduce Ozone From the Initial Peak

Concentrations or “Design Values” Shown,

Down to 0.12 ppm

O /O VOC control required to meet standard

800/0 

I high VOC/NOx ratio

60% 

20% I

low VOC/NOx ratio

0.12 0.13 0.14 0.15 0.16 0.17 0.18 0.19 0.20

Initial design value (ppm)

Control requirements were estimated using EPA’s standard

“EKMA” model, with meteorological, emissions, and transport

conditions set to approximate conditions in a typical area where

transport from upwind cities is not the principal cause of nonattainment. The range of estimates shown for each design value

corresponds to the range of VOC and NOX ratios expected to

prevail across different cities. The percentage reduction needed

to meet the standard in an individual city will typically fall

somewhere between the two curves shown.

SOURCE: Mapted from E.L. Meyer, Jr., U.S. Environmental Protection Agerwy,

personal communication, September 1987.

cities (or 2 days in the same city) with the same peak

ozone concentration, the level of VOC control

required to meet the standard will generally be

highest for the city (or day) with the highest

VOC-to-NOX ratio, i.e., the most VOC-rich conditions. However, local conditions that deviate from

the default values used in our calculations could lead

to different results. For example, a higher level of

pollution transported into a city from upwind could

lead to a relatively high control requirement even if

the city had a low VOC-to-NOX ratio.

To illustrate how to interpret figure 5-1, for a city

with a design value of 0.16 ppm, with no change in

NOX emissions levels, the model predicts that VOC

reductions ranging from about 45 to 70 percent will

be needed to meet the ozone standard. As used here,

the EKMA model is intended to provide only rough

estimates of control requirements. In our judgment,

it seems reasonable that control requirements for

most cities would fall within the ranges shown in

figure 5-1. However, control requirements for individual nonattainment areas could deviate substantially from those presented here.

The Effect of Lowering Volatile Organic

Compound Emissions by 35 Percent

As we will discuss in detail in chapter 6, if all

VOC controls we consider to be currently available

were to be imposed, the total reductions in VOC

emissions estimated for most areas by 1994 would

be between 20 and 50 percent of 1985 levels, falling

short of the amounts estimated to be required to

attain the standard in many cities.

Figure 5-2 shows peak ozone concentrations

predicted to result when VOC emissions are reduced

by 35 percent (with NOX emissions unchanged),

plotted against initial design values. The solid lines

represent estimates of the range of peak ozone

concentrations expected to result from a 35-percent

reduction in VOC emissions with no change in NOX

emissions. The dashed line represents “no change”

in ozone concentrations, i.e., the final concentration

is the same as the initial concentration or design

value. Note that the ozone standard, 0.12 ppm, is at

the bottom of the graph, so that the relative position

of a control scenario line between the ‘‘no change”

diagonal and the bottom of the graph indicates what

fraction of the reduction in ozone that is needed to

obtain the standard is predicted to be achieved. The

range of reductions shown for each design value in

figure 5-2 is based on the range of 6 to 9 a.m.

VOC-to-NOX ratios expected in most cities.

As shown in figure 5-2, we predict that currently

available VOC reductions would be sufficient to

enable most areas with design values equal to 0.13

ppm to meet the standard. Some areas with design

values equal to 0.14 ppm are also predicted to be able

to attain. Reducing VOC emissions by 35 percent is

predicted to lower ozone concentrations in areas

with design values higher than 0.15 ppm by about

one-third to two-thirds of the amounts needed to

meet the standard. As with the control requirement

calculations, the impact of VOC reductions in

individual nonattainment areas could deviate substantially from the results shown in figure 5-2.
Chapter 5-Lowering Ozone: Effect of Controlling Volatile Organic Compounds and Nitrogen Oxides ● 101

Figure 5-2-Ozone Concentrations Predicted To

Result When VOC Emissions Are Reduced by 35

percent, With No Change in NOX Emissions levels

Final ozone concentration (ppm) no change

0.19 i

o.18 1

VOC: -35%, high VOC-to-NOx ratio

o.1 7

0.16

The three solid lines indicate the ozone concentrations predicted

to result in cities with low, medium and high VOC to NO, ratios.

The dashed line illustrates the “no control” ease, i.e., the final

ozone concentrations are the same as the initial design values.

SOURCE: Adapted from E.L. Meyer, Jr., U.S. Environmental Protection Agency,

personal communication, September 1987.

Sensitivity to Emissions From Vegetation

Figures 5-1 and 5-2 were generated using a model

that assumes VOC emissions from vegetation are

negligible. However, rough estimates suggest that

the fraction of total VOC emissions in nonattainment areas that come from vegetation actually

ranges from a few percent up to about 50 percent,

with areas where the contribution appears to be

greater than about 25 percent located almost exclusively in the Southeast.3 If they comprise a significant fraction of total VOCs, vegetative emissions

can substantially reduce the apparent effectiveness

of controlling manmade VOC emissions. In Atlanta,

for example, where over 50 percent of the 1 l-county

nonattainment area is wooded, summertime emissions from vegetation are estimated to be about

equal to manmade VOC emissions [7]. Neglecting

emissions from vegetation, simulations with a version of EPA’s EKMA model predict that a 40

percent reduction in manmade VOC emissions

would be needed to attain the ozone standard in

Atlanta. When vegetative emissions are considered,

a 70-percent reduction in manmade VOCs is predicted to be required [7]. Although the Atlanta case

is an extreme example, it suggests that for some

cities, control requirements may exceed the range

shown in figure 5-1, and reducing manmade VOC

emissions by 35 percent may be less effective than

indicated in figure 5-2.

EFFECT OF CONTROLLING

NITROGEN OXIDES

In its post-1987 policy proposal, EPA has suggested that some areas may be required to consider

reducing emissions of NOx in addition to VOCs [33].

And, the State of California has promulgated new,

more stringent limits on NOX emissions from motor

vehicles, primarily to meet nitrogen dioxide and

particulate matter (PM-1O) standards, but to help

reduce ozone as well [6]. This section considers the

option of controlling NOX emissions in addition to

VOCs.

Balance of Volatile Organic Compounds and

Nitrogen Oxides

The ratio of the average VOC and NOX concentrations measured over the period from 6 to 9 a.m. at a

downtown location is often used as a rough measure

of the precursor balance that exists in the parcel of

air that is expected to produce a city’s peak ozone

concentration later in the day. The higher the ratio of

VOCs to NOX

, the more NOX-limited is the air parcel,

and the more likely it is that reductions in NOX will

be beneficial. Conversely, the lower the ratio, the

more likely it is that reducing NO= will be counterproductive. Because they depend on emissions,

meteorology, topography, and upwind precursor

levels, VOC-to-NOX ratios are expected to differ

from one city to another. However, the actual

balance can also vary significantly from day-to-day

in a given city, as meteorological conditions and

emissions vary, and can also depend significantly on

monitor location.

As a screening method, EPA has suggested that

cities for which the median ratio over the summer is

10:1 (10 ppb carbon per 1 ppb NOx) or greater will

be required to consider reducing NOx emissions in

addition to VOCs. EPA has compiled 6 to 9 a.m.

3B@ on average lev~l~ of VW emissi~s ~m ve~tation estima~ for five regi~s of the u~t~ States [12] ~d manmade VOC emissions

estimated for each nonattainment area.
102 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

VOC-to-NOX ratios for about 40 cities, for summers

between 1984 and 1987 [4]. Of the 40 cities, about

one-third had median VOC-to-NOX ratios lower than

10:1, indicating that they would not be required to

consider NOX controls. Most of these cities were

located in the upper Midwest or Northeast. The

remainder of the cities had median ratios higher than

10:1, with the highest VOC-to-NOX ratios generally

observed in the South (Texas and east), where no

cities consistently had VOC-to-NOX ratios less than

10:1.

VOC-to-NOX ratios give only a preliminary indication of the potential effect of controlling NOX

. The

variability mentioned above is one limitation. A

second is that there is no single ratio that clearly

separates NOX and VOC-limited conditions, but

rather a transition range extending from about 8:1 to

15: 1, encompassing the median ratios of most cities.

Most importantly, additional factors such as the size

of a city, its spatial distribution of emissions sources,

and the reactivity of the mix of VOCs present also

influence whether or not NOX controls would be

beneficial. As recommended by EPA, detailed air

quality models are ultimately needed to reliably

estimate the impacts of controls [33].

The Effects of Nitrogen Oxide Controls in

Urban Areas

Over the past 15 years, urban-scale models have

been used to predict the impacts of NOX controls for

a half dozen United States cities (for example, see

[17,5,24,29]). The conclusions of the studies have

been mixed: compared to VOC control alone, adding

NOX control was found to be counterproductive in

some studies and beneficial in others. A key point

from these studies is that in many urban areas, with

both VOC and NOX reductions, peak ozone concentrations will be higher at some locations and lower

at others than if VOC emissions were controlled

alone. Thus a key question is whether controlling

NOX is beneficial or counterproductive for an area as

a whole, not just at a single location. A Los

Angeles-area study illustrates how complicated this

question can be.

Figure 5-3 illustrates the complexity of reducing

NOX emissions, as predicted using an urban-scale

model, for a 1982 episode in the Los Angeles area

[19]. The figure shows the predicted impact of

uniformly reducing NOX emissions by 35 percent

and holding VOC emissions constant, compared to

estimated 1982 levels. The gray area shows where

peak ozone concentrations were predicted to increase when NOX emissions were lowered. This area

is centered on Los Angeles County, the portion of

the region where NOx emission rates are highest.

Downwind of this area, in San Bernardino and

Riverside Counties, reducing NOX is predicted to

reduce peak ozone.

For the case simulated, the highest ozone concentrations occurred in the eastern part of the Los

Angeles basin, and reducing NOX emissions by 35

percent was predicted to lower the area-wide peak

ozone concentration by slightly more than 10

percent. However, Los Angeles County is the most

densely populated part of the basin, and a 35-percent

reduction in NOX was predicted to lead to about a

5-percent increase in population exposure to ozone

concentrations above 0.12 ppm.

Combined Volatile Organic Compound and

Nitrogen Oxide Control in the Northeast

EPA has used a regional-scale air pollution

model, its Regional Oxidant Model (ROM), to study

the effect of reducing VOC and NOX emissions in the

Northeastern United States. The ROM modeling

region is shown in figure 5-4. The region is divided

into cells with horizontal dimensions of approximately 11.5 miles X 11.5 miles. Emissions, air

quality and meteorological inputs and outputs are

averaged within each cell. Averaging over this scale

is necessary to keep computational requirements

down, but can lead to underprediction of peak ozone

concentrations in urban areas, and may also bias how

ozone levels respond to changes in VOC and NOX

emissions levels. Representation of such large point

sources as utility and industrial boilers is especially

problematic [13].

EPA has used ROM to examine control strategies

involving both VOC and NOX control alone, and

combinations of the two. In keeping with our

premise that future efforts will focus first on

reducing VOCs, but that NOX controls may also be

imposed, we present results here for the following

strategies [23]:

• VOC control alone-reductions of manmade

VOC emissions by 42 percent, averaged over
Chapter 5---Lowering Ozone: Effect of Controlling Volatile Organic Compounds and Nitrogen Oxides ● 103

Figure 5-3—Change In Peak Ozone Concentrations in the Los Angeles Basin, Predicted to Result From Reducing

NOX Emissions by 35 Percent Below 1982 Levels

Orange County

The gray area shows where ozone concentrations. are predicted to increase. Ozone concentrations are predicted to decrease throughout

the rest of the region. The predictions were made using an urban-scale model, with emissions and meteorological conditions corresponding

to the August 30-31, 1982 period.

SOURCE: J.B. Milford, A.G. Russell, and G.J. McRae, “Implications of Spatial Patterns in Pollutant Responses to Reductions in Nitrogen Oxides and Reactive Organic Gas Emissions,”

Environmental Scmnce and T&hnology, accepted, 1989.

●

the entire ROM domain, with reductions in

cells in nonattainment cities ranging from 27 to

70 percent and uniform 30-percent reductions

outside of nonattainment areas.

Combined VOC and NOX control-the same

VOC reductions plus 27-percent reductions in

NOX emissions, averaged over the entire modeling region.

ROM’s development and evaluation are ongoing,

so the results presented here should be considered

preliminary. Uncertainties in the estimates of both

manmade VOC emissions and VOC emissions from

vegetation are significant. VOC emissions from both

mobile sources and area sources were probably

underestimated in the 1980 NAPAP inventory, since

emissions associated with running losses and waste

treatment, storage, and disposal facilities (TSDFs)

were not included. Evaluations of the model conThe results reported here are for a 16-day period ducted to date indicate a tendency to overpredict low

in July, 1980, when winds were generally from the concentrations and underpredict peaks, especially

west or southwest.4 Base case emissions estimates

for manmade VOCs, NOX

, and CO were from the

near major point sources; and to overpredict low

1980 National Acid Precipitation Assessment Proconcentrations in remote areas [14].

gram (NAP’) inventory. VOC emissions from Table 5-1 shows the results for cities (Metropolivegetation are also included. tan Statistical Areas or MSAs) in the ROM modeling

4A]o~g he ~b~~ ~~emse~~md, d~ng this pefi@ surface winds often flow~ from tie sou~west while WhdS at higher altitudes Came frOm

the west [22].
104 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 5-4—Region Covered by the U.S.

Environmental Protection Agency’s Regional

Oxidant Model (ROM)

ROM is being used to study the effect of reducing VOC and NOx

emissions.

SOURCE: W. Battye, L. Langstaff, M. Smith, N. Possiel, E. Meyer and K. Baugues,

“Regional Ozone Modeling For Northeast TranspoR-Development of a

Base Year Emissions Inventory,” papar prepared for the 82nd Annual

Meeting of the Air and Waste Management Association (Anaheim, CA: June

25-30, 1989).

region. Results for rural (non-MSA) areas of New

York, Pennsylvania, and West Virginia are discussed below in the section on rural ozone. Two

measures of the extent of possible exposure are

tabulated for the base case and for the VOC-alone

and combined VOC and NOX control strategies. The

first is an area-weighted measure of the occurrence

of ozone concentrations above specified levels-on

each day, the number of grid cells where ozone

exceeds a threshold concentration is counted, and

then the daily totals are added up over the 16-day

modeling period. The second measure is "populationweighted”—in this case the number of people living

in those parts of a city where ozone exceeds a

threshold concentration is added up for each day,

and then the daily ‘potentially exposed” population

numbers are totaled over the entire 16-day period.

Two threshold levels are displayed in table 5-1: a

peak daily l-hour average concentration of 0.12 ppm

(equivalent to the standard), and a peak daily 8-hour

average concentration of 0.10 ppm (a measure of

multi-hour exposure).

Approximately 61 million people live within all

the metropolitan areas included within the modeling

region. The total metropolitan area covered is about

100,000 square miles. If the entire modeling region

had been blanketed by ozone concentrations exceeding the standard for every day during the 16-day

period modeled, the entries in table 5-1 would be

about 976 million person-days (61 million people

times 16 days) and 1.6 million square mile-days

(100,000 square miles times 16 days). The 16-day

period modeled represents one of the worst episodes

of the 1980-88 period, with the base case occurrence

of ozone concentrations above the thresholds in

table 5-1 equal to about 10 percent of the theoretical

maximum. This total represents a mix of conditions—

some locations where the standard was never

exceeded, and other locations such as New York

City where the standard was exceeded on 11 of the

16 days modeled.

As shown in table 5-1, for the Northeast as a

whole, the net effect of the combined VOC and NOX

control strategy is predicted to be an improvement

over the strategy that would control VOCs alone, in

terms of reducing both the urban area and population

potentially exposed to elevated ozone concentrations. The large reductions in VOC emissions alone

eliminate the majority of potential exposures, with

the combined strategy eliminating 3 to 13 percent

more, depending on the measure of exposure considered. Consistent with the explanation that ozone is

most likely to be sensitive to VOC controls in

densely populated, high-emissions areas, reducing

VOC emissions alone is somewhat more effective

for lowering population-weighted potential exposure than area-weighted exposure.

Despite the fact that the combined strategy is

predicted to be beneficial overall, for urban areas in

the Northeast, the modeling results suggest that NOX

reductions may be counterproductive for individual

locations within the region. In other places, though,

adding NOX controls is predicted to be more

effective than suggested by the regionwide totals

shown in table 5-1. Table 5-2 presents results for the

Pittsburgh, Hartford, and New York City areas.
Chapter 5-Lowering Ozone: Effect of Controlling Volatile Organic Compounds and Nitrogen Oxides . 105

Table 5-l-Predicted Effect of VOC-Alone and Combined VOC and NOX Control Strategies

In Northeastern Cities, Over a 16-Day Period in July 1980

Base case-potential Case 1, VOC control— Case 2, VOC and NOx control

exposure to elevated reduction in potential —reduction in potential

ozonea

exposure (% of base) exposure (% of base)

Areal exposure:

>0.12 ppm, 1-hr average . . . . . . . . . . . . . . 115,000 square miles*days 6 4 % 72%0

Population exposure:

>0.12 ppm, 1-hr average . . . . . . . . . . . . . . 117 million people*days 76% 79%

Areal exposure:

>0.10 ppm, 8-hr average . . . . . . . . . . . . . . 149,000 square miles*days 500/0 63%

Population exposure:

>0.10 ppm, 8-hr average . . . . . . . . . . . . . . 141 million people*days 63% 70%

aA~Ut 61 rnlflbrl-elive in about 100,OW square miles of U* area in - ROM [Regional Oxidant Modal] region. If OZOrlS U.WD3ntrSbOnS kd WCWdd the specified thresholds

every dsy, throughout all of these urban areas, the entries in ttis column would have been 1.6 million aquara-miles.days and 976 million peopb.days.

NOTE: The first column indicates “potential exposure” to elevated ozone (i.e., the occurrence of ozone iaveis above the indicated thraahoid concentration) for the base case, by area

and popuiatbn. The second and third columns give percentage reductions in “potential exposure” compared to the base case, for two control cases: 1 ) a 42 percent reduction

in manmade V(X emissions; and 2) the same 42 percent raductbn in manmade VOCS plus a 27 percent raducdon in NO, emiaabns.

SOURCE: N.C. Poaebl, US. Environmental Protactbn Agency, personal communication, March 1989.

Table 5-2-Predicted Effects of VOC-Alone and Combined VOC and NOX Controls in the Hartford,

New York City, and Pittsburgh Areas, Over a 16-Day Period in July 1980

Base case—potentiai Case 1 VOC control— Case 2, VOC and NOX control

exposure to elevated reduction in potential -reduction in potential

ozone exposure (% of base) exposure (% of base)

Harforda

Areal exposure:

>0.12 ppm, 1 -hr average . . . . . . . . . . .

Population exposure:

>0.12 ppm, 1-hr average . . . . . . . . . . .

New York Cityb

Areal exposure:

>0.12 ppm, 1-hr average . . . . . . . . . . .

Population exposure:

>0.12 ppm, 1-hr average . . . . . . . . . . .

Pittsburg

c

Areal exposure:

>0.12 ppm, 1-hr average . . . . . . . . . . .

Population exposure:

>0.12 ppm, 1-hr average . . . . . . , . . . .

12,000 square miles*days 4 8 % 58%

6.1 million people*days 49% 60%

41,000 square miles*days 660/0 68%

68.6 million people*days 81% 830/0

6,400 square miles*days 69% 69%

3.3 million people*days 82% 780/o

atiut 1.4 minim ~~e IiW in the 2,9txr aware-mile Hanford area.

~About 16.5 million people live in the 12,000”aquare-mile New York City ~ea.

c~ut 2.6 million Pa@e live in the 5,200 Wmre-mile Pittsburgh a~a.

NOTE: sea tatde 5-1 for a full explanation of the ermias.

SOURCE: N.C, Poaaiel, U.S. Environmental Protectbn Agency, personal communication, March 1989.

Of the major urban areas in the Northeast,

controlling NOX appears to be most counterproductive for Pittsburgh. As shown in the table, VOC

control alone is predicted to reduce potential population exposure to concentrations above the standard

by 82 percent; adding NO, control offsets some of

those gains. For Pittsburgh, the net effect of combined controls is a 78-percent reduction in population exposure. In contrast to Pittsburgh, combining

NOX and VOC controls is predicted to be comparatively more effective for Hartford than for the urban

Northeast overall. There, combining VOC and NOX

controls is predicted to reduce both the populationweighted and area-weighted exposure measures by

about 60 percent, whereas 50-percent reductions are

predicted with VOC-control alone.

Finally, in the base case, more than half of the

total potential exposures in northeastern cities occur
106 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

in the New York City area. Totaled over that 12,000

square mile area, the incremental effect of adding

NOx control is predicted to be a relatively small

improvement compared to controlling VOCs alone.

VOC controls alone are predicted to reduce areaweighted exposures by 66 percent, and populationweighted exposures by 81 percent. Combined VOC

and NOX controls yield additional reductions of 2

percent, by both measures.

Key limitations of these results need to be

reiterated. First, they are specific to the meteorological conditions and emissions scenarios modeled. As

discussed above, the emission reductions modeled

are relative to an estimated 1980 baseline. Current

emissions differ from those estimates due to actual

changes in emissions since 1980, as well as methodological improvements in estimating emissions

that have been made since 1980. The results also

depend on the levels of control evaluated. Comparing a different combination of VOC and NOX control

levels might have yielded different results in sign, as

well as magnitude, from those presented here. In

addition to the July episode, EPA has also used

ROM to simulate an August 1980 episode of

comparatively stagnant, recirculating flows. In that

case the combined control strategy generally yielded

more improvement over the VOC-alone case than

for the episode considered here. Of the two, ozone

episodes in the Northeast are more frequently similar

to the July episode than the August episode [23].

Finally, the 11.5 X 11.5-mile resolution of the model

precludes detailed analysis within cities and adds

uncertainty about the effect of emissions from large

sources.

RURAL OZONE, TRANSPORTED

OZONE, AND PRECURSORS

Transported Ozone and Precursors

Even if local, manmade VOC and NOX emissions

were eliminated completely, peak ozone concentrations would not be reduced to zero. A natural

background concentration of 0.04 ppm is generally

assumed to contribute to peak (l-hour average)

ozone concentrations. In most cases, emissions from

upwind areas contribute additional ozone to observed peaks. For example, on days when the peak

ozone concentrations measured downwind of Atlanta exceed 0.10 ppm, concentrations upwind of the

city are typically only 0.02 to 0.04 ppm lower than

the peak concentrations [15]. As another example,

ozone concentrations approaching the standard are

commonly observed upwind of east coast cities such

as New York and Boston on days when the standard

is violated downwind of these cities [21,24].

Urban “plumes” with elevated ozone concentrations have been tracked over 200 miles downwind of

some cities. Aircraft observations show that the New

York City plume can extend to Boston, for example

[21] ozone formed from precursors emitted in .

urban areas within about 100 miles upwind may

exacerbate nonattainment problems of cities along

the Northeast corridor from Virginia to Maine (21

nonattainment areas); along the gulf coast of Texas

and Louisiana (7 nonattainment areas); around Lake

Michigan (5 nonattainment areas); and in California

(8 nonattainment areas apparently affected by transport). Overall, of 74 consolidated metropolitan areas

that did not attain the ozone standard for the 1983-85

period, 41 appear to lie within about 100 miles in

directions commonly downwind of other nonattainment cities. In most of these cases, reducing both

VOC and NOx emissions in the upwind nonattainment areas would probably help improve air quality

in the downwind cities. Over the next 2 to 5 years,

proposed or ongoing modeling studies in the four

major transport areas listed above could provide

quantitative information about the effect of alternative controI strategies in those areas.5

Regional Episodes

In association with certain types of weather

systems that cross the Eastern United States several

times each summer, peak ozone concentrations in

the range of 0.08 to 0.10 ppm have been observed at

rural locations throughout multi-state regions [25,35].

Sk c~wration with the stiles in the Northeast, EPA is using its Regional Oxidant Model (ROM) to try to understand the impact of intercity umsport

there, and to evaluate coordinated control strategies. The application should be completed by the end of 1990. The Agency has also applied ROM to

the gulf coast region, but plans few additional applications to this area prior to 1991, due to limited resources. The California Air Resources Board,

together with local govemmerm in the San Joaquin Valley and California industrws, has planned an $8 to $10 million field experiment and modeling

study to investigate tramsport and control strategies for that area. The 6-week field experiment is planned for summer 1990. State air pollution control

agencies of Michigan, Illinois, Indiana, and Wisconsin have proposed, but not yet found funding for a million-dollar field study and modeling effort for

the southern Lake Michigan area.
Chapter 5—Lowering Ozone: Effect of Controlling Volatile Organic Compounds and Nitrogen Oxides ● 107

During the growing season, episodes of high ozone

in rural areas are of concern due to potentially

adverse impacts on crops and forests. Ozone formed

during regional-scale episodes may also contribute

to violations of the standard in urban areas, where

additional ozone is formed from local emissions.

Based on modeling and analysis of spatial and

temporal trends in ozone concentrations and air

mass movement, some scientists have suggested that

during multi-day episodes, pollutants emitted in

major urban or industrial areas may contribute to

high ozone concentrations observed several hundred

miles away. In particular, they suggest that emissions from the industrial Midwest may contribute to

high ozone concentrations over large areas of the

South [15] and Northeast [27,8]. Carried aloft, it is

plausible that slow-reacting VOCs and ozone could

be carried several hundred miles. However, we are

not aware of any analyses that have quantified the

contributions that major urban or industrial areas

make to ozone concentrations in either rural or urban

areas several hundred miles away.

Rather than originating in distant urban or industrial areas, the ozone concentrations observed in

regional-scale episodes could also build up over 2 or

more days due to emissions from widely distributed

sources, such as powerplants, or motor vehicles in

rural areas or small towns. As an illustration, Trainer

et al. [31] used a simple model to show that at levels

estimated to occur during summer in rural Pennsylvania, manmade NOX emissions and VOCs emitted

from vegetation alone (without any manmade VOC

contribution) could produce peak ozone concentrations of almost 0.12 ppm, built up over a 4-day

episode. (Adding manmade VOCs at levels observed in rural areas in the Northeast was predicted

to increase the peak ozone concentration by less than

10 percent, as ozone production was predicted to be

NOX

-limited.)

Within the next 2 years, EPA’s modeling efforts

should provide some information about the potential

influence of emissions from urban and industrial

areas in Ohio and Pennsylvania on ozone concentrations throughout the Northeast, including the nonattainment areas along the coast. The analysis could

also provide information about the impacts of

emissions from rural areas and small cities within

this region. Regional-scale studies of these issues for

the South and Midwest would also be useful.

Reducing Rural Ozone

Recent modeling studies that have simulated

typical rural conditions suggest that outside of urban

and industrial plumes, reducing NOX emissions will

generally be a more effective strategy for lowering

ozone than reducing VOC emissions [27,31]. Conditions in rural areas tend to be NOX

-limited [1,10]. In

rural areas where vegetative VOC emissions are

high, ozone production may be particularly insensitive to changes in manmade VOC emissions [31]. As

discussed in the previous section, ozone and precursors transported from urban areas also contribute to

elevated ozone levels in rural areas immediately

downwind of cities, and some scientists suggest that

impacts of transported pollutants may extend for

hundreds of miles. In these cases, reductions in

urban VOC and NOX emissions are likely to help

reduce rural ozone. We cannot estimate the comparative contributions to rural ozone levels of local

production versus transported pollution.

Table 5-3 shows results from the ROM simulations discussed above, for non-urban areas in Delaware, New Hampshire, New York, Pennsylvania,

Vermont, Virginia and West Virginia. The total

non-urban area included is about 83,000 square

miles. For the non-urban results, the areal measure

described above is tabulated, for 8-hour average

concentrations exceeding 0.08 and 0.10 ppm, and for

l-hour average concentrations exceeding 0.10 and

0.12 ppm. Because the controls simulated were

applied throughout the region, we cannot sort out the

impacts of reducing precursors in rural areas versus

cities.

As shown in the table, controlling NOX emissions in

addition to VOCs (in both urban and rural areas)

always reduced ozone in non-urban areas more than

controlling VOCs alone, at the level of aggregation

considered. This result is also true for each of these

states individually. Comparing tables 5-1 and 5-3,

shows that the incremental benefit of the combined

strategy over reducing VOCs alone is larger in rural

areas than in cities. This is consistent with the

expectation that NOX controls would be more

effective for reducing ozone in rural areas than in
108 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 5-3—Predicted Effect of VOC-Alone and Combined VOC and NOX Control Strategies

in Nonurban Areas of the Northeast, Over a 16-Day Period in July 1080

Base case-potential Case 1, VOC control— Case 2, VOC and NOX control

exposure to elevated reduction in potential —reduction in potential

ozonea

exposure (o/o of base) exposure (o/o of base)

Areal exposure:

>0.10 ppm, 1-hr average . . . . . . . . . . . . . 78,000 square miles*days 48% 630/o

Areal exposure:

>0.12 ppm, 1-hr average . . . . . . . . . . . . . 16,000square miles*days 68% 81%

Areal exposure:

>0.08 ppm, 8-hr average . . . . . . . . . . . . . 176,000square miles*days 240/o 45%

Areal exposure:

>0.10 ppm, 8-hr average . . . . . . . . . . . . . 30,000 square miles*days 5570 71%

aA~u~ ~,~o ~are ~i~~ “f ~nu~n area is iwluded in the modeli~ region. If thi~entire area had been blanketed byozone ~~tmtiofls ex~ding the SpeCifbd heShO~S eVery

day during ha 16-day period modeled, the entries in table 5-3 would be about 1.3 mdlion square miles.days

NOTE: Sea table 5-1 for a full explanation of the entries.

SOURCE: N.C. Possiel, U.S. Environmental Protection Agency, personal communication, March 1989.

urban areas, and also with the fact that most of the

VOC reductions occurred in cities, rather than rural

areas.

REFERENCES FOR CHAPTER 5

1.

2.

3.

4.

5.

6.

7.

8.

Altshuller, A.P., “Review: Natural Volatile Organic

Substances and Their Effect on Air Quality in the

United States, ” Atmospheric Environment 17:2131-

2165, 1983.

Altshuller, A. P., “Measurements of the Products of

Atmospheric Photochemical Reactions in Laboratory

Studies and in Ambient Air—Relationships Between

Ozone and Other Products,” Atmospheric Environment 17:2383-2427, 1983.

Baugues, K., A Review of NMOC, NOX and NMOCI

NO, Ratios Measured in 1984 and 1985, EPA-450/4-

86-015 (Washington, DC: U.S. Environmental Protection Agency, September 1986).

Baugues, K., U.S. Environmental Protection Agency,

personal communication, September 1988.

California Air Resource Board, Technical Support

Document, prepared for the public hearing to consider a revision to the SIP for Kern County (Sacramento, CA: July 1986).

California Air Resources Board, California’s Post1987 Motor Vehicle Plan for Continued Progress

Toward Attainment of the National Ambient Air

Quality Standar&for Ozone and Carbon iklonoxidt+-

1988 Update, Appendix IV-F, Draft Air Quali~ Plan

1988 Revision (Sacramento, CA: September 1988).

Charneides, W. L., Lindsay, R. W., Richardson, J., and

Kiang, C. S., “The Role of Biogenic Hydrocarbons in

Urban Photochemical Smog: Atlanta as a Case

Study,” Science 241:1473-1475, 1988.

Clarke, J. F., and Ching, J. K. S., “Aircraft Observations of Regional Transport of Ozone in the North9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

eastern United States, ” Atmospheric Environment

17:1703-1712, 1983.

Dodge, M. D., “Chemistry of Oxidant Formation:

Implications for Designing Effective Control Strategies, ” Conference Proceedings, North American

Oxidant Symposium (Quebec, Canada: Feb. 25-27,

1987).

Finlayson-Pitts, B. J., and Pitts, J. N., Jr., Atmospheric

Chemistry (New York, NY: Wiley & Sons, 1986).

Lamb, B., Guenther, A., Gay, D., and Westberg, H.,

“A National Inventory of Biogenic Hydrocarbon

Emissions, ” Atmospheric Environment 21:1695-

1705, 1987.

Lamb, B., Washington State University, personal

communication, October 1987.

Lamb, R. G., “Design and Applications of the Regional Oxidant Model (ROM), ” paper prepared for

the North American Oxidant Symposium (Quebec,

Canada: Feb. 25-27, 1987),

Lamb, R. G., “Diagnostic Studies of Ozone in the

Northeastern United States Based on Applications of

the Regional Oxidant Model (ROM), ” in proceedings, The Scientific and Technical Issues Facing

Post-1987 Ozone Control Strategies (Hartford, CT:

November 1987).

Lindsay, R. W., and Chameides, W. L., “High-Ozone

Events in Atlanta, GA, in 1983 and 1984, ” Environmental Science and Technology 22:426-431, 1988.

Logan, J. A., “Nitrogen Oxides in the Troposphere:

Global and Regional Budgets, ” J. Geophysical

Research 88:10785, 1983.

Meyer, IL L., Jr., Review of Control Strategies for

Ozone and their E#ects on Other Environmental

issues (Research Triangle Park, NC: U.S. Environmental Protection Agency, August 1986).

Meyer, E. L., Jr., U.S. Environmental Protection

Agency, personal communication, September 1987.
Chapter 5-Lowering Ozone: Effect of Controlling Volatile Organic Compounds and Nitrogen Oxides ● 109

19. Milford, J. B., Russell, A. G., and McRae, G.J.,

“Implications of Spatial Patterns in Pollutant Responses to Reductions in Nitrogen Oxides and

Reactive Organic Gas Emissions,” Environmental

Science and Technology, accepted, 1989.

20. Pierce, T., U.S. Environmental Protection Agency,

personal communication, April 1989.

21. Possiel, N. C., Spicer, C. W., Sticksel, P.R., Sverdrup,

G. M., Alkezweeny, A. J., and Davis, W. E., Northeast

Corridor Regional Modeling Project, Ozone and

Precursor Transport in New York City and Boston

During the 1980 Field Program, EPA-450/4-84-Ol 1

(Research Triangle Park, NC: U.S. Environmental

Protection Agency, August 1984).

22. Possiel, N. C., Tikv~ J. A., Novak, J. H., Schere,

K. L., and Meyer, E. L., “Evaluation of Ozone Control Strategies in the Northeastern Region of the

United States,” paper presented at the Third U.S.-

Dutch International Symposium, Atmospheric Ozone

Research and Its Policy Implications (Nijmegen,

Netherlands: May 9-13, 1988),

23. Possiel, N. C., U.S. Environmental Protection

Agency, personal communication, March 1989.

24. Rae, S. T., Application of the Urban Airshed Model to

the New York Metropolitan Area, EPA 450/4-87-01 1

(Research Triangle Park, NC: U.S. Environmental

Protection Agency, May 1987).

25. Samson, P. J., and Ragland, K. W., “Ozone and

Visibility in the Midwest: Evidence for Large-Scale

Transport,” J. Applied Meteorology 16:1 101-1106,

1977.

26. Seinfeld, J. H., “Ozone Air Quality Models: A

Critical Review,” J. Air Pollution Control Association 38:616-645, 1988.

27. Sillman, S., Imgan, J.A., and Wofsy, S. C., “The

Sensitivity of Ozone to Nitrogen Oxides and Hydrocarbons in Regional Ozone Episodes, ” submitted for

publication, 1989.

28. Singh, H. B., “Reactive Nitrogen in the Troposphere, ” Environmental Science and Technology

21:320-327, 1987.

29. South Coast Air Quality Management District, Draft

Air Quality Managment Plan, 1988 Revision, App.

V-S (El Monte, CA: September 1988).

30. Spicer, C. W., Joseph, D.W., Sticksel, P.R., and

Ward, G.F., “Ozone Sources and Transport in the

Northeastern United States,” Environmental Science

and Technology 13:975-985, 1979.

31. Trainer, M., Williams, E.J., Parrish, D. D., Buhr,

M.P., Allwine, E.J., Westberg, H. H,, Fehsenfeld,

F. C., and Liu, S. C., “Models and Observations of the

Impact of Natural Hydrocarbons on Rural Ozone$”

Nature 329:705-707, 1987.

32. U.S. Environmental Protection Agency, Environmental Criteria and Assessment OffIce, Air Quality

Criteria for Ozone and Other Photochemical Oxidants, Volume H, EPA/600/8-84/020bF (Research

Triangle Park, NC: August 1986).

33. U.S. Environmental Protection Agency, Federal Register, Nov. 17, 1987.

34. U.S. Environmental Protection Agency, National

Emissions Data System, “Nationwide Emissions

Report Summary, ” computer printout, January 1988.

35. Vukovich, F. M., Bach, W. D., Jr., Crissman, B. W.,

and King, W. J., ‘‘On the Relationship Between High

Ozone in the Rural Surface Layer and High Pressure

Systems,” Atmospheric Environment 11:967-983,

1977.

36. Vukovich, F. M., Fishman, J., and Browell, E.V.

“Reservoir of Ozone in the Boundary Layer of the

Eastern United States and Its Potential Impact on the

Global Tropospheric Ozone Budget,” J. Geophysical Research 90:5687-5698, 1985.

37. Wolff, G.T, and Lioy, P.J., “Development of an

Ozone River Associated With Synoptic Scale Episodes in the Eastern United States, ” Environmental

Science and Technology 14:1257-1260, 1980.
Chapter 6

Controlling Emissions of Volatile

Organic Compounds

CONTENTS

Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

CHARACTERIZATION OF CURRENT AND

FUTURE EMISSIONS . . . . . . . . . . . . . . . . . . . . . . 113

Sources of Volatile Organic Compounds . . . . . . . 113

Future VOC Emissions . . . . . . . . . . . . . . . . . . . . . . 115

Analysis of Important Assumptions Used in

VOC Emissions Estimates . . . . . . . . . . . . . . . . . 116

POTENTIAL EMISSIONS REDUCTIONS FROM

VOC CONTROL STRATEGIES ANALYZED

BY OTA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Uncertainty Surrounding Estimates of Emissions

Reduction Potential . . . . . . . . . . . . . . . . . . . . . . . 124

Reasonably Available Control Technologies

(RACT) on All Stationary Sources . . . . . . . . . . 129

Adoption of New “Control Technique

Guidelines” (CTGs) . . . . . . . . . . . . . . . . . . . . . . . 131

Controls on Hazardous Waste Treatment, Storage,

and Disposal Facilities . . . . . . . . . . . . . . . . . . . . . 131

Federal Controls on Architectural Surface

Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Controls on Gasoline Emissions From Vehicle

Refueling ... , , . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Enhanced Motor Vehicle Inspection and

Maintenance (1/M) Programs . . . . . . . . . . . . . . . 133

Page

More Stringent Highway-Vehicle Emission

Standards . .. ., . ., . . .. .....0 .. . . . . 133

Limits on Gasoline Volatility . . . . . . . . . . . . . . . . . 134

Methanol Fuels for Motor Vehicle Vehicles in

the Worst Nonattainment Cities . . . . . , . . . . . . . 134

COMPARISON OF POTENTIAL EMISSIONS

REDUCTIONS AND REDUCTIONS NEEDED

TO ATTAIN THE OZONE STANDARD . . . . . . 135

Without Additional Controls . . . . . . . . . . . . . . . . . . 135

With Additional Gasoline Volatility Limitations , 136

With All Control Strategies Analyzed by OTA . 137

Estimates of Possible Excesses and Shortfalls

in Emissions Reductions Required To Attain

the Ozone Standard , . . . . . . . . . . . . . . . . . . . . . . 137

COSTS OF CONTROL STRATEGIES ANALYZED

BY OTA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Reasonably Available Control Technologies

(RACT) on All Stationary Sources . . . . . . . . . . 145

Adoption of New “Control Technique

Guidelines” (CTGs) . . . . . . . . . . . . . . . . . . . . . . . 145

Controls on Hazardous Waste Treatment, Storage,

and Disposal Facilities . . . . . . . . . . . . . . . . . . . . . 145

Federal Controls on Architectural Surface

Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
CONTENTS-continued

Page

Controls on Gasoline Emissions From Vehicle

Refueling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Enhanced Motor Vehicle Inspection and

Maintenance (l/M) Programs. . . . . . . . . . . . . . . . . . . . . . . .146

More Stringent Highway-Vehicle Emission

Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Limits on Gasoline Volatility . . . . . . . . . 147

Methanol Fuels for Motor Vehicle Vehicles in

the Worst Nonmtaimnent Cities . . . . . . . . . . . . . 147

REFERENCES FOR CHAPTER 6 . . . . . . . . . . . . . . 148

Fiures

Figure Page

6-1. VOC Emission in Nonattainment Cities, by

Source Category, in 1985 . . . . . . . . . . . . . . . . . . 115

6-2. VOC Emissions From Mobile Sources in 1985

as a Percentage of Total Emissions in

Nonattainment Cities . . . . . . . . . . . . . . . . . . . . . 115

6-3. Stationary Source Emissions of VOC in 1985

as a Percentage of thc Total Emissions Inventory,

by Size of the Individual Source . . . . . . . . . . . 116

6-4. Summary of Estimated Nationwide VOC

Emissions by Source Category, by Year. . . . . 119

6-5. Uncertainty in Highway-Vehicle VOC

Emissions in Nonattainment Areas in 1994.. 120

6-6. Uncertainty in Stationary-Source VOC

Emissions in Nonattainment Areas in 1994.. 120

6-7. Effect of Running Losses on Passenger-Car

Emission Rates in Nonattainment Cities

in 1985 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

6-8. VOC Emissions Reductions in 1994 and

2004 Compared to 1985 Emissions, by

Control Method . . . . . . . . . . . . . . . . . . . . . . . . . . 125

6-9. Potential VOC Emissions Reductions and

Remaining Emissions in 1994 and 2004

as a Percentage of 1985 Emissions in

Nonattainment Cities . . . . . . . . . . . . . . . . . . . . . 129

6-10. VOC Emissions in Nonattainment Cities in

1994, by Source Category, After all

Additional Control Methods Are Applied . . . 129

6-11. Uncertainty in VOC Emissions Reductions

From All Additional Controls in Nonattainment

Cities in 1994 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

6-12, VOC Emissions Reductions Between 1985

and 1994, Assuming No Change From 1987

VOC Regulations and Assuming Additional

Volatility Controls . . . . . . . . . . . . . . . . . . . . . . . . 136

6-13. VOC Emissions Reductions Between 1985

and 1994, and 1985 and 2004, Including All

Page

Additional Mobile and Stationary Source VOC

Control Methods . . . . . . . . . . . . . . . . . . . . . . . . . 138

6-14. Estimates of Possible Excesses and

Shortfalls in Emissions Reductions Needed to

Attain the Ozone Standard in 1994 . . . . . . . . . 138

6-15. Estimated Cost of VOC Emissions Control

Methods in 1994 and 2004 in Nonattainment

Cities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

6-16. Estimated Cost-Effectiveness of VOC

Emission Control Methods in 1994 in

Nonattainment Cities . . . . . . . . . . . . . . . . . . . . 144

6-17. Cumulative Annual Cost of, and Percent

Emissions Reductions From VOC Control

Methods . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . 145

Tables

Table Page

6-1. Summary of 1985 VOC Emissions in

Nonattainment Cities and Attainment

Regions . . . . . . . . . . . . . . . . . . . . , , . . . . . . . . . . . 114

6-2, Summary of 1984 VOC Emissions in

Nonattainment Cities and Attainment

Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

6-3. Summary of 1989 VOC Emissions in

Nonattainment Cities and Attainment

Regions ., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

6-4. Summary of 2004 VOC Emissions in

Nonattainment Cities and Attainment

Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

6-5. Estimate of Uncertainty in Volatile Organic

Compound Emissions in Nonattainment

Cities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

6-6. Potential Emissions Reductions in 1994

Compared to 1985 Emissions From SourceSpecific Control Strategies . . . . . . . . . . . . . . . . 126

6-7. Potential Emissions Reductions in 1999

Compared to 1985 Emissions From SourceSpecific Control Strategies . . . . . . . . . . . . . . . . 127

6-8. Potential Emissions Reductions in 2004

Compared to 1985 Emissions From SourceSpecific Control Strategies . . . . . . . . . . . . . . . . 128

6-9. Estimate of Uncertainty in VOC Emissions

Reductions After All Controls Are Applied in

Nonattainment Cities in 1994 ..., . . . . . . . . . . 130

6-10. Estimated Costs of Selected Control Strategies

Analyzed by OTA . . . . . . . . . . . . . . . . . . . . . . . . 141

6-11. Estimated Cost-Effectiveness of Selected

Control Strategies Analyzed by OTA . . . . . . . 143
Chapter 6

Controlling Emissions of Volatile Organic Compounds

INTRODUCTION

Controlling emissions of volatile organic compounds (VOC) is the primary strategy used by the

Environmental Protection Agency (EPA) and most

States for reducing urban ozone. In this chapter, we

discuss the sources of VOC emissions, our ability to

control them, and the costs of control.

The first section describes the sources of VOC

emissions and presents our estimates of the changes

in emissions over the next several years. The next

section analyzes the VOC emissions reductions

from source-specific control methods that are currently available. We also compare these potential

emissions reductions with estimates of the overall

emissions reductions needed to attain the ozone

standard in each nonattainment city. In the final

section, we summarize the costs of each control

method.

CHARACTERIZATION OF

CURRENT AND FUTURE

EMISSIONS

This section describes the man-made sources of

VOC emissions and presents our estimates of the

changes in emissions over the next 15 years due to

the offsetting influences of economic growth and

State and Federal regulations in place as of 1987.

These estimates serve as a baseline for considering

the effects of regulatory changes needed to attain the

ozone standard. The focus of this section is on

manmade emissions, since they are subject to

control. VOC emissions from vegetation are discussed in chapter 5.

Sources of Volatile Organic Compounds

Table 6-1 displays estimates of 1985 VOC

emissions, number of cities, and population within

each of five ozone design value categories. The EPA

1985 National Emissions Data System (NEDS) and

the 1985 National Acid Precipitation Assessment

Program (NAPAP) inventories are the sources of our

emissions data and serve as the base inventory for all

future year projections presented in this report.

Three adjustments have been made to these data.

First, highway-vehicle emissions contained in the

1985 NEDS inventory have been updated using

EPA’s most recent estimates of exhaust and evaporative emission rates. 1 Vehicle emission rates were

also adjusted to reflect a higher rate of gasoline

evaporation during vehicle use.2 Highway vehicle

emission rates were estimated for hot summer

temperatures typical of days when the ozone standard is violated. Finally, VOC emissions from residential fuel combustion (primarily from wood burning) have been excluded from our analysis since

these emissions occur primarily during the wintertime when ozone is not a problem. Thus, the

estimates that we present are representative of the

emissions on a typical nonattainment day, multiplied by 365 days per year, rather than estimates of

true annual emissions. For convenience, throughout

the report, we refer to these estimates as annual

emissions rather than as ‘‘nonattainment-dayequivalent-annual-emissions.”

Of the 25 million tons of VOCs emitted in 1985,

nationwide, about 45 percent (11 million tons) were

generated in 94 cities that exceeded the ozone

standard during the 1983-85 period. For our analy -

lwe use EPA’S MOBILE LI rn~e} to estimate highway vehicle cmisslon rates. In a recent effort using MOBILE 4, EPA grouped nonattainment cities

into five categories based on the Reid vapor pressure (RVP) of gasoline and ambient temperatures. These categories included:

% of total VMT in RVP Ambient temperature, OF

61 selected cities (psi) (min.) (max.)

Group 1: 0.18 11.6 62 85

Group 2: 0.23 10.5 69 95

Group 3: 0.21 11.2 72 90

Group 4: 0.16 11.7 61 96

Group 5: 0.22 11.1 81 96

We used the vehicle-miles-traveled (VMT)-weighted average exhaust and evaporative emission rates of these five groups, assuming an average vehicle

speed of 28 miles per hour.

2

Preliminary EPA tests have shown that gasoline evaporation during vehicle operation on warm days (called ‘‘running loss”) is significantly higher

than previously thought. Details of this adjustment are discussed later.

-113–
114 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 6-l-Summary of 1985 VOC Emissions in Nonattainment Cities

and Attainment Regions

VOC Percent Percent 1985

emissions stationary mobile Number of population

(1 ,000 tons)a

(%) (%) cities (millions)

Nonattainment cities by

design value category

(in ppm O3)

0.13-0.14 . . . . . . . . . . . . 3,200 53 47 37 30.2

0.15-0.17 . . . . . . . . . . . . 5,400 51 49 40 55.3

0.18-0.26 . . . . . . . . . . . . 1,600 53 47 14 20.2

>0.26 . . . . . . . . . . . . . . . 970 53 47 3 11.9

Total (nonattainment) . . . . 11,000 52 48 94 117.7

Attainment regions . . . . . . 14,000 49 51 118.8

Total . . . . . . . . . . . . . . . . 25,000 50 50 236.5

RToMl~ are rou~d. T~ estima~s that WI pre~nt are representative of the emissions on a ty~d ~natt~nment day. multiplied by *5

days per year, rather than estimates of true annual emissions. For convenience, throughout the report, we refer to these estimates as

annual emissions rather than as “nonattammentday-equwalent-annual -emlsslons. ”

SOURCE: EPA 1985 National Emissions Data System emissions Inventory, January 1988 printout; 1985 National %id Precipitation

Assessment Program area source erntsslons inventory; populauon data from Bureau of Census. Mobile source inventory is

adjusted to reflect increased emissions from gasoline evaporation. Residential fuel combustion sources are excluded.

sis, an area is considered nonattainment if its design

value is greater than 0.12 parts per million (ppm)

ozone according to EPA-published 1983-85 ozone

monitoring data.

3 EPA’s actual determination of

nonattainment is based on a slightly different

method, but the resulting number of nonattainment

cities are essentially the same. Our number of

nonattainment areas differs Ii-em EPA’s count of 61

because, in several cases, EPA has used Consolidated Metropolitan Statistical Areas (CMSAs), rather than cities. Several of these CMSAs include two

or more cities that we have considered separately.

These regions contain about half of the Nation’s

population.

Our estimates of emissions throughout this analysis are subject to potentially significant uncertainty.

We estimate that VOC emissions in nonattainment

cities could be as low as 8 million or as high as 14

million tons per year in 1985 depending on several

important mobile and stationary source assumptions. Uncertainties in the emissions inventory are

discussed in more detail in a later section.

Figure 6-1 displays the percent contribution of

various source categories to the total 1985 VOC

emissions in nonattainment cities. About threequarters of the emissions are generated from three

main categories: mobile sources, surface coating,

and other organic solvent evaporation from stationary sources, About 43 percent of the 1985 emissions

inventory is composed of highway vehicle emissions. A further breakdown of the data, shown in

figure 6-2, reveals that passenger cars are the largest

contributors within the highway vehicle category,

with about one-third of the total 1985 nonattainment

area VOC emissions, followed by light-duty gasoline trucks with 7 percent.

Surface coatings contributed about 9 percent of

the total VOC emissions in 1985. Surface coatings

are used in the manufacture of a wide variety of

products including automobiles, furniture, large

appliances, and other metal and plastic products;

printing inks and many other applications are also

included. Organic solvent evaporation from stationary sources other than from surface coatings contributed about 15 percent of the total VOC emissions in

1985. The sources within this category are extremely

varied and include such activities as decreasing of

metal parts and products, drycleaning, consumer and

commercial products, and cutback asphalt paving.

The range of individual source sizes (as defined

by their individual annual VOC emission rates) can

also be quite wide, ranging from a small gas station

qThe llst of cities excmding the st~dard during the 19116-88 period had not been released by EPA at the time of this analysis. We used the 1983-85

period in our analysis, rather than the most recent list avadable because we felt it IS more representative of current nonattainment status.
Chapter 6-Controlling Emissions of Volatile Organic Compounds ● 115

Figure 6-l-Volatile Organic Compound (VOC)

Emissions in Nonattainment Cities, by Source

Category, in 1985

Percent of total VOC emissions

o% 10% 20% 30% 40% 50%

Mobile sources

Organic solvent evap

Surface coating

Petroleum industry

Gas marketing

TSDFs

Other industries

Chemical manufact.

Solid waste disposal

Nonresid. fuel comb.

Miscellaneous

Source size

Total emissions = 11 million tons/year

Stationary sources that emit more than 50 tons per year of VOC

are included in the “Large” categories

SOURCE: OTA, from EPA’s National Emissions Data System (NEDS) and National

Acid Precipitation Assessment Program emissions inventories.

decreasing tank that emits less than a ton per year,

to large industrial operations that contain evaporation sources emitting several hundred tons per year.

Figure 6-1 shows that solvent evaporation (including surface coatings) from small stationary sources

emitting less than 50 tons per year contributes about

20 percent of total VOC emissions.

Figure 6-3 displays the breakdown of stationary

source emissions by source size. About 45 percent of

the total 1985 VOC emissions originated from

stationary sources that emit less than 50 tons per

year. Because of the way EPA constructs the NEDS

emissions inventory, it is not possible to show, with

much certainty, a more detailed breakdown of the

“less-than-50-tons-per-year” size class.4 However,

we do know that at least 1 percent of the inventory

comes from sources emitting between 25 and 50 tons

per year, and that this contribution could be as high

Figure 6-2-Volatile Organic Compound Emissions

From Mobile Sources in 1985 as a Percentage of

Total (mobile plus stationary) Emissions in

Nonattainment Cities

Passenger cars

LD gasoline trucks

Off-highway vehicles

Air, rail, marine

HD gasoline trucks

HD diesel trucks

0% 50/ 0 1O% 15% 20% 25% 30% 35%

Percent of total emissions

LD = light-duty; HD ❑ heavy-duty

Total emissions = 11 million tons/year

SOURCE: OTA, from EPA’s National Emissions Data System (NEDS), National Acid

Precipitation Assessment Program emission inventory, and MOBILE-4

modal.

as 30 to 35 percent. We have chosen 15 percent as a

‘‘rough guess,” assuming that about a third of the

small aggregated VOC stationary sources in the

inventory (for which no source size can be identified) may, individually, emit more than 25 tons per

years The uncertainty in actual sizes of the less-than50-ton sources does not diminish the significant

contribution they make to total VOC emissions.

Future VOC Emissions

Tables 6-2 through 6-4 display our projections of

VOC emissions in 5, 10, and 15 years-1994, 1999,

and 2004-assuming that existing State and EPA

regulations do not change. These projections serve

as a baseline from which to gauge the effectiveness

of future regulations; for example, the changes

proposed in recent congressional bills or EPA’s

proposed post-1987 ozone policy. Under regulations

in place as of 1987, total VOC emissions would

decline approximately 6 percent by 1994 compared

%PA ~U~eS states to repofi VOC emissions from individual sources that emit more than 50 tons per year. If a kge ‘fKility ” (that Contfis more

than one source) emits more than 100 tons per year of VOCs, each individual source emitting more than 25 tons per year within that facility must also

be reported, EPA uses a ‘‘market-balance” approach to indirectly estimate the aggregate remaining emissions from small sources that are not required

to report their emissions. Determination of individual source sizes is, therefore, not possible for these small size categories.

SThe 25.ton.Wr-ye~ si~ cutoff waschosen so tilatwe could analyze (in a later section) the emissions reduction potentiat frOm StatlOnw sowces

greater than 25 tons per year. The Clean Air Act currently requires that, at a minimum, all stationary VOC sources that emit more than 100 tons per year

in nonattainment areas must adopt “reasatably available” control methods, though this cutoff is lower for some categories.
116 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 6-3—Stationary Source Emissions of Volatile

Organic Compounds (VOCs) in 1985 as a Percentage

of the Total Emissions inventory, by Size of the

individual Source

- 1

I

4 0 % I

Not known if source size is 1 I

30%

20 ”/0

1O %

less than 25 tons/yr o r

between 25 and 50 tons/yr.

Less

—

than 25 tons/yr – -

Greater than 100 50 to 100 Less than 50

Individual source size (tons/year)

Each bar displays the percentage of total VOC emissions that are

contributed by each source-size class. For example, about 45

percent of total emissions come from sources that emit less than

50 tons per year. Because of the way the 1985 emissions

inventory is constructed, we are unable to give a more precise

detailed breakdown within the ‘*Less-than-50 tons-per-year”

category. We have assumed that sources that emit between 25

and 100 tons per year account for about 15 percent of the total

VOC emissions; this percentage could be as high as 30 to 35

percent.

SOURCE: OTA, from EPA’s National Emissions Data System (NEDS) and National

Acid Precipitation Assessment Program emissions inventories.

to 1985 levels. Note that the baseline does not

include reductions due to the recently promulgated

limit on gasoline volatility of 10.5 psi Reid vapor

pressure (RVP).

Total emissions are expected to start increasing

again sometime after 1999, showing a net increase

of 1 percent in 2004 compared to 1985 levels. Our

estimates of future emissions depend on several key

assumptions regarding stationary and mobile

sources and are subject to potentially significant

uncertainty. These assumptions, and their effects on

total future emissions estimates, are discussed in

more detail in a later section.

Total VOC emissions drop between 1985 and

1994 due to lower emission rates from cars and

trucks.6 Although the number of vehicle-milestraveled is forecast to increase in many areas over

this period, the gradual replacement of current

vehicles with newer, cleaner ones will result in an

overall decline in highway vehicle emissions. Figure

6-4 shows mobile and stationary source VOC

emissions through time. VOC emissions from highway vehicles are projected to decline by about 25

percent between 1985 and 1999. Stationary source

emissions, on the other hand, are forecast to increase

steadily between 1985 and 2004, showing a 10-

percent increase by 1994 and a 23-percent increase

by 2004, over 1985 levels.7 Growth of small (less

than 50 ton-per-year) stationary VOC source emissions is one of the most important reasons why

overall VOC emissions are not expected to decline

more rapidly in the earlier years and why total

emissions may show a net increase after 1999. This

source category effectively offsets much of the

emissions reductions realized from highway vehicles.

Analysis of Important Assumptions Used in

VOC Emissions Estimates

In this section, we address some of the assumptions used in our emissions estimates presented

above. The assumptions we tested include: 1) the

rate of gasoline evaporation from in-use highway

vehicles (“running losses”), 2) average highwayvehicle speeds, 3) exhaust emission rates from

passenger cars after 50,000 miles of use, 4) level of

compliance with existing stationary source VOC

regulations, 5) emissions from organic solvent

evaporation sources, and 6) emissions from hazardous waste treatment, storage, and disposal facilities

(TSDFs). Figures 6-5 and 6-6 and table 6-5 display

our estimates of uncertainty for these categories.

We estimate total VOC emissions in nonattainment cities would be about 10 million tons per year

6

Future highway vehicle emissions were projected using EPA estimates of future highway vehicle VOC emission rates, combined with estimates

of average yearly miles-traveled per person and Census Bureau population projections.

7FutWe lwge ~ationq source (~eater mm 50 tons per yea) emissions were estimat~ using proj~tions of industri~ employment grOWdl Within

various industrial categories, while small source growth was based either on industrial employment, estimates of population growth, or growth in the

gross nationat product per capita [17] [22] [23].
Chapter 6--Controlling Emissions of Volatile Organic Compounds ● 117

Table 6-2-Summary of 1994 VOC Emissions in Nonattainment Cities and

Attainment Regions (emissions in 1,000 tons per year)a

VOC emissions Change from 1985 emissions

Total Stationary Mobile Total Stationary Mobile

Nonattainment cities by

design value category

(in ppm O3)

0.13-0 .14 . . . . . . . . . . 3,000

0.15-0 .17 . . . . . . . . . . 5,100

0.18-0 .26 . . . . . . . . . . 1,500

> 0.26 . . . . . . . . . . . . 890

Total (nonattainment) . . 10,000

Attainment regions . . . . 13,000

1,800

3,000

940

570

6,400

7,500

1,100

2,000

590

320

4,100

5,600

–7% 8%

–770 90/0

–6% 8%

–90/0 10%

–770 90/0

–5% 1 1%

–24%

–23%

–22%

–30%

–24%

–20%

Total . . . . . . . . . . . . . 24,000 14,000 9,700 –6°A 1 0“/’ –22%

aTOtalS am rou~, ASSUmeS no regulali.ns other tharl those in place in 1987. The estimates that w present are repKSw!tative of ths

emissions on a typkal nonattainment day, multiplied by 365 days per year, rather than estimates of true annual emissions. For

convenience, throughout thereport, we refer tothesa estimates asannualemissi.nsrathw U_mnas’’nonattemmentday +quivalent.annual.

emissions.” Note that the baseline doea not include reductions due to the recently promulgated limit on gasoline volatility of 10.5 psI Reid

vapor pressure (RVP).

SOURCE: Office of Technology Assessment, 1989.

Table 6-3-Summary of 1999 VOC Emissions in Nonattainment Cities and

Attainment Regions (emissions in 1,000 tons per year)a

VOC emissions Change from 1985 emissions

Total Stationary Mobile Total Stationary Mobile

Nonattainment cities by

design value category

(in ppm O3)

0.13-0 .14 . . . . . . . . . . . . 3,000 1,900 1,100 –6% 13% –29%

0.15-0 .17 . . . . . . . . . . . . 5,100 3,200 1,900 –60/0 15% –28%

0.18-0 .26 . . . . . . . . . . . . 1,500 980 560 –5% 13% –27%

> 0.26 . . . . . . . . . . . . . . 890 600 280 –9% 160/0 –38%

Total (nonattainment) . . . . 10,000 6,700 3,800 -6%

——

14% –29%

Attainment regions . . . . . . 13,000 8,000 5,400 –3% ——18% –23%

Total . . . . . . . . . . . . . . . 24,000

— —

15,000 9,200 –5% 16% –260/o

aTOtalS are rou~d, ASSUrn~ n. rggUlat&n$ .~r than those In plaea in 1887. The estimates that w present am representative of t~

emissions on a typical nonattainment day, multiplied by 365 days per year, rather than estimates of true annual emissions. For

convenience, throughout Uwreport, we referto these estimates asannualemissions rathw thanas’’nonattainment-day-equivalent-annual

emissions.” Note that the baaelme doee not include reductions due to the recently promulgated limit on gasolim volatility of 10.5 psi Reid

vapor pressure (RVP).

SOURCE: Office of Technology Assessment, 1989.

in 1994, again assuming the regulations in place as have the most significant effect on total VOC

of 1987.8 This total could be as low as 7 million or emissions in nonattainment cities. The following

as high as 13 million tons per year given a range of discussion presents a more detailed account of our

variability in all the assumptions listed above. Of all analysis of the five categories of uncertainty which

the assumptions we tested, running losses appear to we were able to analyze.

8This estimate ~sues fing Io,s=s ~u~ to 1.5 gramspermde, average highway vehicle speeds equal to 28 miles per hour, 100 percent compliance

with all existing stationary source VOC regulations, EPA’s 1985 estimate of organic solvent use and TSDF emissions, and unadjusted in-use vehicle

tailpipe emission rates.
118 . Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 6-4-Summary of 2004 VOC Emissions in Nonattainment Cities and

Attainment Regions (emissions in 1,000 tons per year)a

VOC emissions Change from 1985 emissions

Total Stationary Mobile Total Stationary Mobile

Nonattainment cities by

design value category

(in ppm O3)

0.13-0 .14....., . . . . . . 3,100 2,000 1,100 –20/0 20% –26%

0.15-0 .17 . . . . . . . . . . . . 5,400 3,400 2,000 –10/0 210/0 –240/o

0.18-0 .26 . . . . . . . . . . . . 1,600 1,000 590 0% 19% –22%

> 0.26 . . . . . . . . . . . . . . 930 640 290 –4°/0 24% -36%

Total (nonattainment) . . . . 11,000 7,100 4,000 – 1 % 21 ”/0 –250/’

Attainment regions .’. . . . . 14,000 8,50 0 5,700 3% —26% –18?40 ——.

Total . . . . . . . . . . . . . . . 25,000 16,000 9,700 1% 23% –21%

aTOtalS are rounded. ASSUtneS no regdations other than those in place in 1967. The e$timate$ that we present are representative of the

emissions on a typical nonattainment day, mult@ed by 365 days per year, rather than estimates of true annual emissions. For

convenience, throughout thereport, wereferto these estimates assnnual emissions rather than as “nonattainmentday-equivalent-annualemissions.” Note that the baseline doos not include reductions due to ttre recentfy promulgated Iimlton gasoline volatility of 10.5 psi Reid

vapor pressure (RVP).

SOURCE: Office of Technology Assessment, 1989.

Rate of Gasoline Evaporation From

In-Use Highway Vehicles

Preliminary results from EPA tests on 34 passenger cars and light-duty trucks [31] have shown that

on hot summer days gasoline evaporation from the

fuel system (“running losses”) may significantly

increase total vehicle emissions. The magnitude of

additional emissions from running losses will vary

from city to city depending factors such as ambient

temperature and gasoline volatility. For example, in

nonattainment cities with relatively moderate ambient summertime temperatures (e.g., 79 ‘F) and

gasoline volatilities of around 11.5 pounds per

square inch (psi) (e.g., Washington, DC), EPA’s

MOBILE-4 model estimates that fleet average

running losses are about 1.5 grams of VOC emitted

per mile driven in 1985. In cities with higher ambient

temperatures (87 ‘F) and gasoline volatilities (1 1.7

psi), such as New York City, fleet average running

losses are estimated to be about 2.9 grams per mile.

Figure 6-7 shows how varying running losses

affects individual vehicle emission rates in nonattainment cities.9 A running loss of 1.5 grams per

mile increases passenger car emission rates by about

34 percent; at 2.5 grams per mile, emission rates are

about 58 percent higher than those which do not

account for running losses. For passenger cars,

gasoline evaporation contributes about 60 percent of

the total in-use VOC emissions at a running loss of

1.5 grams per mile. Running losses represent a

potentially large source of VOC emissions which are

not included in EPA’s 1985 NEDS mobile source

inventory.

MOBILE-4 assumes that fleet average running

losses will decline in the future as newer, cleaner

vehicles replace older ones. However, because of the

limited number of vehicles tested thus far, we

believe it would be premature to predict future trends

in running loss emission rates due solely to vehicle

changes made for other reasons. Our estimates of

current and future highway vehicle emissions

presented above, and throughout our analysis,

have been adjusted to reflect an additional 1.5

grams per mile emission rate due to running

gEfiaust emission rates shown in tie figure do not include the effects of current motor vehicle IIISFCtiOXI and maintenance (w) Progr~s. ‘e

estimate that current I/M programs reduce exhaust emissions by about 12 percent. Estimates of exhaust emission rates assume average vehicle speeds

of 28 miles i~er hour, Emission rates for vehicles in California will be lower since the State maintains a summertime gasoline volatility limit of 9 pounds

per square inch.
Chapter 6-Controlling Emissions of Volatile Organic Compounds ● 119

Figure 6-4—Summary of Estimated Nationwide Voiltile Organic Compound Emissions

by Source Category, by Year

Emissions (million tons/yr)

A 1

10.6

6.0

-1

11.4

12.2

13.1

The numbers directly above the boxes are the total emissions within the source category. For example, emissions from highway vehicles

in 1994 are 8.1 million tons per year, nationwide. “Small stationary” sources emit less than 50 tons per year. Assumes no regulations other

than those in place in 1987. The estimates that we present are representative of the emissions on a typical nonattainment day, multiplied

by 365 days per year, rather than estimates of true annual emissions. For convenience, throughout the report, we refer to these estimates

as annual emissions rather than as “nonattainment-day-equivalent-annual-emissions .“ Note that the baseline does not include reductions

due to the recently promulgated limit on gasoline volatility of 10.5 psi Reid vapor pressure (RVP).

SOURCE: Office of Technology Assessment, 1989.

losses (0.5 gram per mile in California).l0 If emissions in nonattainment cities decrease by about

running losses are omitted from current highway 10 percent in 1985. At 2.5 grams per mile, total

vehicle emission rates (i.e., assumed to be zero emissions increase by about 6 percent in 1985.

grams per mile), we estimate that total VOC Although running losses add a potentially signifil~he vMT-we@t~ flcetwidc average running loss for the five regional areas in 1985 (see footnote 1), as derived from EPA’s MOBLE-4 model,

is about 2 grams per mile, while after 20 to 25 years it is predicted to be about 1 gram per mile. For our analysis, we chose a fleetwide average estimate

in the middle of this range-1.5 grams per mile—which, based on MOBILE-4 data, would be expected to occur sometime in the 1990s. In regions with

relatively higher ambient summertime temperatures and gasoline volatilities, MOBJLE-4 estimates that fleetwide average running losses are between

about 2 and 3 grams per mile in 1985. Therefore, we chose 2.5 grams per miie as a high estimate. MOBILE-4 data estimates that lowering gasoline

volatility from 11.5 to 9.0 psi will reduce running losses by about two-thirds, In general, light-duty gasoline trucks probably have lower running losses

than passenger cars. California emission rates are estimated assuming a gasoline volatility of 9.0 psi.
120 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 6-5—Uncertainty in Highway-Vehicle VOC

Emissions in Nonattainment Areas in 1904

I

024 6 8 10 12

1994 VOC emissions (million tons/year)

Throughout our analysis, we assume a 1.5 grams-per-mile

running loss and average vehicle speeds of 28 miles per hour.

SOURCE: Office of Technology Assessment, 1989.

cant amount of emissions to existing inventones,

these additional emissions, as we will show later,

can be largely controlled by lowering current

gasoline volatility limits.

Average Highway-Vehicle Speeds

Vehicle speed affects the rate at which pollutants

are emitted from the tailpipe. VOC exhaust emissions generally increase with decreasing vehicle

speed. A recent study found that the average

automobile speed in 10 principal U.S. cities was

about 27 miles per hour in 1980 [14]. In southern

California, highway vehicle speeds are expected to

decrease to about 19 miles per hour by 2010 if no

further regional transportation improvements are

adopted [16].

Our estimates of current and future highway

vehicle emissions throughout our analysis are

calculated assuming average speeds of 28 miles

per hour for all cities [12,14]. If average speeds are

reduced from 28 to 20 miles per hour, we estimate

that total VOC emissions in nonattainment areas

increase by about 7 percent, from about 11.2 million

Figure 6-6-Uncertainty in Stationary-Source VOC

Emissions in Nonattainment Areas in 1994

O 2 4 6 8 10 12

1994 VOC emissions (million tons/year)

Throughout our analysis, we assume that: 1) stationary sources

are in 100 percent compliance with existing VOC regulations, and

2) emissions from hazardous waste treatment, storage, and

disposal facilities (TSDFs) (shown in the “medium” category) and

organic solvent evaporation sources (shown in the “base”) are the

same as what is reported in the 1985 NAPAP inventory.

SOURCE: Office of Technology Assessment, 1989.

tons to about 12.1 million tons per year in 1985. If

speeds increase from 28 to 35 miles per hour,

nonattainment area total VOC emissions decrease

by about 4 percent, to about 10.8 million tons per

year in 1985.

Lower Passenger Car Tailpipe Emission Rates

We have also analyzed one automobile manufacturer’s assertion that cars built over the past several

years emit at lower rates than EPA estimates. The

manufacturer claims that improvements in passenger car emission control systems since 1981 were

not reflected in the data used by EPA to estimate

emissions from this vehicle class [10]. Test results

on several hundred 1982-through-1986 model-year

cars showed lower tailpipe VOC emissions after

50,000 miles of vehicle use compared to estimates

used by EPA in compiling the 1985 mobile source

inventory.

11 If these new passenger car estimates are

11

EPA ~smes that h-w Cfiaust emis~on raks for cars manufactured after 1982 are about 1 gram per mile. The test results showed emission rates

about 0.6 gram per mile lower than EPA’s estimate which would mean that these vehicles now meet the current 0.41-gram-per-mile hydrocarbon standsrd

after 50,000 miles of use,
Chapter 6—Controlling Emissions of Volatile Organic Compounds . 121

Table 6-5-Estimate of Uncertainty in Volatile Organic Compound Emissions in

Nonattainment Cities

Emissions (million tons/year)a

Highway

vehicles Total

Source category only mobile Stationary Total

Mobile sources

Running losses (grams/mile):

1985:

o 3.8

1.5 b : : : : : : : : : : : : : : : : : : : : : : : : : : 4.9

2.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6

1994:

o 2.3

I . 5

b ::::::::::::::::::::::::::: 3. 6

2.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4

Average highway-vehicle speeds (miles/hour):c

1985:

20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.7

28 b . . . . . . . . . . . . . . . . . . . . . . . . . 4.9

35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5

1994:

20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1

28 b . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6

35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3

Lower in-use emission rates

After 50,000 miles(in1994):C

3.4

Stationary sources

Level of compliance with existing

stationary source regulations (in 1994)$

100 percent . . . . . . . . . . . . . . . . . . . . . . .

80 percent . . . . . . . . . . . . . . . . . . . . . . .

Hazardous waste treatment,

storage and disposal facility

emissions uncertainty (in 1994)?

Low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Medium . . . . . . . . . . . . . . . . . . . . . . . . . .

High . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Organic solvent emissions

uncertainty (in 1994)!

Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Combination of mobile and stationary

source emissions uncertainty

(in:1994)

1.9 2.4 4.5 6.9

Medium b. . . .. . . . . . . . . .. . . . . . . . 3.6

High. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.0

4.1 6.4 10.5

5.5 7.8 13.3

aEstimatas areroundad.

bhlsesfimatewasuaad asa ”baaa ~~”th~ughoutour~alytis.

‘Thlsestimate includes running lossasof 15 gr”rnSparrnit~.

throughout ouranalysi~ wehveassurnedthatswtionary sour~com@ian~ wtihe~sting r~UlatiOnS has been 100pwcent. The

estimate presentedhera n~e~nts emissims timrnpfian~was acualiy80percent.

~he low, medium, and high estimates for treatment, storage, and disposal tactilities represent 50, 100, and 150 percent of reported

emissions, respectively, from the NAPAP inventory.

f’i~~’ is tie estimate con~ined tn tie NApAp Inventory; low esttmate IS 50 percent of the organic solvent emissions conrained m the

NAPAP inventory (TSDF emissions are unchanged),

~ombination includes: 1) no running losses, 2) average vehicle speeds of 35 miles per hour, 3) lower passanger vehicle in-use emission

rates, 4) 100 percent stationary sourca regulatory compliance, 5) low estimate of reported TSDF emissions, and 6) low estimate of

reportad orgamc solvent emissions.

~ombmation includes: 1) runmng losses equal to 2.5 grams par mile, 2) average vehicle speeds of 20 miles per hour, 3) increased

stationary source emissions due to lower comphance with existing regulations, 4) hgh estimate of reported TSDF emissions, and 5)

organic solvent emissions as reported In the NAPAP Inventory

SOURCE: Office of Technology Assessment, 1989.

4.3

5.4

6.1

5.9

5.9

5.9

10.2

11.2

12.0

2.8

4.1

5.0

6.4

6.4

6.4

9.2

10.5

11.3

6.2

5.4

4.9

5.9

5.9

5.9

12.1

11.2

10.8

4.6

4.1

3.8

6.4

6.4

6.4

11.0

10.5

10.2

3.9

4.1c

4 . 1

C

4 . 1

C

4.1

4.1

4 . 1

C

4.1

6.4

6.0

6 , 4

6.7

6.4

4.9

10.3

10.5

11.5

10.1

10.5

10.8

10.5

9.0
122 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 6-7-Effect of Running Losses on PassengerCar Emission Rates in Nonattainment Cities in 1985

Running

loss

(g/mi),—-—–— —

o

1.5

2.5

Emission rate category

Exhaust emission rates do not include the effects of current motor

vehicle inspection and maintenance (l/M) programs. We estimate

that current l/M programs reduce exhaust emissions by about 12

percent. Estimates of exhaust emission rates assume average

vehicle speeds of 28 miles per hour. Emission rates for vehicles

in California will be lower since the State maintains a summertime

gasoline volatility limit of 9.0 pounds per square inch.

SOURCE: Office of Technology Assessment, 1989.

substituted into the current emissions inventory, we

estimate that total VOC emissions in nonattainment

cities will be reduced by about 2 percent in 1994.

Level of Compliance With Existing Stationary

Source VOC Regulations

Each year, the States submit emissions data to

EPA for inclusion in the NEDS inventory. Most

States assume that all affected sources have complied fully with existing emission control rules and

regulations. However, EPA no longer believes that

rules are fully effective across all sources, all source

categories, and over time. In fact, EPA recently

proposed that States estimate their emissions based

on an assumed compliance of no more than 80

percent [7]. Therefore, VOC emissions for some

source categories in the 1985 NEDS inventory may

be much higher than reported.12

We estimate that at least 1 million tons could be

missing from 1985 stationary source totals for

nonattainment cities, assuming that existing controls

on selected stationary sources are only 80 percent as

effective as reported. *3 Therefore, total nonattainment area emissions reported in 1985 may be 10

percent too low.

Uncertainty in Hazardous Waste Treatment,

Storage, and Disposal Facility Emissions

VOC emissions data from hazardous waste TSDFs

in the 1985 NAPAP inventory were derived from

two EPA reports [30,34]. Because of discrepancies

in total TSDF emissions between these two sources

and local air pollution control agency emission

inventories, we believe that the 1.4 million tons per

year of emissions in the 1985 NAPAP inventory

could be subject to significant uncertainty. If we

assume that TSDF emissions are 50 percent higher

than what is reported in the NAPAP inventory, our

estimate of total VOC emissions in 1994 in nonattainment cities would increase by about 3 percent.

Similarly, if we assume that TSDF emissions are 50

percent lower than what is currently reported, total

emissions would decrease by about 3 percent.

Uncertainty in Organic Solvent Emissions

As figure 6-1 shows, organic solvent evaporation

sources, including surface coatings, account for

about one-quarter of total 1985 emissions in nonattainment cities. The majority of these emissions

originate from sources that emit less than 50 tons per

year. The uncertainty associated with the method

that EPA uses to estimate emissions from these

small sources (see footnote 4) may be quite significant. In particular, since many State and local

regulations requiring emission controls on these

l’2For exmple, if fie State re~~~ hat a con~ol technology on a particular source was 75 percent effwtive at KdllCing uncon~oll~ emissio~$ ‘e

may assume that the actual control efficiency was SO percent of this value. The resulting controlled emission would then be 60 percent higher than

previously reported.

13TMS estimate includes only l~ge station~ sources that reported using control equipment designed to trap ordest.roy excess emi~ions (e.g.> car~n

adsorber, incinerator).

14EPA*5 ~e~~ ~5ue5 hat ~1 tie organic ~lvent prodw~ and co~um~ n~ionwide is ernitt~ to tie a~~phem. h f~t, some Of the SOIVent

used in various processes may be captured by control devices mandated by State or local regulations. Therefore, in some cases, solvent emissions may

be less than solvent consumption.
Chapter 6--Controlling Emissions of Volatile Organic Compounds ● 123

sources may not be factored into the estimates

contained in the inventory, these emissions may be

overestimated. 14

If we assume, as a lower bound estimate, that

organic solvent emissions are 50 percent lower than

what is reported in the inventory, total VOC

emissions in nonattainment cities in 1994 would

decline about 14 percent from 10.5 million to about

9 million tons per year.

Our projections for large stationary source emissions in all source categories (including organic

solvents) could be somewhat high because we are

unable to explicitly model all of the control requirements in the Clean Air Act pertaining to new and

modified large VOC emission sources in nonattainment areas.15 However, the effect on our overall

emissions estimates is small because, as illustrated

in figure 6-4, small stationary source growth will

have a much more significant impact on future

estimates of total VOC emissions than large stationary sources. Inmost States, these more stringent new

source regulations do not apply to small sources.

Finally, it is important to recognize that all

emission inventories have an inherent, unquantified,

level of uncertainty. Given this drawback, any

interpretation of emissions inventory data, including

those presented in this report, must be made with

caution.

POTENTIAL EMISSIONS

REDUCTIONS FROM VOC

CONTROL STRATEGIES

ANALYZED BY OTA

In this section we analyze the VOC emissions

reductions from source-specific control strategies

currently being considered by the Congress and

EPA. We also show how these potential emissions

reductions compare with estimates of the overall

emissions reductions needed to attain the ozone

standard in each nonattainment city. Discussion of

the costs of these control strategies appears in the

section Costs of Control Strategies.

We are able to analyze the following sourcespecific control strategies:

●

●

●

●

●

●

●

●

●

●

adoption of ‘reasonably available control technologies” (RACT) on all existing stationary

sources for which a regulation already exists in

any State Implementation Plan;

adoption of new Control Technique Guidelines

(CTGs)—RACT-level controls for several existing stationary sources of VOC for which

EPA has not issued control guidelines and not

previously subject to regulation in any State

Implementation Plan;

emission controls on hazardous waste TSDFs;

establishment of new federally regulated controls on architectural surface coatings;

“Onboard” technology on motor vehicles to

capture gasoline vapor during refueling;

“Stage II” control devices on gas pumps to

capture gasoline vapor during motor vehicle

refueling;

inspection and maintenance (I/M) programs for

highway vehicles;

more stringent exhaust emission standards for

gasoline highway vehicles;

new Federal restrictions on gasoline volatility;

and

the use of methanol instead of gasoline as a fuel

for vehicles in centrally owned fleets in the

worst nonattainment cities.

Transportation control measures that limit motor

vehicle use are potentially important control strategies that we are unable to analyze. These measures

are discussed in more detail in chapter 7.

Throughout the analysis, emissions reductions

reported apply to the change occurring between

1985 and the relevant future year. The emissions

reductions reported in our analysis result from

currently available control technologies that we

believe can be applied in the near-term. We were

able to analyze the emissions reduction potential and

associated control costs for methods applicable to

about 85 percent of current VOC emissions. The

remaining 15 percent of VOC emissions come

primarily from stationary sources for which we

l~These regulations r~tire ~at new s~tion~ sources with the potential to emit more than 100 tons per year install the most stringent emission

controls possible and that VOC emissions from other existing sources in the area be reduced so that there will be a net decline in emissions after new

operations commence. These same control requirements apply to major modifications of existing sources that result in a VOC emissions increase of more

than 40 tons per year.
124 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

either could not find applicable control technologies

or that we could not analyze because of a lack of

suitable information. We believe that the large

majority of emission reductions possible with currently available control technologies are accounted

for in our analysis. This does not imply that

additional VOC reductions beyond those analyzed

here are not possible, but that they should not be

counted on within the next 5 to 10 years.

All control methods listed above apply to nonattainment cities. Several control methods apply

nationwide, not just in nonattainment cities, including: Federal controls on architectural surface coatings, Onboard controls, more stringent highwayvehicle emission standards and gasoline volatility

limitations.

Figure 6-8 displays our estimates of emissions

reductions resulting from each control category in

1994 and 2004, as a percentage reduction below total

1985 emissions in nonattainment cities. By 1994,

total reductions average about 34 percent in nonattainment cities. The largest reductions come from

limiting gasoline volatility and controls on hazardous waste TSDFS.

l6 The percentage reductions for

most categories are about the same in 1994 and

2004, except for Onboard controls and new highwayvehicle standards which increase because more of

the older vehicles will have been replaced by newer

ones equipped with additional controls.

Tables 6-6 through 6-8 present estimates of

emissions reductions achieved in 1994, 1999, and

2004, respectively, if the various control strategies

listed above are applied. We estimate that VOC

emissions in nonattainment cities can be reduced by

3.8 million tons per year in 1994, about 34 percent

below 1985 levels.17 Due to uncertainty in the

emissions inventory and the degree to which future

emissions can be controlled, total emissions reductions from all the control measures we analyzed in

1994 may range between 1.5 million to 5.0 million

tons per year in nonattainment cities, or about 18 to

37 percent of 1985 levels. (Emissions reduction

uncertainties are discussed in more detail in a later

section.) Because some measures are not restricted

to nonattainment areas, about 6.5 million tons per

year would be eliminated nationwide. Total emissions reductions in 2004 in nonattainment areas are

about the same as those in 1994.18

Again, we must stress that these estimates are for

emissions reductions from the additional controls

that we are able to analyze. Higher percentages may

be possible, but they should not be counted on in the

near term. In addition, the remaining 15 percent of

the inventory for which we were unable to identify

any controls may, in fact, be controllable to some

extent. Therefore, actual emissions reduction potential available from these additional controls may be

greater than represented here. Other potential control strategies, such as transportation control measures, are not included in our analysis.

Figure 6-9 displays potential emissions reductions and the percentage of emissions that remain

after all of the reductions have been accounted for in

1994 and 2004. In 1994 and 2004, after all controls

are applied, nonattainment area emissions are approximately two-thirds of the 1985 total. Most of the

remaining emissions are from small stationary

sources that emit less than 25 tons of VOCs per year.

Figure 6-10 displays a more detailed breakdown of

the nonattainment emissions inventory in 1994 after

all controls have been applied. About 35 percent of

the remaining emissions in 1994 are from surface

coatings and other organic solvent evaporation

sources. As stated earlier, we are unable to identify

controls for approximately 15 percent of the emissions inventory. Over one-third of this (about 6

percent of the entire inventory) is emissions from

small stationary sources.

Uncertainty Surrounding Estimates of

Emissions Reduction Potential

In an earlier section, we analyzed the effects of

various assumptions on our estimates of future VOC

emissions before additional controls are applied. In

IGAS we discuss in a later Wtion, due to uncertainty in TSDF emissions reported in the 1985 NEDS inventory and the degree to which they can ~

controlled, the percentage reduction for this source category may range between 3 and 8 percent of total 1985 emissions.

ITThi,s estimate includes (he 760,0tXl tons that would be eliminated as a result of the current Federal Motor Vehicle control program, which is

equivalent to a 7-percent reduction based on 1985 emissions.

18Note mat the tot~ ~~uctions me s~l~~y lower thm the sm of the component categories. This is because tie emissions r~uctions achieved by:

a) lowering gasoline volatility in combination with an I/M program, and b) combining a Stage 11 and Onboard control program, are slightly less than

instituting each one alone.
Chapter 6—Controlling Emissions of Volatile Organic Compounds ● 125

Figure 6-8-Volatile Organic Compound (VOC) Emissions Reductions in 1994 and 2004

Compared to 1985 Emissions, by Control Method

● Gasoline volatility

TSDFs

RACT

Enhanced l/M

Stage II

New CTG’s

+ Methanol fuels

* Architect. coatings

Onboard controls

New mobile std’s.

Emissions reductions in 1994

I

!- ! , , , ! I

● Gasoline volatility

TSDFs

RACT

Enhanced l/M

Stage II

New CTG’s

+ Methanol fuels

* Architect. coatings

● On board controls

● New mobile std’s.

Emissions reductions in 2004

O% 2% 4% 6% 8% 10% 12% 14% O% 2% 4% 6% 8% 10% 12% 14%

Percent reductions from 1985 emissions Percent reductions from 1985 emissions

● Emissions redutions aIso achieved in attainment areas.

+ Percent reductions onIy in those cities in which it is adopted.

See text for description of control methods.

SOURCE: Office of Technology Assessment, 1989.

this section, we analyze how some of these same

assumptions combined with the uncertainty associated with selected VOC control strategies affect our

estimates of potential emissions reductions presented above. The assumptions we tested include: 1)

the rate of gasoline evaporation from in-use highway

vehicles (“running losses”), 2) average highwayvehicle speeds, 3) level of compliance with current

and future stationary source VOC regulations, 4)

emissions from organic solvent evaporation sources,

and 5) emissions from hazardous waste TSDFs and

the degree to which they can be controlled. Table 6-9

and figure 6-11 display our estimates of uncertainty

for these particular categories.

We estimate that by applying currently available

control methods, VOC emissions in nonattainment

cities can be lowered by about 3.8 million tons per

year in 1994, or about 34 percent of 1985 emissions. 19 This total could be as low as 1.5 million or

as high as 5.0 million tons per year given the

variability in all the assumptions listed above.20 As

figure 6-11 shows, as running losses increase, total

emissions reductions also increase. Although baseline highway vehicle emissions increase with increasing estimates of running losses (see figure 6-5),

most of the additional emissions are controllable by

lowering gasoline volatility. Also, as average highway vehicle speeds decrease, some of the resulting

additional exhaust emissions are controllable

through enhanced inspection and maintenance programs. If we assume that organic solvent emissions

are 50 percent lower than what is reported in the

1985 inventory, total emissions reductions in 1994

are also slightly lowered. However, the total percent

reductions compared to 1985 emissions after all

controls are applied increase from 34 to 37 percent

19This estimate assumes running losses equsf to 1.5 grams per mile, average vehicle speeds of 28 miles per hour, and 100 percent compliance with

all current and future statiomuy source VOC regulations.

~westimate is calculated assuming: 1) no running losses from highway vehicles, 2) average vehicle speeds of 35 miles per hour, 3) the level of

compliance with current and future stationary source regulations is 80 percent, and 4) emissions from organic solvent evaporation and TSDFS are 50

percent lower than totals reported in the 1985 NAPAPinventory, and that compliance with new TSDFregulations is only 80 percent. The high estimate

assumes: 1) running losses of 2.5 grams per mile, 2) average vehicle speeds of 20 miles per hour, 3) both current and future regulatory compliance equals

100 percent, and 4) emissions from organic solvent evaporation and TSDFS are 50 percent higher than reported totals.
Table 6-6-Potential Emissions Reductions in 1994 Compared to 1985 Emissions From

(emissions reductions in 1,000 tons per year)a

Source-Specific Control Strategies

Combined Gasoline New highway

New Architectural Stage II volatility Enhanced vehicle emission Methanol (Existing All

RACT CTGs TSDFs coatings Onboard Stage II & Onboard controlb

I/M standards fuelsc

controls)dcontrolse

Nonattainment cities by

design value category

(in ppm o3)

0.13-0.14 . . . . . . . . 120 29 280 15 0 64 64 430 68 0 0 220 1,200

0,15-0.17 . . . . . . . 230 46 330 23 0 100 l00 730 100 0 0 360 1,900

0.18-0.26 ... . . . . . 73 11 31 8 0 31 31 190 31 0 8 99 480

>0.26 . . . . ... .. . 15 15 3 0 0 0 0 0 22 0 6 85 150

Total (nonattainment) 440 100 640 47 0 200 200 1,300 220 0 14 760 3,800

Attainment areas . 0 0 0 61 0 0 0 1,900 0 0 0 680 2,700

Total . . . . . . . . . . . 440 100 640 110 0 200 200 3,300 220 0 14 1,400 6,500

aTotals are rourded.

bEs~ma~s are eWi~ent annuai reductions, Actual reductions are required only 5 months out of the year.

‘%esa estimates assume the use of fuel that is 85 parant methanol and 15 percent gasoline in Iightduty cars and trucks in fleets of 10 or more.

dEmi~ions r~uctjo~ from uw existing Federal k#OtOr Vehicle tintrol pr%)r~.

e. Ail ~n&ol~II ,Mlu&~ RACT, ~w GTGs, TSDFs, ar~cmrai ~ati~~, ~m~ned s~% II ad Otiard, g=l,ne vo~hll~ con~ol~, en~~ I/M, new h,ghway.ve~cle emission s~nbrds, metianol fuels, and exlstl~ COrltrOIS.

Note that total reducdons are slighffy lower than the sum of each component category This IS because the reductkms achieved by lowering gasoline volatility in combination with an enhanced l/M program, a combined Staga II

and Onboard program, and methanol fuels, are slighity lower than instituting each ow alone

Strategy Descriptions

RACT = “Reasonable &allable Control Technology” on all exlsbng stationary sources that emit more than 25 tons per year of VOC.

New CTGS = new Control Tecfwuqua Guidelines for existing stationary sources that emit more than 25 tam per year of VOC.

TSDFS = controls on hazardous waste treatment, storage, and disposal faalities.

Federal controls on architectural costings.

Onboard controls on motor vehicles to capture gasoline vapor during refueling.

Stage Ii control devices on gas pumps to capture gasotine vapor during motor vehicle refueling.

Gasoline volatility controls which limit the rate of gasoline evaporation,

Enhanced inspection and tnabtenancs (IrM) programs for cars and light-duty trutis.

New highway-vehkleenQeaion atamlerde for pas-r cars and light-duty gasoline trucks

Methanol fusis as a substitute for gasohne as a motor vehicle fuel.

SOURCE: Office of Twhnology Assessment, 1989.
Table 6-7—Potential Emissions Reductions in 1999 Compared to 1985 Emissions From Source-Specific Control Strategies

(emissions reductions in 1,000 tons per year)”

Combined Gasoline New highway

New Architectural Stage II volatility Enhanced vehicle emission Methanol (Existing All

RACT CTGs TSDFs coatings Onboard Stage II & Onboard controlb

l/M standards fuelsc

cortrols)d

controls

Nonattainment cities by

design value category

(in ppm o3)

0.13-0.14 . . . . . . . . . 120 29 320 16 48 65 69 450 54 20 0 210 1,300

0.15-0.17 240 48 380 24 85 110 120 770 80 36 0 320 2,000

0,18-0.26 . . . . . . . . 75 12 36 9 28 33 38 200 25 12 8 90 510

>0.26 . . . . . . . . . 17 15 4 0 19 0 19 0 17 9 7 88 180

Total (nonattainment) . . 450 100 730 49 180 210 240 1,400 180 77 15 710 4,000

Attainment areas . . . . . . 0 0 0 65 190 0 190 2,000 0 100 0 450 2,900

Total . . . . . . . . . . 450 100 730 110 370 210 440 3,400 180 180 15 1,200 6,900

aTotais are rounded.

bE~Omate~ are ~Wivalenl annual reductions ktual reductions are required only 5 months out of the War,

~hese estimates assume the use of fuel that IS 85 percent methanol and 15 percent gasoline in Iightduty cars and tnJcks m ffeets of 10 or more.

dEmi~ions reductions from the existing Federal Motor Vehicle Control program.

e,,All ~n~ls,, ,Wl~s RACT, -CTG5, TSDFs, Fe&rat ~n~ols on archit~~ral ~tings, ~m~ned s-[1 and on~p-J, gasoli~ vo~tifj~ ~nfyols, enha~ I/M, new high s~ndards, methanol fuats, and existing COrltl’cds.

Note that total reductiofrs are slightfy lower than the sum of each compment category. This is because the reductions achieved by lowering gasoline volatility m combination with an enhanced l/M program, a combmed Staga II

and Onboard program, and methanol fuels, are sightly lower than instituting each one afone.

Strategy Descriptions

RACT = “Reasonable Adalie Control Technology” on all existing stationary sources that emit more than 25 tons ~r year of VOC.

New CTGS = new Control Technique Guidelines for existing stationary sources that ermt more than 25 tons per year of VOC.

TSDFS = controls on hazardous waste traatment. storage, and disposal faalities

Fadsrsl controls on architectural costings.

Onboard controls on motor vehicles to capture gasoline vapor during refueling.

Stage If control devices on gas pumps to capture gasoline vapor during motor vehicle refueling.

Gasolhte volatility controls which limit the rate of gasoline evaporation.

Enhanced inspection and rdntensnce (UN) programs for cars and hghtduty trucks

New highwsy-vehkfe emksion stendsrds for passenger cars and hghtduty gasolmo trucks.

Methanol fuels as a substitute for gasoline as a motor vehicle fuel.

SOURCE’ Office of Technology Assessment, 1989.
Table 6-8-Potential Emissions Reductions in 2004 Compared to 1985 Emissions From Source-Specific Control Strategies

(emissions reductions in 1,000 tons per year)”

Combined Gasoline New highway

New Architectural Stage II volatility Enhanced vehicle emission Methanol (Existing All

RACT CTGs TSDFs coatings Onboard Stage II & Onboard controlb

I/M standards fuelsc

controls)d Controls e

Nonattainment cities by

design value category

(in ppm O3

0.13-0.14 . . . . . . . . . 130 30 360 16 68 70 74 470 53 37 0 56 1,200

0.15-0.17 . . . . . . . . . 250 49 440 25 120 120 130 820 80 68 0 40 2,000

0.18-0.26 . . . . . . . . . 78 12 42 9 40 37 43 210 25 22 9 4 460

> 0.26 . . . . . . . . . . . . 19 16 4 0 27 0 27 0 17 17 7 39 150

Total (nonattainment) . . 470 110 840 50 260 220 280 1,500 170 140 16 140 3,700

Attainment areas ., . . . . 0 0 0 68 280 0 280 2,200 0 190 0 310 3,100

Total . . . . . . . . . . . . . 470 110 840 120 530 220 550 3,700 170 330 16 450 6,800

aTotals are rounded.

bEstima@s are ~iv~ent amual r-aductions. Actual reductions are required only 5 tis out of tW ~ar.

~hese estimalas assume the use of fuel that is 85 percat methanol and 15 percent gasoline in Iightduty cars and trucks in fleets of 10 or more.

dEmi@ons rsdu~om from w exi~ng Federal Motor Vehicle Control PrOgrSm.

ef,All ~n~ol~., i~~s RAcT, _CTGs, TSDFs, Federel con~ls on architec~~l -s, com~~ s-II ad ~rd, ~soli~ vohtili~ ~n~ls, anbncad I/M, m high S&lfldSrdS, methanol fuels, and eXistirlg tXmtdS.

Note that total reductions are siightfy iower than ttre sum of each component category. This is because the reductions achieved by lowering gasoline volatility in combination with an enhanced l/M program, a combined Staga II

and Onboard program, and mefhanoi fuels, are slghtty lower than instituting each one alone.

Strategy Descriptions

RACT = “Reasonable Aailat#e Control Technology” on all existing stationary sources that emit more than 25 tons par par of VOC.

Maw CTGs . new tlrntrol Technique Gudelines for ex@ing stationary sources that emit more than 25 tons per year of VOC.

TSDFS = mntrols on hazardous waste treatment, storage, and disposal faalities.

Federal conbole on architectursf coaUngs.

Orboard controls on motor vehicies to capture gasoline v-r during refueling.

Stage II control devices on gas pumps to capture gasoline vapor during motor veticfe refueling.

Gasoline volatility controfs which limit the rate of gasoline evaporation.

Enhanced i~tlon and tnalntenmtce (W) programs for cars and Iightduty trucks.

New highway-vshkle ernlssion s!andarda for passenger cars and Iighrduty gasoline trucks.

Methanol fusfs as a substitute for gasoline as a motor vehicle fuel.

SOURCE: office of Technology Assessment, 1989.
Chapter 6--Controlling Emissions of Volatile Organic Compounds ● 129

Figure 6-9-Potential Volatile Organic Compound (VOC) Emissions Reductions and Remaining

Emissions in 1904 and 2004 as a Percentage of 1985 Emissions in Nonattainment Cities

Emissions reductions and remaining emissions in 1994

● Methanol fuels 0.2%

Emissions reductions and remaining emissions in 2004

Expected reductions withRemaining mobile 19.8% out further control 1.2%

● Methanol fuels 0.1%

● Average percent reduction in cities in which it is required equals about 0.6 percent .

The pulled-out slices represent emissions that can be eliminated by each control method. The three connected slices represent emissions

that remain after ail control methods are applied. The category ‘Expected Reductions without Further Control” represents reductions

achieved from the existing Federal Motor Vehicle Control Program. “Remaining Small Stationary” represents emissions from stationary

sources that emit less than 50 tons per year of VOC. See text for description of control methods.

SOURCE: Office of Technology Assessment, 1989.

Figure 6-10—Volatile Organic Compound (VOC)

Emissions in Nonattainment Cities in 1994, by

Source Category, After All Additional Control

Methods Are Applied

Percent of 1994 VOC emissions

0% 1 0% 20% 30% 40%

Mobile sources

Organic solvent evap

Surface coating

Petroleum industry

Gasoline marketing

TSDFs

Other industries

Chemical manufact.

Solid waste disposal

Nonresid. fuel comb.

Miscellaneous

L

Highway vehicles Air, rail, marine

rce size

Total = 7.5 million tons/year

Stationary sources that emit more than 50 tons per year of VOC

are included in the “Large” categories. (See figure 6-1 for 1985

emissions in nonattainment cities before additional controls

applied.)

SOURCE: Offce of Tehnology Assessment, 1989.

in 1994. Percentage reductions increase because a

large fraction of organic solvent use was not

controllable given the measures we analyzed. Therefore lowering solvent emissions by 50 percent

lowered total “baseline” emissions in 1985 while

not changing future emissions reductions by much.

The following subsections summarize the emissions reduction potential of each individual control

strategy.

Reasonably Available Control Technologies

(RACT) on All Stationary Sources

The Clean Air Act requires that each State adopt,

as part of its State Implementation Plan (SIP),

‘‘reasonably available control technologies” (RACT)

regulations for existing stationary sources of VOC in

nonattainment cities. In our analysis, we have

applied RACT-level controls on 40 stationary

source categories for which a regulation already

exists in any SIP. These sources include petroleum

refining, certain types of chemical manufacturing,

paper surface coating, automobile surface coating,

gasoline terminals, service stations, and drycleaning.
130 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 6—Estimate of Uncertainty in VOC

Emissions Reductions After All Controls Are

Applied in Nonattainment Cities In 1094

Figure 6-n—Uncertainty in VOC Emissions

Reductions From All Additional Controls In

Nonattainment Cities in 1994

Total emissions Percent of

reductions 1985

(million tons/year) emissions

Running losses (grams/mile)

o 3.2

1.5 a ‘.”. ”.”,”.”.”.”.”.”,”.”.”.”.; : : : : 3.8

2.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2

Average highway-vehicle speeds (miles/hour)

20 . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2

28° . . . . . . . . . . . . . . . . . . . . . . . . . . 3.8

35 . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6

Level of compliance with current and/or

future stationary source regulations

Current-100%, Future—100%a . . . 3.8

Current-80%, Future-80% . . . . . 3.6

Hazardous waste treatment,

storage and disposal facility

emissions 1uncertain~

Low . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0

Medium a . . . . . . . . . . . . . . . . . . . . . 3.4

High . . . . . . . . . . . . . . . . . . . . . . . . . . 3.7

Organic solvent emissions uncertainty

Low. . . . . . . . . . . . . . . . . . . . . . . . . . 3.6

Combined uncertainty

Low . . . . . . . . . . . . . . . . . . . . . . . . . 1.5

Medium a . . . . . . . . . . . . . . . . . . . . . 3.8

Highd . . . . . . . . . . . . . . . . . . . . . . . . 5.0

320/o

340/0

350/0

3570

3 4 %

330/0

3 4 %

2 6 %

31%

35%

38%

37%

18%

34%

37%

a~s estima~ wss used Ihrougtwut our analysis.

%-10 low estimate reprwanta SO percent compliance with future regulations assuming

preumfrol emiaabns which are 50 percent of repwtad estimates In the current

emissions inventory. Tha medium estimate rapmaants 100 percent compiianoa on 100

percxmt of reported emissions. High estimate represents 100 percent compliance on

150 parosnt of reported emissions.

c~es~mam is ~ICUISItSd wimut any running losses, with avamga vehioie es of

35 miles per hour, and assuming the 104 of complianoa WWI cumsnt, existing

stationary aourw regulations is SO percent, and the bw estimate for both hazardous

waste treatment, stomga and disposal faoilltfes, and o~nic solvant emlaaions.

dT~ N@ esti~~ a~mes running losses total 2.5 grams per mile, average Vehkle

speeds of 20 miles per hour, current and future regulatory compliance equals 100

percent and 100 percent, respectively, the high estimate for TSDFS, and organic

solvent emisabns as reported in the NAPAP inventory.

SOURCE: Offka of Ttinology Assessment, 19S9.

The sources of our estimates of the percentage

reduction in VOC emissions from RACT and of the

data we used to calculate the cost of these controls,

are reports prepared for EPA by Alliance Technologies Corp. [3] and E.H. Pechan & Associates, Inc.

[4]. EPA made available to us a series of memos

detailing the methods used, technical references, and

economic assumptions used by Alliance, from

which our estimates are drawn. A complete list of

our control cost assumptions, including control

efficiencies and associated costs for each source

type, is included in an appendix.

Currently, many States require RACT-level controls only on existing sources which emit more than

Uncertainty category:

Running losses

Average speeds

Level of compliance

Solvent emissions

TSDF emissions

Combined uncertainty

I

40 ”/0

Percent reduction from 1985 emissions

The following assumptions were analyzed: 1) the rate of gasoline

evaporation from in-use highway vehicles (“running losses”), 2)

average highway-vehicle speeds, 3) level of compliance with

current and future stationary source VOC control regulations, 4)

emissions from organic solvent evaporation sources, and 5)

emissions from hazardous waste treatment, storage, and disposal

facilities (TSDFs).

SOURCE: Office of Technology Assessment, 1989.

100 tons of VOC per year in nonattainment areas.

We estimated the emissions reductions achievable

through RACT-level regulations by simulating controls on all existing stationary sources that emit more

than 25 tons of VOCs per year in those nonattainment cities that did not have an existing RACT

regulation for a particular source category in their

SIP as of 1985. States are only required to provide

EPA with emissions data from individual sources

which emit more than 50 tons per year; emissions

from sources less than 50 tons per year are calculated

indirectly by EPA and then aggregated at the county

level. Therefore, we had to make assumptions

regarding the fraction of inventory that originates

from sources which emit between 25 and 50 tons per

year.

We estimate that applying RACT-level controls

to all sources in nonattainment cities would lower

VOC emissions by approximately 440,000 tons per

year in 1994, representing a 4-percent decline based

on 1985 levels. Reductions increase slightly over
Chapter 6-Controlling Emissions of Volatile Organic Compounds • 131

time, with total reductions in nonattainment cities in

2004 estimated to be about 470,000 tons per year,

from 1985 levels.

Adoption of New “Control Technique

Guidelines” (CTGs)

In the previous subsection, we analyzed the

emissions reduction potential of applying all RACTlevel regulations currently in place in any State to all

existing stationary VOC sources emitting more than

25 tons per year of VOC. Many States now are

urging EPA to develop new RACT guidelines for

several additional stationary source categories. These

would be issued as “Control Technique Guidelines” (CTGs). Like the RACT controls analyzed in

the previous section, nonattainment cities would be

required to adopt these ‘new” RACT regulations on

all existing stationary VOC sources that emit more

than 25 tons of VOCs per year.

We are able to analyze the emission reduction

potential from controls on: 1) wood furniture coating, 2) autobody refinishing, 3) plastic parts coating,

4) coke oven byproduct plants, 5) publicly owned

treatment works, and 6) bakeries. (Hazardous waste

treatment, storage, and disposal facilities is another

category, but is discussed in the next subsection.)

These six categories represent about 2 percent of the

entire VOC inventory. The control efficiency assumptions we used for these sources are listed in an

appendix.

Emissions reductions from applying RACT-level

controls to these categories are estimated to be about

100,000 tons per year in 1994, or about a l-percent

reduction based on 1985 emissions. This annual

total is expected to increase by a few thousand tons

in 2004.

Controls on Hazardous Waste Treatment,

Storage, and Disposal Facilities

Hazardous waste TSDFs have recently been

recognized as potentially significant sources of

VOC, accounting for about 1.4 million tons per year,

nationwide, and about 580,000 ton per year in

nonattainment areas in 1985 (or about 6 percent of

the total emissions) [34]. More recent data has

shown that the nationwide total could be as high as

2 million tons per year [30]. By 2004, nonattainment

area TSDF emissions are about 930 million tons per

year. These totals are not based on emissions data

from individual facilities, but are estimated indirectly on a nationwide basis and, therefore, are

subject to potentially large, unquantified uncertainties.

We estimate that reasonably available controls on

TSDFs can eliminate approximately 640,000 tons

per year of VOCs in nonattainment cities in 1994, or

about 6 percent of 1985 emissions. As mentioned

earlier, if we account for potential uncertainty in

reported TSDF emissions, the emissions reduction

potential from this category may range between 3.1

and 8.4 percent from 1985 levels. Control technologies such as covers placed over TSDFs together with

add-on emission control devices (e.g., carbon adsorbers, incinerators, etc.) and/or process modifications can reduce VOC emissions by about 90 percent

[30].

Federal Controls on Architectural

Surface Coatings

Many small sources of VOCs do not lend themselves to traditional forms of regulation (e.g.,

application of an add-on control device to reduce

emissions). These sources individually emit small

amounts of VOCs, but when aggregated over a

region, they collectively contribute a significant

portion of the VOC inventory. Such sources include

consumer and commercial solvents, architectural

surface coatings, agricultural pesticides, adhesives,

and others. Although several categories have been

proposed as candidates for new Federal controls in

recent bills, we are only able to analyze architectural

surface coatings. This category represents about 2

percent of the NAPAP emissions inventory as

adjusted by OTA.

EPA control efficiency estimates range between

23 percent [25] and 65 percent [26] for architectural

surface coatings. For our analysis, we assume a 25

percent control efficiency. Since this category would

be federally regulated, emissions reductions would

occur nationwide (in nonattainment and attainment

areas).

In 1994, federally regulated controls on architectural surface coatings are estimated to reduce VOC

emissions by 47,000 tons per year in nonattainment
132 . Catching Our Breath: Next Steps for Reducing Urban Ozone

cities, and about 61,000 tons year in attainment

areas. By 2004 in nonattainment cities, emissions

reductions will reach about 50,000 tons per year.

Consumer and commercial products are also a

potentially large source of VOC emissions, but

because control technology information is lacking

for this category we have excluded it from our

overall emissions reduction potential and cost analyses. According to the 1985 NAPAP inventory,

emissions from consumer and commercial products

are about 860,000 tons per year in nonattainment

cities, representing about 8 percent of total emissions. We must stress that the emission estimates for

this category are subject to potentially large uncertainties. It is interesting to note that, on a per-capita

basis, the 1985 NAPAP inventory contains about

two times more VOC emissions from consumer

products than local California emissions inventories

such as the South Coast air basin [18].

Also, the degree to which VOCs can be eliminated

from consumer products is not well understood at

the present time. However, the South Coast Air

Quality Management District estimates that VOC

emissions from these products can be reduced by

about 50 percent in the year 2000 through a ban of

aerosols products containing VOCs and reformulation of other non-aerosol products [19]. Controlling

emissions from consumer products is discussed

further in chapter 7.

Controls on Gasoline Emissions From

Vehicle Refueling

Gasoline vapors that escape from vehicle fuel

tanks during refilling can be controlled by two

fundamentally different methods. One method involves installation of a vapor recovery system on

service station gasoline pumps, referred to as ‘Stage

II” vapor recovery. The other method relies on a

control device installed on each vehicle as part of the

emission control system (referred to as “Onboard”

controls) .21 Stage II programs can become fully

effective within a few years. The emissions reduction benefits of an Onboard control program gradually increase over time and achieve full potential

after about 10 years, when most older, non-equipped

vehicles have been replaced. In the following

subsections, we describe the emissions reduction

potential of each program individually, and in

combination.

“Onboard” Refueling Controls on

Motor Vehicles

For this analysis, we assume that Onboard controls are required on all new gasoline vehicles

starting in 1994 and that by 2004, most gasoline

vehicles on the road will be equipped with Onboard

controls due to fleet turnover. Assumptions regarding fleet turnover and control efficiencies are

obtained from EPA’s recent gas-marketing regulatory impact analysis [28].22 Because these controls

apply to all new gasoline vehicles, emissions reductions will occur nationwide (in both nonattainment

and attainment areas).

We estimate that in 1999, Onboard controls will

eliminate about 180,000 tons per year of VOC

emissions in nonattainment cities, and 370,000 tons

per year nationwide, representing about a 1.6-

percent reduction, compared to 1985 emissions. In

2004, total nationwide VOC reductions increase to

about 530,000 tons per year, or about a 2. l-percent

reduction based on 1985 levels. These results reflect

only Onboard controls for vehicle refueling and do

not include reductions from additional Stage II

controls. An analysis of a combined Onboard and

Stage II vapor recovery program is presented later.

"Stage II" Refueling Vapor Recovery

Unlike Onboard controls, which are applied

nationwide, we assume Stage 11 controls are only

installed in nonattainment cities. Congressional

proposals have generally limited the Stage 11 requirement to these areas. Emissions reductions in

1994 and 2004 are estimated to be about 200,000 and

220,000 tons per year, respectively, which amounts

to about a 2-percent reduction in both 1994 and

2004, relative to 1985 emissions. We assume a

control efficiency of 79 percent, which represents

21There 15 a contin~ng debate between EPA, industry, and the National Highway Transportation Safety Administration, over possible safety concerns

and in-use feasibility of Onboard controls.

zzwe ~sme that the ~rcent reduction in refueling emissions from use of Onbwwd controls, as derived from EPA’s ga$ marketing analysis [28, P.

3-18], is 28 percent, 58 percent, and 76 percent in 1994,1999, and 2004, respectively. EPA estimates that Onboard controls can reduce refueling emissions

by about 93 percent [28, p. 2-9].
Chapter 6---Controliing Emissions of Volatile Organic Compounds ● 133

EPA’s average estimate for a Stage II program with

annual enforcement [28].23 Note that the percent

emissions reductions ultimately achievable with

Stage II and Onboard controls are roughly comparable. However, in 1999, Onboard is less effective than

Stage II because complete fleet turnover will not

have occurred yet.

Combined Stage II and Onboard Controls

If both Stage II and Onboard controls are adopted,

the percent emissions reductions in nonattainment

cities in 1999 and 2004 are estimated to be about 2

and 3 percent, respectively, relative to 1985 emissions. As the reduction benefits from Onboard

controls increase through time (due to fleet turnover), the benefits from the combined strategy is

only slightly greater than either method above. We

assume a combined control efficiency of about 83

percent derived from EPA data [28].

Enhanced Motor Vehicle Inspection and

Maintenance (I/M) Programs

For this analysis, we define an enhanced motor

vehicle inspection and maintenance (I/M) program

as one including all requirements of the existing

California I/M program (among the most stringent in

the Nation), plus the following improvements:

annual testing for all pollutants (VOC, NOX, carbon

monoxide, and particulate) on all vehicles, improved visual inspection of the emissions control

system to detect tampering and other functional

defects, and a repair cost ceiling of $500 per year.24

We have assumed that enhanced I/M programs are

instituted in all nonattainment areas.

For cities without an existing I/M program as of

1987, the full emission reduction benefit of an

enhanced I/M program is applied. If a city already

had an I/M program as of 1987, then an incremental

emission reduction benefit, representing the reductions achieved by going from an existing to an

enhanced program, is applied. Estimates of the

percentage reduction in emissions are taken from

Sierra Research, Inc. [15]. We assume that the VOC

emission reduction potential of existing I/M programs is about 12 percent. The full benefit of

enhanced programs is about 29 percent, while the

incremental benefit gained by switching from an

existing to an enhanced program is about 17 percent.

These control benefits apply only to the exhaust

fraction of light-duty car and truck emissions, and do

not affect emissions resulting from the gasoline

evaporation.

We estimate that enhanced I/M programs in

nonattainment cities will reduce VOC emissions by

about 220,000 tons per year in 1994 and by 170,000

tons per year in 2004.25 This represents about a 2-and

l-percent reduction in 1994 and 2004, respectively,

based on 1985 emissions. The emissions reduction

benefits decline through time because average fleetwide exhaust emission rates also decline due the

benefits from the existing Federal Motor Vehicle

Control Program.

More Stringent Highway-Vehicle

Emission Standards

This analysis includes the VOC emissions reduction potential of instituting more stringent tailpipe

controls on new passenger cars and light-duty,

gasoline-fueled trucks. The standards we analyzed

were determined to be the most stringent technologically feasible, given currently “available” control

technology, according to Sierra Research [15].26

Sierra Research assumes that these standards can be

met during 50,000 miles of controlled test driving

(certification testing) for passenger cars, and 120,000

miles for light-duty trucks; however, VOC emission

Zsunder his scen~o, s~tions which pump less than 10,000 gallons per month are not required to install cOntrOls.

zd~cord~g t. Sicma Rewmch, ~c. [ 16], if expnsive major emission control systems were covered by a lo-ye~/loo,()()@mile IIl~UfaChiRr’S

warranty, the repair cost ceiling could be lowered to $200 per vehicle per year.

zSNi~ogen oxides, ~M~n ~onoxidc, ad p~culate emissions reduction benefits me ~so g~ne.d by~progr~s. c~bon monoxide ad piUliCdtite

reduction benefits are not calculated in our analysis; NOX benefits are calculated in a later chapter.

26The new emission s~~dsused in o~ ~~ysiswe ~ follows: (in gr~s of po~u~t emitted per mile Uavelti [g/mile] fOr 11011 -Illdl~t2

hydrocarbons [NMHC] and NOX)

Passenger cars- NMHC: 0.25 g/mile; NOX: 0.4 @mile

Light-duty gasoline trucks (by truck weight+

(less than 3,750 Ibs) NMHC: 0.34 g/mile; NOX: 0.46 @mile

(3,751 to 6,000 lbs) NMHC: 0.43 ghile; NOX: 0.80 @mile

(6,000 to 8,500 lbs) NMHC: 0.55 g/mile; NOX: 1.15 #mile
134 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

rates after 50,000 miles (for cars) and 120,000 miles

(for trucks) of actual use by vehicle owners would

likely exceed these standards. We assume that new

standards go into effect in 1994 for both passenger

cars and light-duty trucks.

We estimate that in 1999 new highway vehicle

standards reduce VOC emissions by about 77,000

tons per year in nonattainment cities and 180,000

tons per year, nationwide, or about 0.7 percent

compared to 1985 emissions. By 2004, reductions

increase to about 140,000 tons per year in nonattainment cities and 330,000 tons per year, nationwide, or

about 1.3 percent compared to 1985 levels. The

slight increase in emissions reductions during this

period is due to the gradual replacement of older

vehicles with newer, cleaner ones.

As mentioned above, we assumed that the 0.25

gram-per-mile hydrocarbon emission standard for

new passenger cars will be met during 50,000 miles

of certification testing. Some congressional proposals have called for this standard to be met during

50,000 miles of actual driving use. If this more

stringent ‘‘in-use” requirement was actually

achieved by passenger cars, total emissions reductions from all new emission standards would increase from 140,000 to 210,000 tons per year in

nonattainment cities in 2004. If passenger cars were

required to meet a 0.25 gram-per-mile “in-use”

standard during 100,000 miles of actual driving, if

achieved, total reductions from new emission standards would increase to 250,000 tons per year in

nonattainment cities in 2004.

Limits on Gasoline Volatility

Lowering gasoline volatility (i.e., lowering the

rate of evaporation) reduces emissions during refueling at the gas pump and during refilling of underground gasoline storage tanks, reduces evaporative

emissions from vehicle fuel systems, and lowers

exhaust emission rates. For this analysis, we assume

that gasoline volatility is reduced to 9 pounds per

square inch (psi) Reid Vapor Pressure (RVP) during

the 5-month summertime period when ozone concentrations most often exceed the standard. Emissions reductions would occur only during the

summer period and not year-round. However, for the

purposes of comparison with other VOC control

methods which are in effect over the entire year, we

have scaled up seasonal emissions reductions fromI

volatility control to an equivalent annual estimate.

This scaled-up estimate should not be viewed as a

year-round estimate, but as an equivalent annual

tons-per-year estimate based on the highway-vehicle

evaporative and running loss emissions which would

occur on a typical summertime day in a nonattainment city. Data for the analysis comes from EPA

[27].

We estimate that limiting gasoline volatility

would lower VOC emissions in 1994 by about 12

percent in nonattainment cities, and about 14 percent

in attainment areas. Equivalent annual emissions

reductions in 1994 are about 3.3 million tons per

year, nationwide, of which about 1.3 million tons per

year are eliminated in nonattainment cities. Again,

these estimates are based on highway-vehicle evaporative emissions occurring on a typical summertime

day, when ozone concentrations exceed the standard, not on an average annual day.

The above estimates assume that gasoline evaporation from in-use highway vehicles (running losses)

averages about 1.5 grams per mile on warm summer

days with gasoline volatility at levels prevailing

during 1985. It does not take into account the

recently promulgated regulation requiring volatility

limits of 10.5 psi during the summer months.

Given the uncertainty in running loss estimates,

the percentage reduction, in 1994, due to gasoline

volatility limits in nonattainment cities could be as

low as 6 percent (assuming running losses equal

zero) or as high as 16 percent (running loss equal to

2.5 grams per mile). We have assumed that running

loss emissions can be reduced by 65 percent if

gasoline volatility is reduced from levels prevailing

in 1985 to 9.0 psi based on data from EPA’s

MOBILE 4 model.

Methanol Fuels for Motor Vehicle Vehicles in

the Worst Nonattainment Cities

Methanol vehicles used within the next 10 years

will probably operate on blends of methanol and

gasoline (probably 85 percent methanol and 15

percent gasoline, by volume). EPA estimates that

both exhaust and evaporative emission rates for

light-duty vehicles operated on blends of methanol
Chapter Controlling Emissions of Volatile Organic Compounds ● 135

and gasoline would effectively27 be about 30 percent

lower than for gasoline vehicles meeting current

standards and operated on low-volatility gasoline (9

psi) [1,29]. Beyond the next 10 years, if vehicles can

be produced to operate on 100 percent (straight)

methanol and they are designed and adjusted to

generate minimal VOC emissions, EPA suggests

that rates for both exhaust and evaporative emissions

could effectively be reduced by up to 90 percent [1 ].

However, significant advances in vehicle technology would be required to achieve such low VOC

emission rates. EPA’s proposed regulations for

light-duty methanol vehicles would apply the same

carbon monoxide and nitrogen oxides emissions

standards for methanol as for gasoline [9], so no

reductions in these pollutants would be expected.

In our analysis, we consider the use of alternative

fuels in fleets of 10 or more vehicles, in areas with

ozone design values of 0.18 ppm or higher. In 1986,

6 million cars and 2 million light-duty trucks in

centrally owned fleets of 10 or more vehicles

accounted for about 13 percent of light-duty vehiclemiles-traveled nationwide [2].28 Use in fleets is

expected to be easier to promote or require than

general use, because a less extensive network of

refueling stations would be required. Because methanol is likely to be expensive, at least in the near term,

we assume that its use would be limited to those

areas with the most severe ozone problems.

For areas with design values of 0.18 ppm or

higher, if 30-percent reductions in VOC emission

rates were obtained, we estimate that year-round

operation of fleet vehicles on methanol would be

equivalent to total annual reductions of VOC emissions of about 14 thousand tons per year in 1994, or

about 0.5 percent of total 1985 emissions in these

areas. An upper bound on the level of reductions that

could ultimately be achieved with methanol is about

53,000 tons per year29 in 1994, or about 2 percent of

1985 emissions in cities with design values of 0.18

ppm or higher. This estimate assumes that emission

rates are reduced by 90 percent using straight

methanol.

Use of methanol or compressed natural gas

(CNG) as fuel for light-duty vehicles is discussed in

more detail in a later chapter.

COMPARISON OF POTENTIAL

EMISSIONS REDUCTIONS AND

REDUCTIONS NEEDED TO

ATTAIN THE OZONE STANDARD

Without Additional Controls

The graph on the left-hand side of figure 6-12

shows the variability among nonattainment cities in

the changes in VOC emissions predicted to occur

between 1985 and 1994, assuming no change in

State and EPA regulations in place as of 1987. For

each city, at its design value, we have graphed the

percentage change in emissions from the 1985

baseline expected to occur due to the regulations

included in State Implementation Plans (SIP) as of

1985, the current Federal Motor Vehicle Control

Program, and population and economic growth.

We have graphed cities by design value because

it is a reasonable predictor of the emissions reductions needed to reach the standard. The graph also

displays estimates of the reductions needed to reach

the ozone standard of 0.12 ppm, as a function of

design value. As discussed in chapter 5, the two

curves arching across the graph represent high and

low estimates of the percentage reduction in emissions that typical cities falling within a given range

of design values need to attain the standard. The five

vertical bars to the right of the two curves represent

estimates of emissions reduction requirements for

individual cities with design values above 0.19 ppm.

We have omitted three cities with design values

greater than 0.26 ppm (all three are in southern

California). As stated in chapter 5, control require27Un&r EPA’S propo~ regulations [9] for methanol-fueled vehicles, total VOC emissions, i.e. the total mass of carbon emitted, would h the sme

as with gasoline, but the emissions would ‘‘effectively” be lower because methanol produces less ozone than the VOCS emitted with gasoline.

zgCen~~ly own~ flw~ Mcomt for such a large fr~tion of VMT because on average, fleet vehicles are driven over two times as many miles in a

year as the vehicles in general use.

Z5’R~uctlons in Vehicle refiel~g from tie ~of s~~ght me~~ol accounts for about 22 prcent of MS tow. R~uctions in vehicle exhaust ad

evaporative emissions account for the remaining 78 percent. No reductions in refueling emissions would be anticipated if gasoline were displaced by

a methanol/gasoline blend. This is assuming that refueling controls would have been in place anyway, and that reductions in VOC emissions from

refueling are proportional to the amount of gasoline displaced.
136 . Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 6-12-Volatile Organic Compound (VOC) Emissions Reductions Between 1985 and 1994,

Assuming No Change From 1987 VOC Regulations and Assuming Additional Volatility Controls

No additional controls

1 .

0,12 0.14 0.16 0.18 0.20 0.22 0.24 0.26 0.12 0.14 0.16 0.18 0.20 0.22 0.24 0.26

1983-85 design values (ppm ozone) 1983-85 design values (ppm ozone)

Each square represents a nonattainment city. In the chart on the left, the Iocation on the graph shows the VOC emissions reductions (as

a percentage of 1985 levels) by 1994 given the local, State, and federal VOC regulations in place in 1987. The chart on the right shows

the reductions each city can achieve by 1994 if gasoline volatility limits are adopted in addition to the local, State, and Federal VOC

regulations in place as of 1987. Cities below the “O%” line experience a net increase in emissions between 1985 and 1994. The horizontal

axis shows the “design value,” a measure of peak ozone concentration used to determine the emissions reductions needed to attain the

ozone standard. The two curves arching across the graph and vertical bars to the right of the curves show the upper and lower bounds of

VOC reductions needed to attain the standard. The vertical bars show estimated control requirements explicitly for major urban areas with

area-wide design values greater than 0.19 ppm.

SOURCE: Office of Technology Assessment, 1989.

ments for individual nonattainment areas could

actually fall outside of the ranges presented here. In

particular, areas with large contributions from transported pollutants or vegetative VOC emissions are

not well represented. Moreover, the model used in

the calculations is intended to provide only rough

estimates of control requirements, based on a

minimal amount of input information,

Summarizing how to read figure 6-12, the squares

show the change in VOC emission in each nonattainment city projected for 1994 (assuming existing

regulations) and the curves and vertical bars show

the upper and lower bounds of the change needed, in

each city, to attain the ozone standard by 1994.

As the graph on the left-hand side of figure 6-12

illustrates, the change in VOC emissions that would

occur by 1994 without further control ranges from an

increase of about 20 percent to a reduction of about

15 percent. Emissions in most cities are expected to

decline, due to the replacement of today’s cars with

lower emitting, new cars. However, emissions may

increase in some cities that are expected to experience high population growth.

Note that without additional controls only a few

cities with design values of 0.13 ppm maybe able to

attain the ozone standard by 1994. Most nonattainment areas will not be much closer to meeting the

standard than they are today.

With Additional Gasoline Volatility

Limitations

In the previous subsection, we analyzed the

emissions reductions which would be expected in

1994 if only State and Federal regulations existing

in 1985 were to be applied; these estimates represent

a ‘‘no-further-control” scenario from which we can

gauge the effectiveness of additional control measures. Recently, EPA announced proposals requiring

limits on gasoline volatility [8]. Several States in the

Northeast have already adopted regulations which

would limit gasoline volatility to 9 pounds per
Chapter 6--Controlling Emissions of Volatile Organic Compounds ● 137

square inch (psi) during the summer months [5].

Because this control method could become law,

nationwide, in the near future, its exclusion from a

baseline “no-further-control” scenario in a future

year may not be appropriate. Therefore, this subsection shows how the adoption of volatility controls,

alone, would affect future emissions reductions.

The graph on the right-hand side of figure 6-12

illustrates the percent reductions that would be

achieved in 1994 from existing regulations plus

gasoline volatility limits of 9 psi. On average, in

1994, gasoline volatility limits in nonattainment

cities will lower emissions by about an additional 12

percent below 1985 levels. As noted earlier, this

percentage represents emissions reductions that

would likely occur on a typical day when ozone

concentrations might exceed the standard and have

been scaled up to equivalent annual reductions for

the purposes of comparison with other year-round

control methods. As illustrated in figure 6-12, when

volatility controls are added, the percent reductions

in many cities with design values of 0.13 ppm fall

between the two curves. These cities may be able to

attain the ozone standard in 1994.

With All Control Strategies Analyzed by OTA

Figure 6-13 illustrates the percent reduction in

VOC emissions that could be achieved by requiring

all the control strategies listed in the beginning of

this section. In most cities, emissions in 1994 would

be lowered between about 20 and 50 percent,

depending on the city. As the figure shows, emissions reductions do not substantially change between 1994 and 2004. This “flat” trend between

1994 and 2004 is due to the competing influences of

population growth (which drives new emissions

growth) and the effects of additional emission

control measures. The emissions reduction benefits

from these measures act to cancel out new emissions

growth due to rising populations.

For typical cities with design values between 0.13

and 0.14 ppm, the VOC emissions reductions from

all controls may be more than needed to attain the

ozone standard. For other nonattainment cities with

slightly higher design values, the reductions projected for 1994 fall within the range of reductions

which might be needed. However, for most cities

with design values of 0.16 ppm or higher, projected

reductions fall considerably below the amount

needed to meet the standard. (Recall from chapter 5

that in each range of design values, the reduction

requirements shown in the above figures may

underestimate the reductions in local manmade

VOC emissions that are needed in areas that have

atypically large contributions from transported pollutants or vegetative VOC emissions.) In a later

section, we discuss the extent to which the adoption

of all control strategies in nonattainment cities

achieves less than, or more than the emissions

reductions required to attain the standard.

As stated earlier, the emissions reductions reported here represent control methods that we know

can be applied in the near term. This does not imply

that additional VOC reductions beyond those analyzed here are not possible, but that they should not

be counted on within the next 5 to 10 years.

Estimates of Possible Excesses and Shortfalls

in Emissions Reductions Required To Attain

the Ozone Standard

In this section we estimate: 1) the extent of

overcontrol in nonattainment cities with the lowest

design values, and 2) the shortfall in nonattainment

cities with higher design values, expected to occur

after applying all of the VOC controls discussed

earlier. Figure 6-14 displays our estimates of potential overcontrol and undercontrol from all VOC

control strategies in 1994 expressed in tons of

emissions reductions and as a percentage of 1985

emissions. The bars shown in the figure represent

ranges of uncertainty associated with our method of

estimating the VOC reductions needed to attain the

standard in each city.

As discussed in an earlier section and in chapter

5, because of the uncertainty associated with estimating the emissions reductions required to attain

the ozone standard, the reduction target we chose for

each city could be too low or too high. Therefore, the

adoption of all additional controls in an individual

city may result in either a shortfall or an excess in the

emissions reductions required to meet the standard.

For this reason, we present estimates for both

undercontrol and overcontrol.

We estimate that adoption of all controls in all

nonattainment areas might overcontrol VOC emission by about 160,000 to 920,000 tons per year in
138 . Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 6—13-Volatile Organic Compound (VOC) Emissions Reductions Between 1965 and 1994, and

1985 and 2004, Including All Additional Mobile and Stationary Source VOC Control Methods

All additional mobile and stationary

source control methods in 1994

-20% - Individual city

1 1 I I 1

All additional mobile and stationary

source control methods in 2004

% reduction from 1985 emissions

80%

60°%

40%

20%

o%

-20% -. Individual city

1 I 1 I

0.12 0.14 0.16 0.18 0.20 0.22 0.24 0.26 0.12 0.14 0.16 0.18 0.20 0.22 0.24 0.26

1983-85 design values (ppm ozone) 1983-85 design values (ppm ozone)

Each square represents a nonattainment city. The location on the graph shows the projected VOC emissions reductions (as a percentage

of 1985 levels) that each city can achieve by 1994 and 2004 if all additional mobile and stationary source control methods we analyzed

are adopted in addition to the State and EPA VOC regulations in place in 1985. The horizontal axis shows the “design value,” a measure

of peak ozone concentration used to determine the emissions reductions needed to attain the ozone standard. The two curves arching

across the graph and vertical bars to the right of the curves show the upper and lower bounds of VOC reductions needed to attain the

standard. The vertical bars show estimated control requirements explicitly for major urban areas with area-wide design values greater than

0.19 ppm.

SOURCE: Office of Technology Assessment, 1989.

Figure 6-14-Estimates of Possible Excesses and Shortfalls in Emissions Reductions

Needed to Attain the Ozone Standard in 1094

Ozone design

value (ppm)

0.13

0.14

0.15

0.16

0.17

0.18-0.26

> 0.26

I n m i I lion tons per year

Shortfalls in Excesses in

reductions needed reductions needed

to meet standard to meet standard

I ! 1 r 1 r , 1 1 (

Ozone design

value (ppm)

0.13

0.14

0.15

0.16

0.17

0.18-0.26

> 0.26

As a percentage of 1985 emission s

Shortfalls in

=

Excesses in

reductions needed reductions needed

to meet standard to meet standard

1.0 0.8 0.6 0.4 0.2 0.0 0.2 0.4 0.6 0.8 1.0 80% 60% 40% 20% O% 20% 40% 60% 80%

Excess reductions Reduction shortfall Reduction shortfall Excess reductions

The graph on the left shows reductions and shortfalls expressed as tons of emissions in 1994 while the graph on the right displays these

results as a percentage of 1985 emissions. The bars shown above represent ranges of uncertainty associated with our method of estimating

the VOC reductions needed to attain the standard in each city. Because of the uncertainty associated with estimating the emissions

reductions required to attain the ozone standard, the reduction target we chose for each city could be too low or too high. Therefore, the

adoption of all additional controls in an individual city may result in either a shortfall or an excess in the emissions reductions required to

meet the standard. For this reason, we present estimates for both undercontrol and overcontrol.

SOURCE: Office of Technology Assessment, 1989.
Chapter 6--Controlling Emissions of Volatile Organic Compounds ● 139

1994, or about 1 to 8 percent of 1985 emissions in

these cities. Figure 6-14 shows that the adoption of

all VOC control strategies in cities with 1983-85

ozone design values equal to 0.13 ppm (17 in all)

will very likely result in excess emissions reductions of about 160,000 to 680,000 tons per year in

1994, or about 7 to 29 percent of their total 1985 total

emissions. Even given the uncertainty in estimating

emissions reduction targets, these cities probably

will not likely fall short of the reductions needed to

meet the ozone standard. Potential overcontrol in

cities with design values equal to 0.14 and 0.15 ppm

may average about 26,000 tons and 21,000 tons in

1994, respectively, or about 3 percent of their 1985

emissions. Overcontrol, therefore, may not be as

much of a factor here compared to the cleaner cities.

We estimate that undercontrol in cities with design

values of 0.14 and 0.15 ppm may be more of a

problem, averaging about 37,000 and 58,000 tons in

1994, or about 5 and 8 percent of their 1985

emissions, respectively.

VOC reductions in attainment areas are a potentially significant source of overcontrol in the sense

that these areas do not need to reduce their emissions

any further to meet the ozone standard locally. We

know that there will be some benefit to nonattainment cities from controls in attainment areas,

especially those in ozone transport regions, but we

are not able to estimate how much. Moreover, even

in cities that already meet the standard, lowering

ozone concentrations even further will provide some

benefit. The total emissions reduction in all attainment areas from application of the nationwide

control measures only30 is about 2 million tons of

VOCs per year, in 1994, or about 14 percent, based

on 1985 emissions.

Figures 6-14 also presents our estimates of the

additional VOC emissions reductions nonattainment

cities must achieve to attain the ozone standard after

all controls have been applied. Calculation procedures are similar to those discussed above. We

estimate that after all controls are applied, nonattainment cities still fall about 1.2 to 3.1 million tons per

year short of the emissions reductions needed to

attain the standard in 1994, or about 11 to 27 percent

of 1985 emissions. Given that the adoption of all

additional controls will reduce total VOC emissions

by about 34 percent in 1994, we estimate that

nonattainment cities will still need an additional

one-third more emissions reductions to attain the

standard, based on 1985 levels. Of course, individual

cities may require higher or lower percentage

emissions reductions to achieve the standard depending on severity of the nonattainment problem.

(Possible long-term strategies that cities could use to

further reduce VOC emissions and measures to

control NOX emissions are discussed in chapter 7.)

The shortfall of emissions reductions will be most

significant in cities with design values greater than

or equal to 0.16 ppm (48 cities). In general, as the

severity the ozone problem in individual cities

increases, so too does the relative magnitude of the

shortfall, measured as a percentage of 1985 emissions. Undercontrol will be most severe in cities

with design values greater than 0.26, with a possible

shortfall of about 630,000 tons per year in 1994, or

about two-thirds of 1985 emissions .31 The emissions

reduction shortfall in cities with design values

between 0.18 and 0.26 ppm (13 cities) is estimated

to be about 300,000 to 630,000 tons in 1994, or about

18 to 38 percent of 1985 emissions. Therefore, given

that the adoption of all control methods will reduce

VOC emissions by about 29 percent in 1994, based

on 1985 levels, an additional 50-percent reduction

would be necessary to attain the standard in these

cities. The reduction shortfall in cities with design

values 0.16 and 0.17 ppm is estimated to be, on

average, about 880,000 tons per year, or about 18

percent of 1985 emissions.

COSTS OF CONTROL

STRATEGIES ANALYZED BY OTA

This section summarizes the costs of the control

strategies analyzed by OTA. Because we are unable

to analyze the cost of additional emission controls

required to make up the shortfall discussed above,

we are not able to estimate the total costs of attaining

the standard in all nonattainment cities.

SoIncludes Feder~ controls on ~hitect~al coatings and gasoline volatility limits. Emissions reductions from Onboard controls and more stringent

tailpipe standards are also achieved in attainment areas but are assumed to go into effect after 1994.

slThese cities have ~e~y adopted g~line volatility limits, Stage 11 refueling controls, and architectural surface COatingS regU1atiOXIS (a ProPO*

federal control), and therefore, additional emissions reductions benefi~s for these controls were not assigned.
140 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

We estimate that the total cost of all controls

analyzed by OTA in nonattainment cities will be

about $4.2 billion to $7.1 billion per year, in 1994.32

By 2004, costs will increase to about $6.6 billion to

$10 billion per year in nonattainment cities, primarily because of the higher percentage of highway

vehicles with more stringent controls. However,

some controls that we considered apply nationwide.

Total nationwide costs in 1994 and 2004 are about

$4.4 billion to $7.9 billion per year and $8.8 billion

to $13 billion per year, respectively. Again, this is

total cost of achieving about two-thirds of the VOC

reductions needed to attain the standard in all areas.

Some of the control methods we analyzed simultaneously reduce other air pollutants in addition to

VOCS. Since enhanced motor vehicle inspection and

maintenance (1/M) programs also reduce carbon

monoxide, about $1.2 billion of the total cost in 1994

is attributable to the control of this pollutant ($1.5

billion per year in 2004).33 Also, both enhanced I/M

programs and more stringent highway-vehicle standards reduce NOX emissions and, hence, we estimate

that about $2.5 billion per year of the total nationwide costs in 2004 are attributable to the control this

pollutant.

Table 6-10 displays the costs in 1994, 1999, and

2004 by source category. Figure 6-15 displays the

ranges of costs in nonattainment cities in 1994 and

2004. Table 6-11 presents the “cost-effectiveness”

(the cost per ton of VOC eliminated) of specific

control measures for the three forecast years. Figure

6-16 illustrates the cost-effectiveness of control

measures in nonattainment cities in 1994.34 The solid

bars represent the average cost-effectiveness in all

nonattainment cities. Uncertainty in the costeffectiveness estimates is denoted by the thin

horizontal lines. Note the wide range in average

cost-effectiveness across control measures, from

about $440 per ton for limits on gasoline volatility

to about $30,000 per ton for methanol fuels.

We also analyzed the cost and emissions reduction impacts of excluding control methods that cost

more than $5,000 per ton of VOC reduced. We

estimate that in 1994, by not requiring controls

costing more than $5,000 per ton, total costs would

drop to about $2.7 billion to $5.1 billion per year in

nonattainment areas, representing a 30- to 35-

percent decline. Nationwide costs would drop to

about $2.9 billion to $4.7 billion per year. In 2004,

total costs would drop to about $2.9 billion to $3.3

billion per year in nonattainment cities, representing

a drop of about 56 to 67 percent. Nationwide costs

would drop to about $5.1 billion to $6.1 billion per

year in 2004, representing a decline of about 42 to 53

percent. The percentage decrease in total costs in

2004 is larger than in 1994 because the costeffectiveness of I/M programs is greater than $5,000

by 2004 and, therefore, these programs would be

excluded.

In 1994, about 190,000 tons per year of VOC

emissions reductions would be lost in nonattainment

cities if a $5,000 cost-effectiveness cap is imposed,

increasing total emissions from about 34 percent

below, to about 32 percent below, 1985 levels. In

2004, about 360,000 tons of the emissions reductions in nonattainment cities would also be lost,

increasing emissions from about 33 percent below,

to about 30 percent below, 1985 levels. Controls on

many sources in the “RACT” and “New-CTGs”

categories exceed the $5,000 per ton cost ceiling;

methanol fuels would be completely eliminated

while enhanced I/M programs would be eliminated

in 2004. Since I./M programs would not be required

in 2004 under this scenario, the costs associated with

carbon monoxide control no longer have to be

considered when interpreting total costs.

Figure 6-17 shows the cumulative cost of achieving various levels of VOC emissions reductions in

nonattainment cities in 1994 and 2004. This figure

shows that in 1994, a 25-percent reduction in VOC

emissions (from 1985 levels) will cost about $900

million per year, while in 2004, the same reduction

will cost about $1.6 billion per year. The total cost

of a 25-percent emissions reduction is somewhat

3ZIII ~dition to vw con~ol COSt.s, thaeestimates dso include the cost of NOX and carbon monoxide control associated with enhanced ~ PWWU

and NOX control associated ,wit!! more stringent highway-vehicle standards.

qqMotor ve~cle ins~tion and m~nten~ce progr~s reduce VOC, NOX, and carbon monoxide. since many ozone nonattainment CiUeS dso viOhte

tbe Federal carbon monoxide standard, we arbitrarily assume that about 50 percent of the cost are attributable to carbon monoxide control.

Mk tie fiWe, tie cost-eff~tivenessof Onboard controls, combined Stage II and Onboardcontrols, and more stringent tilpipe st~dards ~epremnti

for 2004 since mobile source-related measures take effect after 1994.
Table 6-1 O—Estimated Costs of Selected Control Strategies Analyzed by OTA (costs in million dollars per year)”

1994 1999 2004

Nonattainment Attainment Nonattainment Attainment Nonattainment Attainment

cities areas Total cities areas Total cities areas Total
142 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 6-15-Estimated Coat of Volatile Organic Compound Emission Control Methods

in 1994 and 2004 in Nonattainment Cities

● Gasoline volatiIity

TSDFs

RACT

Enhanced l/M

Stage II

New CTGs

Methanol fuels

● Architect. coatings

● On board controls

● New mobile std’s.

04

not effective in 94

04

not effective in 94

04

9 4 — .

04

I I I I I I

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Cost (biIIion dolIars per year)

● Costs in attainment cities not shown.

In 1994, total annual costs in nonattainment cities range between $4,2 billion and $7.1 billion per year. Total costs in nonattainment areas

in 2004 range between $6.6 billion and $10 billion per year. See text for description of control methods.

SOURCE: Office of Technology Aessessment, 1989.

more expensive in 2004 because additional reductions are needed to offset anticipated emissions

growth over the intervening decade. A 30-percent

reduction in nonattainment area VOC emissions will

cost about $2 billion per year in 1994 and about $3.4

billion per year in 2004. Total annual costs begin to

increase more sharply beyond a 30-percent reduction. A 33-percent reduction will cost about $4.6

billion per year in 1994 and $8.4 billion per year in

2004. Again, control costs are greater in the later

years because greater reductions are required to

offset emissions growth. Greater reductions are also

possible because more stringent tailpipe standards

and Onboard controls have become effective by the

later year.

Control methods in figure 6-17 are ranked by

cost-effectiveness; that is, the total cost of control

per ton of VOC reduced. The most cost-effective

controls are represented in the lower lefthand portion

of the curve, while the less cost-effective controls

appear farther up the curve, to the right. For this

figure, the cost-effectiveness of enhanced I/M programs and new highway-vehicle standards includes

the VOC control costs and the cost of NOX and
I

Table 6-11—Estimated Cost-Effectiveness of Selected Control Strategies Analyzed by OTA (dollars par ton of VOC reducedr

1994 1999 2004

Nonattainment Attainment Nonattainment Attainment Nonattainment Attainment

cities areas Total cities areas Total cities areas Total

RACT . . . . . . . . . . . . . . . . . . . 2,200-6,600 — b — 2,300-6,700 — — 2,400-6,800 — —

New CTGs . . . . . . . . . . . . . . . 5,300-6,600 — — 5,400-6,700 – — 5,400-6,700 — —

TSDFs . . . . . . . . . . . . . . . . . . 900 — — 900 — — 900 — —

Architectural coatings . . . . . . 1,100 1,100 1,100 1,100 1,100 1,100 1,100 1,100 1,100

Onboard . . . . . . . . . . . . . . . . . -not effective in 1994- 1,000-1,200 1,100 1,000-1,200 1,000-1,200 1,100 1,000-1,200

Stage II . . . . . . . . . . . . . . . . . 1,000 — — 1,000 — — 1,000

Combined Onboard &

— —

Stage II . . . . . . . . . . . . . . . . 1,000 — 1,200-1,700 1,100 1,100-1,700 1,200-1,900 1,100 1,100-1,900

Enhanced l/Me . . . . . . . . . . . 2,100-5,800 — — 3,000-8,500 — 3,300-9,700 — —

Gasoline volatilit@ . . . . . . . .

—

120-760 120-770 120-770 120-730 120-750 120-740 120-740 120-750 120-750

New highway vehicle

standards . . . . . . . . . . . . . -not effective in 1994- 2,700 2,700 2,700 2,700 2,700 2,700

Methanol fuels . . . . . . . . . . . . 8,700-51,000 — — 8,700-51,000 — — 8,700-51,000 — —

a~W~ ~PeS~ Variatil@ ~ong rrona~iflrnefrr cities and should not be CO- as umn~flw in mr

estimates.

~-,, nleafls ~n~l s~~egy @iecf only in nonattainment CitiSS.

CEStirna~S reflect COStS as s.ociated witi VOC control ody. We assume that om-thkd of the total cost of finced l/M programs IS attributable to VOC control, with em-half and one-sixth to carbon monoxide and Nox control,

reapacdwly. Range in IM4 coats represents uncertainty in repair cost and -my. dEs~mteS re~t ~st-effectiveness ckxing the 5-monfh summertime period when Cc+Mds are required.

Strategy Descriptions

RACT. “Reasonable Aailable Control Technology” on all existing stationary sources that emit more than 25 tons par year of VOC.

New CTGS = new Control Tecimiqua Guidelines for existing stationary sources that emit more than 25 tons per year of WC.

TSDFS = controls on hazardous waste treatment, storage, and disposal faalities.

Federal controfs on archltaclum I coatings.

Onboard COtltrots on motor whicles to capture gasoline vapor during refueling.

Stage N control devices on gas pumps to capture gasoline vapor tiring motor vehida refueling.

Gasoline vofatflity controfs which limit the rate of gasoJina evaporation.

Enhanced inapaction and rnafntsnanos (W) programs for cars and light-duty fru~s.

New hfghway-vsttfcla adaaloa sfandads for passenger c.ws and Iightduty gasoline trucks.

Methanol fuels as a substitute for gasoline as a motor vehicle fuel.

SOURCE: Office of Technobgy Assessment, 1969.
144 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 6-16-Estimated Cost-Effectiveness of Volatile Organic Compound Emission Control Methods

in 1994 in Nonattainment Cities

r

Gasoline volatility

TSDFs

RACT

Enhanced l/M

Stage II

New CTGs

Methanol fuels

Architect. coatings

On board controls

New mobiIe std’s.

Stage II & On board

I

— Cost-effectiveness in 2004

I I I

t

) —

o 1 2 3 4 5 6 7 8 9

$1,000/ton of VOc reduced

The cost-effectiveness of enhanced inspection and maintenance (l/M) programs and new mobile standards include only the cost of VOC

control. Since Onboard controls and new mobile standards do not take affect until after 1994, we present the cost-effectiveness in 2004.

The thick horizontal bars represent the average cost-effectiveness in nonattainment cities. The thin horizontal lines for gasoline volatility,

methanol fuels, and l/M programs represent ranges of uncertainty associated with assumptions we used to estimate total annual costs.

The very large uncertainty associated with the methanol fuels is due to the uncertainty of methanol prices relative to gasoline prices. We

were unable to estimate cost-effectiveness uncertainty for other control methods. See text for a description of control methods.

SOURCE: Office of Technology Assessment, 1989.

carbon monoxide control (1/M programs, only). If

the two least cost-effective control programs in

2004-enhanced I/M programs and methanol fuelsare eliminated, total costs would drop by approximately $3.6 billion per year, representing a 40-

percent decline.

As described in an earlier section, the adoption of

all additional control measures in nonattainment

cities with design values of 0.13 ppm may result in

about 400,000 tons per year more emissions reductions than what is necessary to attain the ozone

standard. If "New-CTGs, ” hazardous waste TSDFs,

and enhanced I/M programs are not required in these

areas, excess emissions reductions could be cut by

about 380,000 tons per year in 1994, representing a

30-percent decline in emissions reductions. Total

costs in these areas would drop from about $1.7

billion per year to about $0.5 billion per year, or

about a 70-percent decline.

A brief discussion of the costs and costeffectiveness of each of the control strategies,
Chapter 6--Controlling Emissions of Volatile Organic Compounds ● 145

Figure 6-1 7-Cumulative Annual Cost of, and Percent

Emissions Reductions From, VOC Control Methods

Control methods are ranked by cost-effectiveness; that is, the total

cost of control per ton of VOC reduced. For example, the most

cost-effective controls (e.g., gasoline volatility) are located in the

lower left portion of the curve. In this figure, the costs of enhanced

l/M programs and new highway-vehicle standards includes the

VOC control costs and the cost of NOX and carbon monoxide

control (1/M programs, only).

SOURCE: Office of Technology Assessment, 1989.

including the data sources from which the estimates

are calculated, follows.

Reasonably Available Control Technologies

(RACT) on All Stationary Sources

Total costs in nonattainment cities for this category are estimated to be about $1.1 billion per year

in 1994, averaging about $2,200 to $6,600 per ton of

VOC removed depending on city.

As mentioned in an earlier subsection, this control

strategy applies to about 40 broad source categories

such as petroleum refining, certain types of chemical

manufacturing, gasoline stations, etc. A complete

list, with our assumptions about control efficiencies

and cost-effectiveness for each source type, is

included in an appendix.

Adoption of New “Control Technique

Guidelines” (CTGs)

As stated earlier, we analyzed six stationary

source categories currently being considered as

candidates for new CTGs: wood furniture coating,

plastic parts coating, automobile refinishing, cokeoven byproduct plants, bakeries, and publicly owned

treatment works. (Hazardous waste treatment, storage and disposal facilities are discussed in the next

subsection.)

We estimate that new CTGs would cost about

$570 million per year in 1994, all of which would be

incurred in nonattainment cities. The cost-effectiveness

averages about $5,700 per ton with a range of $5,300

to $6,600 per ton depending on the cities in which

these controls are adopted.

Controls on Hazardous Waste Treatment,

Storage, and Disposal Facilities

We estimate that emission controls on TSDFs will

cost about $580 million per year in nonattainment

cities in 1994. This estimate is based on a costeffectiveness of $900 per ton of VOC reduced for

controls such as covered storage tanks and carbon

adsorbers.

Federal Controls on Architectural

Surface Coatings

The small amount of cost data available for

architectural surface coatings revealed a wide range

of estimates, from a net savings to default costs of

$2,000 per ton of reduction. We assume that controls

for this source cost about $1,100 per ton of VOC

reduced. Commercial and consumer products are

also potentially important sources of VOC emissions, but were excluded from our analysis because

of a lack of adequate control technology information.

We estimate that, in 1994, Federal controls on

architectural surface coatings would cost about $120

million per year, nationwide, with about $54 million

per year incurred in nonattainment cities.

Controls on Gasoline Emissions

From Vehicle Refueling

“Onboard” Refueling Controls on

Motor Vehicles

We estimate the cost of Onboard controls by 1999

to be about $410 million per year, nationwide, with

about $190 million per year incurred in nonattainment cities. By 2004, costs would total $590 million

per year, nationwide, because of the higher percent-
146 . Catching Our Breath: Next Steps for Reducing Urban Ozone

age of Onboard-equipped vehicles on the road. The

average nationwide cost-effectiveness is estimated

to be about $1,100 per ton in 1999.

For this analysis, we assume that all gasoline

vehicles manufactured in 1994 and later will be

equipped with Onboard controls to capture gasoline

vapors during refueling. By 2004, most gasoline

vehicles on the road will be equipped with these

controls. We assume that Onboard controls cost

about $25 per vehicle, which is close to EPA’s upper

bound estimate [28]. Note, however, that others

conclude that the costs are higher. A study for the

Motor Vehicle Manufacturers Association estimates

that the average per-vehicle cost of Onboard controls

for the first model year is about $80 [13].

“Stage 1199 Refueling Vapor Recovery

We estimate the cost of Stage II controls to be

about $200 million per year in 1994, all of which is

incurred in nonattainment cities. This estimate is

based on a cost-effectiveness of $1,000 per ton of

VOC removed. This figure represents EPA’s upper

bound range as presented in the recent gasmarketing regulatory impact analysis [28]. EPA

estimates that the total installed cost of Stage 11

controls, per station, ranges from $5,270 for the

smallest stations to $22,190 for the largest [28].

Combined Stage 11 and Onboard Controls

We assume that the cost of a combined Stage 11

and Onboard program is the sum of the cost of each

individual program. Therefore, in 1999, we estimate

the cost to be about $610 million per year, nationwide, with approximately $400 million per year

incurred in nonattainment cities. Nationwide costs

increase to about $810 million per year in 2004. The

combined cost-effectiveness in nonattainment cities

in 1999 is estimated to be about $1,600 per ton of

VOC reduced and is expected to increase to about

$1,800 per ton by 2004 because of fleet turnover.

The cost-effectiveness is higher than either Stage 11

and Onboard alone because the emissions reductions

achieved from a combined system do not substantially increase compared to each one separately. The

nationwide combined cost-effectiveness in 1999 and

2004 is estimated to be about $1,400 and $1,500 per

ton, respectively. The cost-effectiveness is lower

nationwide because we assume that Stage 11 controls

are not required in attainment areas.

Enhanced Motor Vehicle Inspection and

Maintenance (I/M) Programs

We estimate that enhanced I/M programs in

nonattainment cities cost between about $1.5 billion

and $3.5 billion per year in 1994. In 2004, costs are

expected to rise to between $1.9 billion and $4.3

billion per year. About half of this total is for ozone

control ($0.74 billion to $1.7 billion per year in

1994, and $0.93 billion to $2.2 billion per year in

2004),35 Of the portion that is assigned to ozone

control, we estimate that about two-thirds would be

for VOC control and one-third for NOX control.

Thus, the cost-effectiveness for VOC reductions is

estimated to be between $2,100 and $5,800 per ton

in 1994. In 2004, the cost-effectiveness will increase

to between $3,300 to $9,700 per ton; this rise is due

to the fact that cars and trucks will be cleaner in

2004. Note that we have estimated the costeffectiveness of improving existing I/M programs to

the more stringent “enhanced” program described

earlier.

Our estimates of enhanced I/M program costs are

based on an analysis of the California I/M program,

prepared for the California Air Resources Board by

Sierra Research, Inc. [15]. We use Sierra Research’s

finding that an enhanced I/M program costs about

$34 to $55 per vehicle per year. About $20 of this

cost is for the inspection fee and program administration. The remainder is for repair costs, which we

assume to range between $70 and $100 per vehicle.

We also assume that 20 and 35 percent of the

vehicles tested will fail.36 Sierra Research’s analysis

concludes that an enhanced I/M program can reduce

VOC emissions from cars and light-duty trucks by

about 30 percent. This is about 17 percent higher

than current I/M programs. For those cities that

already have an I/M program in place, we credit $20

per vehicle as the cost of the existing program.

These costs are quite a bit higher than EPA

estimates [11]. The major difference seems to be

ssThe ~~er h~f of the costs are assigned to carbon monoxide Control.

s~e 1OW J/M cost e~ate ~mes that a repair cost of $7o per vehicle will be levied on the 20 percent of the vehicles which fttil; the h@ estimate

assumes $1(XI repair cost on 35 percent of the vehicles,
Chapter Controlling Emissions of Volatile Organic Compounds ● 147

assumptions about whether repair costs drop after

the program has been operating a few years.

More Stringent Highway-Vehicle

Emission Standards

We estimate that the total cost of tighter emission

standards for highway vehicles in 1999 will be about

$1.6 billion per year, nationwide, of which about

$0.66 billion per year will be incurred in nonattainment cities. By 2004, costs will total about $2.9

billion per year, nationwide, because a higher

percentage of vehicles on the road will be equipped

with new controls. These totals include the costs

attributed to both VOC and NOX control on new

passengers cars and light-duty gasoline trucks. Costs

are based on an OTA contractor report by Sierra

Research, Inc., that estimated new emission control

costs of about $140 per vehicle for combined VOC

and NOX control [15]. Reductions of VOC in

nonattainment cities in 1999 and 2004 are estimated

to cost about $2,700 per ton of VOC reduced. As

described earlier, we analyzed more stringent standards that can be met up to 50,000 miles of driving

under controlled conditions for cars, and 120,000

miles for light-duty trucks; tailpipe VOC emissions

may exceed these standards after 50,000 miles (for

cars) and 120,000 miles (for trucks) of actual use by

individual vehicle owners.

Limits on Gasoline Volatility

We estimate that reducing gasoline volatility (i.e.,

the rate of evaporation) during the 5-month summertime period costs between about $0.17 billion and

$1.0 billion per year nationwide in 1994. During the

5-month summer period, costs are between about 0.5

and 3.2 cents per gallon of gasoline. The lower cost

estimate is derived from a recent EPA analysis of

proposed nationwide limits on gasoline volatility

[27], while the high estimate was obtained from a

petroleum industry analysis [20,33] .37 In 1994, the

cost-effectiveness ranges between $120 to $800 per

ton of VOC reduced. Our estimates of costeffectiveness are lower than EPA’s because we have

increased the emissions reduction potential from

highway vehicles by including a 1.5 gram-per-mile

running loss to the existing inventory.

Methanol Fuels for Motor Vehicle Vehicles in

the Worst Nonattainment Cities

In the near term, use of blends of methanol and

gasoline could easily be several times more expensive per ton of VOCs reduced than any other

measure we have considered. If advances in vehicle

technology yielded reductions in emissions rates on

the order of 90 percent, the estimated costs of using

straight methanol could be more in line with other

control measures we have evaluated. In all cases, the

costs are extremely sensitive to prices assumed for

gasoline and methanol.

Automobile manufacturers estimate that in production runs of fewer than about 100,000 vehicles,

cars and light-duty trucks designed to operate on

methanol would cost $500 to $1,000 more than

gasoline-fueled vehicles [32]. In larger runs, methanol and gasoline-fueled vehicle production costs

could be comparable [32]. For centrally owned

fleets, assuming a vehicle life of 6 years (150,000

miles) and an 8 percent discount rate, the annualized

added cost of a methanol vehicle could thus range

from $0 to about $215.

Based on a range of 40 to 60 cents per gallon as

the wholesale price of methanol, we estimate that

straight methanol would be sold to consumers at

$0.64 to $0.84 per gallon, or $1.15 to $1.51 per

gasoline-gallon equivalent, adjusting for the difference in the energy content and thermal efficiency of

the two fuels.38 These estimates can be compared to

current national average prices for regular and

premium unleaded gasoline of $0.95 and $1.10 per

gallon, respectively [24]. Assuming that fleet vehicles average 26,000 miles per year and get the

energy equivalent of 26.5 miles per gallon of

gasoline, use of a blend of 85 percent methanol and

15 percent gasoline would increase annual fuel costs

by about $130 to $480 per vehicle.

In the near term, assuming methanol is blended

with 15 percent gasoline and yields VOC emissions

sTThe smdy by her, Mason & CO. for the American Petroleum Institute (API) estimated that EPA’s volatility proposal would COst about $1.5 billion

per year. The standard we analyzed was somewhat less stringent than EPA’s original proposal and, hence, total costs, as evaluated by API, were estimated

to be about $1.0 billion per year.

38s= A. 7 for details.
148 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

rates that are 30 percent lower than gasoline-fueled

vehicles, we estimate that using methanol in fleets

would cost about $120 million to $710 million per

year in 1994, or about $8,700 to $51,000 per ton of

VOC reduced. The low estimate assumes vehicle

and fuel costs most favorable to methanol, while the

high estimate represents costs which are least

favorable.

Use of methanol or compressed natural gas

(CNG) as fuel for light-duty vehicles is discussed in

more detail in the next chapter.

REFERENCES FOR CHAPTER 6

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

Alson, J. A., ‘The Emission Characteristics of Methanol and Compressed Natural Gas in Light Vehicles, ”

paper 88-99.3, presented at the 81st Annual Meeting

of APCA, Dallas, TX, June 19-24, 1988.

Automotive Fleet 1987 Fact Book, Volume 26 Supplement (Bobit Publishing Co., 1987).

Battye, W. H., Smith, M. G., and Deese, M., Cost

Assessment of Alternative National Ambient Air

Quality Standards For Ozone, Draft Report, prepared by Alliance Technology Corp., contract No.

68-02-4317 (Research Triangle Park, NC: U.S.

Environmental Protection Agency, October 1987).

E.H. Pechan & Associates, Inc., Nationa! Assessment

of VOC, CO, and NOX Controls, Emissions, and

Costs, Contract No. 68-W8-0038 (Washington, DC:

Office of Policy, Planning and Standards, U.S.

Environmental Protection Agency, September 1988).

Environment Reporter, “Most Northeast States To

Have Final Rules on Fuel Volatility Before 1989

Ozone Season,” Current Developments 19(37):1835,

Jan. 13, 1989.

Jack Faucett Associates, Methanol Prices During

Transition (U.S. Environmental Protection Agency,

September 1986).

52 Federal Regis~er 45060 (Nov. 24, 1987).

52 Federal Register 31274 (Aug. 19, 1987).

54 Federal Register 14425 (Apr. 11, 1989).

bonard, Samuel A., Director, Automotive Emission

Control, General Motors Corp., letter to Charles L.

Gray, Director, Emission Control Technology Division, U.S. Environmental Protection Agency, Mar. 7,

1988.

Lorang, P., “Further OMS Reflections on the Cost of

Mobile Source Provisions of the Mitchell Bill” (Ann

Arbor, MI: U.S. Environmental Protection Agency,

Office of Mobile Sources, Sept. 10, 1987).

Lorang, Phil, Office of Mobile Sources, U.S. Environmental Protection Agency, personal communication, April 1989.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

Multinational Business Services, Inc., Costs and

Cost-Effectiveness of Stage II and Onboard Refueling Vapor Controls (Motor Vehicle Manufacturers

Association of the United States, Inc. and the

Automobile Importers of America, Inc., April 1987).

Newman, P. W. G., and Kenworthy, J. R., “Gasoline

Consumption and Cities: A Comparison of U.S.

Cities With a Global Survey, ” Journal of the

American Planning Association 55:24-37, 1989.

Sierra Research, Inc., “The Feasibility and Costs of

More Stringent Mobile Source Emission Controls, ”

contractor report for Ofilce of Technology Assessmen~ Jan. 20, 1988.

Southern California Association of Governments,

Regional Mobility Plan, Draft (Los Angeles, CA:

October 1988).

South, David, et al,, ‘‘Industrial VOC Model: Regionalized Forecasts of Uncontrolled Emissions by

Source Category, Draft Discussion Paper No. 19 for

Task Group B of the Interagency Task Force on Acid

Precipitation” (Washington, DC: U.S. Department

of Energy, Office of Planning and Environment, June

1985).

South Coast Air Quality Management District, Draft

Air Quulity Management Plan, 1988 Revision, Appendix III-A, 1985 Emissions Inventory, South Coat

Air Basin (E1 Monte, CA: March 1988).

South Coast Air Quality Management District, Draft

Air Quality Management Plan, 1988 Revision, Addendum to Appendix IV-A, Tier 1 and Tier 11 control

Measures (El Monte, CA: August 1988).

Thrner, Mason & Co., “U.S. Gasoline RVP Reduction Capabilities and Costs, ” Comments of the

American Petroleum Institute, Volume III, Concerning EPA’s August 19, 1987 Proposed Regulation of

Fuels and Fuel Additives and Regulation of Refueiing Emissions (Washington, DC: American Petroleum Institute, Feb. 11, 1988).

U.S. Department of Commerce, Bureau of the

Census, Statistical Abstracts of the United States,

1982 (Washington, DC: U.S. Government Printing

OffIce, 1987).

U.S. Department of Commerce, Bureau of Economic

Analysis, Survey of Current Bwiness (Washington,

DC: U.S. Government Printing Ofllce, October

1985).

U.S. Department of Commerce, Bureau of Economic

Analysis, Survey of Current Business (Washington,

DC: U.S. Government Printing OffIce, July 1987),

U.S. Department of Energy, Monthly Energy Review

(Washington, DC: U.S. Government Printing Office,

September 1988).

U.S. Environmental Protection Agency, Offke of

Air, Noise, and Radiation/Office of Air Quality
Chapter 6-Controlling Emissions of Volatile Organic Compounds . 149

26.

27.

28.

29.

Planning and Standards, Control of Organic Emissions From Architectural Surj4ace Coating, Preliminary Draft (Research Triangle Park, NC: March

1981).

U.S. Environmental Protection Agency, OffIce of Air

Quality Planning and Standards, “Implications of

Federal Implementation Plans (FE%) for Post-1987

Ozone Nonattainment Areas” (Washington, DC:

March 1987).

U.S. Environmental Protection Agency, Office of Air

and Radiation, OffIce of Mobile Sources, Draft

Regulatory Impact Analysis: Control of Gasoline

Volatility and Evaporative Hydrocarbon Emissions

From Motor Vehicles (Research Triangle Park, NC:

July 1987).

U.S. Environmental Protection Agency, Offke of Air

and Radiation, Draft Regulatory Impact Analysis:

ProposedRejh.eling Em”ssionRegtdations for GasolineFueled Motor Vehicle+Volume I, Analysis of Gasoline Marketing Regulatory Strategies, EPA-450/6-87-

OOla (Research Triangle Park, NC: July 1987).

U.S. Environmental Protection Agency, Guidance on

Estimating Motor Vehicle Emission Reductions From

the Use of Alternative Fuels and Fuel Blends,

EPA-AA-TSS-PA-87-4 (Research Triangle Park,

NC: January 1988).

30.

31,

32.

33.

34.

U.S. Environmental Protection Agency, Hazardous

Waste TSDF-Background Information for Proposed

RCRA Air Emission Standards, Volume l-Chupters,

Preliminary Draft EIS (Research Triangle Park, NC:

March 1988).

U.S. Environmental Rotection Agency, Office of

Mobile Sources. Preliminary data presented at the

MOBILE4 Workshop, Ann Arbor, Michigan, Nov.

30, 1988.

Vice President’s Task Force, “Cost and Cost Effectiveness of Alternative Fuels” (Washington, DC:

July 1987).

Yosie, Terry, Vice President, American Petroleum

Institute, memorandum to Robert Friedman, Office

of Technology Assessmen4 Mar. 31, 1989.

Zimmerman, D., Tax, W., Smith, M., Demmy, J., and

13attye, R., Anthropogenic Emissions Data for the

2985 NAPAP Inventory EPA-600/7-88-022, prepared by Alliance Technologies Corporation (Research Triangle Park, NC: U.S. Environmental Protection Agency, Air and Energy Engineering Research Laboratory, November 1988).
Chapter 7

New Opportunities for

Controlling Ozone
CONTENTS

Page

INTRODUCTION ..... . . . . . . . . . . . . . . . . . . . 153

OPPORTUNITIES FOR LOWERING

EMISSIONS OF NITROGEN OXIDES . . . . . . . 154

Sources of Nitrogen Oxides . . . . . . . . . . . . . . . . . . 154

Potential NOXEmissions Reductions From

Control Strategies Analyzed by OTA. . . . . . . . 156

Costs of NOXControI Strategies Analyzed

by OTA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

OPPORTUNITIES FOR LOWERING EMISSIONS

FROM SOLVENT USE . . . . . . . . . . . . . . . . . . . . . 165

Sources of Organic Solvent Use . . . . . . . . . . . . . . . 166

Organic Solvent Use by Source Size.... . . . . . . . 166

Opportunities for Additional Emissions

Reductions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

Further Regulation of Solvents . . . . . . . . . . . . . . . . 171

LOWERING EMISSIONS FROM HIGHWAY

VEHICLES: TRANSPORTATION CONTROL

MEASURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

Requirements in the 1977 Clean Air Act

Amendments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

Potential Reductions From Transportation

Control Measures . . . . . . . . . . . . . . . . . . . . . . . . . 180

Role of Transportation and Land-Use Planning . 182

Trip Reduction Ordinances . . . . . . . . . . . . . . . . . . . 182

Financial Incentives for Reducing Vehicle Use . 183

LOWERING EMISSIONS FROM HIGHWAY

VEHICLES: ALTERNATIVE FUELS ...... 184

Emissions From Alternatively Fueled Motor

Vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

Vehicle Operation and Performance . . . . . . . . . . . 186

Potential Emissions Reductions from

Alternative Fuel Use . . . . . . . . . . . . . . . . . . . . . . 187

Cost-Effectiveness of Alternative Fuel Use

in Light-Duty Vehicles . . . . . . . . . . . . . . . . . . . . 188

REFERENCES FOR CHAPTER 7 . . . . . . . . . . . . . . 190

Figures

Figure Page

7-1. NOX Emissions in 1985, by Source Category. 156

7-2. NOX Emissioms from Mobile Sources in1985

as a Percentage of Total (Mobile plus Stationary)

Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

7-3. Summary of Estimated Nationwide NOX by

Source Category, by Year ........ . . . . . . . . 158

7-4. NOX Emissions Reductions in 1994 and

2004 Compared to 1985 Emissions, by Control

Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

7-5. Potential NOX Emissions Reductions and

Remaining Emissions in 1994 and 2004 as a

Percentage of 1985 Emissions in Nonattainment

Cities . . . . . . . . . . . . . . . . . .. ............. 161

7-6. Estimated Cost of NOX Emission Control Methods

in 1994 and 2004 in Nonattainment Cities . . . 164

Page

7-7. Estimated Cost-Effectiveness of NOX Emission

Control Methods in 1994 in Nonattainment

Cities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

7-8, Total Solvent Use as a Percentage of 1985 Total

VOC Emissions in Nonattainment Areas . . . . 166

7-9. Total 1985 Solvent Use in Nonattainment Areas, by

Source Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

7-10. Industrial Solvent Use in 1985 by Four Source-Size

Cutoffs in Nonattainment Cities . . . . . . . . . . . . 168

7-11. Total Solvent Use Covered by Existing Regulations

in 1985 in Nonattainment Cities . . . . . . . . . . . . 169

7-12. Total Solvent Use Covered by Existing Regulations

in 1985, by Source Category in Nonattainment

Cities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

7-13. Identifiable Industrial Solvent Use Covered by

Existing Regulations; and the Number of Firms by

Source Size . . . . . . . . . . . . . . . . . ... . ....... 171

Tables

Table Page

7-1. Summary of 1985 NOX Emissions in Nonattainment

Cities and Attainment Regions . . . . . . . . . . . . . 155

7-2. Summary of 1994 NOX Emissions in Nonattainment

Cities and Attainment Regions . . . . . . . . . . . . . 157

7-3. Summary of 1995 NOX Emissionsin Nonattainment

Cities and Attainment Regions . .. . ........ 157

7-4, Summary of 2004 NOX Emissions in Nonattainment

Cities and Attainment Regions . . . . ........ 157

7-5. Potential NOX Emissions Reductions in 1994

Compared to 1985 Emissions from SourceSpecific Control Strategies . . . . . . . . . . . . . . . . 159

7-6. Potential NOX Emissions Reductions in 1999

Compared to 1985 Emissions from SourceSpecific Control Strategies . ............ 159

7-7. Potential NOX Emissions Reductions in 2004

Compared to 1985 Emissions from SourceSpecific Control Strategies . . . . ... ....... 160

7-8. Estimated Costs of Selected NOX Control

Methods in Nonattainment Cities in 1994 and

2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

7-9. Estimated Cost-Effectiveness of Selected NOX

Control Methods in Nonattainment Cities in

1994 and 2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

7-10. Effective VOC Reductions in 2004, From Use of

CNG and Methanol as Light-Duty Motor Vehicle

Fuels in Areas with Design Value of O.15 ppm

or Higher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

7-11. Cost-Effectiveness of Alternative Fuel Use.. 169
Chapter 7

New Opportunities for Controlling Ozone

INTRODUCTION

In the previous chapter, we examined progress

that could be made towards attaining the current

ozone standard by applying currently available

control measures. We predicted that most of the

cities with design values of 0.16 parts per million

(ppm) or higher and some of the cities with design

values of 0.14 and 0.15 ppm would still fall short of

attainment after implementing all of the measures

we could identify.

As shown in figure 6-10, after all controls have

been applied, two categories of sources—organic

solvent evaporation, and highway vehicles (and

associated gasoline marketing)—acount for over

two-thirds of the volatile organic compound (VOC)

emissions remaining in nonattainment cities in

1994. This chapter addresses the possibility of

further controlling emissions from these source

categories, using new regulatory approaches or

technology that is not yet ready for application.

As discussed in chapter 5, NOX reductions in

addition to VOC controls would be counterproductive for some cities, actually increasing ozone

concentrations compared to levels that would have

resulted if just VOC emissions had been reduced.

However, other cities may need to control NO,

emissions in addition to VOCs in order to meet the

ozone standard. Although we assume that the

primary strategy for reducing urban ozone will

continue to be controlling VOCs, in this chapter we

also discuss measures that are currently available for

reducing NOX emissions.

The first section of this chapter examines opportunities for controlling nitrogen oxides. Of the 20

million tons of NOX emitted per year, nationwide,

approximately 35 percent were generated in ozone

nonattainment areas. Without additional controls,

NOX emissions are projected to increase by almost

30 percent by 2004, with most of the increase

coming from stationary sources. We analyzed potential NOX emissions reductions from highway vehicles and stationary sources including electric utility

boilers, industrial boilers, stationary engines, gas

turbines, and process heaters. We estimate that by

2004, application of controls to all of these categories would result in reductions in nonattainment

areas of about 28 percent, compared to 1985 levels,

and would cost about $3.7 to $6.2 billion per year in

nonattainment cities, and about $5.4 to $7.9 billion

per year, nationwide.

The second section focuses on emissions from

organic solvent evaporation. We first describe categories of organic solvent use, and identify which

categories provide opportunities for further control.

We estimate that only about one-fourth of total

solvent use is covered by existing regulations, and

that an additional one-fourth could be covered by

broader application of these rules. Of the remaining,

‘‘unregulated” solvent uses, the majority of emissions come from very small sources such as consumer and commercial products and miscellaneous

surface coating uses. To suggest approaches for

reducing emissions from these sources, we present

examples of innovative State programs, and discuss

the alternative of market-based controls.

Addressing motor vehicles, the third section looks

at transportation control measures (TCMs)----such as

encouraging use of mass transit or carpooling-that

attempt to reduce vehicle use. TCMs have to be

tailored to individual cities, and the emissions

reductions that could be obtained from them will

vary significantly from one city to another. However, to suggest the magnitude of reductions that

could be achieved from an aggressive program, we

review the assessment of TCMs that was recently

completed for the Los Angeles area. With full

funding and authority, it is hoped that the proposed

measures will reduce highway-vehicle VOC emissions by a total of 30 percent by 2010, compared to

projected baseline emissions for that year. Growth

management measures aimed at matching new jobs

with nearby housing account for almost 50 percent

of the reductions.

In the final section on alternative fuels, we first

discuss their effect on motor vehicle emission rates

and other aspects of vehicle operation and performance. We then present estimates of total emissions

impacts of using alternative fuels, and the costs per

ton of VOC emissions effectively eliminated. We

–153–
154 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

conclude that in the near term, effective VOC

emission rates with alternative-fueled vehicles will

be only moderately lower than rates that could be

obtained with gasoline vehicles meeting current

standards. Using either methanol blends or dualfueled compressed natural gas (CNG) vehicles

would be an extremely costly means of reducing

ozone. With significant advances in vehicle technology, greater and more cost-effective reductions

may eventually be possible.

OPPORTUNITIES FOR

LOWERING EMISSIONS OF

NITROGEN OXIDES

Ozone is produced in the atmosphere from

reactions involving two “precursor” pollutants:

volatile organic compounds and nitrogen oxides.

The focus of efforts to reduce ozone has historically

been on controlling local VOC emissions. This focus

is expected to continue. In some cities, controlling

NOX emissions in addition to VOCs would be

counterproductive, increasing ozone concentrations

compared to levels that would have resulted if just

VOC emissions had been reduced. In other cities,

however, controlling NOX emissions in addition to

VOCs might help reduce ozone.

At present, our ability to make reliable predictions

about whether or not NOx controls will be helpful is

limited. For most cities, the data gathering and

modeling needed to assess the impact of NOX

emissions reductions have not been done. In the

best-studied area, Los Angeles, the issue is clouded

by the fact that reducing NOX emissions would

apparently lower peak ozone concentrations at some

locations but increase them at others, compared to

VOC controls alone. Such mixed outcomes might

occur in other cities, as well.

The effect of reducing NOx emissions in the

Northeastern United States has been studied using

EPA’s Regional Oxidant Model. The analysis

should be considered preliminary, and consideration

of different meteorological conditions or levels of

control might change the conclusions. The results

suggest that totalled over all of the urban areas in the

region, reducing NOX emissions by 27 percent and

VOC emissions by 42 percent below estimated 1980

levels would improve air quality more than reducing

VOC emissions alone. However, for a few individual cities, the NOX reductions were predicted to be

counterproductive. In all of the northeastern States,

the NOx reductions were predicted to be beneficial

for nonurban areas, supporting the theoretically

based expectation that NOX control would help

reduce ozone in most rural areas.

Modeling calculations comparable to those performed for the Northeast have not been done for the

South. However, measurements of VOCs and NOX

in urban air, and estimates of VOC emissions from

vegetation, give a very preliminary suggestion that

cities in the South are even more likely to benefit

from NOx control than cities in the Midwest or

Northeast.

This next section describes the sources of NOX

emissions and presents our estimates of the changes

in emissions over the next 15 years due to the

offsetting influences of economic growth and State

and Federal regulations in place as of 1987. These

estimates serve as a baseline for considering the

effects of regulatory changes that could be required

to attain the ozone standard. We analyze potential

NOX emissions reductions and control costs for

highway vehicles, and stationary sources including

electric utility boilers, industrial boilers, stationary

engines, gas turbines, and process heaters.

Sources of Nitrogen Oxides

Table 7-1 displays estimates of 1985 NOX emissions, number of cities, and population within each

of five ozone design value categories. The EPA 1985

National Emissions Data System (NEDS) inventory

is the source of our emissions data and serves as the

base inventory for all future year projections presented in this report. Residential fuel combustion

sources have been excluded from our analysis since

these emissions occur primarily during the wintertime when ozone is not a problem. Of the 20 million

tons of NOX emitted per year, approximately 35

percent were generated in cities that exceeded the

ozone standard during the 1983-85 period.l

IFor ~w ~~ysis, ~ mea is considered k nmattainment if its design value is greater than 0.12 ppm ozone Kcording to EpA-publi*ed 1983-85 o~ne

monitoring data. EPA’s actual determination of nonattainment is based on a slightly different method, but the resulting number of nonattainment cities

are essentially the same. Our number of nonattainment areas differs from EPA’s count of 61 because, in several cases, EPA has used Consolidated

Metropolitan Statistical Areas (CMSAS), rather than cities. Several of these CMSAS include two or more cities that we have considered separately.
Chapter 7—New Opportunities for Controlling Ozone ● 155

Table 7-l-Summary of 1985 NOX Emissions in Nonattainment Cities

and Attainment Regions

NOx Percent Percent 1985

emissions stationary mobile No. of population

(1,000 tons)a

(%) (%) cities (millions)

Nonattainment cities by

design value category

(in ppm O3

)

0.13-0.14 . . . . . . . . . . . . 2,300 5a 42 37 30.2

0.15-0.17 . . . . . . . . . . . . 3,300 49 51 40 55.3

0.18-0.26 . . . . . . . . . . . . 970 51 49 14 20.2

>0.26 . . . . . . . . . . . . . . . 490 25 75 3 11.9

Total (nonattainment) . . 7,100 50 50 94 117.7

Attainment regions . . . . 13,000 60 40 118.8

Total . . . . . . . . . . . . . . 20,000 56 44 236.5

aTotals are rounded.

SOURCE: EPA 1985 National Emissions Data System emissions inventory, January 1988 printout: population data from Bureau of

Census. Residential fuel combustion sources are excluded.

Figure 7-1 displays the percent contribution of

various source categories to total 1985 NOX emissions. About three-quarters of the emissions are

generated from two main categories: mobile sources

and electric utility boilers. About a third of the 1985

emissions inventory is composed of highwayvehicle emissions. A further breakdown of the data,

shown in figure 7-2, reveals that passenger cars are

the largest contributors within the highway-vehicle

category, with about 17 percent of the total 1985

NOX emissions, followed by heavy-duty diesel

trucks with 9 percent. It is interesting to note that in

cities with ozone design values greater than 0.26

ppm (southern California), mobile sources account

for almost three-quarters of the total NOX emissions.

In other nonattainment cities, mobile sources contribute between about 42 and 49 percent of total NOx

emissions.

Tables 7-2 through 7-4 display our projections of

NOX emissions in 1994, 1999, and 2004, assuming

that existing State and EPA regulations do not

change. Under current regulations, total NOX emissions increase steadily between 1985 and 2004,

showing an increase of about 7 percent between

1985 and 1994, and 27 percent between 1985 and

2004.

Although the number of vehicle-miles traveled is

forecast to increase in many areas through 2004, the

gradual replacement of current vehicles with newer,

cleaner ones will result in an overall decline in

highway-vehicle emissions by 1994. However after

1994, total highway-vehicle emissions will begin to

increase because of the dominant influence of

increasing vehicle-miles traveled. Stationary source

emissions, on the other hand, are forecast to increase

continuously between 1985 and 2004, showing an

18-percent increase by 1994 and a 45-percent

increase by 2004, over 1985 levels.2 About 60

percent of the stationary source growth between

1985 and 1994 is contributed by electric utility

boilers. These sources are estimated to increase

about 18 percent by 1994, and 38 percent by 2004,

from 1985 levels. Figure 7-3 shows mobile and

stationary source NOX emissions through time. The

net increase in total emissions from 1985 to 1994

would be much greater were it not for the 12-percent

decline in highway-vehicle emissions by 1994.3

Our emissions projections for large stationary

sources other than utility boilers may be somewhat

high because we do not model the effect of New

Source Performance Standards (NSPS), control

requirements that apply to new and modified large

zFuture emissions from elatric utility Wilers were estimated based on growth in electricity demand per capita. We assume that between 1985 and

1994 expansion of existing sources will account for all the growth in utility boiler emissions; after 1994, growth is assumed to come from new sources

(which have lower NOX emission rates). For industrial boilers, gas turbines, process heaters, and stationary engines, estimates were based on growth

in Gross National Product per capita. Population growth rates were used for all other stationary source categories.

sFuture highway vehicle emissions were proj~ti using EPA estimates of future highway vehicle VOC emission rates, combined with estimates

of average yearly miles-travelled per person, and Census Bureau population projections.
156 . Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 7-1—NOX Emissions in 1985, by

Source Category

Percent of total NOX emissions

o% 10% 20 % 30% 40% 50%

Mobile sources

Elec utility boilers

Industrial boilers

Industrial processes

Stationary engines

Comm/instit. boilers

Process heaters

Gas turbines

Other sources )

Total emissions = 20.3 million tons/year

Stationary sources that emit more than 50 tons per year of NO, are

included in the “Large” categories.

SOURCE: OTA, from EPA’s National Emissions Data System (NEDS) and National

Md Prwpkatiotl As eeaament Progrsm emissions inventories.

NO, emission sources.4 However, the effect on our

overall emissions estimates is small because, as

illustrated in figure 7-3, utility boiler emissions

(which do factor in NSPS requirements) will have a

much more significant impact on future estimates of

total NOx emissions than other large stationary

sources.

Potential NOX Emissions Reductions From

Control Strategies Analyzed by OTA

In this section we analyze the NOX emissions

reductions from, and costs of, the following sourcespecific control strategies:

● controls on major existing stationary sources;

● inspection and maintenance (1/M) programs for

highway vehicles; and

. more stringent exhaust emission standards for

gasoline highway vehicles.

Throughout the analysis, emissions reductions

reported apply to the change occurring between

1985 and the relevant future year. The emissions

Figure 7-2—NOX Emissions from Mobile Sources in

1985 as a Percentage of Total (Mobile plus Stationary) —

Emission s

Passenger cars

LD gasoline trucks

Off-highway vehicles

Air, rail, marine

HD gasoline trucks

HD diesel trucks

1

0% 5 % 1 0 % 1590 20%

Percent of total emissions

LD = light-duty; HD = heavy-duty

Total NOX emissions = 20.3 MM tons/year

SOURCE: Office of Technology Assessment, 1989.

reductions reported in our analysis result from

currently available control methods that we know

can be applied in the near-term. We were able to

analyze the emissions reduction potential and associated control costs for strategies applicable to about

86 percent of current NO, emissions. Source categories for which we had emission control information

include electric utility and large industrial boilers,

gas turbines, stationary engines, process heaters, and

highway vehicles. The remaining 14 percent of NOX

emissions for which we did not have control

information include commercial and institutional

boilers, industrial processes, and miscellaneous

small sources.

All control strategies listed above can be restricted to ozone nonattainment cities if desired,

except for more stringent tailpipe standards which

would apply nationwide. Tables 7-5 through 7-7

present estimates of emissions reductions achieved

in 1994, 1999, and 2004, respectively, if the various

control strategies listed above are applied. We

estimate that NOX emissions in nonattainment cities

can be reduced by 1.2 million tons per year in 1994,

about 17 percent below 1985 levels. By 2004, total

d~ew ~~atiom ~~re that new stitionq sowces with the potentkd to emit more than 100 tons per year install stringent emission controls. These

same control requirements apply to major modifications of existing sources that result in a NOX emissions increase of more than 40 tons per year. More

stringent controls are required in nitrogen dioxide nonattainment areas; as of 1986, the Ims Angeles metropolitan area was the only region in the Nation

that exceeded this standard,
Chapter 7—New Opportunities for Controlling Ozone ● 157

Table 7-2--Summary of 1994 NOX Emissions in Nonattainment Cities

and Attainment Regions (emissions in 1,000 tons per year)a

NOX emissions Change from 1985 emissions

Total Stationary Mobile Total Stationary Mobile

Nonattainment cities by

design value category

(in ppm O3)

0.13-0.14 . . . . . . . . . . . 2,400 1,500 880 5% 16% –lo%

0.15-0.17 . . . . . . . . . . . 3,500 1,900 1,600 4% 18% –870

0.18-0.26 . . . . . . . . . . . 1,100 620 450 1 0%0 250/. –6%.

>0.26 . . . . . . . . . . . . . . —490 150— 340 I % 21% –6%

Total (nonattainment) . . 7,400 4,200 3,200 5% 18% –8%

Attainment regions ‘. .. 14,000 9,400 5,000 80/0 180/0 –6%

— —

Total . ............22,000 14,000 8,200 7% 180/0 –7%

aTotals are routi.

SOURCE: Office of Tschncrbgy Aaaasament, 1989.

Table 7-3-Summary of 1999 NOX Emissions in Nonattainment Cities

and Attainment Regions (emissions in 1,000 tons per year)a

NO, emissions Change from 1985 emissions

Total Stationary Mobile Total Stationary Mobile

Nonattainment cities by

design value category

(in ppm O3)

0.13-0.14 . . . . . . . . . . . 2,600 1,700 900 1 1% 260/. –8°7&

0.15-0.17 . . . . . . . . . . . 3,700 2,100 1,600 1 20/0 290/o –50/0

0.18-0.26 . . . . . . . . . . . 1,200 700 460 20% 43% –3%

>0.26 . . . . . . . . . . . . . . 510 170 340 5 % 3 8 % – 6 % — —

Total (nonattainment) . . 7,900 4,600 3,300 12% 30%0 –60/0

Attainment regions .. .16,000 — 10,000— 5,200 170/’ 31% –2%0 — —

Total . ..............23,000 15,000 8,500 16% 30% –3%

aTotals are roundad.

SOURCE: Office of Technology Asaassment, 1989.

Table 7—Summary of 2004 NOX Emissions in Nonattainment Cities

and Attainment Regions (emissions in 1,000 tons per year)a

NOxemissions Change from 1985 emissions

Total Stationary Mobile Total Stationary Mobile

Nonattainment cities by

design value category

(in ppm O3

0.13-0.14 . . . . . . . . . . . 2,800 1,800 960 21% 37% –1%

0.15-0.17 . . . . . . . . . . . 4,000 2,300 1,700 22% 42% 2%

0.18-0.26 . . . . . . . . . . . 1,300 810 500 350/0 640/. 50/0

>0.26 . . . . . . . . . . . . . . — — 550 190 360— 13% 56% –1%

Total (nonattainment) . 8,700 5,100 3,600 230/. 44% 1%

Attainment regions .. .17,000 — — 11,000 5,700— 300/o 45% 80/0 — — —

Total . ............26,000 17,000 9,300 27% 45% 5%

aTotals are rounded.

SOURCE: Office of Technology Assessment, 1989.
158 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 7—Summary of Estimated Nationwide NOX by Source Category, by Year

Emissions (miIIion tons/yr)

10.0

8.0

6 . 0

4 . 0

2 . 0

0 . 0

6 . 8

4.18

8 . 6

I

9 . 3

F

the r large stat ion.

ilers

es

198 5 1994 199 9 200 4

Year

The numbers directly above the boxes are the total emissions within the source category. For example, emissions from highway vehicles

in 1994 are 6.0 million tons per year, nationwide. Assumes no regulations other than those in place in 1987.

SOURCE: Office of Technology Assessment, 1989.

emissions reductions from these control measures in Figure 7-4 displays our estimates of emissions

nonattainment areas increase to about 2 million tons reductions resulting from each control strategy in

per year, about 28 percent below 1985 levels. An 1994 and 2004, as a percentage reduction below total

additional 810,000 tons per year would be elimi- 1985 emissions in nonattainment cities. The largest

nated in attainment areas by 2004 due to new reductions come from instituting controls5 on elechighway-vehicle emission standards. tric utility boilers. The percentage reductions are

SFO~ tie= ~~~~te~ we ~~w~ tie ~ of m~erately ~gent control t~~iques which we co~ider to ~ reasonably available COtltI’01

teehnohgiea (RACY). Controls include boiler combustion modiilcatiom such as tie tistallation of low NOx-emi~g fwl b~erss r~uc@3 ~r flow

through the boiler, and other techniques.
Chapter 7—New Opportunities for Controlling Ozone ● 159

Table 7-5-Potential NOX Emissions Reductions in 1994 Compared to 1985 Emissions From

Source-Specific Control Strategies (emissions reductions in 1,000 tons par year)a

Stationary source controls

Industrial boilers,

gas turbines, New highwayUtility stationary engines vehicle emission Total

boilers process heaters Enhanced l/M standards reductions

Nonattainment cities by

design value category

(in ppm O3

)

0.13-0.14 . . . . . . . . . . . . . 440 83 54 0 570

0.15-0.17 . . . . . . . . . . . . . 290 110 86 0 480

0.18-0.26 . . . . . . . . . . . . . 63 48 27 0 140

>0.26 . . . . . . . . . . . . . . . . 5 12 19 0 37

Total (nonattainment) . . . 790 250 190 0 1,200

Attainment areas . . .’. . . . 0 0 0 0 0

Total . . . . . . . . . . . . . . . 790 250 190 0 1,200

aTotals are roundad.

Straragy descriptions;

Statlonaw aourw controfa = moderately stringent controls on all existing stationary sources that emit more than 100 tons par year of NO,. considered to be “reasonably available

control tachndogias.”

Enhmcad l~tlon and maln~ (1#) programs for cars and Iightduty trucks.

New highway-vehkfa afWaafon standanls for passenger cars and Ightduty gasoline trucks.

SOURCE: Offfca of Ttiogy Assessment, 1969.

Table 7-6—Potential NOX Emissions Reductions in 1999 Compared to 1985 Emissions From

source-specific Control Strategies (emissions reductions in 1,000 tons per year)a

Stationary source controls

Industrial boilers,

gas turbines, New highwayUtility stationary engines vehicle emission Total

boilers process heaters Enhanced l/M standards reductions

Nonattainment cities by

design value category

(in ppm O3)

0.13-0.14 . . . . . . . . . . . . .

0.15-0.17 . . . . . . . . . . . . .

0.18-0.26 . . . . . . . . . . . . .

>0.26 . . . . . . . . . . . . . . . .

Total (nonattainment) . . .

Attainment areas . . . . . . .

Total . . . . . . . . . . . . . . .

460

300

69

6

0

840

97

120

57

14

o

290

55

88

27

19

190

0

190

100

170

43

0

310

470

780

710

680

200

38

1,600

490

2,100

aTotafs are rOUfldSd.

StitWy daacnpfions:

StaMOrUry source COntrola = moderately strfngant controls on all existing stationary sources that emit more than 100 tons par year of NO,. considered to be “reasonably available

control technologies.”

EIMImcad Impoctbn md malntananca (l/M) programs for cars and Iightduty mucks.

Naw highway.vehkfe ~aalon statirda for passenger cars and Iightduty gasoline trucks,

SOURCE: office of Technology Assessment, 1989.

about the same for each category between 1994 and Figure 7-5 displays potential emissions reduc2004, except for new highway vehicle standards, tions and the percentage of emissions that remain

which increase over time due to the gradual replace- after all of the reductions have been accounted for by

ment of older cars with newer ones equipped with 1994 and 2004. In 1994, after all controls are

additional controls, applied, emissions are approximately 83 percent of
160 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 7-7-Potential NOx Emissions Reductions in 2004 Compared to 1985 Emissions

From Source-Specific Control Sttategies (emissions reductions in 1,000 tons per year)a

Stationary source controls

Industrial boilers,

gas turbines, New highwayUtility stationary engines vehicle emission Total

boilers process heaters Enhanced l/M standards reductions

Nonattainment cities by

design value oategory

(in ppm 03

)

0.13-0.14 . . . . . . . . . . . . . 490 110 58 170 830

0.15-0.17 . . . . . . . . . . . . . 320 130 94 290 840

0.18-0.26 . . . . . . . . . . . . . 75 67 29 74 240

>0.26 . . . . . . . . . . . . . . . . 6 16 19 0 41

Total (nonattainment) . . . 200 530 2,000

Attainment areas . . . . . . . 0 0 0 810 810

2,800

aTotals am rounded.

Strategy desc@ona:

Slalfonmy aourca mntrofs. modemteiy strfrrgsnt controls on all existing stationary sources that emit more than 100 tons per year of NO,. Considered to be Weasonsbly available

control teotrrd “

mmcod Sn ● f~ln~ (l/N) programs for cars and li@t4uty trucks.

Naw highway-vohkle emlnion stati@a for passenger cars and Iightduty gasoline trucks.

SOURCE: Office of Technology Assessment, 19S9.

Figure 7-4—NOX Emissions Reductions in 1994 and 2004 Compared to 1985

Emissions reductions in 1994

Emissions, by Control Method

Emissions reductions in 2004

+ Elec utility boiler

+ Other RACT

Enhanced l/M

New mobile std’s.

+ Elec utility boiler

+ Other RACT

Enhanced l/M

Not effective in 1994 ● New mobile std’s.

t 1 1 r

( 1 I , I I r , r 1 I

-l

O% 2% 4% 6% 8% 10% 12% O% 2% 4% 6% 8% 10% 12%

Percent reductions from 1985 emissions Percent reductions from 1985 emissions

+ Controls o n sources emitting more than 100 tons per year.

● Reductions are also achieved in attainment areas.

See text for description of control methods.

SOURCE: Office of Technology Assessment, 1989.

the 1985 total. By 2004, the emissions that remain emissions between 1994 and 2004 is due to the

after all controls are applied declines to about 72 increased effectiveness of more stringent highwaypercent of 1985 levels. The drop in remaining vehicle emission standards.
Chapter 7—New Opportunities for Controlling Ozone ● 161

Figure 7-5-Potential NOX Emissions Reductions and Remaining Emissions in 1994 and 2004 as a Percentage of

1085 Emissions in Nonattainment Cities

Emissions reductions and remaining emissions in 1994 Emissions reductions and remaining emissions in 2004

Highway vehicles 30.1% Highway vehicles 21.1%

● Other large stationary- includes: industrial boiIers,

stationary engines, gas turbines, and process heaters.

The pulled-out slices represent emissions that can be eliminated by each control method. The six connected slices represent emissions

that remain after all control methods are applied. “Large” emission sources are defined as those which emit more than 50 tons per year

. .

N OX. See text for description of control methods. -

SOURCE: Office of Technology Assessment, 1989.

Approximately 22 percent of the remaining

emissions in 1994 comes from two categories

(shown in figure 7-5): 1) commercial and institutional boilers, and industrial processes, and 2) small

industrial and other boilers. The 14 percent of the

inventory for which we were unable to identify

control methods is composed entirely of these two

categories. Although controls were applied to utility

boilers, this category still accounts for about 16

percent of the inventory after control in 1994 (based

on 1985 emissions). As we will discuss later, these

estimates do not reflect the most stringent level of

control possible for existing stationary sources.

The following subsections summarize the emissions reduction potential of each individual control

strategy.

Controls on All Major Stationary Sources

The following subsection presents estimates of

emissions reduction potential after applying NOX

controls at two levels of stringency. The first level

represents control techniques of moderate stringency, or what we may consider reasonably available control technologies (RACT). This is the

control level used in the estimates discussed in the

previous section. The second level represents the

most stringent level of control achievable given

current technology.

In our analysis, we have applied controls on five

source categories: electric utility boilers, industrial

boilers, stationary engines, gas turbines, and process

heaters. 6 Data on the emissions reduction potential

6For exmple, NOx Cmiwiom ~m utdi~ and industri~ ~ilers can be reduced by installing devices which alter the way he] is combusti i~ide

the boiler.
162 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

and associated costs of the control technologies used

in our analysis were supplied by E.H. Pechan &

Associates, Inc., and were used in a recent report to

EPA [34].

Moderately Stringent Controls. We estimate emissions reductions achievable through RACT-level

regulations by simulating controls on all existing

stationary sources that emit more than 100 tons of

NOX per year in those cities that did not have an

existing regulation for a particular source category

as of 1985.7 For this analysis, additional RACT

controls are applied only in nonattainment cities.

We estimate that applying RACT to all sources

would lower NOx emissions by approximately 1

million tons per year in 1994, representing a

15-percent decline based on 1985 levels. Electric

utility boilers, alone, account for about threequarters of this total reduction. By 2004, RACT

reductions are estimated to increase to about 1.2

million tons per year, from 1985 levels.

Most Stringent Controls. If the most stringent

control technologies are required on sources that

emit more than 100 tons of NOX per year, about 2.1

million tons per year could be eliminated from

nonattainment cities in 1994, more than double the

amount achieved through RACT-level control. Lowering the source size cutoff from 100 to 25 tons per

year while requiring the most stringent controls adds

about an additional 100,000 tons per year of

emissions reductions to this total.

Enhanced Motor Vehicle Inspection and

Maintenance (I/M) Programs

The definition and scope of our analysis of an

enhanced I/M program were outlined in chapter 6.

Emissions reduction benefit assumptions were taken

from Sierra Research, Inc. [37]. We assume that the

NOX emissions reduction potential from existing I/M

programs is about 4 percent. The full benefit from

enhanced programs is about 14 percent, while the

incremental benefit gained by switching from an

existing to an enhanced program is about 10 percent.

We estimate that enhanced I/M programs in

nonattainment cities will reduce NOX emissions by

about 190,000 tons per year in 1994 and by 200,000

tons in 2004.9 This represents about a 3-percent

reduction in both 1994 and 2004, based on 1985

emissions.

More Stringent Highway-Vehicle Emission

Standards

This analysis includes the NOX emissions reduction potential of instituting more stringent tailpipe

controls on new passenger cars and light-duty

gasoline-fueled trucks. The standards we analyzed

were determined to be the most stringent technologically feasible, given currently “available” control

technology, according to Sierra Research, Inc. [37] .10

Sierra Research, Inc., assumes that these standards

can be met after 50,000 miles of controlled test

driving for passenger cars, and 120,000 miles for

light-duty trucks.ll These standards are discussed in

more detail in chapter 6. We assume that new

standards go into effect in 1994 for both passenger

cars and light-duty trucks.

We estimate that new highway-vehicle standards

will reduce NOX emissions in 1999 by about 4

percent, both nationwide and in nonattainment

cities. By 2004, reductions increase to about 7

percent in both nonattainment and attainment areas,

based on 1985 emissions. Again, the increase in

emissions reductions over time is due to the gradual

vIf a so~ce &eady had a con~o] device mat res~t~ in an emissions reduction of more than 10 percent, a regdation was ttSSUMed tO exiSt for that

source and no further controls were applied.

8we ~we tithe hi~estlevel of NOx con~ol could& achiev~ ~ou@ a process c~l~ ~efe~tive c~a~tic red~t~n which eliminates nitrogen

oxides hm fuel combustion exhaust gases.

9vo]~11e Orgaic compound emission5r~uction5 from efi~c~~pro~~s Me discus~ in chapter 6. c~bon monoxide ~d particulate

emissions reduction benefits are also gained, but are not calculated in this analysis.

1O~cor@ t. Siema Re~~h, ~c., more s~ngent Nox stan&& for heavy-duty die~l-fuel~ ~kswere not considered to k tdlnolOgkdly

feasible given current technology and, thus, were not analyzed.

ll~e new Nox emission standards used in our analysis are as follows: (in “grams of NOX emitted per mile ~avekd,” ~mile)

Passenger cars: 0.4 g/mile

Light-duty gasoline trucks (by weight)

(less thn 3,750 pounds): 0.46 @mile

(3,75 1 to 6,000 pounds): 0.80 g/mile

(6,001 to 8,000 pounds): 1.15 g/mile
Chapter 7—New Opportunities for Controlling Ozone ● 163

replacement of older vehicles with newer, cleaner

ones. Since California has already adopted standards

to those we analyze here, further emissions reduction credits due to this control strategy are not

assigned to cities in this State.12

Costs of NoX Contol Strategies

Analyzed by OTA

This section summarizes the costs of the three

NOX control strategies discussed previously. Of the

three, only one—RACT-level controls on stationary

sources emitting more than 100 ton per year-was

not included in the cost of more “traditional”

controls presented in chapter 6. Thus, the costs of the

NOX controls that we considered, over and above the

VOC control costs presented earlier, are about $550

million per year in 1994 and about $670 million per

year in 2004. We have assumed that stationary

source controls are applied in all nonattainment

areas, regardless of their effectiveness for lowering

ozone concentrations.

The costs for all three programs, of course, is quite

a bit higher. We estimate that, in 1994, the total cost

of all controls is about $2.0 to $4.0 billion per year

in nonattainment cities, and about $2.8 to $4.8

billion per year, nationwide. By 2004, costs will

increase to about $3.7 to $6.2 billion per year in

nonattainment cities, and to about $5.4 to $7.9

billion per year, nationwide. This increase is primarily because of the higher percentage of highway

vehicles equipped with more stringent controls.

Again, two of the programs will provide multiple

emissions reduction benefits. In addition to reducing

NOX emissions, enhanced I/M programs and more

stringent highway-vehicle standards also reduce

VOC emissions. Furthermore, I/M programs also

reduce emissions of carbon monoxide. Table 7-8

displays the ranges of costs in nonattainment in 1994

and 2004 by source category. Figure 7-6 displays the

ranges of costs in nonattainment cities in 1994 and

2004.

Table 7-9 presents the “cost-effectiveness” of

specific control measures for 1994 and 2004. Figure

7-7 illustrates the cost-effectiveness of control

measures in nonattainment in 1994. The solid bars

represent the average cost-effectiveness in all nonatTable 7-8--Estimated Costs of Selected NOX Control

Methods in Nonattainment Cities in 1994 and 2004

(In million dollars per year)aNonattainment

cities

1994 2004

Stationary source controls

Electric utility boilers . . . . . . . . . . . . . . . . . 320 360

Industrial boilers, stationary

engines, gas turbines,

process heaters . . . . . . . . . . . . . . . . . . . 230 310

Enhanced I/M (for NOx, VOC,

and CO)b . . . . . . . . . . . . . . . . . . . . . . . . 2,500 3,100

New highway-vehicle emission

standards (for NOx, and VOC)C. . . . . . — 1,200

Total (high estimate)e . . . . . . . . . . . . . . . . 4,000 6,200

aTotals are mmded.

hhasa estimates ara also presented in ch. 6. Enhanced IIM costs range between $1.5

billion and $3.5 billion per year in 1994. NO, costs are approximately one-sixth of this

total.

CThse estirna~s we al~ pre%rlted in ch. 6. Costs in attainment areas are about $1.7

billion h 2004. On average, about two-thirds of the cost is attributable to NO, contrul.

dA~ut $1.5 Mllion and $.3. I billion per year in 1994 and 2004, respectively, am also

presented in ch. 6.

eAbout $3,5 billion and $5.5 billion par year in 1994 and 2004, respectively, are ~so

presented in ch. 6.

.Wategy daacriptbns

Stationary ammo controls = moderately stringent oontrols on all existing stationary

sources hat emit more than 100 tons par year of NO,. Considerad to be “reasonably

available control technologies.”

Enheneod ln8poetton ● d rnalntemnea (t/M) programs for cars and Iightduty trucks.

New htghway-vohlcto ondaalon standar~ for Pamer cars and Iightdutygesoline

trucks.

SOURCE Ofhc.e of Technology Assessment, 1969.

tainment cities. Uncertainty in cost-effectiveness

estimates is denoted by the thin horizontal lines. The

average cost-effectiveness for control strategies

varies between $400 per ton of NOX reduced (for

electric utility boilers) to about $2,200 per ton

(enhanced I/M programs). Note that for cities with

ozone design values greater than 0.26 ppm (southern

California), the cost of controls on electric utility

boilers is much higher than the average nonattainment city estimate. Since this region has already

adopted measures to control NOX emissions from

these, and other, sources (e.g., use cleaner burning

fuels), each dollar spent on further NOX controls

yields relatively less emissions reductions.

A brief discussion of the costs and costeffectiveness of each of the control strategies,

12c~1fofia’S ~optionof Sfiilm highway.vehicle emi~ion ,q~dard5 is refl~ted in ow estimates of fume emissio~ that will OCCLU with (3XlSthlg

controls as presented in tables 7-2 through 7-4.
164 • Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 7-6-Estimated Cost of NOX Emission Control

Methods in 1994 and 2004 in Nonattainment Cities

Not effective in 1994

New mobile std’s

,

0.0 0.5 1.0 1.5 2.0 2:5 3.0 3.5

Cost (billion dollars per year)

● Assumes sources emitting greater than 100 tons/year

are subject to RACT controls.

Of the four control methods shown above, only two—controls on

electric utility boilers and RACT-level controls on other stationary

sources emitting more than 100 ton per year-were not included

in the cost of more “traditional” controls presented in Chapter 6.

Thus, the costs of the NOx controls that we considered, over and

above the VOC control costs presented earlier, are about $550

million per year in 1994 and about $670 million per year in 2004.

See text for description of control methods.

SOURCE: Office of Technology Assessment, 1989.

including the data sources

are calculated, follows.

from which the estimates

Controls on All Major Stationary Sources

If moderately stringent controls13 are required,

total costs in nonattainment cities for this category

are estimated to be about $550 million per year in

1994, averaging about $240 to $1,100 per ton of NOX

removed. 14 Controls on electric utility boilers account for about 58 percent of this total ($320 million

per year).

If the most stringent level of control15 is required,

the total cost for this category increases dramatically

to about $8.3 billion per year in 1994. As mentioned

earlier, these controls buy about an extra 15 percent

more emissions reductions than RACT-level controls. While lowering the source-size cutoff from

100 to 25 tons per year adds an additional 2 percent

Table 7-9-Estimated Cost-Effectiveness of Selected

NOX Control Methods in Nonattainment Cities in

1994 and 2004 (in dollars per ton of NOx reduced) a

Cost-effectiveness

1994 2004

Stationary sources controls

Electric utility boilers . . . . . . . . . . 240-5,50@ 240-5,500 b

Industrial boilers, stationary

engines, gas turbines,

process heaters . . . . . . . . . . . 690-1,400 670-1,400

370-2,700 390-2,500

Enhanced I/Mc. . . . . . . . . . . . . . 1,200-3,300 1,400-4,400

Nswhighwsy-vehicle emission

standanrds c . . . . . . . . . . . . . . . — 1,600

aTomls are rounded.

bExcludi~ U-W sou~m California cities, the upper-bound estimate is about $1,000 PW

ton of NOX reduced.

CI~u*s COStS of NO, only.

Strategy descriptions

Stattonaty aoureo controls = moderately stringent controls on all existing stationery

souroes that emit more than 100 tons per year of NOX. Considered to be “reasonably

available control technologies.”

Enhmeed Irmpoctlon and rnalntortsnea (Vu) programs for cars and Iightduty trucks.

Naw highway-v.hlctoomt8slon atandardsfor passenger csrsand Iightduty gasoline

trucks.

SOURCE: offkx of Technology Assessment, 19S9.

onto the reductions achieved using the most stringent level of control, it does so at an additional cost

of $1.7 billion per year.

Enhanced Motor Vehicle Inspection and

Maintenance (I/M) Programs

We estimate that enhanced I/M programs in

nonattainment cities cost between about $1.5 billion

and $3.5 billion per year in 1994. In 2004, costs are

expected to rise to between about $1.9 billion and

$4.3 billion per year. We assume that about half of

the costs are attributable to carbon monoxide control

and the other half to ozone control. Of the ozone

fraction, we assign about one-third of the cost to NO,

and the other two-thirds to VOC. Assuming that

one-sixth of the total cost of I/M programs is for NOX

reductions, the cost-effectiveness in 1994 is estimated to be between $1,200 and $3,300 per ton of

NOx, eliminated.

13wC define m~entely s~ngent ~m~ol ~~ques to include ~iler combustion m~fications such M tie ins~]ation of IOW NOx-emitting fuel

burners, reducing air flow through the boiler, and other techniques.

IdAverage ~o~-eff=tiveness excludes ~tima~s for tie ~w sou~em &Ii fornia cities wi~ o~ne design v~ues greakr b 0.26 ppm. The average

cost-effectiveness for electric utility boiler controls in these areas is about $5,500 per ton. The cost-effectiveness is higher in these regions because

measures to control NOX emissions have already been adopted, so that each dollar spent buys leas emissions reductions.

lswe &fiW mmt agent con~ol ~~iques to include selective catalytic reduction which eliminates NOX from fuel combustion efiaust gws.
Chapter 7—New Opportunities for Controlling Ozone ● 165

Figure 7-7—Estimated Cost-Effecttveness of NOx

Emission Control Methods in 1994 in Nonattainment

cities

I

* Elec utility boilers

* Other RACT

Enhanced l/M

New mobile std’s

* 100-ton/year RACT

Est. $/ton for cities

with ozone design values

greater than 0.26 ppm

,

Cost-effectiveness in 2004 I

7

012345 6

$1OOO per ton of NOX reduced

source-size cutoff

The cost-effectiveness of enhanced inspection and maintenance

(l/M) programs and new mobile standards include only the cost of

NOX control. The thick horizontal bars represent the average

cost-effectiveness in nonattainment cities. The thin horizontal line

for l/M programs represents the range of uncertainty associated

with assumptions we used to estimate total annual costs. We were

unable to estimate cost-effectiveness uncertainty for other control

methods. See text for a description of control methods.

SOURCE: Otfke of Technology Assessment, 19S9.

Our estimates of enhanced I/M program costs

are based on an analysis of the California I/M

program, prepared for the California Air Resources

Board by Sierra Research, Inc. [37]. We use Sierra

Research’s finding that an enhanced I/M program

costs about $34 to $55 per vehicle per year. About

$20 of this cost is for the inspection fee and program

administration. The remainder is for repair costs,

which we assume to range between $70 and $100 per

vehicle. We also assume that 20 and 35 percent of

the vehicles tested will fail.l6

More Stringent Highway-Vehicle Emission

Standards

We estimate that the total cost of more stringent

VOC and NOX exhaust standards for highway

vehicles in 1999 will be about $1.6 billion per year,

nationwide, of which about $0.66 billion per year

will be incurred in nonattainment cities. By 2004,

costs increase to about $2.9 billion per year,

nationwide, because a higher percentage of vehicles

on the road will be equipped with new controls.

About 70 percent of the costs are for controlling

NOX.

The cost-effectiveness of these controls in 2004 is

about $1,600 per ton of NOX reduced. As discussed

in an earlier section, our cost estimates are based on

a Sierra Research, Inc. report which concluded that

more stringent emission standards would cost about

$140 per vehicle (combined cost for NOX and VOC

emissions control) [37].

OPPORTUNITIES FOR

LOWERING EMISSIONS FROM

SOLVENT USE

To find the additional VOC emissions reductions

needed to meet the ozone standard, many nonattainment cities may want to consider new ways of

controlling emissions from organic solvent use.

Although some State and Federal regulations controlling organic solvent emissions already exist,

most have traditionally focused on larger sources.

Much of the emissions from organic solvent use,

however, originate from smaller sources (which

vastly outnumber their larger counterparts). Because

controls on some of the smaller organic solvent

emission sources have been considered to be either

technically, economically, or administratively infeasible, many of these sources are exempt from

current regulations.

This section characterizes several aspects of

organic solvent use in nonattainment areas that may

be of interest when developing new control strategies. The first part describes: a) the relative contribution of various solvent end uses to total VOC

emissions in nonattainment areas, b) the distribution

of solvent emissions by source size, c) the fraction

of solvent emissions that are currently covered by

existing Federal and State regulations, and d) source

categories where future significant emissions reductions may be possible. The section continues with a

description of how various States are planning to

capture uncontrolled organic solvent emissions. The

section concludes with a discussion of market-based

approaches to controlling solvent emissions.

l~e 1OW ~ ~X -ate ~swes that a repti c~t of $7o per vehicle will be levied on the 20 percent of the vehicles which fail; the hi@ estimate

assumes $lW repair cost on 35 percent of the vehicles.
166 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Sources of Organic Solvent Use

Solvents are used in such diverse applications as

surface coatings, cleaning agents, decreasing, and

drycleaning, and in many other industrial applications. Solvents are also used in a wide variety of

commercial and consumer products such as insecticides, various household cleaners, nail polish and

remover, underarm deodorants, hair spray, window

cleaners, spot removers, automotive products, adhesives and sealants, pesticides, and many others. In

1985, VOC emissions from organic solvent evaporation in nonattainment areas were about 2.7 million

tons per year, or about 27 percent of total emissions. 17

The above estimate assumes that 100 percent of

the solvent purchased in 1985 is eventually emitted

to the atmosphere. However, in response to existing

regulations, some sources may recycle or destroy

excess solvent emitted from their operations. Therefore we may have overestimated actual emissions.

Figure 7-8 displays organic solvent emissions as a

percentage of total emissions in nonattainment

areas. We use the same end use categories, and

solvent purchased therein, as EPA used in the 1985

National Acid Precipitation Assessment Program

(NAPAP) inventory. Industrial solvent use18 accounts for about 14 percent of total nonattainment

area VOC emissions, followed by commercial and

consumer solvents, and architectural coatings at 8

and 2 percent, respectively.

Organic Solvent Use by Source Size

The Clean Air Act currently requires existing

stationary sources in nonattainment areas that emit

more than 100 tons per year of VOC to adopt

“reasonably available” control technologies. Since

bills from the l00th Congress have proposed lowerFigure 7-8-Total Solvent Use as a Percentage of 1985

Total VOC Emissions in Nonattainment Areas

Industrial uses

Consumer and

commercial

products

Architectural

coatings

—

0.23 million tons/year

I

ing the 100-ton-per-year cutoff, it is useful to see

what fraction of total solvent use in nonattainment

areas originates from sources of various sizes.

Because the 1985 NAPAP emissions inventory

does not contain source-by-source emissions data

for sources that emit less than 50 tons per year, we

had to estimate the breakdown of emissions by type

of application and by source size using a method

developed by EPA [18] based on the relationship

between solvent use and employment. By using the

number of employees 19 as surrogates for solvent use

we were able to apportion EPA estimates of solvent

use [19] to three source sizes: greater than 100, 50,

20 Since we had no employment and 25 tons per year.

data for architectural coating, consumer and commercial products, and miscellaneous surface coating, we assumed that these sources all individually

emit less than 25 tons per year.

17S~lv~~tU~d~t~U~ @U@OUt MS ~tion ~~calc~at~ b~don~e 1$)85 NatiOn~ ~id~ipi~tion As~ssment~ogr~ emissions hlVentO1’y

[59].

18~ i~~~l~o/ve~We ca~gow inclu&s the follo~g 15 su~ategofies w defin~ by WA forthe 1985 N@wemissions inventory: automobile

refinishing, new motor vehicle manufacturing, furniture and fixtures, fabricated metal products, machinery and equipment, paper coating,

factory-fmkhed wood products, non-automobile transportation equipment, elecrncal insulation, shipbuilding, metal cleaning (decreasing), dry cleaning,

printing, rubber and plastics production and other miscellaneous surface coatings.

lgData on tie num~r of employees and fms are fkom U.S. Department of Commerce, Bureau of the Census [~].

we assume that the ratio of solvent use to the number of employees in a particular solvent category is the same (i.e., each employee uses the same

amount of solvent) for all three source size categories. The ratio of emissions (rather than solvent W) to employment will be smaller if individual sources

choose to comply with existing State or Federal regulations by incinerating or recycling excess solvent.
Chapter 7—New Opportunities for Controlling Ozone ● 167

50- 9

25-4

Figure 7-9-Total 1085 Solvent Use In Nonattainment Areas, by Source Size

18% ‘/ \ \

9 tons/yr

5%

.9 tons/yr

6%

major i t y

< 50 ton

<

. .

25 tons

58%

. .

/ y r

Consumer and

Commercial Products ●

56%

Architect. Coatings ●

14%

Small Industrial

29%

Solvent use =

Total solvent use - 1.5 miIIion tons/year

2.7 m i I I ion tons /year

● These sources em i t much less t ha. 25 tons per year.

Solvent use in the “less-than-25-tons-per-year” category is probably understated since an unknown fraction in the “majority

less-than-50-tone-per-year” category may actually originate from sources using lees than 25 tons per year. The latter category contains

solvent use that EPA has identified as miscellaneous surface coatings. Because of the way EPA constructs this category, we were

unable to disaggregate solvent use below 50 tons per year.

SOURCE: Off&x of Tti~y Asssmament, 1W9.

Figure 7-9 displays the contribution of different

source sizes to total solvent use in nonattainment

areas. Note that about three-quarters of the total

solvent use (2.1 million tons per year) originates

from sources that emit less than 50 tons per year.

Sources less than 25 tons per year account for about

1.5 million tons per year, or about 60 percent of the

total.21 About one-quarter of the solvent used came

from sources greater than 50 tons per year.

Figure 7-10 displays a more detailed breakdown

of 1.6 million tons per year of industrial solvent use

in nonattainment areas presented in figure 7-8.

About 480,000 tons originate from sources greater

than 100 tons per year. As mentioned earlier, this is

the size category that existing State and Federal

VOC regulations have traditionally targeted.22 As

we will discuss later, not all sources in this size class

have been subject to regulations.

Figure 7-10 also shows that at least 30 percent of

the industrial solvent use, or nearly 450,000 tons,

originate from sources emitting less than 25 tons per

year, mostly in the decreasing, printing, and drycleaning categories. This estimate should be considered a

lower bound since an unknown fraction of use from

miscellaneous surface coatings may also come from

less-than-25-ton sources. Therefore, if we include all

miscellaneous surface coatings in our estimates,

sources less than 25 tons per year may contribute as

much as 810,000 tons per year, or about 50 percent

of total nonattainment industrial solvent use.

Figure 7-11 displays the breakdown of total

solvent use, by source size, that is covered by State

and Federal regulations as of 1985. Information on

the regulatory status of various source categories

was obtained from EPA summaries of State VOC

regulations [57,58]. We estimate that approximately

W’his peremtage is probably underestimated since some of the solvent use in the majori(y-kss-than-50-tom slice shown in the figure may belong

in& less-than-25-ton category. The former category contains solvent use that EPA has identified as miscellaneous surface coatings, and could include

sources that are both less than and greater than 50 tons per year. Since we were unable to determine employee fkxions associated with this category,

we chose not to disaggregate the solvent use below 50 tons per year.

~some Stm ~Wl~ms, however, IW@m c.ntroIs on sources in nonattainment SKMJ tittit 10SS th~ 1~ tons P’ Ye~”
168 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 7-10-industrial Solvent Use in 1985 by Four Source-Size Cutoffs in Nonattainment Cities

Rubber & plastics

Auto refinishing

Paper coating

Degreasing

Printing

Furniture & fixtures

Automotive

Dry cleaning

Machinery & equip.

Fab. metal products

Transp. (non-auto)

Electrical insulat.

Marine Surf. Coating

Facto ry-F in. Wood

Misc. Surface Coat

o 50 100 150 200 2 50 3 00 350 4 00

Solvent use (1000 tons/yr)

Because of the way EPA constructs the miscellanous surface coating category, we were unable to disaggregate solvent use below 50

tons per year.

SOURCE: Office of Technology Assessment, 1989.

one-quarter of all the solvent used in nonattainment

areas in 1985 was subject to VOC emission regulations. About 45 percent of the solvent used by

sources greater than 50 tons per year was covered by

regulations, while 20 percent of the solvent used by

sources emitting less than 50 tons per year was

covered. Overall, there is about four times as much

unregulated solvent use from less-than-50-ton

sources than by sources emitting more than 50 tons

per year.

Our estimates of solvent use may overestimate

actual solvent emissions since many sources which

are subject to solvent regulations (especially those

emitting more than 50 tons per year) may use control

devices which capture or destroy excess solvent

emissions. Hence, solvent use is not always synonymous with solvent emissions.

Because many State VOC regulations are applied

on the basis of the amount of solvent used by a

source (e.g., gallons of solvent used, pounds of

clothes cleaned, etc.) rather than on the amount of

VOC emitted to the atmosphere during a year, it is

difficult to know the precise source-size cutoff for

which a particular regulation applies. Therefore, the

estimates presented here should be considered only

rough approximations.
Chapter 7—New Opportunities for Controlling Ozone . 169

Figure 7-11—Total Solvent Use Covered by Existing

- Regulations in 1985 in Nonattainment Cities

Source size

(tons/year)

All sizes

Less than 50

Greater than 50

Greater than 100

0.0 0.5 1.0 1.5 2.0 2.5

Solvent use (million tons/year)

3.0

Determinations of the regulatory status of solvent use categories

in nonattainment cities were made using EPA summaries of State

and local VOC regulations in place as of 1985 [57,58]. The

estimates presented here should be considered only rough

approximations. See text for explanation.

SOURCE: Office of Technology Assesment, 1989,

Opportunities for Additional Emissions

Reductions

Figure 7-12 displays a detailed breakdown of

solvent use, by end-use and source size, that is

covered by existing regulations. We show solvent

use that is: 1) covered by existing regulations, 2) not

covered, but for which applicable regulations exist,

and 3) not covered and for which no regulations

exist. The “Regs-Not-Applied” category refers to

solvent use that could be covered: a) if existing

regulations for larger sources were applied to

smaller sources in the same end-use category, orb)

if existing regulations in some nonattainment areas

were applied to the same end-use categories in all

other nonattainment areas. The “No-Regs-Exist”

category contains solvent use for which no regulations exist anywhere in the Nation.

Figure 7-12 shows that an additional 550,000 tons

of solvent use in nonattainment cities, or about 20

percent, could be covered if regulations currently

applied in some areas are adopted in all other areas.

This category is important because it highlights

solvent use that has the most immediate potential for

additional emissions reductions.

Of the 2.7 million tons per year of total solvent use

shown in figure 7-12, about 1.2 million tons of

solvent were used by identifiable industrial

sources

23 in nonattainment cities. Figure 7-13 presents a slightly different breakdown of this category

together with the number of firms that contain 24 We estimate that about sources of various sizes.

650,000 tons per year of solvent is used by about

150,000 identifiable industrial sources that are

already covered by control requirements. About

580,000 tons per year of solvent is used by about

90,000 sources in nonattainment areas that are not

covered by control requirements.

About 270,000 tons of unregulated solvent use in

this category, or about 45 percent, could be covered

by targeting the small number of unregulated firms

that contain sources emitting more than 100 tons per

year. The emissions reductions achieved will be

lower than our estimated solvent use and will depend

on the type of control technique required by new

regulations. 25 If unregulated sources emitting 50

tons per year or more are targeted, we estimate that

about 60 percent of the total unregulated solvent use

among identifiable industrial sources could be

covered. At this source-size cutoff, roughly 3,000

firms in nonattainment cities would need to be

identified. If the source-size cutoff is lowered from

50 to 25 tons per year, about 10 percent more solvent

use—about 410,000 tons per year-could be covered, but about two-thirds more firms would then

have to be identified. Finally, we estimate that the

addition of sources emitting less than 25 tons per

year would require the identification of about 86,000

more firms. Although including these smaller

sources would allow about 40 percent more solvent

use to be covered, about 20 times as many firms

ms= fm~ote 18 fm a list of tie 14 sources included in the identifiable industrial category.

24~ @fiw we d. not AOW ~lvent use ~m other less-than-50-ton sources including consumer prOdUCtS, ~ChiteChWd coatings and otier

miscellaneous coatings because we were unable to determine the number of firms associated with their use.

~For exmp]e, cm~ol devi~s such m incinerators can r~uce emissions from organic solvent use by about ~ percent. ~erefore tie emissions

reductions achieved by targeting unregulated IOO-ton-per-year sources would be about 240,000 tons per years.
170 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Figure 7-12—Total Solvent Use Covered by Existing Regulations in 1985, by Source Category in

Nonattainment Cities

Solvent use (m ill ion tons/year)

1.6 —

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

architectural coating

I

I

Covered

architectural coating

ident.

identifiable industria l

industrial

Regs not applied

consumer and

commercial products

miscellaneous

surface coating

No regs exist

The Identifiable industrial category includes the same sources as those in figure 7-10, except for miscellaneous surfacecoatings which

is a seperate category in the figure shown above. We show solvent use that is (1 ) covered by existing regulations in place as of 1985, (2)

not covered in a particular nonattainment area, but for which regulations do exist in other areas, and (3) not covered and for which no

regulations exist as of 1985. See text for further explanation.

SOURCE: Office of Technology Assessment, 1989.

would have to be identified compared to a strategy

which targeted sources emitting more than 25 tons

per year.

Figure 7-13 shows that solvent use from sources

greater than either 25 or 50 tons per year offers

regulators a relatively attractive target for future

emissions reductions. While including sources that

emit less than 25 tons per year would offer a

somewhat greater potential for emissions reductions, regulators would be faced with the difficult

task of locating and keeping track of a much larger

number of fins.

While some identifiable industrial sources present

a good opportunity for capturing unregulated VOC

emissions (at least from an administrative efficiency

standpoint), figure 7-12 shows that consumer and

commercial products and miscellaneous surface

coatings accounted for about 1.2 million tons, or

about 60 percent, of total unregulated solvent use in
Chapter 7—New Opportunities for Controlling Ozone ● 171

Figure 7-13—Identifiable Industrial Solvent Use Covered by Existing Regulations; and the Number of Firms

by Source Size

Solvent use (million tons/year) Firms (1000)

0.70

0.60

0.50

0.40

0.30

0.20

0.10

0.00

0.16

0.48

Less than 25 25-4 9 50-100

Source size (tons/year )

More than 100

- 250

- 2 0 0

- 1 5 0

- 100

5 0

“o

The identifiable Industrial category includes the same sources as those in figure 7-10, except for miscellaneous surface coatings which

Is excluded.

- .

SOURCE: Office of Technology Assessment, 1989

nonattainment cities.26 A large fraction of this forms of “command-and-control” regulations may

solvent use originates from sources emitting less be difficult to administer and enforce. In the next

than 50 tons of VOC per year; and in some cases, section, we review how some States are planning to

these sources emit very much less than 25 tons per control this fraction of solvent use.

year per source (e.g., consumer products). Because

these solvent uses originate both in the home and Further Regulation of Solvents

from a large number of small commercial, institu- As the preceding analysis indicates, only about

tional, and industrial establishments, traditional one-quarter of total solvent use is covered by
172 • Catching Our Breath: Next Steps for Reducing Urban Ozone

existing regulations. Most of this is from industrial

solvent use by both large and small sources. At most,

we believe that another one-quarter of total solvent

use could be controlled (to some extent) given more

widespread application of current regulations. Much

of these additional reductions would come from use

of industrial solvents and architectural coatings by

predominantly small sources, although some emissions reductions could be realized from controlling

selected large sources. Of the remaining ‘ ‘unregulated” solvent use, we believe that small sources

offer the greatest opportunity for additional emissions reductions. These sources are mainly consumer and commercial products, miscellaneous

surface coating uses, and some industrial solvent

use.

While it is conceivable that a “command-andcontrol” approach could be devised to reduce part of

the remaining uncontrolled emissions, the large

number, small size, and diversity of sources might

make this approach costly and difficult to administer. For these reasons, some have proposed alternative, market-based strategies to controlling emissions. In the following section, we will present some

examples of innovative State programs designed to

capture uncontrolled solvent emissions and will

discuss some market-based alternatives to the traditional “engineering” approach.

State Efforts To Capture Uncontrolled Solvent

Emissions

The solvent end uses that are currently subject to

some form of regulation are listed in appendix A.

Here we see that most industrial solvent use

categories have some form of regulatory requirements. However, regulation of some surface coating

uses, as well as architectural surface coatings and

consumer and commercial products, is limited. A

recent national ozone control strategy proposed by

STAPPA-ALAPCO also identified these three solvent end use categories as being the least wellregulated at this time and as having significant

emissions reduction potential [43].

Although very few Federal controls have been

issued for these uses of solvents, a few States have

begun to devise ways to control their emissions, as

well as ways to get further reductions from end uses

already subject to some control. The following

policy options represent the major approaches that

States have either already taken or are proposing at

this time:

1.

2.

3.

4.

lowering source-size exemption cutoffs of

existing regulations to capture smaller sources

within particular end use categories;

developing new regulations directed towards

specific end uses, in some cases bringing in all

sources in the category irrespective of size

(e.g., lithographic printing, consumer solvents,

architectural coatings);

placing limits on the VOC content of certain

products or processes to encourage reformulation of solvents or use of non-solvent-based

alternatives; imposing bans on the sale of

products that fail to meet these control requirements by a specified date; and

establishing emissions fees or marketable permit systems to discourage the use of products

with high VOC content.

Generally, States have been inconsistent in their

degree of VOC emissions control requirements for

solvent uses. While some have stringent regulations

applicable to a broad range of end uses, others are

less far-reaching in their requirements. For example,

Massachusetts allows very few exemptions from its

requirements for surface coating sources, whereas

Rhode Island has no regulations for many of the

same types of sources. In some cases, States are

developing their own “allowable limits” on VOC

emissions from source categories for which EPA has

not yet issued any Control Technique Guidelines

(CTGs) (e.g., New York is developing regulations

for wood furniture coating). Most States follow

EPA’s lead in applying RACT requirements mostly

to greater than 100-ton” sources, although some have

begun to lower control requirements to apply to

smaller sources. A few States are eliminating

applicability limits altogether, so as to capture all

VOC sources within an end use category. Others are

issuing exemptions from certain regulatory requirements for using alternative, 1ow-VOC products in

place of traditional solvents (e.g., North Carolina

exempts waterborne inks with low VOC content for

use in graphic arts).

One reason many States give for having resisted

lowering the source-size cutoffs in their regulations

is a lack of resources. Because States already have
Chapter 7—New Opportunities for Controlling Ozone ● 173

resource limitations in trying to enforce existing

regulations, they are wary about their ability to

account for and monitor additional sources. Some

States or nonattainment areas, such as Illinois,

Philadelphia, and the San Francisco Bay area, have

used their source permitting systems to improve

their inventories. These areas have been able to

maintain inventory data on sources as small as 10

tons per year for many categories. However, most

areas do not keep records on such small sources.

With regard to consumer and commercial product

regulation, many of the regulators from States that

have attempted or proposed some form of this

regulation stated that such efforts would perhaps

best be done on a national basis. Because most of

these products are being sold across State lines, they

believe it will be a very difficult strategy to enforce

on a State-by-State basis. Inconsistencies in the

stringency of such regulations from State to State

may cause manufacturers to abandon some markets

and relocate to other regions of the country.

Two nonattainment areas in particular have been

at the forefront in developing innovative or stringent

approaches to controlling VOC emissions: the South

Coast Air Quality Management District (AQMD) of

California and the New York City metropolitan area.

Many of their requirements apply to solvent-related

activities and cover the range of the four policy

options presented above. The control approaches

designed by these two areas provide examples of

some of the options available to policy makers for

reducing VOC emissions from solvents.

The South Coast AQMD has proposed a threetiered approach to controlling VOC emissions from

solvent uses that would make its regulations the

most stringent in the country. More rigorous requirements are phased-in with each new tier. The first two

tiers consist mainly of limiting the reactive solvent

content of products and establishing a minimum

transfer efficiency requirement for several coating

categories. Tier I requires application of existing

technologies. Tier 11 aims to cut in half the remaining

emissions by improving and refining the applicability of these technologies. The third tier aims to

almost eliminate VOC emissions from solvents in

the Basin, by fostering “technological breakthroughs"

to process changes that do not rely on solvents, new

product formulations, and substitute products. The

proposed third tier would culminate with a Basinwide ban on noncompliant products and processes.

Tier I of the South Coast’s strategy requires the

application of all currently known technologies to

existing sources. State regulators have listed 22

control measures directed at controlling VOC emissions from various categories of solvent use, including selected surface coating uses, architectural

coatings, graphic arts operations, metal cleaning and

decreasing, plastics manufacturing operations, drycleaning operations, and underarm and other domestic products. The AQMD estimates that VOC

emissions from solvents could be reduced by approximately 45 percent of projected levels for the

year 2000 by implementing Tier I controls. The

greatest reductions are expected to come from

regulations on domestic products (33 percent of total

reductions in solvent emissions expected from Tier

I controls), automobile refinishing (19 percent) and

wood furniture coating (14 percent). Tier I is to be

implemented over the next 5 years. Most of the

measures included are expected to be “reasonably

available” at the time the regulations take effect.

However, at least for the domestic products category, the efforts necessary to bring about the

anticipated reductions (e.g., total phaseout of aerosol

propellants) seem more extraordinary than ‘reasonably available. ”

Three forcing mechanisms are set up to ensure

that the objectives established under Tier I are met:

1) compliance schedules with interim dates for

progressively reducing the VOC content of products

and limiting process emissions; 2) emissions

charges for architectural coatings to discourage

purchase of coatings with high VOC content; and 3)

the threat of a ban on the sale or limitations on the

use of a product if its manufacturer fails to comply

with regulations.

The goal of Tier II is to obtain a reduction of 50

percent of the emissions remaining from solvent

evaporation after Tier I has been implemented, for

cumulative reductions with Tiers I and II of about 70

percent compared to projected emissions levels in

the year 2000. While categories for reduction are

only generally described, controls on surface coating

and consumer products are targeted. The South

Coast hopes to reduce VOC emissions from coating
174 . Catching Our Breath: Next Steps for Reducing Urban Ozone

operations by one-half through the use of alternative

coating technologies, more efficient application of

coatings, and the use of low- or non-solvent-based

coating products and processes. They hope to cut, in

half, emissions from consumer products through

further development and widespread application of

such controls as product reformulation and alternative propellant or dispensing mechanisms. The time

frame for implementing Tier II is within the next 10

years. In addition to broader application of technologyforcing compliance schedules and emissions

charges, the following actions have been proposed

by the AQMD to facilitate achieving Tier II goals: 1)

a cooperative effort with the State, product manufacturers and end users, to fully assess obstacles to

and options for reducing solvent evaporation; 2) a

Basin-wide program to disseminate information and

educate business owners or operators about alternative products and processes; and 3) a program to

increase public awareness, to enhance the marketability of newly formulated or packaged products.

Tier 111 sets forth the ambitious goal of “near-total

phase-out” of VOC emissions from solvents by the

year 2007. At present, no detailed strategy for

achieving this goal has been proposed. However,

Tier III does appear to rely on more full application

of efforts begun in the earlier two tiers, such as

adoption of alternative, non-solvent products or

processes. The underlying assumption is that Tiers

I and 11 will pave the way. As proposed, Tier 111

culminates with a ban on products that cannot

comply with restrictions on solvent content, and

processes that cannot meet emissions limitations.

A variety of impacts could result from the South

Coast’s three-tiered strategy. Sources may be moved

out of the area or forced out of business because of

the regulatory burden. In some cases, greater use of

exempt solvents such as chlorinated solvents, would

increase air toxic emissions. In other cases, as with

controls on solvents used in drycleaning, emissions

of potentially toxic air contaminants would be

reduced. Also, additional liquid or solid waste could

be produced from some add-on control devices.

There would also be some administrative burden due

to increased source permitting and additional enforcement needs.

While New York’s approach is perhaps less

ambitious and far-reaching than the South Coast’s,

it also aims to significantly reduce VOC emissions

from solvents. Rather than exempting sources that

emit VOCs below a certain level, all users of

VOC-based solvents in some end use categories

(e.g., all lithographic printers) will be required to

meet limitations on the use of products with certain

VOC contents. This approach is also designed to

bring the supplier of such products into the regulatory loop, so that both the user and supplier are held

accountable.

Two types of new regulations are being issued by

the State: 1) regulations that bring in all sources in

categories that are already regulated, and 2) regulations that apply to new, previously unregulated end

use categories. By removing exemptions from RACT

for selected categories-e.g., EPA’s 100-ton source

exemption for graphic arts facilities, and the exemption for surface coating sources using less than 5

gallons per day—the State is making all sources in

a particular end use category subject to control

requirements. And, because EPA has issued little or

no technical guidance to States for regulating some

categories, New York is developing its own control

requirements independent of the Agency. For example, the State has recently issued final regulations for

the following previously unregulated categories:

graphic arts, surface coating uses (wood, plastic,

glass and leather coating, auto refinishing), architectural coatings, and consumer and commercial products.

With the eventual goal of controlling all emissions from selected solvent categories, many of New

York’s regulations place strict limits on the VOC

content in paints, inks, and other surface coatings.

By 1990, new regulations are expected to reduce

emissions from these three categories by about 40

percent compared to 1987 levels. This will constitute a 20-percent reduction in VOC emissions from

all solvent uses. Eighty percent of these emissions

reductions are expected to be from graphic arts

facilities. The remainder of the anticipated reductions would come from limits on the VOC content of

eight surface coating categories, autobody refinishing shops, and architectural paints. Regulations

prohibit the sale (in the New York City metropolitan

area) of architectural coatings that exceed a specified

VOC content after July 1, 1989. Manufacturers of

some consumer products (air fresheners, disinfectants, and insecticides) are required to study ways of
Chapter 7—New Opportunities for Controlling Ozone ● 175

reducing VOC emissions from these products. There

is an accompanying ban on the sale of these products

if the manufacturer has not registered them with the

New York Department of Environmental Protection

(DEP) and if a study protocol has not been submitted

and approved by specified dates. While actual

emissions reductions are not specified, projected

schedules for implementation of measures proposed

in the study are not to go beyond January 1, 1997.

In implementing these new regulations, the major

issue as far the DEP is concerned seems to be how

previously unregulated sources are going to be

notified of the new regulatory requirements. The

State plans to notify major manufacturers that their

products are now subject to regulations, and let them

tell their distributors, who in turn can notify the end

users. Both users and manufacturers will be considered liable if users are found to be using nonapproved products.

Alternatives to Traditional Methods of

Controlling Solvent Emissions

Solvent emissions can be lowered in many ways.

In some instances it is possible to switch to

alternative products that use no solvent (e.g., using

water-based rather than oil-based paints). Products

can be reformulated using low-solvent technologies

or using solvents which are not involved in ozone

formation. Manufacturing methods can be changed

so that less solvent is emitted per unit manufactured.

And finally, emissions can be captured or destroyed

through control methods such as incineration so that

VOCs are not released to the atmosphere.

Most regulation under the Clean Air Act follows

a traditional “engineering control” approach. Pollution control engineers within EPA or the States

define “reasonably available control technology”

(RACT) or the “lowest achievable emission rate”

(LAER) for many different types of sources, and

then source-specific regulations are issued. However, for many products and processes, this traditional approach may not produce the desired emissions reductions. Low- or non-solvent alternatives

may not be available, and alternative manufacturing

methods may not deliver the desired quality end

product. Congress, EPA, and the States must find

new ways to force the development of new products,

manufacturing processes, and control methods.

The California Air Resources Board (CARB) is

currently looking at alternatives to the traditional

engineering approach to help reduce VOC emissions

from solvent use in cases where new products or

processes are needed. CARB has examined three

basic options: 1) setting limits on solvent content or

VOC emissions, together with deadlines for compliance and penalties for failure to meet the deadlines;

2) setting fees or taxing products that contain

solvents or are manufactured using solvents; and 3)

allocating permits to emit VOCs, and gradually

phasing out allowable emissions by reducing the

number or value of permits. CARB has not completed its evaluation of these options, and we have

not analyzed them in detail. However, we attempt to

provide a broad description of each, in this section,

along with examples of how they might apply to

solvents.

Compliance Schedules and Penalties-When

Congress directed EPA in 1970 to develop regulations to lower motor vehicle emission rates by 90

percent, the technology to achieve this target was not

available. Congress decided to force development of

technology by choosing a percentage reduction

target and a date by which it was to be reached, and

by adopting penalties to give manufacturers incentives to develop the technologies needed to comply.

Deadlines slipped many times, and several have yet

to be reached, but tailpipe emissions of VOCs,

nitrogen oxides, and carbon monoxide have been

lowered considerably.

A similar framework could conceivably be developed for solvents. For domestic products, for example, increasingly stringent limits on solvent content

could be set, along with compliance schedules and

penalties for noncompliant products. Emissions

reduction targets and deadlines could also be established for specific categories of sources, and flexibility provided for meeting them through process

changes that eliminate or reduce solvent use, or

add-on devices to control emissions.

Although it might work for large manufacturers of

solvent-containing products or large businesses that

use solvents, a potential problem with this approach

is that numerous small businesses that one would

like to cover through such regulations lack the

resources to develop new products, processes, or

control methods needed to comply. Furthermore,
176 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

State or local regulatory agencies may lack the

resources needed to enforce such an approach on the

large number of small end users. Market-based

strategies, that allow sources to “trade” emissions

reductions, might help to ease this problem.

Marketable Emissions Permits—EPA’S proposed

regulations for chlorofluorocarbons (CFCs and

Halons—two chemicals that deplete stratospheric

ozone

27—combine technology forcing with a marketbased approach to minimize the costs of cutting back

production of these chemicals [52]. After considering the traditional engineering approach to control,

EPA opted for a regulatory scheme that allocates

production rights to CFC manufacturers based on

their production in a historical year (1986), and

gradually cuts back production rights from that level

over a 12-year period.

In EPA’s proposal, manufacturers are given the

rights to produce 100 percent of their baseline levels

each year through 1993. Manufacturers that produce

less can sell their extra rights to produce CFCs to

other firms. Any firm wishing to produce more than

the amount they produced in 1986 must purchase

rights from another manufacturer. In 1993, firms

will be allowed to either produce--or sell the rights

to produce—80 percent of their baseline levels. Each

firm must return 20 percent of their rights to produce

CFCs to EPA. In 1998, firms will be allowed to

produce, or sell the rights to produce, 50 percent of

the amount they produced in 1986. Theoretically,

allowing trades should minimize the costs of cutting

back production, as those firms for which reductions

are most economical reduce more than necessary,

and sell their unused production rights to other firms

for whom reductions are more expensive.

Regulating CFC use and VOC emissions has one

striking similarity: engineers cannot at this moment

sit down and list all the control methods that one

would need to achieve the desired reductions. A

market-based approach has the advantage of actively

involving industry in the search for new control

methods. There are enough differences between the

characteristics of the two control problems, however, so that one cannot just substitute the word

“VOC” for “CFC” throughout the EPA regulations and expect a market-based program to work.

(For example, CFC control applies nationwide,

while VOCs are controlled primarily in nonattainment areas.)

In the case of CFCs, EPA preferred to regulate

producers because there are far fewer of them than

users, thus lowering EPA’s record keeping burden.

For solvents, there are reasons why it might be

preferable to regulate users. First, VOCs are of

concern primarily in nonattainment areas, and it

might not be desirable to limit solvent production

and hence restrict their availability everywhere.

Second, it might be desirable to allow solvent users

the option of destroying or capturing VOCs before

they are released to the atmosphere. Because some

record of emissions by end users is required for

States’ emission inventories anyway, EPA might

choose to allocate solvent emission rights directly to

users in nonattainment areas. The phase-out and

trading provisions of the CFC proposal would still

apply.

One controversial issue associated with a marketable permit system is how the permits will be

initially allocated. In the case of emissions permits,

allocation based on a historical year could be

considered to place sources that have controlled

stringently in the past at an unfair disadvantage. An

alternative approach would be to require initial

controls on some source types and then allocate

production rights from this new, “post-control”

baseline. While rejected for CFCs, this approach

might be useful for regulating solvent use. Unlike

CFCs, emissions from solvent use are already

regulated, to some extent. Some States stringently

regulate some types of solvent use, some do not.

Defining a “fair baseline” for allocation of permits

would be an important, if difficult frost step in

implementing a market-based strategy.

Emission Fees or Taxes— In addition to marketable permits, EPA also considered placing fees on

production of CFCs, with the intent that a high

enough fee would discourage production. Agency

staff rejected this approach because they felt they

could not ensure that the required control levels

would be reached by specified date. Manufacturers

could opt to continue producing CFCs and pay the

fees rather than lower production. Through trial and

error the agency would eventually determine the

270mne in me ~~ato~phere, 6 t.’30 milesabovetieEd’ss~~e,s~elds pl~ts ~d fim~s from h~fully high levels of ultraviolet radiation.
Chapter 7—New Opportunities for Controlling Ozone ● 177

level of the fee necessary to achieve the required

production limit, but it would be difficult to meet a

target date. In considering the approach for solvents,

the California Air Resources Board similarly notes

that political difficulties associated with setting and

subsequently adjusting emissions fees could be a

major drawback.

One place where a fee or tax system seems

particularly useful is in giving consumers incentives

to purchase products with low solvent content.

While it would be difficult to project how much

emissions would be reduced by taxing spray deodorants to make them more expensive than stick

deodorants, it might be one way to significantly

reduce VOC emissions from consumer products that

are sold on the national market, without banning

them from nonattainment areas altogether.

A final problem with fees is that it is unclear

whether the Clean Air Act gives EPA the authority

to set fees for purposes other than recovering the cost

of regulation. Congress needs to clarify its intent on

this matter if market-based approaches are to be

given full consideration.

LOWERING EMISSIONS FROM

HIGHWAY VEHICLES:

TRANSPORTATION CONTROL

MEASURES

Of the VOC emissions remaining in nonattainment cities in 1994 after all of the controls we

analyzed in chapter 6 are applied, highway vehicles

account for about 28 percent, and gasoline marketing contributes 6 percent. Especially in fast-growing

areas, efforts to further reduce emissions associated

with highway vehicles involve a race between

tighter controls that reduce emissions per vehicle

mile, and increases in the number of vehicles on the

road. Averaged nationwide, motor vehicle exhaust

emissions are projected to decline through the late

1990s as an increasing percentage of vehicles on the

road meet new standards, but rise after that due to

growth in vehicle use.

Based on current trends in population and travel,

and trends in age and income distributions, the

number of vehicle-miles traveled (VMT) nationwide

is projected to increase by 2 to 3 percent per year

from now through 2005, resulting in a cumulative

increase of about 40 to 60 percent [23]. The national

average projections understate the increase expected

in some cities: for example, 3.5 and 4 percent per

year increases are projected for Houston and Phoenix, respectively, compared to increases of 1.5 and

2 percent per year in Detroit and Philadelphia.

Obviously, VMT growth could have a major

impact on traffic flow in urban areas, as well as on

air pollution. According to the Federal Highway

Administration [23], traffic volumes in 1985 equalled or exceeded 80 percent of capacity on over 40

percent of the Interstate highways in the Nation’s 45

largest metropolitan areas, indicating “extensive

congestion during peak-traffic periods. ” Coping

with, or limiting future growth in motor vehicle use

presents major challenges to both air quality and

transportation planners, who face the twin problems

of congestion and air pollution.

To address motor vehicle use, the 1977 Amendments to the Clean Air Act required some urban

areas to implement transportation control measures.

28 

TCMs are a set of interrelated measures that

have the general objective of reducing emissions by

reducing driving or improving traffic flow.29 Examples include improved public transit, exclusive

highway lanes for buses and carpools, bicycle lanes,

modified schedules for work, parking management,

and road use charges or tolls. Because they try to

change the behavior of large segments of the public

(e.g., getting people to use mass transit or share rides

to work), public awareness of congestion and air

quality problems is a key to the success of TCMs. In

most cases in which these measures have been used,

they have been justified on broad grounds of

improving urban mobility as well as air quality.

In this section, we first review the TCM requirements in the 1977 Amendments, including requirements for integrating air quality and transportation

28s=. I lqc)(~)(B) of the Clean Air M, as ~end~.

29v~ efi=ion rates d=l~e ~ “chic.e s@~ ~cm=, e~wi~ly up to abut ’35 to 40 mph. Also, emission rates we lower when spw& are held

constant, than under stop/start conditions,
178 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Photo credit: South Coast Air Quality Management District, El Monte, CA

The number of miles traveled on our Nation’s highways is projected to increase by about 40 to 60 percent by 2005. The adoption

of transportation control measures, such as ridesharing, carpool lanes, alternative work schedules, and transit improvements could

help reduce congestion and the accompanying increased highway vehicle emissions by improving traffic flow.

planning. We then provide estimates of the magnitude of reductions that can be expected from TCMs,

based on the 1988 Air Quality Maintenance Plan for

the Los Angeles area. In addition to “traditional”

measures that focus on the transportation system of

roads and mass transit facilities, measures that seek

to reduce driving by managing land-use are also

considered. Finally, we discuss key implementation

issues, including transportation and land-use planning and policy, and strategies to ensure participation.

Requirements in the 1977 Clean Air Act

Amendments

The 1977 Amendments to the Clean Air Act

required urban areas that would not be able to meet

the ozone or carbon monoxide standards by 1982 to

implement transportation control measures (TCMs)

as necessary to attain the ozone and carbon monoxide standards.30 The Act specified that development

of TCM programs had to be coordinated with the

transportation planning process that the Department

of Transportation requires as a condition for receipt

30s=S. 1 IO(@(s)(D) and 11O(C)(5)(B) of the Clean Mr Act* m mended.
Chapter 7-New Opportunities for Controlling Ozone ● 179

of Federal highway and mass transit assistance.31

One-time-only grants to Metropolitan Planning Organizations (MPOs) for integrated air quality and

transportation planning were authorized.32 About

$50 million was awarded. The Amendments also

tried to provide a check on the air quality impacts of

all projects supported by Federal highway and mass

transit finds, by requiring the Secretary of Transportation to ensure that federally funded projects

“conform” to State Implementation Plans (SIPS) .33

Some transportation control measures were included in most States’ 1979 and 1982 SIP revisions.

In most cases the TCM programs were not very

aggressive, and accordingly, expectations of VOC

emissions reductions from TCM programs were

generally modest. Many of the TCMs included in the

1979 and 1982 SIPS were adopted primarily to help

reduce carbon monoxide emissions, or even to ease

congestion or meet other transportation or developmentrelated goals [51]. For example, a review of a few

1982 SIP submittals found that in the two from

Louisville and St. Louis, TCMs such as transit

improvements, ridesharing programs, parking controls and traffic flow improvements were expected to

yield 6 to 7 percent of the VOC reductions anticipated through 1987. In SIPs from two other areas—

Baltimore and Chicago-expected reductions from

transportation control measures amounted to 1

percent or less of the anticipated VOC reductions

[22].

Unfortunately, we cannot evaluate whether previous SIP projections generally overestimated or

underestimated the effect of transportation control

measures, because the impact of the measures that

have been implemented has not been systematically

monitored by EPA or the States. EPA’s Office of

Transportation and Land Use Policy was eliminated

in 1982 due to budget constraints and shifted

priorities, and the Agency has not subsequently

required detailed program evaluations and reports

from the States. Moreover, it is generally difficult to

evaluate the impact of individual TCMs on air

quality, due to errors and uncertainty in baseline

estimates of vehicle use, and confounding factors

such as local economic conditions, fuel prices, and

unrelated changes in the local transportation system

(e.g., freeway construction).

Several key generalizations about TCMs can be

drawn from interviews and reports on programs in

various cities [27,1 1]:

●

●

●

TCM programs have to be tailored to each

individual area. Critical local characteristics

that need to be considered in developing TCM

programs include population and employment

distributions and densities, city layout and

transportation routes, highway system capacity

and level of congestion; access to mass transit;

and parking availability and costs.

The success of many transportation control

measures depends to a large degree on

public acceptance and participation. In the

absence of widespread public concern about air

pollution and/or traffic congestion problems,

past experience indicates that political resistance to involuntary restrictions on people’s

modes or amount of travel will be insurmountable. From a political standpoint, it is apt to be

much easier to initiate voluntary TCM programs than mandatory ones. However, the

ultimate success of voluntary programs can

also depend critically on public awareness.

And, due to turnover in participation, promotional efforts for strictly voluntary programs

have to be sustained over time. For example,

carpools typically have turnover rates of 1 to 2

years. Two approaches other than promotional

campaigns that attempt to give people incentives to participate in TCM programs are

discussed below: “trip reduction ordinances”

directed at employers, and financial incentives

and disincentives.

Long leadtimes and sustained efforts are

required to implement TCMs. Major capital

projects such as development of mass transit

obviously require long lead times. Other measures may be directed at new employers or

qlF~er~ aid for highwaysand m~s transit totals about $16 billion, annually, most of which is supported through Federal motor fuels tues. TO be

eligible for Federal highwpy and mass transit assistance, metropolitan areas are required to coordinate transportation plans and transportation

improvement programs across local jurisdictions within the area. Metropolitan Planning Organizations (MPOs) with elected representatives from each

local jurisdiction, perform this function. MPOS typically do not have authority to implement or enforce transportation plans.

32s=. 175 Of the Clean Air Act.

33sW, 17qc) of the Clean Air ~t.
180 . Catching Our Breath: Next Steps for Reducing Urban Ozone

commercial developments, and thus take effect

only gradually. Ordinances requiring new employers to encourage employees to share rides,

use transit, or otherwise collectively reduce

their driving are one example. Ridesharing

programs and parking restrictions could help

reduce emissions within a very short time,

although their continuing impact may depend

on long-term land use and transportation policies.

The effectiveness of one transportation control measure may depend substantially on

concurrent implementation of another. For

example, ridesharing programs and mass transit are likely to be more successful if some

highway lanes are restricted to buses and

carpools, or if parking in business districts is

restricted or expensive. A recent comparison of

the business districts of San Francisco, Portland, Seattle and Denver found that transit

shares were highest in the cities with the

highest parking prices and most limited parking

[28]. In general, larger reductions in emissions

are likely to be achieved if TCM programs are

coordinated throughout an area and over an

extended time horizon, than if measures are

developed on a piecemeal or sporadic basis.

For TCMs to be effective, air quality has to

be considered a priority in urban transportation and land-use planning. Because TCMs

involve highway and transit facilities and

operations, it is obvious that State and local

organizations with responsibility for transportation system operations, maintenance and

improvements have to be involved in their

development and implementation. Since TCMs

can also involve zoning laws and requirements

for new developments, the participation of

local organizations with authority over landuse policies is also needed. Land-use policies

that affect VMT are discussed further in the

next section,

The planning grants made under the 1977 Amendments were judged to have been effective in getting

MPOs to examine transportation control measures

(many of them for the first time). The grants also

enabled areas to obtain local data on mobile sources

that were needed to evaluate potential TCM impacts.

However, the one-time-only grants apparently fell

short of convincing transportation planners in most

areas to give continuing priority to improving air

quality [51].

The requirement that federally funded projects

conform to SIPS also failed to institute improvement

or maintenance of air quality as a goal in urban

transportation planning. The U.S. Department of

Transportation (DoT), which distributes Federal

highway and mass transit assistance, has sought to

equate “conformance” with a narrow finding that a

transportation plan or project does not interfere with

transportation control measures included in SIPS

[50]. EPA has suggested a broader requirement that

transportation plans and projects “should not cause

or contribute to existing or new standard violations,

or delay attainment” [12]. While DoT and EPA have

debated the meaning of ‘conformance,” transportation plans, projects and programs have not generally

been required to address air quality concerns proactively.

Potential Reductions From Transposition

Control Measures

One of the most up-to-date and comprehensive

assessments of transportation control measures is

the review that the South Coast Air Quality Management District (AQMD) and the Southern California

Association of Governments recently completed for

the Los Angeles area [38,40]. For each of the

transportation control measures listed below, the

AQMD estimated the VOC reductions that would be

possible using existing authority and funds (the low

end of the range) as well as reductions dependent

upon additional funding or new legislative initiatives (the upper end of the range). Reductions are

estimated for the period 2000-10.

Without the measures listed below, VMT in the

Los Angeles area is projected to increase by almost

70 percent by the year 2010, as the population living

in the area increases by 35 percent, to 18.3 million.

Due to congestion, the average vehicle speed on area

freeways is predicted to fall from 47 to 24 mph [41].

In 2010 total VOC emissions from highway vehicles

are projected to be reduced by about 40 percent from

1985 levels, to about 320 tons per day, despite

increased VMT and without the measures listed

below [40].
Chapter 7—New Opportunities for Controlling Ozone ● 181

With full funding and authority, the proposed

measures are expected to reduce highway-vehicle

VOC emissions by a total of 30 percent, by 2010,

compared to levels projected without them. Note

that under these circumstances, growth management

measures that are aimed at matching new jobs with

nearby housing account for over 40 percent of these

reductions. (Total reductions in highway vehicle

emissions of NOX, sulfur oxides, carbon monoxide,

and particulate matter from the set of measures listed

below are also expected to be about 30 percent,

compared to emissions levels projected for 2010

without the TCMs listed below.)

. strategies to reduce the number of singleoccupancy car trips, including: employer ride

share and mass transit incentives, parking

management (increase parking meter fees, eliminate peak-period on-street parking, eliminate

employer-subsidized parking, etc.), vanpool

purchase incentives, auto use restrictions, and

high-occupancy vehicle (HOV) lanes. Businesses in the Los Angeles area with more than

100 employees are already required to encourage ride sharing and transit use; requirements

for employers would be strengthened and

expanded. New laws would regulate commercial parking and eliminate parking subsidies.

New funding is sought for transit improvements and HOV lanes. Federal legislation is

called for to restore tax credits for vanpool

purchases. The South Coast AQMD estimates

that all such measures will reduce highway

vehicle emissions by about 0.2 to 3 percent,

compared to levels projected without TCMs.

• traffic flow improvements, including: metering on highway ramps, synchronized traffic

signals, and intersection improvements. Making these improvements is primarily a matter of

obtaining funds for roadway modifications and

installation and maintenance of metering and

synchronization technology. The South Coast

AQMD estimates that these measures will

reduce highway vehicle emissions by about 0.5

to 1.5 percent.

. rescheduling and rerouting of truck deliveries away from congested areas during peak

commute hours. Truck delivery routes and

schedules were altered voluntarily during the

1984 Olympic Games. To implement these

measures on a wider scale, local ordinances

such as those that restrict night deliveries might

have to be modified. The AQMD estimates

reductions of about 0.3 to 3 percent from this

measure.

. alternative work schedules (e.g., work weeks

consisting of 10-hour days), and telecommuting. As examples, businesses would be

required to adopt alternative work scheduling

as a condition for permit renewal, and new

employment developments in business or industrial districts with more jobs than available

housing would be required to establish satellite

work centers in predominantly residential areas.

Employers in the Los Angeles area have some

experience with alternative work schedules,

which were adopted voluntarily to help reduce

traffic congestion and air pollution during the

1984 Olympic Games. Although the State of

California is currently conducting a pilot project on telecommuting, the idea of requiring

new businesses to have satellite work centers is

unprecedented, and would require changes in

zoning, licensing, tax and possibly labor laws

to implement. Highway-vehicle emission reductions of about 0.5 to 7 percent are estimated

to be available from these measures.

. freeway capacity enhancements. The AQMD

estimates that by building an additional 880

lane miles, highway vehicle emissions can be

reduced by about 1.5 to 4 percent. This step

constitutes an extremely ambitious highway

construction program, and AQMD acknowledges that obtaining sufficient funding will be

a major challenge. The projection that net

reductions in emissions would result from

freeway expansion means that in the Los

Angeles area, lower emissions due to reduced

congestion are expected to offset increased

travel that might be encouraged by new roads.

● growth management. The population in the

South Coast is projected to grow to 18.3 million

by the year 2010, almost a 50-percent increase

since 1984. This measure proposes to use

land-use management measures to help match

new jobs with nearby housing, and vice versa.

Specific measures include assessing development fees, modifying zoning rules, and strategically locating new public facilities and infrastructure. Though growth management is likely
182 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

to be politically contentious, it is becoming

more common for fast-growing municipalities

to use zoning laws, development fees, etc. to try

to do so. However, the scale of the AQMD

proposal, which entails coordination over dozens of municipalities, is unprecedented. The

AQMD estimates that shifting 10 percent of

new jobs to housing-rich areas, and 4 percent of

new housing to job-rich areas, would reduce

highway vehicle emissions by 0.6 to 14 percent.

Role of Transportation and Land-Use

Planning

Land-use patterns play an important role in either

tying people to their cars or facilitating other modes

of transportation. As an illustration, people who live

within a few miles of work might choose to walk or

bike. But where urban areas consist of sprawling

residential suburbs and separate business districts or

industrial parks, few people have these options. A

recent comparison of ten U.S. cities found that per

capita gasoline consumption (which we assume to

be a reasonable surrogate for VMT) is relatively low

in cities with high population and job density, and

relatively high in cities with abundant roads and

parking. Per capita gasoline consumption is 10 times

higher for residents of suburbs outside of Denver

than for residents of Manhattan [32].

Between 1980 and 1986, about 85 percent of the

population growth in the United States was in

metropolitan areas. About three-fourths of that

growth occurred in the suburbs of those areas.

According to a task force formed to advise the

Federal Highway Administration (FHWA), this

pattern of growth is expected to continue [23].

However, growth in the suburbs does not necessarily

have to mean more and longer commutes in private

cars. The FHWA’s task force anticipates that the

density of residential development in the suburbs

will increase as rising housing costs and declining

household sizes necessitate construction of apartments and compact townhouses rather than expansive subdivisions [23]. This increase in density

could facilitate transit service. And, some analysts

have suggested, land-use policies could guide development to limit reliance on driving,

Land-use planning and regulation are traditionally activities carried out by local governments,

whereas transportation planning is more apt to be a

State or regional responsibility. Land-use policies

are implemented through local zoning laws and

permit requirements for subdivision and commercial

site development. Permit reviews typically ensure

that public works (e.g., water, sewers, roads, interchanges, and parking) are adequate to support the

development. Interaction between transportation

and land-use planning agencies usually takes the

form of assessing the impacts of new developments.

The number of trips that would be generated by a

proposed development is estimated and compared

with the capacity of nearby roads and intersections.

If a transportation system is inadequate to support

new development, it maybe expanded, sometimes at

a developer’s expense. Increasingly, where funds are

limited or congestion is already an issue, developers

are being required to take steps such as providing

convenience stores on site, or providing transit

shelters or bike paths, in order to reduce potential

transportation impacts. Downtown developers in

several cities have been faced with caps on the

number of parking spaces they can provide. As

mentioned above for Los Angeles, area-wide landuse regulations can also be modified to help reduce

traffic congestion and air pollution. The guiding

principles include: promoting development in areas

with existing mass transit services; encouraging

development within developed areas to increase

population density and thus make transit services

easier to provide; and promoting housing construction in job-rich areas or employment opportunities in

residential areas. Due to the links between land-use

policies, jobs, and tax revenues, local political

resistance is apt to be the major problem in trying to

modify land-use regulations [15].

Trip Reduction Ordinances

To circumvent problems in getting people to

accept and participate in transportation control

measures, some areas have passed ‘‘trip reduction

ordinances” requiring companies to provide services, facilities, or incentives to encourage their

employees not to drive to work alone. Companies

are required to promote transportation alternatives,

but the participation of individuals is voluntary.

Some companies have increased the proportion of
Chapter 7—New Opportunities for Controlling Ozone ● 183

their employees who do not drive alone to more than

80 percent [11]. Services and incentives provided

include preferential parking, shuttle services, on-site

sale and subsidies of mass transit passes, and

subsidized vanpools.

Examples of trip reduction ordinances include a

regulation passed in 1987 in the Los Angeles area

that is designed to increase average ridership from

the current level of 1.13 to 1.5 people per vehicle

during peak periods. The ordinance applies to all

employers of 100 or more people and thus affects

more than 8,000 businesses. Employers are required

to prepare comprehensive trip reduction plans for

their companies. Failure to submit a plan or annual

update, or offer any incentive included in the plan is

a violation of the ordinance; failure to meet ridership

goals is not. The regulation is expected to reduce the

number of private motor vehicle trips made each day

by about 10 percent, resulting in VOC emissions

reductions of about 4 percent of current highway

vehicle emissions [25].

An ordinance passed in Pleasanton, CA in 1984

set a goal of reducing peak hour commuting traffic

by 55 percent, from a baseline that assumes everyone drives alone. Employers are expected to achieve

a 15-percent reduction in the first year, and additional reductions of 10 percent each of the next 4

years. In the second year of the program, only three

companies failed to achieve the targeted 25 percent

reductions, and twelve companies had already exceeded the fourth year target of 45 percent. Companies are fined for failing to provide required survey

data, but not for failing to meet goals [24].

Financial Incentives for Reducing Vehicle Use

Because the cost of driving influences the number

of miles per year that people travel, another approach to reducing VMT involves the use of fees to

make driving more expensive, and subsidies to

encourage use of alternative modes of transportation. Financial incentives have the potential to affect

a greater fraction of urban travel than trip reduction

ordinances, because less than 30 percent of local

travel is work-related [49]. Targets that have been

proposed for fees or taxes include gasoline, parking,

and road-use (i.e., tolls).

Ironically, Federal income tax policy currently

provides a financial incentive that encourages driving to work alone over using mass transit or ride

sharing. Employers’ provision of free or subsidized

parking is a tax free benefit, worth up to $300 per

month if valued at commercial rates charged in the

business districts of some cities. In contrast, provision of more than $15 per month worth of mass

transit passes is a taxable benefit. The amount by

which the market value of vanpool trips exceeds

what employees are charged to participate is also

taxable under current law [31].

Although many studies have looked at the relationship between the price of and demand for

gasoline, only a few have explicitly estimated the

effect of gasoline price on automobile travel.34 Of

these, most have concentrated on the effect over the

first few years of a price change, not on changes that

might persist over many years. When estimating the

effect of gasoline price on travel from historical data,

several factors must be considered simultaneously.

Income, average fuel economy, and the cost of more

fuel-efficient cars must all be taken into account as

factors that influence how a consumer will respond

to changing gasoline prices. Data from different time

periods and countries indicate that the likely response to a $0,50 per gallon tax is a reduction in

automobile travel of between 5 and 25 percent, for

the first few years the tax is imposed.35 Thus a

reasonable assumption is that a 15-percent reduction

in automobile travel would result from a $0.50 per

gallon tax. Similarly, one would expect about an

8-percent reduction in automobile travel from a

$0.25 per gallon tax.

The effect of a gasoline tax over the long term is

quite a bit more uncertain. Some studies have found

that the effectiveness of a gas tax increased through

time. Others found that it dropped. In many cases,

the latter trend seems most likely. Rather than

reducing travel, consumers will respond by purchasing more fuel-efficient cars when it is time to replace

their old ones. However, this is not the only response

34TW0 ~went ~eview~ of tie ~elati~nship ~tw=n gwline price and automobile ~ave] we ~~, ]98C [14] and lbhi and Zimmerman, 1984 [6].

35~e. studies ~~mate tie “elmticlty” of miles ~aveled m changes in fie price of g~line, hat is tie ratio of tie change in miles traveled to the

change in the price of gasoline, Short-tetm elasticities of -0.1 to -4.5 have been reported in the literature and summarized by Dahl [14],
184 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

possible. If a gasoline taxis combined with improvements in mass transit, for example, consumers may

permanently shift their mode of transportation.

If the only benefit from a gasoline tax that is

considered is the reduction in VOC emissions, the

cost-effectiveness of a gasoline taxis quite high. We

estimate that emissions reductions from a gasoline

tax would cost about $35,000 to $75,000 per ton of

VOCs over the first few years. Over the long term,

costs might rise to about $100,000 to $200,000 per

ton. Of course, other benefits would also result,

including lower emissions of carbon monoxide,

nitrogen oxides, and carbon dioxide, reduced highway congestion, and less reliance on imported oil.

LOWERING EMISSIONS FROM

HIGHWAY VEHICLES:

ALTERNATIVE FUELS

Two motor vehicle fuels, methanol and compressed natural gas (CNG),36 are currently being

considered as alternatives to gasoline, to help reduce

urban ozone. Roughly 1,000 vehicles in the United

States, mostly in demonstration fleets in California,

are currently operated on methanol blended with a

small amount of gasoline [47,1]. About 30,000

vehicles in the United States have been retrofit to run

on either CNG or gasoline [47].

Based on experience in the United States and

elsewhere, it appears feasible to modify or design

light-duty vehicles (i.e., cars and light trucks) to

operate on either CNG or methanol, and give

performance that is generally comparable to that of

vehicles running on gasoline. The limited distance

that can be driven on CNG before refueling is

currently a disadvantage for it, compared to gasoline. Problems that still need to be addressed with

methanol vehicles include starting them on straight

(100 percent) methanol in cold weather, and safety

concerns related to the fuel’s acute toxicity and

invisible flame. Partly because of these limitations,

methanol vehicles used within the next 10 years will

probably operate on blends of methanol and gasoPhoto credit: South Coast Air Quality Management District, El Monte, CA

Methanol-fueled vehicles emit less ozone-forming pollutants than traditional gasoline-fueled vehicles. The use of

compressed natural gas also represents a promising

alternative to gasoline.

line. CNG vehicles will most likely be dual-fueled,

operating on CNG part of the time, and gasoline part

of the time.

The potential for reducing ozone when methanol

or CNG are substituted for gasoline stems from the

fact that methanol and natural gas (methane) are

VOCs that react more slowly in the atmosphere and

consequently lead to less ozone production than the

complex mixture of VOCs emitted from the combustion and evaporation of gasoline. In the near term,

“effective” VOC emission rates with alternatively

fueled vehicles will be only moderately lower than

rates that could be obtained with gasoline vehicles

meeting current standards.37 In the short term, using

either methanol blends or dual-fueled CNG vehicles

is likely to be an extremely costly means of reducing

ozone. With major advances in vehicle technology

over the next 10 years, and use of straight methanol

(rather than a blend) or exclusive use of CNG (rather

than dual-fuel operation) greater and more costeffective reductions may be possible.

36111 ti5~tion,4‘me~ao]” refers to fuels that are 100 percent or ‘neat” methanol, orgasoline-methanol blends that are at least 85 percent methanol,

by volume. “Compressed natural gas” is natural gas that is stored on a vehicle under high pressure-typically at 2,400 psi or higher.

JTWe we fie PIMW “eff~tive VW emissions” throughout this section to indicate relauve ozone-forming potential, m opposedto the @Wd mo~t

of VOCS (i.e., tons of carbon) emitted. Because different organic compounds are emitted from methanol or CNG versus gasoline-fueled vehicles,

aftemative fiel use can “effectively” lower emissions in terms of how much ozone is produced when various compounds react, even if the total amount

of VOCs emitted is unchanged.
Chapter 7—New Opportunities for Controlling Ozone . 185

In the sections that follow, we first discuss

estimates of the effect of alternative fuel use on

emission rates and other aspects of motor vehicle

operation and performance. We then present estimates of total emissions impacts of using alternative

fuels in: 1) fleets of 10 or more light-duty vehicles,

and 2) light-duty vehicles in general use. Finally, we

present a range of estimates of the costs per ton of

VOC emissions effectively eliminated by using

methanol or CNG. Throughout the analysis, we

adopt estimates of effective emissions reductions

attainable with methanol blends or dual-fueled CNG

vehicles as our best estimates. We use projections of

reductions that might be obtainable with advanced

technology and use of straight methanol or exclusive

use of CNG, to get upper bound estimates of the

potential benefits of alternative fuels.

Emissions From Alternatively Fueled

Motor Vehicles

Estimates of emissions rates for methanol-fueled

vehicles are speculative because the vehicles tested

to date have been versions of vehicles originally

designed to operate on gasoline, which were retrofit

or modified in limited production runs. Massproduced vehicles could have different emissions

characteristics. Moreover, most methanol vehicles

tested had not accumulated much mileage, and it is

not known how much emissions rates would deteriorate in use. Our best estimate is that vehicles likely

to be available in the next 10 years, which would be

operated on blends of 85 percent methanol mixed

with 15 percent gasoline (by volume), would have

total rates of evaporative and exhaust VOC emissions that are effectively 30 percent lower (in terms

of ozone-forming potential) than those of light-duty

vehicles meeting current standards and operating on

low volatility gasoline (9.0 psi Reid Vapor Pressure

(RVP)) [3,47].

Estimates of emission rates that might eventually

be obtainable with technological advances and with

operation on straight methanol are very speculative.

As an upper bound, we adopt EPA’s assumption that

effective reductions of up to 90 percent may be

possible, compared to gasoline vehicles meeting

current standards [56]. A major advance needed

before such large reductions could be obtained is to

improve engine and catalyst designs to control

emissions of formaldehyde, a highly reactive, toxic

VOC produced when methanol is burned. Some

engineers and analysts are skeptical that formaldehyde emissions can be controlled well enough to

reduce overall ozone-forming potential by 90 percent [33,4].

Emissions reductions that could be achieved

using CNG are even more speculative than those for

methanol vehicles, because emissions have only

been measured for a few dual-fuel CNG vehicles,

and the results have varied significantly from one

test to another [3,7]. EPA has preliminarily estimated that while operated on CNG, dual-fuel vehicle

exhaust emissions would effectively be 40 percent

lower, and evaporative emissions 100 percent lower,

than emissions from vehicles meeting current emission standards and operating on low volatility

gasoline [56]. Adding up the exhaust and evaporative impacts, total emissions would be reduced by

about 75 percent.38 As an upper bound for CNG, we

assume that if vehicles are designed and adjusted for

minimal emissions with exclusive operation on

CNG, total effective reductions of up to 90 percent

might be realized.

It is important to emphasize that the relative

ozone-producing potential of vehicles operated on

gasoline versus alternative fuels will depend on

future regulations, including volatility limits set for

gasoline, and exhaust and evaporative emissions

limits imposed on both gasoline and alternativefueled vehicles. With any fuel, considerable leeway

exists in trading off emission rates for engine

performance, starting and warm-up characteristics,

and vehicle costs. EPA has promulgated emissions

standards for methanol-fueled vehicles that allow

the same levels of exhaust and evaporative VOC

emissions for methanol as for current gasoline38BWd on EpA’~ model of motor “Chicle ~mis5ion5,MOB~E 4, for a vehicle m~ting c~ent exhaust s~dmds ~d operating on 9.0 psi RVP

gasoline, and for atypical hot summer day, we assume in-use exhaust, evaporative and ‘running loss” emissions are 42,21, and 37 percent, respectively,

of total emissions.
186 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

fueled vehicles.39 Under the proposed regulations,

the improvement in air quality anticipated with

methanol would be due solely to the reduced

ozone-forming character of the emissions, rather

than reduced emissions, per se. To date, EPA has not

proposed standards for CNG vehicles.

Switching to alternative fuels could affect levels

of several air pollutants besides ozone. In addition to

VOCs, gasoline vehicles also emit nitrogen oxides,

benzene and other toxic organic compounds, carbon

monoxide, and particulate. In theory, methanol and

CNG have the potential to reduce emissions of all of

these pollutants, although the reductions that actually occur will depend on regulations, and on vehicle

design and operation. Replacing diesel with methanol or CNG might be especially helpful in allowing

heavy-duty buses and trucks to obtain concurrent

reductions in emissions of both particulate and

nitrogen oxides.40 For light-duty vehicles, EPA

applies the same carbon monoxide and nitrogen

oxides emissions standards for methanol as for

gasoline [52], so potential reductions in these

pollutants would probably not be realized. A critical

problem that needs to be addressed with methanol

vehicles is emissions of formaldehyde. With catalyst

designs tested to date, methanol vehicles cannot

meet the in-use standards California has proposed

for formaldehyde emissions [33].

One final air quality consideration associated with

the use of motor vehicle fuels other than gasoline is

their comparative emissions of “greenhouse” gases

that trap heat in the atmosphere, such as carbon

dioxide (Co2) and natural gas (methane). Considering production of the fuels as well as combustion in

motor vehicles, and assuming that on an energy

equivalent basis the fuel economy is the same, use of

CNG would be expected to reduce greenhouse gas

emissions by about 20 percent, compared to gasoline

[16]. Greenhouse gas emissions from methanol

produced from natural gas would be about the same

as emissions from gasoline [16]. However, use of

methanol produced from coal could increase emissions of greenhouse gases by 50 to 100 percent,

depending on the efficiency of the process of

producing methanol [16,25]. At present, methanol is

produced almost exclusively from natural gas,

because production from coal is not economically

viable [46].

Vehicle Operation and Performance

Because methanol is incompatible with some

metals and polymers currently used in automotive

fuel systems, straight methanol cannot be used in

vehicles designed to run on gasoline. However, in

California tests, vehicles that were built to run on

methanol have given comparable performance and

maintenance records and equal or improved fuel

economy (on an energy equivalent basis41) compared to gasoline-fueled vehicles of the same model

[1]. Gasoline was generally added to the methanol

used in these demonstration programs for safety, so

that in case of an accident the fuel would burn with

a visible flame, and because cars run on straight

methanol are difficult to start in cold weather [1].

Theory suggests that if these two problems can be

overcome, vehicles that are modified to operate on

straight methanol could get 10 to 15 percent higher

fuel economy (energy equivalent basis) and give

improved performance (due to methanol’s high

octane rating) than gasoline-fueled vehicles [1].

Finally, methanol is much more toxic than gasoline.

39u.s. EPA’,s standards for light-duty-me~~ol-fiel~ vehicles are exhaust emissions of 0.41 g/mi hydrocarbon (HC), and evaporative emissions of

2.0 #test HC [52]. The State of California’s standards for methanol-fueled passenger vehicles are similarly equivalent to their proposed gasoline-fueled

vehicle standards (California has proposed a new exhaust emissions limit for 1992 and subsequent model year passenger vehicles of 0,25 g)mi) except

that limits on formaldehyde in exhaust are specified explicitly (0.015 g/mi at certification and 0.023 ~mi in-use for the 1993 to 1995 period, and 0.015

g/rni at certification and in-use after 1995) [9].

WII 1990, tie NOX emission5 standard for all heavy duty vehicles will be reduced from the current Standard of 10.7 @bhp-hr to 6.0 g/bhp-k and to

5.0 g/bhp-hr in 1991. in 1991 the particulate standard for urban transit buses will be reduced from 0.6 g/bhp-hr to 0.1 g/bhp-hr and for other heavy duty

vehicles to 0.25 g/bhp-hr. In 1994, all heavy duty vehicles will be required to meet a 0.1 g/bhp-hr particulate emissions standard, The particulate and

NOX standards may be difficult to meet concurrently with the add-on control technology anticipated to be available for heavy-duty diesel vehicles. In

a demonstration program in California, transit buses with either spark or compression ignition engines that were designed or significantly modified to

run on methanol emitted lower levels of NOX and particulate than diesel-fueled buses. However, methanol buses have had problems with limited

durability of parts and restricted range between refueling [1]. Several heavy-duty engine manufacturers have research underway to develop spark

ignition engines to operate on CNG [35].

ql~e energy content of a gallon of gasoline is approximately 2.0 times greater than that of a gallon of methanol.
Chapter 7--New Opportunities for Controlling Ozone ● 187

Ingestion can cause permanent blindness or death.42

Widespread use of methanol would require safety

precautions that have not been taken with gasoline.

The advantages of CNG include its very high

octane rating, high combustion efficiency, and good

characteristics for starting in cold weather. The main

disadvantages of the fuel are related to its low

volumetric energy content. The distance that current

CNG vehicles can be driven without refueling is

currently limited to about 200 miles, whereas a

typical light-duty vehicle has a range of up to 350

miles on 15 gallons of gasoline. In providing a

200-mile range, current CNG-fueled vehicles carry

extra weight and displace about five times the space

that gasoline tanks providing the same range would

require. The most commonly used steel tanks weigh

up to 400 pounds, while more recently developed

fiberglass-wrapped aluminum tanks weigh about

200 pounds [17]. For comparison, the average

weight of current passenger cars is about 3,000

pounds, including a 25-pound gasoline tank.

Most of the CNG vehicles that are currently in

operation in the United States have been retrofitted

for dual CNG or gasoline use. Adjustments made to

allow dual fuel operation affect performance and

fuel efficiency. Dual-fuel vehicles have generally

given poorer performance and had worse fuel

economy on both gasoline and CNG than comparable gasoline vehicles [46,7]. Some experience with

CNG vehicles that operate exclusively on CNG has

been gained with 27 light-duty trucks built by the

Ford Motor Company. The truck tested by U.S. EPA

gave performance and fuel efficiency comparable to

an equivalent gasoline-fueled truck [3].

Potential Emissions Reductions from

Alternative Fuel Use

In the following sections, we consider the total

emissions impacts of alternative fuel use in the year

2004, in: 1) fleets of 10 or more light-duty vehicles

(e.g., vehicles owned by corporations or police

departments), and 2) light-duty vehicles in general

use. We also estimate the costs per ton of VOC

emissions effectively eliminated.43 Emissions impacts are calculated assuming that refueling emissions and gasoline volatility have already been

controlled, and that light-duty vehicles are subject to

current standards. Because of the potentially high

cost of using methanol and natural gas, it may be

desirable to limit their use to those areas with the

most severe ozone problems. Therefore we only

consider alternative fuel use in areas with design

values of 0.15 ppm or higher. The other control

measures OTA has identified are projected to be

insufficient to bring most of these areas into

attainment by the year 2004 (see chapter 6).

In the sections that follow, as our best estimates,

we assume that emission rates with methanol blends

would effectively be 30 percent lower than those of

gasoline vehicles; and that emissions from dual-fuel

vehicles operated on CNG would effectively be 75

percent lower. We assume full-time use of methanol

blends, but that dual-fuel vehicles are only operated

on CNG 75 percent of the time.44 As an upper bound

for exclusive use of either CNG or methanol in

vehicles incorporating technological advances, we

use an effective reduction in emission rates of 90

percent, compared to gasoline.

In addition to motor vehicle exhaust and evaporative emissions, refueling emissions would also be

reduced if gasoline were displaced by straight

methanol or by CNG. Negligible reductions in

refueling emissions would be anticipated if gasoline

were displaced by a methanol/gasoline blend. With

straight methanol or CNG use, we assume that

refueling controls would have been in place anyway,

and that reductions in VOC emissions from refueling are proportional to the amount of gasoline

displaced. 45

42J~tover z Omces of me~~ol couId ~~nti~ly be leth~ if sw~]ow~ by a 150.pound adult. ~s amount could readily be ingested accidentally

by someone siphoning fuel. Swallowing less than half an ounce of methanol could be lethal to a young child [30].

4sNote tit~ estfi~ng VW con~ol cost.eff~tlveness, we have used the full cost differential betwcxm gasoline and the alternatives. [f, compared

to gasoline, use of alternative fuels also reduced emissions of otier pollutants such as carbon monofide, the COStS associated with fuel substitution should

be distributed across pollutant control programs.

tiwe ~sme mat some oWration on gaW1ine wo~d ~ necess~ for du~-fuel CNG vehicles, ~ause the distance they Cm be drivenon CNG without

refueling is limited, and because CNG would not be available everywhere. Nationwide, about 15 percent of vehicle males are driven on trips that cover

more than 75 miles in distance, one-way [48].

dsv~ e~sslons from ~Wo]ew refi~g could ~W ~ r~uc~, ~swing that they arc ti~ to g~line ales. However, we c~ot be sure where

such reductions would occur, so we do not count them in the totals for the areas where alternative fuels are used.
188 • Catching Our Breath: Next Steps for Reducing Urban Ozone

Light-Duty Fleet Vehicles

In 1986,6 million cars and 2 million light trucks

in centrally owned fleets of 10 or more vehicles

accounted for about 13 percent of light-duty vehicle

miles traveled (VMT) nationwide [5]. Centrally

owned fleets account for such a large fraction of

VMT because on average, fleet vehicles are driven

over two times as many miles in a year as vehicles

in general use. Use of alternative fuels in centrally

fueled fleets is expected to be easier to promote or

require than general use, because the latter would

have to be preceded by development of a much more

extensive network of refueling stations than the

former.46

In 2004, in areas with design values of 0.15 ppm

or higher, about 4.5 million light-duty vehicles are

expected to be operating in centrally owned fleets of

10 or more. About 7.9 billion gallons of methanol

per year would be required to operate these 4.5

million vehicles.47 This amount is about equal to the

worldwide capacity for production projected for

1990 [21].48 About 520 billion cubic feet of natural

gas (approximately 3 percent of current U.S. production) would be required annually to operate 4.5

million light-duty vehicles exclusively on CNG.

Table 7-10 summarizes the effective VOC reductions that could be obtained with CNG or methanol

use in areas with design values of 0.15 ppm or

higher. Our best estimate is that by 2004, use of

methanol in fleets would be equivalent to reducing

emissions by 0.7 percent of total 1985 levels. Using

CNG in fleets (75 percent of the time) is estimated

to be equivalent to reducing VOC emissions by 1.3

percent of 1985 levels. As an upper bound, with

technological advances and exclusive use of either

CNG or straight methanol, we estimate that emissions might be reduced by 2.1 percent.

Vehicles in General Use

By 2004, it might be possible to expand the supply

and distribution of alternative motor vehicle fuels to

satisfy a large portion of the general market. To

illustrate the magnitude of potential VOC emissions

reductions and fuel consumption involved, we

consider the impacts of using alternative fuels in 25

percent of the light-duty vehicles in general use in

2004, in nonattainment areas with current design

values of 0.15 ppm or higher.

About 15 billion gallons of methanol are estimated to be needed to fuel 25 percent of the general

population of light-duty vehicles in nonattainment

areas with design values of 0.15 ppm or higher.

About 1 trillion cubic feet of natural gas (5 percent

of U.S. production in 1987) is estimated to be needed

if CNG is used.

As shown in table 7-10, our best estimate is that

if 25 percent of the light-duty vehicles in areas with

design values of 0.15 ppm or higher used methanol

or CNG, emissions would be effectively reduced by

1.3 or 2.5 percent, respectively, compared to 1985

levels. Our upper bound estimate is that emissions

might be effectively reduced by up to 4.1 percent,

again with technological advances and exclusive use

of either CNG or straight methanol.

Cost-Effectiveness of Alternative Fuel Use in

Light-Duty Vehicles

Methanol

One automobile manufacturer has estimated that

in production runs of fewer than about 100,000

vehicles, cars and light-duty trucks designed to

operate on methanol would cost $500 to $1,000

more than gasoline-fueled vehicles; whereas in

larger runs, methanol and gasoline-fueled vehicle

production costs could be comparable [53]. For

centrally owned fleets, assuming a vehicle life of 6

years (150,000 miles) and an 8-percent discount rate,

the annualized cost differential for a methanol

vehicle could thus range from $0 to about $215. For

a vehicle in general use, with a 10-year (100,000

mile) life and again assuming an 8-percent discount

rate, the annualized added cost could range from $0

to $150.

46B~au~ of da~ limitations, we focus our an~ysis on centrally owned fleet vehicles, rather ~on centrally fueled fl~t vehicles.

qT~s ~wes~Cas average 27.5 mllespergaWl~e g~]on ~uiv~ent fuel, ad that lightduty ~cks average 20 miles pr gallon. About 690 billion

cubic feet of natural gas would be required to produce 7.9 billion gallons of methanol.

48UOS, ~r~uctim ~.WiV in 1~ is ~rojwt~ t.~abut 2 billiong~lons.me pficip~ ~ of me~~ol is c~ndy as a chemical f@stock.
Chapter 7-New Opportunities for Controlling Ozone ● 189

Table 7-10-Effective VOC Reductions in 2004, From Use of CNG and Methanol as Light-Duty

Motor Vehicle Fuels in Areas with Design Value of 0.15 ppm or Highera

New vehicle Area-wide total fleetsc Area-wide total generald

reduction

(percent) (tons) (percent) (tons) (percent)

Methanol blends . . . . . . . . . . . . . . . 30 54,000 0.7 102,000 1.3

(best estimate)

Straight methanol . . . . . . . . . . . . . . 90 173,000 2.1 328,000 4.1

(upper bound)

Dual-fuel CNGe

. . . . . . . . . . . . . . . . 75 108,000 1.3 205,000 2.5

(best estimate)

Exclusive CNG . . . . . . . . . . . . . . . . 90 173,000 2.1 328,000 4.1

(upper bound)

aT~ ~~uC~n ~~~ & ~~~ht ~e~~ and ~~~lu~i”e cNG u= i~l@ refu~ing emiss~ns r~u~ns of 11,~ mns for fleets, and 21,000 tOnS fOr generahlSS VdliCieS. For

dual-fu~ CNG whides, 75 mrosnt of those reductions are counted. Reductions in refueling emissions are expected to be negligible, with methanol blends.

b~mw~ @ ~fl~~ me&g ourrent standards On 9.0 P& ~li~.

cA~M~ ~el UU in ~nfrally owned fteets of 10 or more Iightduty vehicles.

d~rmtive ~el IJSIS in 25 pereent of all Iightduty V8hiCks.

eA~mes 75 ~r~nt operation on CNG, 25 percent OWadOn on @$oli~-

SOURCE: Office of Twhnology Assessment, 19S8.

Based on a range of 40 to 60 cents per gallon as

the wholesale price of methano149 we estimate that

methanol would be sold to consumers at $0.64 to

$0.84 per gallon, or $1.15 to $1.51 per gasolinegallon equivalent, adjusting for the difference in the

energy content of the two fuels.50 These estimates

can be compared to national average prices for

regular and premium unleaded gasoline of $0.95 and

$1.10 per gallon, respectively [47]. Assuming that

fleet vehicles average 26,000 miles per year and get

the energy equivalent of 26.5 miles per gallon of

gasoline, straight methanol use would increase

annual fuel costs by about$130 to $480 per vehicle.

Annual fuel costs would be about $50to$180 higher

for a vehicle in the general population averaging

10,000 miles per year and 26.2 miles per gallon.

Table 7-11 summarizes our cost-effectiveness

estimates for methanol-fueled vehicles. In the near

term, assuming that methanol is blended with 15

percent gasoline and yields effective VOC emissions rates that are only 30 percent lower than

gasoline-fueled vehicles, we estimate that using

methanol would cost $9,000 to $66,000 per ton of

VOCs eliminated. If

reductions in VOC

the equivalent of 90-percent

emissions can be achieved

through advanced technology, we estimate that

using straight methanol would cost $3,000 to

$22,000 per ton. In each case, the low estimate

assumes both vehicle and fuel costs that are most

favorable to methanol, and the high estimate assumes costs that are least favorable.

Compressed Natural Gas

Retrofitting a gasoline vehicle to operate on both

CNG and gasoline costs about $1,000to $1,500 [53].

Because a special fuel tank is required, a cost

differential of about $500 is expected between CNG

and gasoline-fueled vehicles even in large production runs. The annualized added cost of a vehicle that

would be run on CNG is expected to fall between

$110 and $325, for a fleet vehicle, and between $75

and $218, for a vehicle in general use.

Based on 1987 national average commercial

natural gas prices of $4.76 per thousand cubic feet

[47], or $0.56 per gasoline-gallon equivalent, and

$0.20 to $0.30 per gasoline-gallon equivalent com49whOl@& me~ol ~flces in Smer, 1988, Wem $ojo” ~r ~~lon, delivered to the Gulf ~~t[29]. Me~~ol UStiin demonstration fkts in

California is supplied at $0.59 per gallon, but tbe State has new commitments for delivery of 9 million gallons at $0.45 per gallon [10]. Wifh new plants

and sufficient demand to ship methanol by tanker, various analysts estimate long-run costs for methanol ranging from less than $0.35 to more than $0.70

~r @on [ 13~1,20,10,42,2]. Relatively cheap methanol is expected to come from countries such as Trinidad or Saudi Arabia, whew it co~d be retie

from natural gas that is recovered in the process of oil production and would otherwise be vented or flared. U.S. methanol production costs would be

relatively high due to the high cost of U.S. natural gas. Because of the dominance of fecdstock costs, the cost of producing methanol domestically would

increase with demand.

50we have ~d~ .$f)m ~g~l~ for t~~, dis~bution to refueling stations, and retail markup. The gasoline-gallon wulv~ent Price is estirnat~

by assuming that a gallon of methanol is cxquivalent to 1.8 gallons of gasoline, based on the 2:1 ratio of gasoline to methanol energy content and a

10-pereent improvement in energy efficiency with methanol.
190 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 7-ll+Xet-Effectiveness of Alternative Fuel Use

Fuel price New vehicle Fleet cost- General cost-

($/gas. differential effectiveness effectiveness

gal. equiv.) ($) ($/ton) ($/ton)

Methanol blends . . . . . . . . . . . . . . . . . 8,700-51,000 8,700-66,000

Straight methanol . . . . . . . . . . . . . . . . 1.15-1.51 0-1,000 3,200-18,000 3,200-22,000

Dual-fuel CNGa 

. . . . . . . . . . . . . . . . . 400-12,000 3,900-22,000

Exclusive CNG . . . . . . . . . . . . . . . . . . 0.85-0.95 500-1,500 0-7,400 1,600-14,000

aAssumes 75 percent operation on CNG, 25 percent operation on gasoline.

NOTE: A retail gasoline price of $1.025 per gallon is used to calculate fuel cost differentials.

SOURCE: Office of Techology Assessment, 1989.

pression costs [46,17,36], we estimate that CNG

would be sold to consumers at about $0.89 to $0.99

per gasoline-gallon equivalent.51 At these prices, use

of CNG in fleet vehicles could save from $35 to

$130 per vehicle per year. In general, light-duty

vehicles’ use of CNG could save $10 to $50

annually per vehicle.

As shown in table 7-11, if three-quarter time use

of CNG in dual-fuel vehicles resulted in 56-percent

reductions in VOC emissions overall (averaged over

operation on gasoline and CNG), the cost of using

CNG would be $400 to $22,000 per ton of VOCs

removed, depending on vehicle and fuel costs, and

distance traveled (which determines how much fuel

cost savings offset vehicle purchase costs). If

90-percent reductions could be realized with advanced vehicles operated exclusively on CNG, use

of CNG in fleets could result in a net savings,

compared to gasoline, or cost up to $7,000 per ton of

VOCs removed; in the general population, costs

would be $1,600 to $14,000 per ton.

REFERENCES FOR CHAPTER 7

1.

2.

3.

Acurex Corp., California’s MethanolProgram. Evaluation Report, Volume II: Technical Anulyses, report

P500-86-012A prepared for the California Energy

Commission (Mountain View, CA: June 1987).

Acurex Corp., “Discussion Review of Draft Final

Report and Findings, AB234 Economics Commit-

“ presentation to the Advisory Board on Air

~~bity and Fuels (Sacramento, CA: Apr. 19, 1989).

Alson, J. A., ‘The Emission Characteristics of Methanol and Compressed Natural Gas in Light Vehicles, ”

paper 88-99.3, presented at the 81st Annual Meeting

of the Air Pollution Control Association, Dallas, TX,

June 19-24, 1988.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

Austin, T. C., Sierra Research, letter to Richard

Rapoport, Office of Technology Assessment, Mar.

17, 1989.

Automotive Fleet 1987 Fact Book, Volume 26

Supplement (Bobit Publishing Co., 1987).

Bohi, D.R., and Zimmerman, M. B., “An Update on

Econometric Studies of Energy Demand Behavior,”

Ann, Rev. Energy 9;105- 154, 1984.

Bruetsch, R. I., Emissions, Fuel Economy, and Performance of Light-Duty CNG and Dual-Fuel Vehicles (Ann Arbor, MI: U.S. Environmental Protection

Agency, June 1988).

California Air Resourus Board, California’s Post1987 Motor Vehicle Plan for Continued Progress

toward Attainment of the National Ambient Air

Quulity Standar&for Ozone and Carbon Monoxide

1988 Update, Appendix IV-F, Draft Air Quality Plan

1988 Revision (El Monte, CA: September 1988).

California Air Resources Board, “Notice of Public

Hearing to Consider the Adoption of Regulations

Regarding Certification of Methanol-Fueled Motor

Vehicles and Motor Vehicle Engines for Sale in the

State of California” (El Monte, CA: March 1989).

California Energy Commission, Cost and Availability of Low-Emission Motor Vehicles and Fuels, Draft

AB234 report (Sacramento, CA: April 1989).

Cambridge Systematic, Inc., lrnproved Air Quality

in Maricopa and Pima Countie_he Applicability

of Transportation Measures (Cambridge, MA: November 1986).

Clay, D.R., and Wilson, J. J., U.S. Environmental

Protection Agency, letter toR.E. Farris, Nov. 8,1988.

Cohen, L.H., and Muller, H. L., “Methanol Cannot

Economically Dislodge Gasoline,” Oil and Gas

Jourrud, 83:1 19-124, 1985.

Dahl, C. A., “Gasoline Demand Survey,” The Energy Journal 7:67-82, 1986.

Deakin, E., “Land Use and Transportation Planning

in Response to Congestion: A Review and Critique, ”

sl~nt forums proj~t that natur~ gas prices will roughly track gasoline prices though the YCXU 2m [45].
Chapter 7-New Opportunities for Controlling Ozone ● 191

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

paper no. 880586, presented at the 68th Annual

Meeting of the Transportation Research Board (Washington, DC: Jan. 22-26, 1989).

DeLuchi, M. A., Johnston, R. A., and Sperling, D.,

Transportation Fuels and the Greenhouse Effect,

Universitywide Energy Research Group report UER182 (Davis, CA: University of California December

1987).

DeLuchi, M.A., Sperling, D., and Johnson, R.A., A

Comparative Analysis of Future Transportation

Fuels, Research Report UCB-ITS-RR-87-13 (Berkeley, CA: Institute of Transportation Studies, University of California, October 1987),

Demmy, J.L., Tax, W. M., and Warn, T.E., Area

Source Documentation for the 1985 National Acid

Precipitation Assessment Program Inventory, pp.

55-59, B-107 to B-I1O, prepared for the U.S.

Environmental Protection Agency, Office of Research and Development, EPA Contract 68-02-4274,

Work Assignment Nos. 2 and 23 (Alliance Technologies Corporation, November 1987).

Demmy, J. L., Alliance Technologies Corporation,

letter to Robert Friedman, Office of Technology

Assessment, Aug. 19, 1988.

Energy and Environmental Analysis, Inc., A4etharwl’s Potential as a Fuel for Highway Vehicles, draft

contractor report prepared for the Office of Technology Assessment February 1987.

Jack Faucett Associates, Methanol Prices During

Transition, report prepared for the U.S. Environmental Protection Agency (Bethesda, MD: September 1986).

Federal Highway Administration, Transportation

and Air Quality: A Review of the 1982 State

Implementation Plans (U.S. Department of Transportation, June 1983).

Federal Highway Administration, America’s Challenge for Highway Transportation in the 21st Century, interim report of the Future National Highway

Program Task Force, FHWA-PL-89-020 HPP-1-1 1-

88(2M)E (U.S. Department of Transportation, November 1988).

Flynn C.P., and Glazer, L., “Ten Cities’ Approach to

Transportation Demand Managemen~” paper no.

880640, presented at the 68th Annual Meeting of the

Transportation Research Board (Washington, DC:

Jan. 22-26, 1989).

Guensler, R., “Compliance Perspectives on Transportation Control Measures: South Coast AQMD

Regulation XV,” presented at the 68th Annual

Meeting of the Transportation Research Board (Washington, DC: Jan. 22-26, 1989).

Gushee, D.E., Carbon Dioxide Emissionsfiom Methanol as a Vehicle Fuel, CRS report for Congress,

27.

28.

29.

30.

31.

32.

33.

34.

35.

36.

37.

38.

39.

88-407 S (Washington, DC: Congressional Research

Service, June 1988).

Gushee, D. E., and Sieg-Ross, S., The RoZe of

Transportation Controls in Urban Air Quality, CRS

88-101 S (Washington, DC: Congressional Research

Service, January 1988).

Higgins, T., “Parking Management and Traffic

Mitigation in Six Cities: Implications for Local

Policy,” paper no. 880396, presented at the 68th

Annual Meeting of the Transportation Research

Board (Washington, DC: Jan. 22-26, 1989).

Information Resources, Inc., AZcohol Update (Washington DC: July 1988).

Litovitz, T., “Acute Exposure to Methanol in Fuels:

A Prediction of Ingestion Incidence and Toxicity, ”

submitted, October 1988.

Martin, R. E., Transit and Parking: Public Policy,

Report prepared for Senators Bradley, Lautenberg,

D’Amato and Moynihan (Urban Mass Transportation Administration, U.S. Department of Transportation, February 1989),

Newman, P. W. G., and Kenworthy, J. R., “Gasoline

Consumption and Cities: A Comparison of U.S.

Cities With a Global Survey,” J. American Planning

Association 55:24-37, 1989.

Nichols, R.J., Clinton, E.L., King, E.T., Smith, C. S.,

and Winekmd, R. J., “A View of Flexible Fuel

Vehicle Aldehyde Emissions,” SAE Technical Paper

Series no. 881200 (Warrendale, PA: Society of

Automotive Engineers, August 1988).

Pechan, E.H. and Associates, Inc., Natiorud Assessment of VOC, CO, and NOX Controls, Emissions, and

Costs, prepared for the (Mike of Policy Planning and

Evaluation, U.S. Environmental Protection Agency,

Contract No. 68-W8-0038 (Washington, DC: September 1988).

Seisler, J., American Gas Association, presentation at

the Alternative Fuels for Vehicles Outlook Conference (Ames, 1A: Iowa State University, June 15,

1988).

Seisler, J., American Gas Association, personal

communication, April 1988.

Sierra Research, Inc., The Feasibility and Costs of

More Stringent Mobile Source Emission Controls,

contractor report prepared for the Office of Technology Assessment, Jan. 20, 1988.

South Coast Air Quality Management District and

the Southern California Association of Governments,

The Path to Clean Air: Attainment Strategies (El

Monte, CA: December 1987).

South Coast Air Quality Management District, Draft

Air Quality Management Plan, 1988 Revision, Appendices IV-A (incl. Addendum) and IV-C (El

Monte, CA: May 1988).
192 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

51.

Southern California Association of Governments,

Draji Air Quality Management Plan, 1988 Revision,

Appendix IV-G, “Transportation, Land Use, and

Energy Conservation Measures” (Im Angeles, CA:

September 1988).

Southern California Association of Governments,

Regional Mobility Plan, draft report (Ims Angeles,

CA: October 1988).

SRI International, “The Economics of Alternative

Fuels and Conventional Fuels,” presentation to the

Advisory Board on Air Quality and Fuels (Sacramento, CA: Feb. 2, 1989).

State andTdtorial Air Pollution Program Adrnuns “ “ tratorsAssociation of Imcal Air Pollution Control Officials,

The STMPA-ALAPCO National Ozone Control

Strategy, Executive Summary, May 1988.

U.S. Department of Commerce, Bureau of the

Census, County Business Patterns 198S-United

States, CBP-85-1 (Washington, DC: U.S. Government Printing Office, November 1987).

U.S. Department of Energy, Annuul Energy Outlook

1987, DOE/EIA-0383(87) (Washington, DC: March

1988).

U.S. Department of Energy, Assessment of Costs and

Benefits of Flexible and Alternative Fuel Use in the

U.S. Transportation Sector. Progress Report One:

Context and Analytical Framework (Washington,

DC: January 1988).

U.S. Department of Energy, Monthly Energy Review

(Washington, DC: September 1988).

U.S. Department of Transportation, PersonaZ Travel

in the U.S., Volume I (Washington, DC: August

1986).

U.S. Department of Transportation, Personal Travel

in the U.S., Volume II (Washington, DC: November

1986).

U.S. Department of Transportation, Federal Register

53:35178-35185, notice of proposed rulemaking,

Sept. 9, 1988.

U.S. Environmental Protection Agency, Office of

Transportation and Land Use Policy, Transportation

and Air Quality (Washington, DC: July 1981).

52.

53.

54.

55.

56.

57.

58.

59.

U.S. Environmental Protection Agency, Federal

Register 54:14425-14612, Apr. 11, 1989.

U.S. Environmental Protection Agency, Cost and

Cost Effectiveness of Alternative Fuels, prepared for

the Vice Pmident’s Task Force on Alternative Fuels,

July 1987.

U.S. Environmental Protection Agency, FederaZ

Register, Nov, 17, 1987.

U.S. Environmental Protection Agency, Federal

Register 53:30566-30602, Aug. 12, 1988.

U.S. Environmental Protection Agency, Guidance on

Estimating Motor Vehicle Emission ReductiorM from

the Use of Alternative Fuels and Fuel Blends,

EPA-AA-TSS-PA-87-4 (Research Triangle Park,

NC: January 1988).

U.S. Environmental Protection Agency, OffIce of Air

Quality Planning and Standards, Summary of State

VOC Regulations, EPA-450/2-85-O03 (Raleigh, NC:

April 1985).

U.S. Environmental Protection Agency, Office of Air

Quality Planning and Standards, Summary of State

VOC Regulatio*Volume 2, Group III CTG and

Greater Than 100 Ton Per Year Non-CTG VOC

Rt?gulatkmr, EPA-450/2-88-004 (Raleigh, NC: May

1988).

U.S. Environmental Protection Agency, Of35ce of

Research and Developmen~ Anthropogenic Emissions Data for the 1985 NAPAP Invento@inal

Report, prepared for the National Acid Precipitation

Assessment Program, EPA-600/7-88-022 (Springfield, VA: National Technical Information Service,

November 1988).
Chapter 8

Policy Options
CONTENTS

Page

INTRODUCTION .. .. .. .. .. .. .. ... ... ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

OVERALL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

Deadlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

Interim Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

Penalties and Corrective Actions in the Event of Failure . . . . . . . . . . . . . . . . . . . . . . . . . 204

State and Local Planning Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

Research ....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . ... ....... . . . . . . . 210

CONTROL REQIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

Federally Implemented, Nationwide Control Requirements . . . . . . . . . . . . . . . . . . . . . . . . 213

Control Requirements To Be Implemented by States in Nonattainment Areas . . . . . . 216

Managing Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

NEW DIRECTIONS FOR THE CLEAN AIR ACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

Controls on Emissions of Nitrogen Oxides in Nonattainment Areas . . . . . . . . . . . . . . . 222

Controls in Upwind AReas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

Reducing Ozone in Rural Attainment Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...... 227

Long-Term Control Strategies for Chronic Nonattainment Areas . . . . . . . . . . . . . . . . . . 228

REFERENCES FOR CHAPTER 8... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

Tables

Table Page

8-1. Options for Amending the Clean Air Act: Overall Requirements . . . . . . . . . . . . . . . . 196

8-2. Options for Amending the Clean Air Act: Currently Available Control Methods . . 197

8-3

8-4

8-5

8-6

8-7

8-8

Options for Amending the Clean Air Act New Directions . . . . . . . . . . . . . . . . . . . . . . 197

Time Requirements for SIP Process Under the 1977 Clean Air Act Amendments . 198

Sanctions for Failure To Meet the Requirements of the Clean Air Act . . . . . . . . . . . 204

VOC Sources For Which Nationwide Regulations Exist.. . . . . . . . . . . . . . . . . . . . . . . 214

Options for New Car and Light-Duty Truck Exhaust Standards . . . . . . . . . . . . . . . . . . 215

VOC Sources For Which EPA Has Issued Control Technique Guidelines . . . . . . . . 217
Chapter 8

Policy Options

INTRODUCTION

More than 10 years have gone by since the

passage of the last major set of amendments to the

Clean Air Act. While some progress has been made

in reducing VOC emissions and lowering ozone

concentrations, most major metropolitan areas still

do not meet the ozone standard. Ozone has been the

most difficult of the major air pollutants to control

over the almost 20-year history of the Clean Air Act.

The Nation has failed several times to meet the

attainment deadlines set by Congress in the Clean

Air Act-first in 1975 and again in 1982 and 1987.

One of the most important findings of our

assessment is that about half of the nonattainment

cities will still not be able to attain the standard with

currently available VOC control measures. According to our calculations, most areas with peak ozone

concentrations above 0.16 ppm will not be able to

attain the standard with existing VOC controls.

Some areas with even lower peak concentrations

may have great difficulty, as well. These include:

cities that are heavily affected by pollution transported from neighboring areas, cities that have

already implemented most of the available VOC

control measures, and cities where ozone levels are

more sensitive to NOX emissions, for example,

southern cities that are surrounded by areas with

high emissions of VOCs from natural sources.

If Congress once again sets ambitious near-term

targets for the next decade, but ignores the decade

that follows, we will likely fail one more time. An

effective ozone strategy must incorporate two components: 1) measures to address near-term VOC

reductions possible with currently available control

methods and 2) measures to ensure that we can

continue to make progress after the year 2000, when

many areas will still exceed the standard even after

substantial emissions reductions are made in the

next 5 to 10 years.

In this final chapter, we present options for

Congress in three broad categories. First we present

options for overall requirements, including deadlines for attaining the standard; interim requirements

to ensure continuing progress towards attainment;

and penalties in the event of failure. We also present

options for State planning, and for further research.

Table 8-1 outlines these more general policy decisions facing Congress and the options that we

present.

We then provide options for the near-term VOC

reductions that are possible using currently

available control methods. Because air pollution

control under the Clean Air Act relies on a partnership between EPA and the States, these fall naturally

into two categories: a list of federally implemented,

nationwide control requirements and control requirements to be implemented by the States. The

section concludes with options for managing emissions growth in nonattainment areas. An outline of

these options is found in table 8-2.

Because many areas will not be able to attain the

ozone standard by relying solely on currently

available VOC control measures, we discuss some

new directions for the Clean Air Act in the final

section. These include controls on nitrogen oxides in

nonattainment areas, controls on both nitrogen

oxides and VOCs in upwind areas, and several

alternatives for long-term strategies for the worst

nonattainment areas. We also present options for

lowering ozone concentrations in rural areas to

protect crops and forests. Table 8-3 summarizes the

options discussed in this final section.

OVERALL REQUIREMENTS

Deadlines

Discussion

The 1977 Amendments established two major

categories of nonattainment areas, each with its own

attainment deadline. Areas with less severe problems were to attain the standard within 5 years, by

the end of 1982. Those areas that could not attain the

standard by the end of 1982 by adopting all

reasonably available control measures were given an

additional 5 years. However, by December 1987, the

deadline for all areas to attain the standard, more

than 60 areas were still not in compliance.

Congress is once again faced with the problem of

setting new deadlines. An important finding of our

–195–
196 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 8-l-Options for Amending the Clean Air Act: Overall Requirements

Deadlines:

Decision 1: How many categories of nonattainment areas, each

with its own deadline and other requirements, should

be established?

. Option 1: Two categories-those that can attain the standard

with currently available controls and those that cannot.

● Option 2: Three or more categories, including more than one

category of areas that cannot attain with currently available

controls.

Decision 2: What deadline should be set for those areas that can

attain the standard with currently available control

methods?

. Option 1: Maintain the Act’s current 5-year schedule from start

of planning to attainment.

. Option 2: Require detailed inventories, modeling, and planning

and allow 5 to 7 years.

Decision 3: What deadline(s) should be set for those areas that

cannot attain the standard with currently available

control methods?

. Option 1: 8 to 10 years for the “best” of the areas that cannot

attain with currently available control measures; at least 20

years for the ‘(worst” (Los Angeles).

. Option 2: Eliminate deadlines.

Interim Requirements:

Decision: What interim requirements are needed to ensure

continuing progress towards attainment?

. Option 1: Interim air quality targets.

. Option 2: Areawide emission reduction schedules.

. Option 3: Source-specific controls.

● Option 4: Some combination of the above options.

Penalties and corrective actions in the event of failure:

Decision 1: For what kinds of failures should States be penalized?

. Option 1: Sanctions for failing to make “sufficient” efforts.

. Option 2: Sanctions for failing to identify enough controls to

meet a congressionally specified reduction schedule.

• Option 3: Sanctions for failing to attain the standard by the

Decision 2: What types of sanctions should be adopted?

. Option 1: Sanctions that limit growth in nonattainment areas, for

example, a ban on construction of new sources of pollution or

a moratorium on hookups to publicly owned drinking water

distribution systems or sewage treatment systems.

● Option 2: Limits on Federal assistance, for example, withholding Federal highway funds (except those for safety, mass

transit, and transportation improvement projects related to air

quality) or sewage treatment grants.

Decision 3: What types of corrective actions should be adopted?

. Option 1: Planning requirements.

. Option 2: Source-specific controls.

● Option 3: Market-based control programs, for example, emissions fees or marketable emissions permits.

State and local planning requirements:

Decision 1: What types of planning should be required and

where?

Ž Option 1: Minimal requirements for all nonattainment areas.

. Option 2: Enhanced efforts in areas with the worst ozone

problems or atypical conditions.

Decision 2: Who pays for enhanced State and local planning

activities?

. Option 1: Increase funding for section 105 grants or make

special, separate appropriations for ozone nonattainment area

planning.

● Option 2: Develop a nationwide user-fee program (administered by EPA) or a fee requirement (administered by the

States) on nonattainment area emissions.

Research:

Decision 1: What areas of research deserve increased funding?

● Improving the planning process, developing new control methods, and further evaluating the risks from ozone.

Decision 2: Who pays for the research?

● Option 1: General revenues.

. Option 2: User fees.

required date or to meet an interim requirement.

SOURCE: Office of Technology Assessment, 1989.

assessment is that many areas will not be able to

attain the standard with the adoption of “currently

available” control methods.1 Thus when considering potential attainment deadlines, Congress must

once again address two separate questions:

. What is an appropriate deadline for those areas

that are now close enough to meeting the

standard that they can do so using currently

available control methods?

. What is an appropriate deadline or set of

deadlines for areas that cannot meet the standard with currently available control methods?

Both EPA and STAPPA/ALAPCO (the State and

Territorial Air Program Administrators, which represents State-level air pollution regulators, and the

Association of Local Air Pollution Program Administrators, representing local regulators) have stated

that about 5 years is an appropriate timeframe for

areas that can meet the standard with currently

1These me con~ol me~~s bat are well enou@ understood that we are able to estimate their emission reduction potential and costs. While we are

certain that some additional controls are possible, we believe that the large majority of VOC emissions reductions possible with currently available

conuol methods are accounted for in our analysis.
Chapter 8—Policy Options ● 197

Table 8-2—Options for Amending the Clean Air Act:

Currently Available Control Methods

Federally implemented, nationwide

control requirements:

. Option 1: Limits on gasoline volatility.

. Option 2: More stringent tailpipe exhaust standards for cars and

trucks.

. Option 3: “Onboard” technology for cars and trucks to control

refueling emissions.

. Option 4: Federal solvent regulations, for example, for architectural coatings.

Control requirements to be implemented by States

in nonattainment areas:

● Option 1: Lowered source-size cutoff for requiring “reasonably

available control technology” (RACT).

. Option 2: Require EPA to define RACT for additional source

categories.

● Option 3: More stringent requirements for motor vehicle

inspection and maintenance programs.

● Option 4: Required use of alternative fuels by centrally owned

fleets.

● Option 5: Transportation control measures.

● Option 6: Tax on gasoline.

Managing growth:

● Option 1: Lower the cutoff for new source control requirements.

. Option 2: Eliminate “netting” out of new source control

requirements.

● Option 3: Areawide emission ceilings.

SOURCE: Office of Technology Assessment, 1989.

available control measures to both plan and implement emissions reductions [15,22]. For those areas

where currently available controls will not be

sufficient, EPA has proposed to require a 3 percent

per year reduction in VOC emissions. Under the

resulting schedule, some of the worst areas might

take over 20 years to attain the standard.

When addressing the question of timing, there are

several factors that Congress might wish to consider.

First, sufficient time must be allowed for planning

and other administrative requirements under the

Clean Air Act. The amount of time Congress

allowed for planning in the 1977 Amendments

turned out to be about half the time required. Once

controls are mandated, sufficient time must be

allowed for them to be implemented. For those areas

that cannot meet the standard with currently available measures, Congress must allow time for new

methods to be developed. Finally, Congress must

weigh the urgency of the problem against the

difficulty of the task. Allowing more time for

development and implementation of control measures might reduce their cost or facilitate their

Table 8-3-Options for Amending the Clean Air Act:

New Directions

Controls on emissions of nitrogen oxides in

nonattainment areas:

. Option 1: Congressionally mandated NOX controls.

● Option 2: Presumptive NOX controls on stationary sources, with

EPA authority to exempt areas under specified situations

● Option 3: Requirements to analyze NOX controls under certain

situations.

Controls in upwind areas:

● Option 1: Enlarge nonattainment areas to include the entire

extended metropolitan area.

. Option 2: Congressionally specified NOX controls in designated

“transport regions” or nationwide.

● Option 3: Strengthen the interstate transport provisions of the

Clean Air Act.

● Option 4: Provide EPA with clear authority to develop regional

control strategies based on regional-scale modeling.

Reducing ozone in attainment (rural) areas:

● Option 1: Specify a deadline for EPA reconsideration of the

ozone secondary standard and a schedule for Option by the

States.

. Option 2: Congressionally specified NOX controls.

Long-term VOC control strategies:

. Option 1: Lowering emissions from solvents, either through

traditional engineering approaches or through market-based

mechanisms.

● Option 2: Transportation control measures.

● Option 3: Requirements for widespread use of alternative fuels

in nonattainment areas that are far from meeting the standard.

SOURCE: Office of Technology Assessment, 1989.

acceptance. However, allowing more time also

means that more people will be exposed to concentrations above the standard. Each of these factors is

discussed in greater detail below.

Factors to Consider When Choosing Deadlines

How Much Administrative Lead Time Is Necessary?—History is probably the best guide to the

amount of time required to complete the process of

State planning for emissions reductions and for

subsequent EPA approval. Under the 1977 Clean Air

Act Amendments, EPA was to identify and list

nonattainment areas by early 1978. The States had to

revise plans for each of their nonattainment areas

and submit SIPS to EPA by January 1, 1979, about

16 months after enactment. EPA was required to

approve or disapprove these plans by June 30, 1979,

6 months after the States submitted them.

EPA and the States did not succeed in meeting

many of the deadlines established in the 1977

Amendments. By April 1980, 15 months after they
198 . Catching Our Breath: Next Steps for Reducing Urban Ozone

were due, SIPS had been submitted for only about 20

percent of the areas. Half of these were either

incomplete or considered deficient by EPA [9]. This

failure to have SIPs developed and approved in the

time allotted continued through the 1980s.

Table 8-4 displays the SIP actions required of the

States and EPA, and compares the amount of time

allowed by Congress in the 1977 Amendments with

the amount of time it actually took to complete these

actions. As the table shows, the time frame specified

by Congress was substantially exceeded by the

States and EPA, Rather than taking a little under 2

years from enactment to approval or disapproval of

a SIP, as required under the 1977 Amendments, the

entire process took about 3 to 41⁄2 years.

Three years seems to be a reasonable allowance

for the time needed between EPA’s call for revision

of a SIP to EPA approval, assuming the type of

planning undertaken is similar to that followed

under the 1977 Amendments. An extra year or two

should be added if more detailed inventorying,

modeling, and planning are required. The advantages and disadvantages of enhanced planning

requirements are discussed in a later section.

How Quickly Can Emissions Be Lowered?—

Once the planning process is complete, time must be

allowed for controls to be implemented. For control

methods that are well understood and can be applied

to existing sources, a year or two could be sufficient.

For example, the San Francisco Bay Area Air

Quality Management District allowed gas stations 7

months to install devices to capture gasoline vapors

lost during refueling. Large drycleaners were given

21 months to install control devices, once regulations were issued. Smaller facilities were given an

additional 1 or 2 years. Most available controls fall

into this category-of the emissions reductions we

were able to identify, about 35 percent are available

now and could be implemented and effective within

a few years.

Other controls, however, require a much longer

lead time. Lowered exhaust emission standards for

Table 8-4—Time Requirements for SIP Process Under the 1977 Clean Air Act Amendments

Action Required time Actual time Difference

9 to 23 months

1. Designation of 6 months 8 months 2 months

a State’s attainment (from promulgation

status of Amendments)

2. States’ development 3 to 6 months minimum

of technical database 15 to 24 months maximuma

3. State submission By January 1, 19 to 33 monthsb c d

of revised SIP 1979 (10 months

(development of new from attainment

ozone control strategy designation)

and adoption of regulations

by State or local agency)

4. EPA review and Act allows 6 months

approval or disapproval between date SIPS

of SIP were due (1/79) and

date construction

ban was to have

been imposed (6/79)

Total time 22 months 36 to 53 months 14 to 43 months

(1.8 years) (3.0 to 4.4 (1.2 to 3.6

years) years)

9 to 24 monthsb e 3 to 18 months

*“Study of the 1979 State Implementadon Plan Submittals: An overview of the SIP Review Process at the State Level and the SIPS for Particulate Mattar, Sulfur Dioxide and Ozone,”

Pacific Environmental ServiceS, ho., for tie National Commission on Air Quality, December 1980.

bpxific Envimmm@ ~~=s, Ire., Sdy ~ffhe 1979 S@fe /@smen@Iion Plan Subnitta/s (Washington, DC: National Commission on Air QualifY, ~-m~r 19~).

GNat~nal commis~on on Air Ouali~, To Sreatb C/ear Air (Washington, DC: March 1~1 ).

dmny Smws smn~ ~~ng on sip re~s~n~ as eady as 1975 or 1976, abut 12 t. 26 months ~fore t~ 1977 clean Air ~t Amendments. This time was not inCbdad In the 19- to

33-month “actual” timeframe listed for Action #3.

etimments of ~ti~lWt in OTA I’ommand the Clean Air kt” workshop, Sept. 30.1987.

SOURCE: office of Technology Assessment, 1969.
Chapter 8-Policy Options ● 199

Photo credit: South Coast Air Quality Management Dostroct, El Monte, CA

Stage II control devices installed on service station pump

nozzles help control the release of gasoline vapors during

motor vehicle refueling, Such devices can be installed and

working in under a year from the time regulations are

promulgated. Another method of controlling refueling

emissions, installing canisters directly “onboard” cars,

requires about a decade to take full effect.

new cars require over a decade to take full effect.

About 4 years of lead time is needed for manufacturers to bring cars equipped with additional controls to

market. After another 5 years, enough new cars will

have been purchased so that about half the cars on

the road will have the new controls. Replacement of

the second half will take even longer.

The greatest uncertainty, of course, surrounds the

time needed to develop new control methods. For

example, close to 20 percent of VOC emissions

come from a variety of solvent uses. For many of

these uses, reformulated products, substitutions, or

process changes might be used to lower emissions.

We have no way of anticipating how long it will take

to develop these alternatives. The deadlines that

Congress sets will certainly influence the rate of

development of new control methods, but Congress

cannot be assured that any deadline can be met.

How Urgent is the Problem?—Human exposure

to ozone primarily affects the lungs. Ozone has been

shown to cause immediate, short-term changes in

lung function and increased respiratory symptoms,

and is suspected of playing a role in the long-term

development of chronic lung diseases. The immediate or ‘‘acute” effects may include some breathing

difficulty and coughing, but such effects appear to be

reversible, usually disappearing after a few hours.

Although the short-term effects are important,

many health professionals appear to be more concerned that repeated exposure to ozone over a

lifetime may result in permanent respiratory impairment. Since ozone damages the tissues lining the

airways of the lung, ozone could play a role in

accelerated aging of the lung, retardation of lung

development in children, or the development of

pulmonary fibrosis, a chronic lung disease. We are

not yet able to confirm or dismiss many of the

concerns about these effects.

The Clean Air Act has set a societal goal of

achieving air quality necessary “to protect the

public health . . . with an adequate margin of

safety. ” The Administrator of EPA is responsible

for setting national ambient air quality standards

based on health effects information alone, with no

consideration of the difficulty of achieving them.

While there is certainly some disagreement about

the precise concentration at which the standard

should be set, ozone concentrations in many major

U.S. cities are well above the range of controversy

on at least a few days each year.

Without explicit direction from Congress that

avoiding the types of effects described above is no

longer a societal goal-and there are few indications

that society as a whole feels that this is the case-the

ozone standard is unlikely to be relaxed. Rather,

since recent studies point to health effects at

concentrations below the standard when exposure

occurs over several hours, if the standard is changed

it is likely to be tightened.

However, Congress sets not only the level of

protection that the standard is to achieve, but the

date by which it is to be met. In this latter decision

Congress cannot avoid some balancing of the

magnitude of the health problem with the costs and

difficulty of achieving the standard. At issue is not

just how quickly areas must install well-understood

control technology, but also how quickly new

technology can be developed and whether too short

a schedule will result in wasted resources or less

efficient or socially acceptable control methods. An
200 . Catching Our Breath: Next Steps for Reducing Urban Ozone

understanding of how many people are affected by

ozone, and how seriously they are affected, can help

with this decision.

No doubt, most Members and staff have heard

many conflicting statements about the seriousness of

the ozone problem. Some people have characterized

it as a problem that affects a few asthmatic joggers

who do not have the good sense to avoid running on

a few hot, smoggy afternoons each year. Others state

that it is a major public health problem adversely

affecting over 100 million Americans.

While it is true that over 100 million people live

in U.S. cities that do not meet the ozone standard, not

everyone is in the right place at the right time to be

exposed to concentrations above the standard. Taking into account when and where people are

outdoors, we estimate that about 25 percent of

people who live in these cities are actually exposed

to ozone concentrations above the standard. Even

then, ozone is thought to be a problem primarily

when people are exercising. We estimate that about

20 million people are exposed to concentrations

above the standard while exercising at moderate

levels of exertion and that on average, these people

are exposed about 9 hours per year. Of course, the

number of hours of exposure varies considerably by

region.

In chapter 3, we attempt to quantify many of the

health improvements one can expect from lowering

ozone levels. We estimate that if ozone concentrations were lowered enough to meet the standard in

all areas, about 110 to 350 million cough incidents

each year, and about 60 to 200 million incidents each

of shortness of breath and chest pain, might be

avoided each year. About 8 to 50 million “restricted

activity days” might also be eliminated. These are

days when someone feels ill enough to disrupt most

of the day’s activities, but generally not to spend the

day in bed or stay home from work. About 2 million

days of asthma attacks would also be eliminated.

These health benefits become more meaningful

when expressed on a per person basis. For example,

among every 100 people, averaged across all nonattainment areas, meeting the standard would eliminate about 100 to 300 cough episodes per year.

However, the average improvement varies considerably from nonattainment area to nonattainment area,

depending on the severity of the ozone problem. In

those areas where peak ozone concentrations are

close to the standard (between 0.12 and 0.14 ppm),

meeting the standard would eliminate about 15 to 55

cough episodes per year and about 3 days of

restricted activity among every 100 people. In those

areas with the worst ozone problems, meeting the

standard would eliminate 400 to 1,400 cough

episodes per year and about 120 days of restricted

activity, among every 100 people.

Unfortunately, we cannot similarly add up the

longer term, chronic effects of exposure to ozone

that would be avoided if ozone levels were lowered.

Whether there are chronic effects from exposure

over many years and, if so, their magnitude, is still

unknown. This too, must be factored into the

congressional decision on setting attainment deadlines.

Options

Decision 1: How many categories of nonattainment areas and associated deadlines should be

established?

Option 1: Two categories.

At a minimum, Congress must establish two

categories of nonattainment areas, recognizing that

while many areas will be able to attain the standard

with currently available control methods, many will

not. Congress could directly specify the dividing

line, for example, based on each area’s “design

value” (a measure of peak ozone concentrations),

which is a reasonable predictor of the reductions

necessary to attain the standard. OTA estimates that

the dividing line falls somewhere between design

values of 0.15 and 0.16 ppm, that is, most cities with

design values of 0.16 ppm or greater will not be able

to attain the standard with currently available VOC

control methods. Alternatively, Congress could

require EPA to make a determination of the likelihood of each area being able to attain the standard

using known control methods.

Option 2: Three or more categories.

Congress may want to divide nonattainment areas

that cannot attain the standard with known technology into three or more categories, based on the

severity of the problem.
Chapter &Policy Options ● 201

Decision 2: What deadline should be set for

those areas that can attain the standard with

currently available control methods?

Option 1: Maintain the Act's current 5 year

schedule from start of planning to attainment.

Under the 1977 Clean Air Act Amendments,

Congress allowed 5 years for those areas that were

able to meet the standard with the “application of

reasonably available control measures. ” Though

many areas took longer than 5 years to achieve the

reductions specified in their SIPS, the timeframe

seems reasonable, assuming that the planning process remains about as complex as is currently

required. As mentioned above, both EPA and

STAPPA/LAPCO, the associations of State and

local air program administrators, have proposed

timeframes of about 5 years.

Option 2: Require detailed inventories, modeling

and planning and allow 5 to 7 years.

Allowing additional time for detailed inventories,

modeling and planning will help identify those areas

that at first might appear to be able to meet the

standard by applying currently available technology,

but because of atypical conditions (e.g., areas with

unusually predominant sources of one type or

significant emissions from vegetation) will need to

identify additional VOC controls, controls in upwind areas, or possibly undertake NOX reductions.

While a simpler planning process will be adequate

for many nonattainment areas with low design

values, the simpler process can yield overly optimistic results in some atypical nonattainment areas.

In those areas that actually can meet the standard

using currently available controls, allowing additional time for detailed planning and modeling might

prevent some overcontrol in some areas or identify

more cost-effective emissions reductions. The disadvantage of such an approach is that ozone

concentrations could remain high longer. The benefits and costs of detailed planning exercises are

discussed in a later section of this chapter.

Decision 3: What deadline(s) should be set for

those areas that cannot attain the standard with

currently available control methods?

Under the 1977 Amendments, Congress chose 10

years as the appropriate timeframe for meeting the

standard in those nonattainment areas that could not

do so with control measures “reasonably available”

in 1977. Assuming appropriate incentives exist so

that new control methods will be developed, the

additional 5 years over and above the time needed

for basic planning and implementation should allow

some areas to attain the standard. However, in many

areas the shortfall between emissions reductions

needed and currently available is so large that

considerably longer time may be needed. For

example, the Los Angeles region, the worst nonattainment area in the country, anticipates that at least

20 years are needed to develop and implement the

control measures necessary for it to attain the

standard.

Option 1:8 to 10 years for the “best” of the areas

that cannot attain with currently available control

measures; at least 20 years for the “worst.”

The amount of time necessary to develop new

control methods is simply not known. Shorter time

frames might be achieved with additional Federal

R&D funds (discussed in a later section) and careful

attention to the penalties of missing the deadline.

The very real possibility of missing these deadlines

must be accepted, however.

Option 2: Eliminate deadlines.

In its 1981 report, the National Commission on

Air Quality (established by Congress under the 1977

Clean Air Act Amendments to analyze strategies for

achieving the goals of the Act) recommended that

deadlines be eliminated. In their place, they recommended a technology driven process. Every 3 years,

EPA would identify additional reasonably available

control technologies. Remaining nonattainment areas

would be required to adopt those controls or

measures that would lead to equivalent reductions.

The advantages and disadvantages of available

substitutes for deadlines are discussed below under

the section on “Interim Requirements. ”

Interim Requirements

Discussion

As described above, the 1977 Clean Air Act

Amendments required nonattainment areas to attain

the standard within 5 or 10 years. Though the

Amendments also included some requirements for
202 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

annual increments of emissions reductions, in practice, this requirement seems to have had little effect.

There were few Federal requirements that the States

had to meet between the time plans were submitted

and the eventual 5- or 10-year deadline.

Many of the recent proposals to amend the Act

have specified “interim” requirements. Because

many of the proposals would allow more time to

meet the standard than the 1977 Amendments, the

need for some type of interim milestone is greater.

There are two distinct purposes for interim

requirements: 1) to establish the minimum level of

effort towards attaining the standard and 2) to

establish a mechanism for tracking progress and

taking early corrective action. Both the form of the

interim requirements and the types of sanctions

applied for failure to meet them depend on which of

these two goals one is trying to achieve.

Congress could choose among three types of

interim requirements: 1) air quality targets, for

example, lowering ozone concentrations half of the

way between current levels and the standard by a

specified date, 2) areawide emission reduction

requirements, for example, requiring a 10 or 15

percent reduction in VOC emissions every 3 years,

and 3) source-specific technology or performance

standards. The advantages and disadvantages of the

three approaches are discussed below.

Options

Option I: Interim air quality targets.

Rather than setting only one air quality target—

attaining the standard by a specified date—Congress

could establish one or more additional air quality

levels that must be met by earlier dates. These might

be specified in the same form as the standard-i. e.,

peak concentrations must be lower than a specified

target—or by using a different indicator of air

quality, for example, number of exceedances of the

standard each year.

Air quality measurements are the most direct way

to determine whether progress is being made towards meeting the goal of the Act. If fewer

exceedances of the standard or lower peak ozone

concentrations are measured—and enough years

have been averaged to have overcome year-to-year

climatic variability—one can be confident that an

increment of progress has been made. Uncertainties

about emissions inventories, air quality models, and

implementation effectiveness are all avoided.

Unfortunately, feedback about whether progress

is being made can be delayed by several years.

Several years of monitoring data must be averaged

to be assured that the progress observed is not due to

a somewhat cooler summer or similar, natural

fluctuation. It may be possible to correct for such

variation, but the approach would lose some of its

attractiveness-its direct relationship to what is

measured at an air quality monitor.

If one of the purposes of adopting an interim

requirement is to have a yard stick against which to

judge each State’s performance-and penalize those

that are not moving quickly enough—an air quality

target may be an inappropriate choice. Success

meeting the target depends on efforts of both State

and Federal regulators and an accurate understanding of the science of ozone formation. Thus some

feel it is unfair to penalize a State in the event of

failure to meet the target if the fault is not clearly

identified as the State’s.

However, if the purpose for adopting an interim

requirement is to identify that something is not

working as planned and to signal the need for an

examination of the cause of failure, an air quality

target is highly appropriate. Thus rather than linking

a failure to achieve the target to a sanction, Congress

might consider linking it to a requirement to reopen

the planning process.

Option 2: Areawide emission reduction schedules.

A second option for an interim requirement is a

schedule of areawide total emission reductions. In

1977, Congress added a provision to the Act that

required areas to achieve “annual incremental

reductions in emissions . . . sufficient in the judgment of the Administrator” to attain the standard

within 5 or 10 years. A somewhat different approach

has been proposed by both EPA and several bills

introduced in the 100th Congress. Directly specified

rates of progress—3 percent to 5 percent per year,

depending on the proposal-are required of most

areas. Rather than “back calculating” the rate of

progress needed to attain the standard by a specified

date, the new proposals opt for a rate of progress
Chapter 8-Policy Options ● 203

based on a judgment of a reasonable rate to

implement (and in many cases, both develop and

implement) new emission controls.

One of the reasons for the popularity of this

approach is that it is not affected by the uncertainties

inherent to modeling future air quality. States are

given an identifiable target over which they feel they

have direct control. Success or failure to meet the

target is judged by whether the State achieved the

reductions stated in their plan, not whether the air

quality model used in the plan proves to be

scientifically accurate.

Moreover, the approach retains considerable flexibility for the States. Assuming enough control

alternatives exist for a State to have a choice, source

categories that might be particularly difficult or

expensive to control in a given nonattainment city

could be left alone. This type of requirement is well

suited to a market-based approach to reducing

emissions, should Congress or the States decide to

adopt one.

There are, however, some disadvantages to this

approach, as well. Some State agencies may not have

sufficient expertise to design the regulations needed

to meet their emission reduction schedule. Others

may not have the political clout necessary to require

the new regulations. For such States, a list of

federally prescribed regulations would be preferable.

In addition, emissions inventories can be “gamed,”

that is, reductions can be exaggerated by using

overly optimistic assumptions about the level of

control actually achieved. Gaming of SIPS submitted

after the Clean Air Act Amendments of 1977 is often

given as one reason for the failure of some areas to

achieve the reductions they needed to attain the

standard.

Option 3: Source-specific controls.

A third option for an interim requirement is for

Congress to directly specify controls for specific

source categories, and to direct the Administrator of

EPA to issue appropriate regulations. States would

be required to adopt the specified controls, for

example, inspection and maintenance programs for

motor vehicles, by a specified date.

STAPPA/ALAPCO, the associations of State and

local air pollution regulators, is one of the foremost

advocates of this approach. Federal assignment of

the source categories that must control their emissions and the degree of control removes the burden

of making these assignments from the States. This

would be most helpful in those States with minimal

expertise in designing regulations and in States

where legislatures have been hesitant to approve

regulations not specifically required by EPA. In

addition, under this option, States know exactly

what they are required to do. Failures to achieve the

interim target are relatively easy for EPA to identify,

and clearly the responsibility of the State, not the

fault of a modeling error.

Industry often prefers this approach as well,

especially if the control requirements are specified

by EPA through agency rule-making rather than

directly by Congress. The rule-making process

provides greater protection that the controls are

feasible.

From another point of view, however, this approach imposes a very large burden on EPA to come

up with new methods of lowering emissions. There

are no incentives for industry to actively develop

new control methods, as there would be if they were

required to meet a progressively tightened schedule

of emissions reductions.

Possible candidates for congressionally specified

controls are included in a later section, “Control

Requirements. ”

Option 4: Some combination of the above options:

Congress might choose to combine some or all of

the interim requirements discussed above to take

advantage of the strengths of each. For example,

Congress might require several particularly costeffective, source-specific controls to be implemented by an early date. A congressionally specified

percentage reduction in emissions might apply until

attainment. For the worst nonattainment areas,

Congress might also add an interim air quality target,

to keep the program firmly linked to identifiable

improvements in air quality.
204 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

Table 8-5-Sanctions for Failure To Meet the

Requirements of the Clean Air Act

1. For failure of a state to submit inadequate SIP by the required

date:

a. Section 110 requires the Administrator of EPA to

prohibit the construction of major stationary sources in

nonattainment areas if a SIP revision is inadequate.

b. Section 176(a) requires the EPA Administrator to withhold

Federal highway funds, except those for safety, mass

transit, and transportation improvement projects related to

air quality. EPA interprets this sanction to be dependent

upon a discretionary finding by the Administrator that an

area both failed to submit and failed to make a reasonable

effort to submit a plan meeting Part D requirements. Under

this interpretation, an area which made a reasonable effort

to submit a plan by the deadline but failed to do so would not

have its highway funds withheld. EPA’s interpretation was

recently upheld in Court.a

2. For failure of a State or local area to adequately implement

their SIP:

a. Section 176(b) enables the EPA Administrator to halt

Federal air program grants. EPA has interpreted this

sanction to apply only to areas that it “finds” not to have

implemented requirements under its SIP. Without this

formal finding by EPA, the Agency believes it has the

discretion not to impose this sanction. Others disagree,

however, and believe this sanction to be nondiscretionary.

b. Section 316 allows the EPA Administrator discretion to

withhold, condition, or restrict Federal grants for sewage

treatment plant construction.

3. For failure to attain the standard by the required date:

Section lo requires the Administrator of EPA to

prohibit the construction of major stationary sources. There is

some difference of interpretation with regard to this sanction.

Some believe that a construction moratorium should be

imposed if a State fails to meet the standard by the deadline.

EPA believes that the sanction should not apply to areas with

approved plans that predicted attainment by the deadline but

failed to actually attain the standard by the deadline.

a~c~yv. Thomas, District tiuti, Arizona, Aug. 10, 1987.

SOURCE: Offica of Technology Aaaeaament, 1989.

Penalties

Discussion

and Corrective Actions in the

Event of Failure

The Clean Air Act includes a series of sanctions

for the EPA Administrator to impose on States if

certain requirements are not met. As detailed in table

8-5, the Act includes different penalties for failing to

submit a revised plan for how each nonattainment

area intends to lower emissions, penalties for failing

to implement the requirements of the plan, and

penalties for failing to attain the standard by the

required date.

Few would disagree that some type of penalty is

appropriate for failing to submit a revised plan or for

adequately implementing that plan. At issue is

whether a State should be penalized for failures that

are in some ways beyond its control. For example, if

Congress sets a 10-year deadline for an area that

needs greater emissions reductions than current

control methods can provide, should the area be

penalized for not being able to find as-yetundeveloped control methods to meet the standard?

Congress must match appropriate penalties or

corrective actions to the different types of possible

failures. When considering what types of sanctions

are appropriate to impose on States, it is helpful to

understand the possible causes of failure. These

include:

1.

2.

3.

4.

Failure that is primarily the fault of the State,

including poor planning, implementation, and

enforcement.

Failure that is due to reasonable scientific or

technical errors, for example, uncertainties

inherent in air quality modeling.

Failure due primarily to poor EPA performance.

Failure to maintain a congressionally specified

reduction schedule or attain by the deadline

because progress in developing new control

methods turn out to be slower than hoped for.

Again, sanctions such as those included in the

current Act may be appropriate for the first type of

failure-those primarily the fault of the State. But

many consider it unfair to sanction the State for

failures due to poor scientific understanding. Corrective actions may be more appropriate for those

failures that are beyond a State’s control. Such

corrective actions might include instructions to

revise implementation plans or requirements to

adopt source-specific controls that previously were

left to the State’s discretion.

Options

Decision 1: For what kinds of failures should

States be penalized?

Congress may wish to penalize the States for only

certain types of failures. The options listed below

are not mutually exclusive.

Option 1: Sanctions for failing to make “sufficient” efforts.
Chapter 8-Policy Options ● 205

Few would disagree that penalties are appropriate

for States that violate requirements of the Act over

which they have complete control. For example,

States should be required to submit revised SIPS by

a reasonable date and implement and enforce the

control measures included in their plan.

Option 2: Sanctions for failing to identifiy enough

controls to meet a congressionally specified reduction schedule.

Congress faces a difficult choice deciding whether to penalize areas that need greater emissions

reductions than can be expected from currently

available control methods. These areas cannot specify the details of their plan to attain the standard by

the required date or how they will meet interim

reduction requirements.

If Congress decides not to penalize States for

these failures, it must provide some guidance to EPA

about what should be considered an available

control method. Congress must indicate whether the

dividing line should be “reasonably available”

control methods, “lowest achievable” emission

rates, or some similar descriptor of what constitutes

a “sufficient” effort on the States’ part.

Arguments against imposing sanctions for failure

to identifiy enough controls center on concerns for

fairness. Should States be penalized for the limits of

current technology? Arguments for imposing sanctions under these conditions rest on the idea behind

“technology forcing” requirements. How can one

expect to rapidly develop new technology if there are

no incentives to do so?

Option 3: Sanctions for failing to attain the

standard by the required date.

Last, Congress must decide whether States should

be penalized for not meeting their attainment deadline, even if they meet all other requirements of the

Act. States that have fulfilled all the requirements of

their plans might still fail to attain the standard due

to uncertainty inherent in predicting future air

quality or to failures on EPA’s part. STAPPAALAPCO, in particular, has objected to penalizing

States for failing to attain by a specified date.

Arguments against imposing sanctions for failure

to attain the standard again center on concerns for

fairness. Should States be penalized for failures

beyond their control? Others argue that deadlines

without sanctions will not be taken seriously.

Decision 2: What types of sanctions should be

adopted?

Option 1: Sanctions that limit growth in nonattainment areas.

The current Act includes as one of its sanctions a

ban on the construction of major stationary sources

(sources that have the potential to emit greater than

100 tons per year). In a series of workshops held by

OTA, there was general agreement that in low- or

no-growth areas, the construction ban has had little

effect. One of the participants noted that a construction ban has been in effect in Chicago for over five

years, but ‘‘no one cares”. As a remedy, some have

suggested lowering the threshold to 50 tons per year

or lower.

However the construction ban, or a variant, might

be quite influential in areas experiencing higher

growth. One participant at our workshops commented that the Michigan State legislature did not

improve an automobile inspection and maintenance

program until auto manufacturers complained that

they could not construct new facilities under the

construction ban.

Variants on a construction ban might be almost as

effective, but allow a bit more flexibility. Rather

than imposing an outright construction ban, new

sources would be allowed to locate only if they

offset their emissions with 2, 5 or more times the

emissions reductions at existing facilities. After

additional controls have been imposed, however,

obtaining the necessary offsets should in theory be

extremely difficult and available only for priority

projects.

Recent congressional proposals have also included two additional types of sanctions that would

serve to limit growth in nonattainment areas. These

include a proposal for a moratorium on hookups to

publicly owned drinking water distribution systems

and a somewhat similar proposal for a moratorium

on hookups to publicly owned sewage treatment

systems.

Of course, sanctions that limit growth can have

undesirable economic consequences if they have to
206 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

be imposed. One participant at our workshops noted

that for a sanction to be effective, nonattainment

areas must believe that EPA and the Congress will

be willing to impose the sanction if need be. Thus,

as discussed above, Congress must consider what

types of failures merit sanctions that limit growth,

and whether it will allow them to actually be

imposed. When EPA was considering implementing

construction bans against 144 nonattainment areas

in 1983, Congress added a provision to an appropriations bill to prohibit EPA from imposing sanctions

during fiscal year 1984 [23].

Option 2: Limits on Federal assistance.

The Clean Air Act allows the EPA Administrator

to withhold three types of Federal assistance: 1)

Federal highway funds, except those for safety, mass

transit, and transportation improvement projects

related to air quality, 2) sewage treatment grants, and

3) grants to State air pollution control agencies.

Some have questioned the wisdom of the last of

these provisions. An under-funded agency is less

able to remedy the failure that led to the imposition

of sanctions.

Decision 3: What types of corrective actions

should be adopted?

For failures to meet certain types of interim

requirements, corrective actions may be more appropriate than sanctions. Requirements for additional

source-specific controls or further planning can

serve, in part, as incentives not to fail, but more

importantly, can help remedy the failure before the

attainment deadline has once again passed. A

discussion of the types of interim requirements

Congress might adopt can be found earlier in this

chapter.

Option I: Planning requirements.

If Congress chooses to adopt interim air quality

requirements, Congress could require States that fall

behind their schedules to reexamine the premises

behind their SIP. States could be required to redo

their emissions inventory, collect additional air

quality information, or undertake a detailed modeling exercise to understand the reasons for the failure.

The details of such a program are discussed below.

Option 2: Source-specific controls.

For areas that fall behind interim emission reduction schedules, Congress may choose to require

additional source-specific controls that otherwise

might be optional. Several of the proposals of the

100th Congress adopted this approach. Areas that

cannot meet their deadlines are reclassified to a

category that has more federally prescribed controls.

Option 3: Market-based control programs.

Another option for areas that fall behind interim

reduction schedules is for Congress to require

market-based control programs, such as emissions

fees or marketable emissions permits. Depending on

the stringency of the reduction schedules specified,

areas might miss interim milestones because regulators cannot identify additional control measures to

require. In such cases, the only alternative may be to

provide economic incentives to industry and individuals to identify ways to lower emissions through

market-based control programs. Clearly, there are no

guarantees that such programs will achieve the

desired reduction schedule, but the pace of reductions would most likely quicken.

EPA could be required to develop model regulations for the States to adopt. A program based on

emissions fees might include fees on stationary

sources larger than a specified size, a gasoline tax to

lower highway vehicle usage, and a fee on products

containing high solvent content. In a program

relying on marketable emissions permits, permits

are first distributed to VOC emitters, and then cut

back gradually according to a specified schedule.

Sources must then figure out ways to lower emissions or purchase permits from other sources on the

open market.

State and Local Planning Requirements

Discussion

To fulfill its requirement that by 1987 the ozone

standard was to be met everywhere in the country,

the 1977 Clean Air Act Amendments relied on the

State Implementation Planning (SIP) process, in

combination with several mandatory control programs. Under the SIP process, the States were to

determine how much they would need to reduce

emissions in order to meet the ozone standard, and

then set up control programs (including those

mandated in the Act) to achieve the required
Chapter 8—Policy Options ● 207

reductions. The information required for this planning process included air quality and meteorological

data, an emissions inventory, estimates of growth in

emissions, and estimates of reductions that could be

achieved through the available control measures.

The SIP approach used last time has been

criticized for having depended too much on inaccurate estimates of emissions reduction targets. According to this criticism, many areas failed to meet

the ozone standard by the 1987 deadline because

they underestimated the amount of control they

needed. 2 Errors in projected control requirements

stemmed from uncertainties in emissions inventories, under prediction of growth in emissions,

inadequate monitoring of ambient NOX

, VOC and

ozone concentrations, and limitations of computer

models used to estimate needed reductions.

For the next round of control efforts, EPA has

proposed [22] to require planning exercises similar

to those performed last time, with updated, refined

and expanded emissions inventories, slightly expanded air quality monitoring, and some evaluation

of the effectiveness of specific control measures.3

More detailed exercises would be left to the discretion of the States.

Planning activities can help States in several

ways. First, when done correctly, they can improve

estimates of what level of control will ultimately be

needed to meet the standard. In areas where control

measures beyond those needed to attain the standard

are available, they can identify the most costeffective control measures and prevent over control.

In areas with the worst ozone problems, they can be

used to assess whether NOX emissions should be

controlled in addition to VOCs and whether regional

control measures might be necessary.

The reliability of such information will depend on

the time and resources devoted to refining emissions

inventories, monitoring, modeling, and investigating control alternatives. EPA has proposed to allow

the States two years to develop, adopt and submit

State Implementation Plans, including updated emissions inventories, identification and evaluation of

control measures, and air quality modeling to

demonstrate attainment [22]. For the worst nonattainment areas, where enhanced planning exercises

will be needed, EPA has proposed five years for final

SIP submittal (with an interim submittal after two

years).

EPA has estimated that nationwide, State and

local agencies would need to increase the resources

they devote to ozone and carbon monoxide control

programs by about 50 percent, or about $40 million,

to comply with the proposed new requirements [24].

The additional funds would cover efforts to refine

emissions inventories, plan for implementation of

complex control measures such as use of alternative

fuels, and review the effectiveness of control measures. With the most elaborate planning process

likely to be undertaken anywhere, the South Coast

Air Quality Management District began work on its

new Air Quality Maintenance Plan in June 1987, and

expects to spend three years on it. The District

budgeted $6.2 million for the first two years of the

effort [6].

If state-of-the-art air quality models are used to

predict the effect of emissions reductions on air

quality, costs will be higher. Starting with a special

monitoring program, and including a concurrent

effort to refine emissions estimates, an urban grid

modeling study ‘would typically take one to three

years and cost on the order of $500,000 to complete

[17,18,26]. In some situations, however, costs could

go much higher. For example, the anticipated cost of

a four-year air quality study being planned for

California’s San Joaquin Valley is $8 to 10 million

[4].

Options

Decision 1: What types of planning should be

required and where?

ZAS the Clem ~r ~t Wm ~terpret~ by EM, sanctions were to be imposed for failure to submit SIPS that ‘demonstrated attainment” by specified

deadlines, and for failure to implement SIPS, but not for failure to attain the standard when an acceptable SIP had been implemented in good faith.

sThe prows~ rqu~e~ hat states submit ~ updat~em1s510n5 ~vento~ 12 mon~tierhe Agency C~lS for it, md sub~uently update the

inventory every three years. Previously, process and emissions data were only required for individual sources emitting more than 100 tons per year, with

smaller stationary sources treated as area sources. The requirement for data from individual sources would now be extended to include all sources emitting

10 or more tons per year. As before, the proposal requires that the States usc computer modeling to estimate emissions reductions needed for attainment.

States would be allowed to use the widely criticized “Empirical Kinetics Modeling Approach” (EKMA) model, but the more detailed and expensive

“Urban Airshed Model” (UAM) is recommended. TO monitor each area’s attainmen[ status and provide data for computer modeling, EPA’s proposal

recommends that at least five ozone monitors and two collocated NOX and VOC morutors be operated in each nonattainrnent area.
208 . Catching Our Breath: Next Steps for Reducing Urban Ozone

Option 1: Minimal requirements for all nonattainrnent areas.

The modest planning exercise proposed by EPA

would be beneficial in all nonattainment areas. Air

quality monitoring and an updated emissions inventory are necessary whether control measures are

identified locally or specified at the Federal level.

Modeling is the only way to predict the impact of

emissions reductions on air quality, and thus to

project (at least roughly) progress toward the ultimate goal of attaining the standard.

Option 2: Enhanced efforts in areas with the

worst ozone problems or atypical conditions.

In general, nonattainment areas that have the

highest design values or exceedance rates need to

abate emissions the most to meet air quality standards. Ultimate control costs are likely to be highest

in these areas. Enhanced air quality modeling (with

supporting monitoring and emissions inventory

refinement) and comprehensive assessment of control options would be particularly useful in these

areas to ensure that the controls imposed will be

effective, to target the most cost-effective measures

first, and to recognize and begin to address shortfalls

in needed reductions as early as possible.

In some urban areas, atypical emission sources,

meteorology, topography, or geographical location

may warrant enhanced air quality modeling or

special consideration of certain control options. For

example, special efforts might be warranted in areas

with significant emissions from vegetation, pollutant transport from outside the area, unusually

predominant sources of a specific type, or preliminary indications that NOX controls might be particularly helpful or harmful.

State-of-the-art air quality models (such as the

Urban Airshed Model) are the best means available

for predicting the effect of emissions reductions on

air quality. They are especially preferred for examining the impacts of reducing NOX emissions, or the

effect of emissions reductions that are unevenly

distributed within an area. Application of such

models typically requires a short-term but intensive

pollution and meteorological monitoring program.

New information about the composition of emissions and how they are distributed within the area

may also be needed, In many areas, estimates of

VOC emissions, especially emissions from area

sources, need to be refined if models are to give

reliable results.

Enhanced local efforts to identify and evaluate

control options would help States design control

strategies tailored to local conditions. Such efforts

might improve the cost-effectiveness, political viability, and administrative tractability of controls. In

many nonattainment areas, exhaustive exploration

of potential control measures will be required to

identify reductions to attain (or come as close as

possible to) the standard. In areas where transportation control measures are needed, State and local

agencies involved in transportation and land-use

planning, as well as air quality, need to be involved.

As an example, in developing its 1988 Air Quality

Maintenance Plan (AQMP), the Los Angeles area

South Coast Air Quality Management District attempted to identify “all the potential control measures that could be available by the year 2000. ” The

District included all currently available control

technologies as well as measures ranging from

development of non-reactive solvents to “clean”

motor vehicle fuels. Major transportation and landuse planning studies were conducted in conjunction

with the AQMP.

In chapter 6 we concluded that cities with design

values of 0.16 ppm or higher will probably not be

able to meet the air quality standard for ozone with

currently available VOC control measures. Congress could direct the EPA Administrator to require

these areas to carry out a comprehensive analysis of

potential control measures.

A design value cutoff of 0.16 ppm would also be

appropriate for delineating areas where enhanced

modeling is required. However, because of the

limited availability of people at EPA or State and

local agencies who could perform or oversee enhanced modeling, Congress could allow the Administrator to consolidate efforts across areas, where

appropriate (e.g., New York City and parts of

Connecticut); exempt cities where enhanced modeling would not be useful due to the impact of upwind

areas (e.g., Atlantic City, NJ); or set priorities for the

order in which the analyses are completed.

Decision 2: Who pays for enhanced State and

local planning activities?
Chapter 8—Policy Options ● 209

State and local planning activities are supported

by general State and local revenues, grants from the

Federal Government (authorized under section 105

of the Clean Air Act), and fees assessed by State and

local agencies on pollution sources.4 In addition,

private groups have supported special air quality

modeling and monitoring studies and assessments of

control options that have contributed to official

planning efforts.

In 1986, State air agency budgets ranged from

$270,000 (Nevada) to $54.8 million (California),

with the 50-state average at $4.1 million ($3.1

million excluding California). Of 32 local air

agencies reporting, 1986 budgets ranged from $65,000

(Madera, CA) to $29 million (South Coast Air

Quality Management District, CA).

Federal grants under section 105 contributed

about one-third of State and local air agencies’

budgets in 1987. On average, 50 percent of the

Federal funds received by State and local agencies

are budgeted for administration and planning activities (including monitoring, SIP revisions, development and maintenance of emissions inventories, air

quality modeling, and development of new programs). Permitting and enforcement activities and

other minor categories account for the other 50

percent.

EPA has estimated that altogether, State and local

agencies would need increases in revenues totaling

about $40 million per year, to fulfill all of the new

requirements contained in its proposed “Post1987” ozone and carbon monoxide policy [24].

Option 1: Increase funding for section 105 grants

or make special, separate appropriations for ozone

nonattainment area planning

Congress could increase appropriations for section 105 grants. Federal appropriations for State and

local air programs under section 105 totaled $94.6

million, in fiscal year 1987.5 Appropriations were

reduced to $93.3 million in fiscal year 1988, and

increased to $101.5 million for fiscal year 1989.6 In

1986, Federal contributions to State agencies ranged

from $180,000 (Nevada) to $5.9 million (New

York). Federal contributions to local air agencies

ranged from no funding for some to $1.5 million.

In addition to grants allowed under section 105,

the 1977 Amendments authorized grants for planning transportation control measures. A total of $50

million was appropriated. Most of the grants, which

were administered through the Department of Transportation (DoT), went to Metropolitan Planning

Organizations (MPOs) responsible for developing

urban transportation plans, rather than to air agencies. While it lasted (through 1982), the grants

program was considered successful in introducing

air quality considerations into urban transportation

planning. Congress could consider new authorizations targeted specifically for grants for joint air

quality/transportation planning.

Option 2: Develop a nationwide user-fee program

(administered by EPA) or a fee requirement (administered by the States) on nonattainment area

emissions.

The Clean Air Act requires States to assess fees to

cover the costs of processing, implementing and

enforcing permits. 7 In 1986, 31 States assessed

permit fees.8 Some of these States covered more than

half of their air agency budgets through extensive

d~e inf~ation on Swte and hIcal tir agency budgets and fee programs presented in this section is from referenCe [ 161.

Ss=tion 105(a)(l)(A.C) defines the maxim~ F~er~ share of funding for State and local air pollution COn&O1 m 60 Wrcent for nlfit~ning ~

established program and 75 percent for planning or developing an air quality program for those recipients carrying out a SIP. A major requirement for

receipt of Federal funding is that the agencies’ nonfederal support for ‘recurrent expenditures” cannot be reduced unless the reduction is a nonselective

reduction in expenditures of all executive agencies at the same level of government.

6Due t. relatively flat fud~g levels over the Pmt few Yems, in the f~e of incre~ing responsibilities ~d new priorities, EPA officials note a decline

in Federal support for several fundamental State and local activities including: enforcement, emission inventory maintenance, ambient monitoring, and

preventive activities such as new source review.

TSwtion 1 lo(a)(2)(K) of the Clem Air Act requires States to charge owners/operators of major stat.iOnq SOwces for “tie re~nable costs of

reviewing and acting upon” applications for permits; and for ‘the reasonable costs of implementing and enforcing the terms and conditions” of permits

that are given out.

8E]even other Stites ~d au~on~ t. collWt f~s but did not. Agencies that did not co]l~t f~s cit~ l~k of a s~ong sign~ from EPA that f~ programs

were required; lack of a national policy or regulation that would ensure that fee programs were not perceived as a local disincentive to industry; and

concern that they would not benefit from the revenues generated (because revenues were diverted elsewhere or because other fhnding sources would

be reduced accordingly).
210 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

user-fee programs. 9 About half of the State air

agencies collecting fees retained the revenues; the

other half put them into State general funds. In 60

percent of the States collecting fees, the revenues

were at least reflected in the air agencies’ budgets.

On average, revenues raised by assessing fees

equaled about 10 percent of agency budgets (irrespective of whether or not they retained the fees).10

Congress could shift more responsibility for

funding State and local planning efforts to State and

local governments, encouraging or requiring them to

assess user fees to support their own activities.

Agencies that do not now have permit fee programs

have suggested that a Federal directive would bean

important factor in their ability to obtain local

authorization to assess fees. In addition to or instead

of State and local assessments, Federal user fees

could be instituted, with some portion turned over to

State and local air agencies through EPA.

As discussed above, EPA estimates that in order

to undertake the planning requirements that they

have proposed, State agencies will require an

additional $40 million per year. Adding requirements for state-of-the-art modeling in many areas

might increase this by another 50 percent or more.

Using $100 million per year as an upper bound, we

can get a feel for the magnitude of the fees that would

have to be imposed.

Assuming that fees are to be related to emissions,

fees of about $10 per ton of VOC would be needed

to raise $100 million in nonattainment areas. Identifying and imposing fees on all sources, however,

would be quite difficult. Three source categories,

emitting over half of nonattainment area VOC

emissions, are probably the easiest to locate: large

stationary sources, highway vehicles, and solvents.

Roughly assigning a fee to these sources according

to their contribution to emissions produces a fee

schedule of about: $15 to $20 per ton of VOC

emissions from stationary sources emitting more

than 50 tons per year, about 0.1 to 0.15 cents per

gallon of gasoline, and about 15 to 20 cents per

gallon of the most commonly used solvents (such as

special naphthas).

Research

Discussion

Ozone is probably the least-well understood of the

six “criteria” air pollutants, those for which air

quality standards have been set. This lack of

understanding is one of the reasons why ozone is the

criteria pollutant that we have had the least success

controlling.

The next reauthorization of the Clean Air Act will

include the third major change in the way we have

attempted to control ozone. If, when the second

major initiatives were taken following the 1977

Amendments, we had also launched an aggressive

research program, our task might be easier today.

Research begun today can help the States implement

the changes made during this round of amendments

and help Congress when it considers the fourth

major set of changes 5 or 10 years from now.

We have identified three areas where research

seems most pressing: 1) research to improve the

planning process, 2) development of new control

methods, and 3) research to better understand the

magnitude of the risks posed by ozone. Each of these

is discussed below.

Research To Improve Planning—Two areas are

prime candidates for increased Federal research

funds: 1) methods to allow States to improve

estimates of VOC emissions; and 2) air quality

models that are more accurate than the current

generation of tools used by most States, and at the

same time are easier to use than research-level

models.

VOC Emissions Inventories—Air pollutant emissions are rarely measured, but rather are estimated

using emissions models. The models used for

estimating VOC emissions are far less accurate than,

for example, those used to estimate either sulfur

dioxide or nitrogen oxide emissions.

g~ ~dition ~ ~~~g, ~me State or lm~ agencies msess fees for other services such as source testing, btiing ~d bubble applications, ~d

motor vehicle inspections. Some agencies also assess fees on emissions.

l~ws ~ollWt~ by over 50 ~rcent of the Stites were ~u~ t. less tha 3 percent of heir ~r agency budgets. F~s mount to about 30 percent or

more of the budgets of State air agencies in Kansas, Louisiana, ‘lkxas, and Ohio. Fees contribute about 30 to 80 percent of the annual budgets of local

air agencies in Arizona and California.
Chapter &Policy Options ● 211

About 10 to 20 percent of VOC emissions come

from large stationary sources for which a location is

identified in an inventory, for example, a petroleum

refinery or a factory that manufactures chemicals.

These sources can be surveyed individually and

emissions can be estimated reasonably well based on

production levels.

About 40 percent of VOC emissions come from

highway vehicles. Emissions are estimated using a

model called Mobile-4. Mobile-3, the previous

version of the model, was based on data collected

from about 11,000 vehicles manufactured before

1982 (with about half of these manufactured before

1976). Though Mobile-3 was widely criticized as

not able to adequately simulate emissions under road

conditions, data from fewer than 500 vehicles were

used to update the model [25]. Given the changes in

vehicle design that have occurred over the last

several years-and the importance of highway

vehicle emissions-additional funds to EPA to test

newer vehicles and improve the performance of

Mobile-4 would be well spent.

Another 25 to 30 percent of VOC emissions come

from a diverse range of solvent uses, including

drycleaning, consumer products, and coatings for

everything from furniture to cars to houses. While

nationwide emissions can be estimated from published statistics of total solvent produced, emissions

in any given nonattainment area can only be crudely

guessed. The method currently being used was

developed in 1975 and has been modified little since

that time. Improvements are sorely needed.

The magnitude, distribution, and role of “biogenie ” emissions-natural hydrocarbon emissions

primarily from forests—are also poorly understood

and characterized. Nationwide, summertime VOC

emissions from natural sources are estimated to be

greater than man-made emissions. Natural-source

VOCs are emitted primarily in forested areas, that is,

outside of nonattainment areas where man-made

emissions of VOCs generally predominate. Nevertheless, in some parts of the country (especially the

Southeast), VOC emissions from vegetation may

contribute substantially to ozone nonattainment

problems. Improved understanding of biogenic emissions will help such areas determine how best to

control ozone—in particular, whether emphasis

needs to be placed on reducing NOX emissions if a

significant fraction of VOCs are not subject to

control.

Air Quality Models—A wide disparity exists

between the accuracy of the best available air quality

models and those commonly used by the States to

prepare their SIPS. The best available tools are

expensive to use, require extensive data collection,

and require highly trained personnel to be used

effectively. Thus, state-of-the-art models are beyond

the capabilities of many of the State air pollution

control agencies that might make use of them.

Though the best models may be beyond the

States’ reach, better models are not. More EPA

attention to the operational aspects of modeling—

developing tools for the average rather than the

expert modeller—could improve the States’ abilities

to understand the effectiveness of alternative emission controls.

New Control Methods-As discussed previously,

OTA estimates that controls sufficient to achieve

about two-thirds of the reductions needed to attain

the standard will cost about $10 billion per year. We

cannot estimate the costs of the remaining third

because we do not know how it can be achieved. Yet

EPA’s total research budget for new and cheaper

VOC control measures totals about $1.5 million per

year-much less than one-tenth of a percent of the

projected costs of control.

Once currently available controls are in place, the

remaining emissions will come primarily from small

(less than 50 tons per year) stationary sources and

highway vehicles. High-priority research and development areas include methods to trap or destroy

VOCs from small sources emitting VOCs in low

concentrations, non-ozone producing solvent substitutes, and cleaner vehicle fuels, such as methanol

and compressed natural gas.

Better Understanding of the Problem—The current regulatory program is focused mainly on one of

ozone’s effects, acute health effects resulting from

exposure to short-term peaks. Other effects are also

of concern, including possible chronic health effects

from long-term exposure to ozone and effects on

crops and forests. Additional research is needed in

each of these areas.
212 . Catching Our Breath: Next Steps for Reducing Urban Ozone

Chronic Health Effects—Although the short-term

effects of ozone are important, many health professionals appear to be more concerned that repeated

exposure to ozone over many years may result in

permanent impairment of the lung. Unfortunately,

the limited research that has been conducted to date

has been unable to either confirm or dismiss this

concern.

Most of EPA’s health effects research focuses on

ozone exposures of one to several hours. Information

about the chronic effects of exposure to ozone over

longer time periods—days to years-must come

from a combination of animal studies and carefully

planned epidemiologic studies.

Welfare Effects—For decades we have known that

ozone can harm plants. Just how much damage is

occurring in specific agricultural and forested regions, however, is not well understood. In chapter 4

we estimate that if seasonal, daytime average ozone

concentrations could be lowered by 25 percent of the

amount by which they exceed natural background,

about $0.5 billion to $1 billion per year of agricultural benefits would be gained. We are not yet able

to estimate the amount of forest damage that might

be avoided.

While a fair amount of research on the effects of

ozone on crops and forests is currently underway,

major information gaps remain. Much has already

been learned about crop damage through the EPA

sponsored National Crop Loss Assessment Network

(NCLAN), but many scientists feel that the research

effort was ended prematurely. We are still uncertain

whether productivity declines are due primarily to

intermittent peak concentrations or the accumulated

ozone dose over a growing season. Forest effects are

being studied under the National Acid Precipitation

Assessment Program (NAPAP) and under the new

10-year research program established at the end of

the 100th Congress by the Forest Ecosystems and

Atmospheric Pollution Research Act.

A goalof both research efforts should be to enable

EPA to set a secondary ‘welfare” standard based on

crop and forest effects. The current secondary

standard is identical to the health-based primary

standard. Many feel that the form of the primary

standard (i.e., a peak one-hour standard, not to be

exceeded more than once per year) is inappropriate

for a secondary standard to protect vegetation.

Additional monitoring of ozone and its precursors

in non-urban environments is needed to better

characterize the magnitude of the problem. Moreover, it is not well understood how to lower regional

ozone concentrations, if Congress or EPA were to

pursue this goal. The VOC reductions needed to

lower peak ozone concentrations in nonattainment

cities may have little effect in less populated areas;

reductions in nitrogen oxide would probably be

necessary to reduce ozone in most non-urban areas.

Additional field studies and modeling are needed to

better understand how to lower ozone concentrations

in non-urban areas.

Options

Decision 1: What areas of research deserve

increased funding?

In the discussion above, we outlined three general

research areas that Congress should consider for

increased funding. These include: 1) research to help

the States analyze the emissions reductions needed

to meet the standard, 2) research on new control

methods, and 3) research to better understand other

effects of ozone, including possible chronic health

effects from exposure over many years and crop and

forest productivity declines.

Current research expenditures in each of these

areas is quite modest. EPA gives the States about $3

million per year for improved inventories, monitoring, and air quality modeling. In fiscal year 1990,

EPA’s Office of Air Quality Planning and Standards

will itself spend about $3 million, including staff

time, on developing improved ozone models and a

better emissions data management system. Fiscal

year 1989 expenditures were closer to $1 million [5].

The Mobile-4 model, used by the States to estimate

emissions from highway vehicles, is the responsibility of the Office of Mobile Sources (OMS). In fiscal

year 1989, OMS spent about $2.8 million testing

cars for data needed to build the model, up from

about $0.8 million in fiscal year 1987. Even at the

higher level, about 900 vehicles per year can be

tested (compared to a peak of about 5000 vehicles

tested in 1979) [2].

About $1.5 million per year is spent by EPA’s

Office of Research and Development (ORD) on the

“Regional Oxidants Model” (ROM), a highl y

sophisticated model capable of simulating multi-day
Chapter 8-Policy Options ● 213

ozone episodes in the Northeast. Similar efforts in

the Southeast, Gulf Coast region, and the area

surrounding Lake Michigan would help cities in

each those regions to better understand how to solve

their nonattainment problems. In addition, such

efforts are needed to understand how to lower rural

ozone concentrations.

OMS spent about $2.8 million in fiscal year 1989

on research on alternatively fueled vehicles, primarily methanol vehicles [2]. ORD spends about $1

million per year on research on mobile source

emissions. About $0.6 million is devoted to use of

alternative fuels [8]. The Air and Energy Engineering Research Laboratory of ORD spends about $0.4

million per year on research to develop new control

methods for stationary sources of VOC. Most of the

emphasis is on developing technology appropriate

for small stationary sources, and on developing

environmental impact guidance for manufacturers

reformulating VOC-containing products [7].

ORD spends close to $7 million per year on ozone

effects research. Of this, the single largest component is now research to determine the long-term

health effects from ozone, about $3.6 million in

fiscal year 1989. Given the importance of knowing

whether there are chronic effects from exposure to

ozone and if so, of what magnitude, this level of

research seems extremely modest. ORD also spends

about $2 million per year on forest effects research

and about $1 million on continuing research on the

short-term health effects of ozone [8].

Decision 2: Who pays for the research?

Traditionally the Federal Government has funded

air pollution related research out of general tax

revenues. While this has been generally true for most

pollution related research, there have been a few

exceptions. For example, in the Nuclear Waste

Policy Act of 1982 (Public Law 97-425), Congress

established a fee on electricity generated by civilian

nuclear power reactors to be used to pay for the costs

of radioactive waste disposal. While most of the fee

will be used to pay for the construction and operation

of a waste repository, the costs of research, development, and demonstration activities and the costs of

administering the program are also covered.

Under the Superfund Amendments and Reauthorization Act of 1986 (SARA), Congress established

four hazardous substances research centers, each

with funding of $5 million per year from Superfund.

Though Superfund is jointly funded by industry and

general tax revenues, well over half of the funds

come from industry.

In the discussion above on additional requirements for State planning, we presented several

alternatives for raising revenues for these activities.

If Congress decides to fund these activities through

a fee or tax mechanism, it might also consider

allocating a portion of the revenues raised to

ozone-related research activities.

CONTROL REQUIREMENTS

In addition to the more generic options discussed

above, Congress might want to consider requiring

specific types of controls directly in the Act. We

have organized our discussion of the specific options

available to the Congress in the near term into three

categories. Air pollution control under the Clean Air

Act relies on a partnership between EPA and State

and local governments. Therefore, our first two

categories present: 1) federally implemented controls that apply nationwide and 2) controls to be

implemented by the States in nonattainment areas. A

final category includes options for managing emissions growth due to population increase and expanding economic activity in nonattainment areas

All of the control options presented in this section

are available today and fall, more or less, within the

traditional regulatory bounds of the Clean Air Act.

The last section in this chapter presents some “New

Directions for the Clean Air Act” that Congress

should also consider to augment the more traditional

control strategies presented here.

Federally Implemented, Nationwide

Control Requirements

Discussion

Two major categories of regulations currently

apply nationwide. These include emission standards

for highway vehicles and a series of “new source

performance standards” (NSPS) that apply to certain categories of new facilities locating in attainment areas. While NSPS regulations also apply to

new facilities in nonattainment areas, they are often

superseded by more stringent regulations. Note also
214 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

that highway vehicle emission standards are more

stringent in California, the State with the most

severe nonattainment problems.

Part of the philosophy behind uniform nationwide

car and truck standards is that people as well as

vehicles are mobile. Obviously, it would be extremely difficult to implement and enforce a set of

highway vehicle regulations that applied only to cars

and trucks in nonattainment areas. For pollutants

such as nitrogen oxides and carbon monoxide, the

only source categories that move around are transportation related—cars, trucks, buses, trains, airplanes, and ships—and certain off-highway vehicles

such as construction equipment. For VOCs, however, there are significant sources that do move

around and which are not transportation related.

Paints and other solvent-containing products release

VOCs at the point of end-use. Since controlling the

movement of certain kinds of house paints, pesticides, and similar products with high VOC content

would be difficult, nationwide regulations have been

proposed for these products as well.

Nationwide control requirements under current

law and regulations are listed in table 8-6. Additional controls that Congress might want to specify

are discussed below.

Options

Chapter 6 presented our estimates of the emission

reduction potential and costs of additional pollution

controls. Those regulations that would be federally

implemented are summarized below.

Option 1: Limits on gasoline volatility.

Limiting the volatility (i.e., rate of evaporation) of

gasoline sold during warm weather months would

substantially reduce transportation-related VOC emissions. On a warm summer day, twice as much VOC

comes from gasoline evaporation than from the

tailpipe of a car. Limiting the volatility of gasoline

to 9 pounds per square inch (psi) Reid Vapor

Pressure (RVP) from levels of between about 11.0

and 11.5 psi would lower VOC emissions about

3,700 tons per day on hot summer days in nonattainment cities in 1994. (This is equivalent to an annual

reduction of about 1.3 million tons per year, or about

12 percent). An additional 5,200 tons per day would

be eliminated in attainment areas (equivalent to

annual reductions of about 1.9 million tons).

Table 8-6—VOC Sources For Which Nationwide

Regulations Exist

Current Iaw and regulations include the following controls for

highway vehicles:

1. Tailpipe exhaust standards for passenger cars:

a. 0.41 g/mi HC and 1.0 g/mi NOx.

b. Vehicles must be able to meet these standards for at least

5 years or 50,000 miles.

2. Tailpipe exhaust standards for light-duty trucks (less than

8,500 lb gross vehicle weight rating [GVWR]):

a. 0.8 g/mi HC and 1.2 g/mi NOX for trucks with loaded vehicle

weights up to 3,750 Ibs.

b. 0.8 g/mi HC and 1.7 g/mi NOX for trucks with loaded vehicle

weights over 3,750 lbs. Standards must be met for 120,000

miles.

3. Tailpipe exhaust standards for heavyduty engines and vehicles (over 8,500 lb GVWR):

a.

b.

c.

d.

1.1 grams per brake-horsepower-hour (ghhp-hr)a HC and

10.6 g/hp-hr NOx for gasoline vehicles less than 14,000 lb

GVWR.

1.9 g/bhp-hr HC and 10.6 g/bhp-hr NOX for gasoline

vehicles over 14,000 lb GVWR.

1.3 g/bhp-hr HC and 10.6 g/bhp-hr NOX for diesel vehicles.

For all vehicles, NOx standards drop to 6 g/bhp-hr in 1990

and 5 g/bhp-hr in 1991.

Standards must be maintained for 110,000 to 290,000

miles, depending on fuel and truck weight.

4. Limits on gasoline evaporation from highway vehicles.

Currant Iaw and regulations include the following controls for

stationary sources:

New source performance standards (NSPS) requiring the “best

available control technology” on certain new stationary sources of

VOC and NOx. (Note that the “lowest achievable emission rates”

for VOC required for new sources in nonattainment areas are

more stringent than the nationwide NSPS limits.)

1. Surface coating regulations, including NSPS for coating large

appliances, metal furniture, cars and light-duty trucks, beverage cans, metal coils, magnetic tape, pressure sensitive tapes

and labels, and flexible vinyl coating.

2. Petroleum-related regulations, including NSPS for petroleum

refining, refinery wastewater, bulk gasoline terminals, storage

vessels, and natural gas production.

3. Synthetic organic chemical industry (SOCMI) related regulations, including NSPS for air oxidation equipment, distillation

operations, reactors, and other equipment.

4. Others including NSPS for drycleaning, graphic arts, synthetic

fiber production, and rubber tire manufacture.

% convert ~b~-fr @ @rni, multiply by approximately 0.9 for gasoline vehicles and 2.0

for diesel vehicles.

SOURCE: Offim of Technology Assessment, 1989.

EPA estimates that the costs for lowering gasoline

volatility during the 5 summer months would be

about $0.2 billion per year nationwide; the American

Petroleum Institute estimates that the costs would be

closer to $1 billion per year nationwide. The

resulting cost-effectiveness ranges between about

$120 and $800 per ton of VOC during the 5 summer

month period.
Chapter 8—Policy Options ● 215

Note that the reduction estimates and costs

above assume as a baseline gasoline volatility in the

range of 11.0 to 11.5 psi, which prevailed throughout

most of the United States during the summer months

between 1985 and 1988. They do not use as a

baseline the recently promulgated EPA regulations

requiring gasoline volatility of 10.5 psi beginning

during the summer of 1989 or several northeastern

state regulations requiring 9.0 psi, also beginning in

1989.

Option 2: More stringent exhaust standards for

cars and trucks.

Table 8-7 displays OTA’s estimates of the most

stringent car and truck emission standards that are

feasible with currently identifiable technology.11

About 4 years lead time might be needed for

manufacturers to design, test, and certify vehicles

meeting these lower standards. We feel that the

emission rates listed can be met as “certification

standards, ” that is, emission rates after 50,000 miles

on a test track. The emission rates might also be met

by well-maintained vehicles after 50,000 miles in

customer service. However, vehicle emissions could

easily be higher after 50,000 miles in normal

customer service.

As these are estimates of emission rates from

vehicles not yet designed, they should be viewed

with some caution. On reviewing the contractor

work on which the table is based, the auto and truck

manufacturers felt that the OTA contractor’s estimates of feasible emission standards were too

optimistic. Both EPA and the California Air Resources Board, however, felt that the standards were

too conservative. They felt that the numerical

standards could be met not only during certification

but after 50,000 miles in customer service. Though

they could not identify the particular technology mix

that would assure meeting the standards in customer

service, they believed that the manufacturers have

the technical capability to develop such a system if

forced by law.

Assuming these new highway vehicle standards

go into effect in 1994, costs would total about $2.9

billion dollars per year nationwide and lower VOC

emissions by 330,000 tons per year and NOx,

Table 8-7-Options for New Car and Light-Duty

Truck Exhaust Standards

Alternative 1: Most stringent standarda with

currently identifiable technology

For passenger cars:

0.25 g/mi NMHC 0.4 g/mi NOx

For light-duty gasoline trucks weighing less than 3,750 pounds:

0.25 g/mi NMHC 0.4 g/mi NOX

For light-duty gasoline trucks weighing between 3,750 and 6,000

pounds:

0.32 g/mi NMHC 0.7 g/mi NOx

For light-duty gasoline trucks weighing more than 6,000 pounds:

0.41 g/mi NMHC 1.5 g/mi NOX

Alternative 2: More stringent than current stamdards,

less stringent than those listed above

For passenger cars:

0.25 g/mi NMHC 0.7 g/mi NoX

For light-duty gasoline trucks weighing less than 3,750 pounds:

0.41 g/mi NMHC 0.7 g/mi NOX

For light-duty gasoline trucks weighing between 3,750 and 6,000

pounds:

0.50 g/mi NMHC 1.0 g/mi NOX

For Iight-duty gasoline trucks weighing more than 6,000 pounds:

0.50 g/mi NMHC 1.0 g/mi NOx

aAll ~~ma~~ ara m-d Ofl a so,ooo.rni~” ~tifhtion requirement. Hydrocarbon

stardads are for non-methane hydrocarbons (NMHC), not total hydrocarbons.

SOURCE: Office of Tkchndogy Assessment, 1969.

emissions by 1.3 million tons per year by 2004

(when most older vehicles will have been replaced).

About 45 percent of the emission reductions would

be in nonattainment areas.

Table 8-7 also presents a second possible set of

standards that are more stringent than those in place

today, but not quite as difficult or expensive to

achieve than those discussed above [11]. These new

standards would cost about $1.3 billion per year by

2004 and achieve about 65 percent of the VOC

reductions and 55 percent of the NOX reductions of

the more stringent standards discussed above.

Option 3: “Onboard” technology for cars and

trucks to control refueling emissions.

Gasoline vapors that escape from vehicle fuel

tanks during refilling can be controlled by two

different methods. The first, ‘stage-II” vapor recovery devices on gas pumps, was discussed above as an

option that can be limited to nonattainment areas

only. Control devices can also be installed ‘‘onboard” cars and trucks that can lower refueling

emissions by about 90 percent. VOC emissions

1 l~e= optio~ ~b~~ on a re~rt to C)TA by Siema Research [ 11], a consulting firm that provides services to a variety of auto indus~) oil ~dus~}

and regulatory agency clients.
216 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

could be lowered by about 530,000 tons per year

nationwide, at a cost of about $600 million per year

by 2004. This nationwide cost is based on a per

vehicle cost of $25, the upper bound of EPA’s

estimates. The Motor Vehicle Manufacturers’ Association estimates that the cost would be $80 per

vehicle.

In August 1987, EPA published a notice of

proposed rulemaking in requiring all gasolinefueled cars and trucks manufactured after 1990 to

have onboard technology to control refueling emissions. A final rule has not yet been issued.

Option 4: Federal solvent regulations.

STAPPA/ALAPCO, the associations of State and

local air regulatory agencies, has recommended that

Congress require EPA to develop and implement a

set of Federal regulations for the following solvent

categories: 1) commercial solvents, 2) consumer

solvents, 3) architectural coatings, 4) pesticide

application, 5) traffic-marking coatings, and 6)

metal-parts coatings for military applications and

aerospace-industry applications [15].

STAPPA/ALAPCO’s reason for advocating nationwide requirements, rather than requirements for

nonattainment areas only, is that such products are

‘‘manufactured and marketed regionally and nationally (rather than by individual States).” STAPPA/

ALAPCO states only that they believe that control

measures are technologically feasible, but does not

state the reductions that might be achieved or the

cost.

The emissions reductions from, and costs of,

regulations on the solvent content of architectural

coatings are discussed in chapter 6. Emissions could

be lowered by about 0.5 percent per year at a

nationwide cost of about $0.13 billion. Regulations

on other categories of solvent use are discussed in a

later section on “New Directions for the Clean Air

Act. ”

Control Requirements To Be Implemented by

States in Nonattainment Areas

Discussion

The Clean Air Act divides the responsibility for

air pollution control programs between EPA and

State and local governments. EPA is responsible for

setting emission standards for new motor vehicles.

The States are responsible for implementing inspection and maintenance programs in nonattainment

areas to ensure that motor vehicles continue to

operate properly.

The States are responsible for applying emission

controls to existing stationary sources. While EPA

issues regulations for new stationary sources that

apply nationwide, States are required to apply more

stringent requirements in nonattainment areas, that

is, the ‘lowest achievable emission rates” from new

stationary sources.

In 1985, about half of all VOC emissions came

from stationary sources, and therefore were the

responsibility of the State to control. In the absence

of further regulations, within a decade the percentage could rise to about 60 percent. Thus the

importance of State-implemented, as opposed to

federally implemented, controls will increase.

We will first review the controls that States are

already required to implement in nonattainment

areas under the Clean Air Act, and then present

additional controls that Congress could add to the

Act.

The 1977 Amendments created two categories of

nonattainment areas. The following Stateimplemented controls were required under regulations issued by EPA:

● In areas that could demonstrate attainment by

December 1982:

—“Reasonably available control technology”

(RACT) for all stationary sources of VOC

emitting more than 100 tons per year, for

which EPA issued ‘control technique guidelines” (CTGs) prior to 1979. (Source categories are listed in table 8-8.)

. In areas that received extensions of the attainment deadline to December 1987 (’‘extension”

areas):

—RACT for all stationary sources of VOC for

which CTGs have been issued. (Sourc e

categories are listed in table 8-8.)

—RACT for all stationary sources of VOC

emitting greater than 100 tons per year for

which CTGs have not been issued.

—Inspection and maintenance (1/M) program

for highway vehicles.
Chapter 8-Policy Options ● 217

Table 8-8—VOC Sources For Which EPA Hss Issued

Control Technique Guidelines

EPA has issued “control technique guidelines” (CTGs), which

presumptively determine RACT, for the following source categories:

1. Prior to 1979:

a.

b.

c.

d.

Surface coating regulations, including CTGs for coating

cans, coils, paper, fabrics, autos and light-duty trucks, metal

furniture, magnet wire, large appliances, flatwood paneling,

and miscellaneous metal parts.

Other solvent-related regulations, including CTGs for graphic arts, metal decreasing, and drycleaners using perchloroethylene.

Petroleum-related regulations, including CTGs for bulk

gasoline plants and terminals, liquids in fixed- and floatingroof tanks, miscellaneous sources in petroleum refineries,

gasoline tank trucks, and delivery of gasoline to service

stations.

Several additional regulations, including rubber tire manufacture, pharmaceutical manufacture, and cutback asphalt.

2. 1979 and later:

a. Large petroleum drycleaners.

b. Synthetic organic chemical industry (SOCMI) related regulations, including CTGs for high-density plastic resins, air

oxidation processes, volatile organic storage tanks, and

leaks.

c. Leaks from natural gas and gas processing plants.

SOURCE: Office of Technology Assessment, 1989.

—“Lowest achievable emission rate” (LAER)

of VOC for new stationary sources emitting

more than 100 tons per year or modified

stationary sources emitting more than 40

tons per year.

Options

Chapter 6 presented our estimates of the emissions reductions potential and costs of currently

available currently methods. Those measures from

chapter 6 that can be implemented by States, as well

as a few additional ones, are discussed below:

Option 1: Lowered source-size cutoff for requiring “reasonably available control technology”

(RACT).

EPA currently requires RACT-level controls for

stationary sources that emit, or have the potential to

emit, over 100 tons per year of VOC. (The Act

currently requires all reasonably available control

measures, but is silent on the source size cut-off.)

Congress could lower this cutoff to, for example,

50-or 25-ton-per-year sources in all nonattainment

areas or require progressively lower cutoffs depending on design value. For example, Congress might

maintain the current 100-ton-per-year cutoff in areas

with design values close to the standard (e.g., 0.13

ppm or lower), require a 50-ton-per-year cutoff for

most nonattainment areas, and require a 25-ton-peryear cutoff for the worst areas. Estimating the

reductions from such a change is quite difficult

because the nationwide emissions inventory maintained by EPA does not include detailed information

on sources that emit less than 50 tons per year of

VOC. In chapter 6, we estimate that emissions in

nonattainment cities could be lowered by about 4

percent by requiring RACT-level controls for all

sources that emit more than 25 tons per year.

Option 2: Require EPA to define RACT for

additional source categories.

EPA has issued “control technique guidelines”

(CTGs), which presumptively determine RACT for

about 30 source categories. State and local agencies

are able to use these documents as a basis for

regulations in their nonattainment areas. EPA has

not issued any new CTGs for several years.
218 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

State regulatory agencies have been particularly

strong advocates of requiring EPA to issue additional CTGs, both in OTA sponsored workshops and

in a position paper by STAPPA/ALAPCO [15].

State air program administrators have stated that it

is difficult for many agencies to impose controls on

source categories for which EPA has not issued

CTGs, even though the Act clearly states that all

stationary sources in nonattainment areas must

apply RACT-level controls.

STAPPA/ALAPCO recommends that EPA issue

CTGs for at least the following source categories:

hazardous waste treatment, storage, and disposal

facilities; stage II vapor recovery; wood furniture

coating; autobody refinishing; coke oven byproduct

plants; bakeries; sewage treatment plants; synthetic

organic chemical industry (SOCMI) batch process;

SOCMI distillation; web offset lithography; metal

rolling; plastic parts coating; and marine vessels.

We estimate that RACT-level controls on the frost

seven source categories listed above could lower

nonattainment area VOC emissions by about 8

percent in 1994. Note, however, that most of the

reductions-about 68 percent—come from one

source category, hazardous waste treatment, storage,

and disposal facilities. Costs to implement these

controls would total about $1.3 billion per year in

1994.

Option 3: More stringent requirements for motor

vehicle inspection and maintenance programs.

Improper maintenance, tampering with emissions

control systems, and component defects all result in

vehicle emissions in customer service at rates higher

than the standard. To correct these deficiencies,

Congress, in the 1977 Clean Air Act Amendments,

required motor vehicle inspection and maintenance

(I/M) programs in nonattainment areas that could not

meet the standard by 1982. Thirty States, plus the

District of Columbia, have I/M programs in place.

However, the effectiveness of the program varies

considerably from State to State. A wellimplemented 1/M program, such as California’s, can

lower VOC emissions by about 12 percent and NOX

emissions by about 4 percent [11]. Poorly implemented programs may achieve very little emissions

reductions.

Obviously, for an I/M program to succeed,

improperly functioning vehicles must be both identified and then repaired. Some programs employ test

methods that allow many poorly functioning vehicles to pass; a few programs do not test tailpipe

emissions at all but only perform a visual inspection.

Other programs may identify poorly functioning

vehicles but only require that repairs costing $50 or

less be made.

In a study of ways to improve California’s

existing I/M program, Sierra Research, Inc. identified a series of measures that could increase VOC

reductions from I/M from 12 percent of motor

vehicle emissions (current effectiveness) to about 30

percent [10]. Such an ‘‘enhanced” I/M program

would include: 1) more stringent emission standards, 2) centralized inspections or private garage

inspections using computer-controlled analyzers

with data recording, 3) visual and functional inspection of the emission control system, 4) repair cost

ceilings high enough to ensure that most vehicles

that fail the inspection will be completely repaired

(about $500), and 5) adequate inspection fees to

cover the cost of doing the inspection properly [11].

Such a program would cost about $50 per vehicle

per year-$20 per year for the inspection fee and

program administration and repair costs averaging

$70 to $100 for an estimated 20 to 35 percent of the

vehicles that might fail. The program would lower

total VOC emissions by about 1 percent and NOX

emissions by about 3 percent by 1994. Total costs of

an enhanced I/M program in all nonattainment areas

would be about $1.5 billion to $3.5 billion per year.

Option 4: Required use of alternative fuels by

centrally owned fleets.

In chapter 7, we discuss the emissions reductions

that could be achieved by requiring centrally owned

fleets of vehicles to use either methanol or compressed natural gas instead of gasoline. Methanol

vehicles used within the next 10 years would

probably be operated on blends of methanol and

gasoline. CNG vehicles would probably be “dualfueled, ” operating part time on CNG and part time

on gasoline, Although current projections of VOC

reductions that could be realized are uncertain, our

best estimate is that total (exhaust and evaporative)

emission rates would effectively be about 30 percent

lower for these alternatively fueled vehicles than for
Chapter 8---Policy Options ● 219

gasoline vehicles meeting current standards and

operated on low volatility gasoline (Reid Vapor

Pressure [RVP] of 9.0 pounds per square inch [psi])

[1,20].

Based on experience in the United States and

elsewhere, it appears feasible to modify or design

vehicles to operate on either CNG or methanol, with

performance that is generally comparable to that of

gasoline vehicles. The limited distance that can be

driven on CNG without refueling is currently a

disadvantage, compared to gasoline or methanol.

Safety concerns related to the toxicity of methanol

still need to be addressed before methanol/gasoline

blends are widely utilized. Safety, emissions, and

fuel economy standards are needed for CNG and

methanol vehicles, and fuel storage and handling

standards are needed for methanol.

Our analysis for the period through 2004 considered use of alternative fuels by vehicles that are

owned and operated as fleets of 10 vehicles or more

(e.g., by businesses or local governments) in areas

with peak ozone concentrations of 0.18 ppm or

higher. We limit the requirement to the worst areas

for two reasons: 1) at least over the next decade, the

costs of switching to either methanol or CNG would

be quite high; and 2) if methanol is the fuel of choice,

demand for the fuel from the 17 areas considered

would about equal upper bound estimates of current

excess production capacity worldwide. Additional

demand would increase the cost of the option

further, and could not be met in the near term.

There are several advantages to requiring vehicles

operated in fleets to use alternative fuels, rather than

applying the requirements to vehicles in general

service. Especially for vehicles that are refueled at a

central location, the network of stations needed

would be limited. And, although only about 6

percent of vehicles are in centrally owned fleets,

they account for over 12 percent of the total mileage

traveled each year, improving the cost effectiveness

of conversion. Finally, fleet vehicles are currently

replaced every 3 years, on average, compared to a

10-year turnover rate for vehicles in general use,

suggesting that benefits would accrue more rapidly

with fleets.

We estimate that fleets in the areas we considered

currently purchase about 500,000 vehicles per year.

Subsidies might be needed to dissuade businesses

from simply disbanding their fleets to avoid extra

costs. In addition to requiring that fleets purchase

alternative-fueled vehicles, manufacturers may have

to be provided incentives or required to produce

them.

Our best estimate is that use of methanol blends

would lower in emissions in the areas in which it is

required by about 0.5 to 0.7 percent per year, after

full conversion of fleets of 10 or more vehicles. Use

of CNG in fleets 75 percent of the time would lower

emissions by about 1.3 percent.

Assuming that methanol blended with 15 percent

gasoline is used, these reductions would cost from

$8,700 to $51,000 per ton of VOCs eliminated,

totaling $120 million to $710 million per year in

areas with design values of 0.18 ppm or higher. For

dual-fueled CNG vehicles using CNG 75 percent of

the time and gasoline the remaining 25 percent, the

cost would be from $400 to $22,000 per ton. In both

cases, the costs are extremely sensitive to fuel prices.

Use of alternative fuels in vehicles in general

service is discussed under “Long-Term Control

Strategies,” below.

Option 5: Transportation control measures.

Under the general heading of “transportation

control measures” (TCMs), people refer to a set of

interrelated approaches that either reduce highway

vehicle use or lower emissions per trip by increasing

average vehicle speed. Examples of the former

include improved public transit, highway lanes for

the exclusive use of buses and carpools, bicycle

lanes, parking management, and road-use restrictions or tolls. Measures such as traffic flow improvements and modified schedules for work do not lower

highway vehicle use but can reduce emissions by

reducing congestion, thus cutting the numbers of

hours vehicles are on the road. Transportation

control measures were included in most States’ 1979

and 1982 SIP revisions, typically with only modest

emissions reductions expected from them.

Since transportation control measures have to be

tailored to local conditions, and since different

programs will be most effective in different areas,

States need to be allowed some flexibility in

applying them. Tying the implications of failing to

meet interim emissions reduction requirements to

growth restrictions or limitations on Federal high-
220 . Catching Our Breath: Next Steps for Reducing Urban Ozone

way funds could encourage local officials involved

in transportation and land-use planning to participate in the development and implementation of

TCMs.

The benefits of some programs, such as requiring

companies to give their employees incentives for

ride sharing, designating high occupancy vehicle

lanes, and synchronizing traffic signals, can be

realized fairly quickly. Experience in the Los

Angeles area during the 1984 Olympics illustrated

that some TCMs, for example, modified work and

delivery schedules and increased transit service and

usage, can yield substantial benefits with little lead

time [14]. On the other hand, although the TCMs

contained in the 1988 Air Quality Maintenance Plan

for the Los Angeles area are expected to reduce

highway vehicle VOC emissions by 30 percent in

2010, only a 3-percent reduction is expected from

them in 1994 [13]. Because the potential for

reducing emissions appears greatest if TCMs are

viewed as long-term measures, further discussion of

this option is presented in the section discussing

“New Directions for the Clean Air Act. ”

Option 6: Tax on gasoline.

The cost of using one’s car influences the number

of miles per year that people travel. As the price of

gasoline goes up, vehicle miles traveled go down, at

least in the short term. A gasoline tax, therefore, is

another available option for lowering emissions

from highway vehicles in nonattainment areas. For

the first few years of a tax set at about $0.25 per

gallon, automobile travel would be expected to drop

about 8 percent. If a tax were set at about $0.50 per

gallon, automobile travel would be expected to drop

about 15 percent during the first few years. Over the

longer term, per capita travel might remain at the

lower level, might drop even further if economical

and convenient mass transit were made available, or

most likely, per capita travel would begin to rise

again as people compensated for the gasoline price

hike by buying more fuel efficient cars.

If the only benefits one counts from a gasoline tax

is the reduction in VOC emissions, the costeffectiveness of a gasoline tax is quite high. We

estimate that the emissions reductions from a

gasoline tax would cost about $35,000 to $75,000

per ton of VOC over the first few years, possibly

$100,000 to $200,000 per ton over the long term. Of

course, there are additional benefits, including lower

emissions of carbon monoxide, nitrogen oxides, and

carbon dioxide; reduced highway congestion; and

less reliance on imported oil.

Managing Growth

Discussion

Underestimating emissions growth is one of the

most often cited reasons for the failure to meet the

1987 attainment deadline of the current Clean Air

Act Amendments. In particular, few areas accurately

forecast the increase in automobile use that occurred, offsetting much of the gains made by the

lower motor vehicle emission standards required

under the Act. This illustrates a problem with the

present Clean Air Act. Most regulations control

emission rates (e.g., grams of pollutant per mile

traveled) rather than limiting the total amount of

pollutant emitted throughout a nonattainment area.

Thus, emission trends are the result of a race

between declining emission rates and increasing use

of goods and services.

In chapter 6, we presented our estimates of VOC

emissions trends over the next 15 years, assuming no

change in existing regulations. The projections serve

as a baseline against which to gauge the effectiveness of future regulations, including a way to judge

how well current regulations will manage future

emissions growth. We estimate that total VOC

emissions will continue to drop a few percent

through about 1995 but then return to 1985 levels by

2004.

We project that the current motor vehicle control

program will continue to lower highway vehicle

emissions to about 30 percent below 1985 levels by

1999 and then emissions will begin to rise again.

Without tighter standards or limits on vehicle use,

gains from replacement of older vehicles by newer,

cleaner ones will out pace emissions increases due to

increased vehicle use by the mid to late 1990s in

most nonattainment areas.

In contrast, stationary source emissions in nonattainment areas are forecast to increase steadily,

showing a 10-percent increase by 1994 and about a

20-percent increase by 2004, over 1985 levels.
Chapter 8—Policy Options ● 221

Growth in emissions from small stationary sources

(i.e., those emitting less than 50 tons of VOC per

year) is the primary contributor to this increase.

Under the current Act, in nonattainment areas,

new stationary sources emitting more than 100 tons

per year or modified stationary sources emitting

more than 40 tons per year must install controls that

achieve the “lowest achievable emission rate”

(LAER) for VOC. Moreover, emissions increases

must be offset by emission reductions elsewhere in

the nonattainment area. However, about 14 percent

of stationary source VOC emissions originate from

sources larger than 100 tons per year. Somewhere in

the range of 55 to 80 percent of stationary source

emissions originate from sources smaller than 25

tons per year. Thus, while the stationary source

requirements of the current Act limit growth to some

degree, a large majority of emissions are not affected

by these regulations.

Options

Option 1: Lower the cutoff for new source control

requirements.

As discussed above, current regulations require

that in nonattainment areas, new stationary sources

emitting more than 100 tons per year, or modified

stationary sources emitting more than 40 tons per

year, install controls that achieve the “lowest

achievable emission rate” (LAER) for VOC. Lowering this threshold, for example to 25 or 50 tons per

year for new sources and 10 or 20 tons per year for

modified sources, would further control future

emissions growth. Requirements to offset emissions

increases should also apply to these smaller sources.

Option 2: Eliminate “netting out” of new source

control requirements.

Current regulations allow sources to avoid the

new source control requirements described above by

lowering emissions at one place in a facility to keep

the total facility-wide increase below 100 tons per

year. For example, anew source that emits 120 tons

per year in a larger facility does not have to install

controls that achieve LAER if reductions of at least

20 tons per year are made elsewhere in the facility,

keeping net emissions increases below 100 tons per

year. Concern over this provision stems from the

belief that in many cases, the reductions that are

made elsewhere in the facility would have happened

regardless of whether the new source was installed

or not. Allowing netting, therefore, eliminates the

reductions that might be achieved through normal

operation improvements or retirement. We cannot

estimate how often this loophole is exploited.

Eliminating netting would hold down emissions

growth somewhat, but it is difficult to estimate the

magnitude of reductions or costs from such a

change. EPA has estimated that reductions of about

400,000 tons per year might be possible through

tighter new source control requirements, including

adoption of both this option and option 1 above [21].

A “back-of-the-envelope” calculation using our

estimates of the distribution of source sizes and

expected growth rates yields a considerably lower

reduction estimate, about 100,000 to 150,000 tons

per year.

Option 3: Areawide emission ceilings.

Most regulations under the Clean Air Act limit

emission rates, not areawide emissions. increased

motor vehicle use or growth in the number of, and

therefore emissions from, small sources will eliminate some of the gains made from stringent emission

regulations. In the section above on “Interim

Requirements” we discuss the advantages and

disadvantages of specifying areawide emission reduction schedules in addition to setting a deadline

for attaining the standard. Such interim requirements

might apply to total areawide emissions or apply

only to a subset of sources that are particularly

difficult to control. For example, areas might be

limited to a specified rate of increase in vehicle miles

traveled or might have limits on total solvent use

within the area.

Though implementation of areawide emission

limits would require an extensive and detailed

inventory, the advantage is that nonattainment areas

would be made accountable for all emissions increases on a continuing basis, rather than only by the

attainment deadline, as is currently the case.

NEW DIRECTIONS FOR THE

CLEAN AIR ACT

Controlling local VOC emissions will not be

sufficient in many nonattainment areas to comply

with the ozone standard. Part of the problem, of

course, is that currently available control measures
222 . Catching Our Breath: Next Steps for Reducing Urban Ozone

are inadequate to achieve the reductions that would

be necessary. In some areas, though, it may be

especially difficult to attain the standard if local NOX

emissions and/or VOC and NOX emissions in

upwind areas are not reduced concurrently with local

VOC emissions.

The starting point for this section is the assumption that the primary strategy for reducing urban

ozone that is followed by EPA and most States will

continue to be controlling VOC emissions in nonattainment areas. Focusing on the objective of reducing urban ozone, this section presents options for

additional controls, including: 1) controlling NO,

emissions in nonattainment areas, 2) controls on

NOX and VOCs in areas upwind of nonattainment

areas, and 3) several long-term strategies to attain

and maintain compliance with the standard.

In a fourth section, we present options for

reducing ozone in rural areas to prevent damage to

crops and trees.

Controls on Emissions of Nitrogen Oxides

in Nonattainment Areas

Discussion

Ozone is produced via chemical reactions involving both VOCs and NO,. In the past, EPA has

encouraged exclusive reliance on control of VOC

emissions to achieve compliance with the ambient

air quality standard for ozone.

The effect of controlling NOX emissions in

nonattainment areas will be mixed. If NOX emissions

are controlled, peak ozone concentrations will be

lower in some areas but higher in others, compared

to levels that would have been obtained with VOC

controls alone. Our ability to make reliable predictions about whether or not NOx controls will be

helpful is limited, at present, because the modeling

and data gathering needed to do so have not been

done for most cities. Even in the most well-studied

area, Los Angeles, the issue is not clear cut:

modeling studies suggest that the effects of NOX

control differ across locations within the LA basin,

and that they may change from day to day depending

on meteorological conditions.

EPA has used its “Regional Oxidant Model”

(ROM) to investigate the effect of reducing VOC

and NOX emissions in the Northeast. Totaled overall

of the urban areas in the modeling region, reducing

NOX emissions by 27 percent and VOC emissions by

42 percent below 1980 levels is predicted to yield an

improvement compared to controlling VOC emissions alone. However, underlying the overall improvement are impacts of NOx control that vary from

city to city. For example, in the Pittsburgh area, NOx

controls are predicted to increase potential population exposures to ozone concentrations above the

standard, whereas in Hartford, they are predicted to

be especially helpful in lowering them. These results

should be considered preliminary, because ROM’s

development and evaluation are not complete. Moreover, changes in base emissions levels since 1980,

and consideration of other control strategies or

meteorological episodes might alter these conclusions.

Based on measurements of the balance in urban

air between VOCs and NOX

, a very preliminary

judgment can be drawn that in general, Southern

cities are more likely to benefit from NOX controls

than cities in the Midwest or Northeast. However,

modeling calculations similar to those done for the

Northeast would need to be done for the South

before much confidence could be assigned to such a

generalization.

As with VOC controls, two broad categories of

NOX controls are possible: 1) federally implemented

controls that apply nationwide and 2) controls

implemented by the States in individual nonattainment areas. Given the characteristics of the problem,

Congress may choose to treat the two categories

differently. Congress may wish to allow the States or

EPA to decide where to require those NOX control

measures that can be implemented in some nonattainment areas without being imposed in others. For

those controls that are difficult to implement area by

area-in particular more stringent motor vehicle

standards-Congress must judge whether the reductions will, overall, do more good or harm.

Complicating the decision about whether to

mandate NOx controls is our understanding that NOX

emissions affect more than just nonattainment area

ozone concentrations. NOX emissions contribute to

acid deposition and are a major determinant of

elevated ozone concentrations in agricultural and

forested regions. Thus, Congress’ decision about

how to treat NOX emissions depends on the goals it
Chapter 8-Policy Options ● 223

is trying to achieve: 1) lowering peak ozone concentrations in urban areas, 2) lowering exposure of crops

and forests to ozone over the growing season, and/or

3) reducing acid deposition levels. NO, reductions

can have either a beneficial or detrimental effect on

peak ozone concentrations in nonattainment areas,

depending on city-specific conditions. NO, reductions will most likely lower both acid deposition and

regional ozone concentrations.

In 1985, total NOX emissions in nonattainrnent

areas were about 7.1 million tons. On average,

mobile and stationary sources contribute about

equally to NOX emissions in nonattainment areas,

although the split varies from city-to-city. Without

new controls, NOx emissions in nonattainment areas

in 2004 are projected to be 8.7 million tons (a

23-percent increase), with about 30 percent of the

total from highway vehicles and about 45 percent

from large stationary sources. Almost no growth is

anticipated in highway vehicle emissions between

now and 2004, as increased vehicle miles are

expected to be offset by lower NOX emissions per

vehicle. 12

Options

Option 1: Congressionally mandated NOX controls.

By imposing a package of more stringent lightduty vehicle exhaust standards,13 nonattainment

area NOX emissions could be reduced by about 0.5

million tons (about 7 percent of 1985 levels) in 2004.

Nationwide, a total of 1.3 million tons of NO= would

be eliminated, at a cost of $2.9 billion (combined

cost for both more stringent VOC and NOX controls).

New standards have already been adopted in California, to take effect in 1990, so no reductions there are

attributed to this option (i.e., 1.3 million tons are

reduced outside of California).

Since 1977, California has had more stringent

NOX standards for motor vehicles than the rest of the

United States. As an alternative to legislating a more

stringent standard nationwide, Congress could

choose to continue having two sets of motor vehicle

NOX standards, but extend the applicability of the

stricter standard beyond California. For example,

cars sold in States with ozone nonattainment areas

might be subject to more stringent standards than

cars sold in other States. About 10 States do not have

any nonattainment areas.

Option 2: Presumptive NOx controls, with EPA

authority to exempt areas under specified situations.

In chapter 7, we estimate emissions reductions

from applying “reasonably available” control technology (RACT) for nitrogen oxides to five stationary

source categories: electric utility boilers, industrial

boilers, stationary engines, gas turbines and process

heaters. Imposing RACT-level controls on electric

utility boilers that are located in nonattainment areas

and emit more than 100 tons per year of NOX would

result in emissions reductions in 2004 of about 0.9

million tons (about 13 percent of the 1985 nonattainment area total), at a cost of $360 million per year.

RACT-level controls for the other four source

categories would result in reductions of 0.3 million

tons (about 5 percent) in the year 2004, and cost

about $310 million per year. Control technology also

exists that would reduce NOX emissions from

electric utility boilers by approximately twice as

much as RACT. Application of this technology in all

nonattainment areas would cost over $8 billion.

As discussed in the section above on nonattainment area-specific controls, an “enhanced” inspection and maintenance (I/M) program for highway

vehicles could lower total VOC emissions in nonattainment areas by about 2 percent, and NOX emissions by about 3 percent. Most of the currently

operating I/M programs focus on VOCs, carbon

monoxide, or both. If NOX requirements were added

in all nonattainment areas, reductions of about

200,000 tons could be obtained in 2004 from

enhanced I/M programs. Attributing one-sixth of the

lz~ent efiaust standards for Nox were listed in the earlier seetion on federally Implemented conmols.

13~ new emission ~m~ds used in our analysis are M follows:

(in grams of pollutant emitted per mile travelled [g/mile] for non-methane hydrocarbons [NMHC] and NOX)

Passenger cars- NMHC: 0.25 ghnile; NOX: 0.4 g’mile

Light-duty gasoline trucks (by truck weight%

(less than 3,750 Ibs) NMHC: 0.34 g/mile; NOX: 0.46 ghnile

(3,751 to 6,000 lbs) NMHC: 0.43 ghnile; NOX: 0.80 g/mile

(6,(KKl to 8,500 Ibs) NMHC: 0.55 g’rnile; NOX: 1.15 g/mile
224 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

total cost of enhanced I/M programs to NOX, these

reductions would cost about $500 million. We

assume that enhanced I/M programs would not be

required for the sake of NOX reductions alone, but to

reduce VOC and in some cases CO emissions as

well.

Because both stationary source control measures

and highway vehicle I/M programs are implemented

at the State or local level, Congress can be selective

about where to require them. For example, Congress

might limit imposition of these NOX control requirements to nonattainment areas with design values

above a specified cutoff (e.g., 0.16 ppm and higher).

Congress could also allow the Administrator to

exempt areas where he or she determines that

stationary source NOX controls would be ineffective

or counterproductive.

Option 3: Requirements for evaluating NOx

controls.

Rather than presumptively requiring NOX controls, Congress could require some States to assess

their likely impact on air quality, and require them

if they appear beneficial.14 Areas in which available

VOC controls were not sufficient to enable them to

meet the standard by a specified deadline could be

targeted for this requirement. Based on our analysis,

this would include most areas with design values of

0.16 ppm or higher. NOX controls could be mandated

in these areas if analysis indicates that, for example,

peak ozone concentrations or some measure of

exposure to concentrations above the standard,

would be lower with NOX controls than with the

available VOC controls alone. Note that it might

also be useful for areas with high ratios of VOC to

NOX concentrations (greater than about 12 to 1) to be

included in this requirement, as theory suggests that

controlling NOX is likely to be especially effective

for reducing ozone in these areas. Enhanced air

quality modeling efforts are needed to produce a full

evaluation of the impact of NOX controls. However,

as discussed in an earlier section on planning

requirements, the limited number of people who

know how to run state-of-the-art air quality models

may pragmatically limit the number of areas that can

be required to use them.

Controls in Upwind Areas

Discussion

Both ozone and its precursors, VOCs and NOX,

can be transported into nonattainment regions from

upwind areas. Thus, some fraction of the ozone

found in nonattainment areas is not subject to local

regulatory authority. If the upwind area is also a

nonattainment region, further control will take place

to bring the area into attainment with the standard.

However, if the upwind region already meets the

standard, the only controls that can be expected are

those that are federally mandated nationwide.

Thus, two issues may have to be addressed by

Congress. First, current law does not provide an

adequate mechanism to implement additional controls in selected areas that currently attain the

standard, but contribute to ozone nonattainment

problems in areas downwind. A similar limitation

applies to requiring reductions in nonattainment

areas. Current law does not include an adequate

mechanism to force nonattainment areas to undertake emission reductions in excess of the amount

required to attain the standard, even though the area

might still be contributing to the nonattainment

problem of another area downwind.

In chapter 5 we discuss which areas seem most

likely to be significantly affected by pollutant

transport from outside their region. The Eastern

Seaboard, from Richmond to Maine, is the clearest

situation of an interstate region that might require

coordinated management. In the central part of the

country, interstate transport is likely around Lake

Michigan, and possibly between Cleveland and Erie,

PA. In the South, transport appears likely in the

coastal areas of Texas and Louisiana, and may also

be contributing to nonattainment problems in parts

of the Southeast. Finally, though within State

borders, pollutant transport from one city to another

is also a problem in central California.

Certainly some of these transport-related problems will be helped by the imposition of further

controls in nonattainment cities. However, given the

limits on the emissions reductions feasible with

currently known control measures, many areas will

Iqrfthis Optim is cho~n, it is impo~~t to be explicit about what is meant by the term ‘beneficial, ” beause controlling N% cm @vc mixed resulu.

As a hypothetical but plausible example of the kinds of contrary outcomes that are possible, N% controls could help lower peak ozone concentrations

in a city from 0.18 ppm to 0.15 ppm, but at the same time increase the number of areas within a city where concentradons reach 0.13 ppm.
Chapter 8-Policy Options ● 225

not be able to attain the standard in the near term.

Moreover, in some regions (for example, the Southeast) much of the ozone transported into nonattainment cities may be originating from areas that meet

the standard.

Unfortunately, it is easier to identify that a

transport problem might exist than it is to identify

solutions to the problem. The first question is which

pollutant should be controlled, VOCS or NOX? Next,

one must attempt to define an appropriate control

region size-e. g., 50 miles around nonattainment

cities significantly affected by transport, whole

States, or multi-State regions?

Theoretical considerations suggest that in most

situations reducing NOX emissions in attainment

areas would either reduce ozone in nonattainment

areas or have negligible effect, but would usually not

be counterproductive. NOX reductions in attainment

areas would affect ozone concentrations in nonattainment areas by reducing ozone produced upwind.

NO, controls in attainment areas would be expected

to help reduce ozone in rural areas, as well as acid

deposition.

NOX itself is unlikely to be transported further

than about 100 miles. However, our best guess of an

upper bound to the distance over which major point

sources of NOX could have more than a negligible

influence on downwind ozone is on the order of 300

miles-a distance over which ozone produced from

the NOX could be transported. We guess that

aggregate emissions from mobile or area sources

could have a similar scale of impact.

The relative amounts of NOx emitted in attainment areas versus nonattainment areas varies significantly by region. In the Northeast, about 40 percent

of the region’s NOX is emitted in attainment areas. In

the South and Midwest, attainment areas contribute

about 70 percent of regional NOX emissions.

In 1985, about 60 percent of NOX emissions in

attainment areas came from stationary sources and

40 percent from mobile sources. By 2004, without

further controls, we project the relative contributions

to be about 65 percent from stationary sources and

35 percent from mobile sources.

Reducing manmade VOC emissions in attainment

areas will either reduce ozone in nonattainment areas

or have negligible effect. VOC emissions in attainment areas would affect nonattainment area ozone

primarily by reducing VOCs transported into the

area from upwind. Theory suggests that VOC

controls in attainment areas could help reduce ozone

in some rural areas, but would generally be less

effective than NOX controls. VOC controls would

have a negligible effect on region-wide acid deposition levels. Note that in some parts of the country,

less than half of the total VOC emissions in

attainment areas are subject to control, as VOC

emissions from vegetation exceed manmade emissions. As discussed in chapter 5, emissions from

vegetation are especially high in the Southeast, but

are also high in forested areas of the Northeast,

Southwest, and Northwest.

Distances over which various volatile organic

compounds can be transported range from a few

miles to several hundred miles, depending on how

quickly the individual compounds react away. However, the VOCs that travel farthest tend to be least

efficient at producing ozone—so fresh emissions not

only are more concentrated but are also likely to be

more reactive than transported emissions. Our best

guess of an upper bound distance over which VOCs

from attainment areas would have an observable

impact on ozone in downwind cities is on the order

of 100 miles.

As with NO=, the proportion of VOCs emitted in

attainment areas versus nonattainment areas varies

by region. In the Northeast, about 40 percent of

manmade VOCs are emitted in attainment areas. In

the South, attainment areas contribute about 70

percent of manmade emissions. In the Midwest,

attainment areas contribute about 60 percent of the

region’s manmade VOC emissions.

In 1985, about 50 percent of the manmade VOC

emissions in attainment areas were from stationary

sources and 50 percent were from mobile sources.

By 2004, without further control, we estimate that

about 60 percent will come from stationary sources

and 40 percent from mobile sources.

Options

Option 1: Enlarge nonattainment areas to include

the entire extended metropolitan area.

In its proposed post-1987 policy, EPA suggested

that ozone nonattainment areas be defined as including (at least) the entire “metropolitan statistical
226 . Catching Our Breath: Next Steps for Reducing Urban Ozone

area” (MSA) or ‘consolidated metropolitan statistical area” (CMSA) in which the ozone standard is

violated.15 The Washington, DC MSA, for example,

extends over 100 miles, from the Pennsylvania

border north of Frederick, MD; south and east to

Solomons, VA on the Chesapeake Bay; and west to

Middleburg, VA. In the past, some designated areas

only encompassed the central urbanized city or

county of the metropolitan area. Our analysis of

emissions reductions has used MSA boundaries to

define nonattainment areas.

Congress could adopt EPA’s suggested new

definition of an ozone nonattainment area. Or,

Congress could further expand nonattainment areas

out beyond MSA or CMSA boundaries. For purposes of reducing VOC emissions that may affect

peak ozone concentrations within an urbanized area,

an upper bound on how far nonattainment areas

should be expanded is about 100 miles. Specified

control requirements could automatically be applied

throughout expanded areas. Alternatively, the States

could be required to determine whether controls in

these areas would be beneficial, with imposition left

to their discretion.

Option 2: Congressionally specified NOX controls

in designated “transport regions” or nationwide.

Congress could require “reasonably available”

control technology (RACT) for large stationary

sources of NOX in attainment areas as well as

nonattainment areas. Again, Congress can be selective about where to require stationary source control

measures. If the goal is to lower nonattainment area

ozone concentrations, stationary source NOX control

requirements could be limited to States with or

adjacent to nonattainment areas. Rural ozone impacts (discussed below) and acid deposition might

also be considered in determining where stationary

source NOX controls should be required. Congress

could allow the Administrator to exempt areas where

he or she determines that stationary source NOX

controls would be ineffective.

Excluding States that do not have nonattainment

areas, imposition of RACT-level standards for

utility boilers in attainment areas would result in

NOX emissions reductions of about 15 percent below

1985 levels. RACT for other stationary sources in

attainment areas would reduce emissions by an

additional few percent.

Nationwide imposition of more stringent lightduty vehicle exhaust standards (discussed above)

could result in about a 5-percent reduction in

attainment area NOX emissions.

Option 3: Strengthen the interstate transport

provisions of the Clean Air Act.

Section 110(a)(2)(E) of the Clean Air Act requires

that SIPS “prohibit any stationary source within the

State from emitting any air pollutant in amounts

which will prevent attainment or maintenance [of

standards] by any other State. ” Section 126 allows

States or local areas to petition the Administrator for

a finding that any major source violates section

110, and allows the Administrator 60 days

after receipt of the petition to make the finding. Once

such a finding is made, proposed sources are

prevented from being constructed and existing

sources must be brought into compliance within 3

years.

l6

To date, EPA has not issued regulations to

establish what constitutes compliance with section

110, and has not granted any petitions under

section 126, although some of the petitions filed

have been resolved through the SIP or permit review

processes. EPA has required petitioners to establish

that an actual violation of an applicable standard has

occurred, and that the out-of-state source is a

‘‘significant” contributor to the violation. Claims

have been required to be supported by monitoring

data or modeling studies. But EPA has not considered the modeling techniques used to predict violations to be sufficiently reliable to demonstrate the

connection between emitting and receiving regions

or to distinguish local from interstate contributions.

Sections 110 and 126 of the Clean Air

Act could be amended to define more clearly how

much of an impact of one State’s emissions on

ls~ ~ition, EPA h= suues~ that it will rwtire that emissions from major point sources of VOC and NOX located within 25 miles of the MSA

or CMSA boundaries be included in the area’s emissions inventory. This implies that these sources would be included in the agency’s proposed area-wide

average 3 percent per year VOC emissions reduction requirements.

lbs~tion 126 &SO rq~ms notification if a major proposed or existing source in one State may “significantly contribute” tO Ievek of tir pollution

in excess of the NAAQS in another State.
Chapter 8-Policy Options ● 227

another State’s air quality is prohibited; to clarify

where the burden lies in proving that an impact is or

is not significant enough to take action against; and

to specify factors that EPA should consider in

determining what measures to require of the offending sources. Congress could broaden the applicability of the prohibition in section 110 from

‘‘any stationary source” to include groups of

sources-such as an upwind MSA or State-and

then amend Section 126 accordingly. If Congress

chooses to rely on mechanisms similar to those

provided by sections lo and 126, the

question of whether NOX controls could be required

when they might be counterproductive in the emitting State should be addressed explicitly.

Option 4: Provide EPA with clear authority to

develop regional control strategies based on regionalscale modeling.

Over the past several years EPA has developed,

and is currently working jointly with Northeastern

States to apply, a regional-scale atmospheric model

for the entire Northeast called the Regional Oxidant

Model, or ROM. EPA proposes to use ROM, by the

end of 1990, to test whether the independently

developed, local attainment strategies of nonattainment areas in that region are adequate, or whether

further emissions reductions are necessary. If the

modeling analysis indicates that further controls are

needed, EPA has proposed to use its authority to

require SIP revisions to obtain them. While EPA

‘‘does not anticipate the need for a regional model in

areas outside the northeast region at the present

time” [22], interstate transport may also be complicating the nonattainment problems of areas in the

southern Lake Michigan and Gulf Coast regions.

Affirming EPA’s proposed policy for the Northeast, Congress could require the Agency to apply

regional-scale modeling in specified regions to

ensure compliance with an amended section lo.

The modifications to section 110 specified

above would be applicable. Moreover, Congress

could specify that once the modeling is completed,

EPA is required to review all applicable SIPS. (A

recent court interpretation of section lo

holds that the section does not require reevaluation

and revision of existing SIPS, unless the SIP is being

revised for another reason.17)

Several years and several million dollars would be

required to develop programs for regions other than

the Northeast. As mentioned above, the Gulf Coast,

Southeast, and Great Lakes regions are potential

candidates.

Reducing Ozone in Rural Attainment Areas

Discussion

Elevated concentrations of ozone occur in rural

areas throughout the southern and eastern halves of

the United States. Nationwide, reducing daytime,

growing-season-average ozone concentrations by

about 25 percent18 in crop-producing areas is estimated to result in annual benefits from increased

crop yields in the range of $0.5 billion to $1.0 billion

per year. Reducing ozone concentrations outside of

urban areas would also reduce damage to trees in

national parks as well as commercial timberlands.

However, the impacts of ozone on trees and on forest

ecosystems are not understood well enough to

support evaluation of the forest-related benefits of

reducing ozone.

Rural ozone essentially has two sources, either of

which could be a target for control-pollution that

is transported from urban areas, and pollution that is

produced locally. At present, there are no estimates

of the comparative contributions of these two

sources. Controls imposed in nonattainment areas

(for VOC or VOC and NOX

) will help reduce ozone

at rural sites impacted by urban “plumes” of

elevated ozone concentrations. Such plumes have

been observed to extend more than 200 miles

downwind of some cities.

For reducing ozone produced locally, outside of

urban areas, theory (including modeling exercises

with hypothetical ‘‘typical” rural conditions) suggests that NOX control will generally be more

beneficial than VOC control. Although they do not

allow us to sort out benefits of urban versus

nonurban controls, results from EPA’s ROM sug171852 F.2d 574 (Dtc. Cir. 1988)

18~ ~w ~~yx=, we lower ozone concen~ations by 25 percent of the difference between ctment levels ~d na~al b~k~o~d.
228 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

gest that either controlling VOC emissions alone or

controlling both VOC and NOX emissions would

help reduce ozone in rural areas in the Northeast.

Options

Option 1: Specify a deadline for EPA reconsideration of the ozone secondary standard for ozone and

a schedule for adoption by the States.

The Clean Air Act establishes two types of air

quality standards. “Primary” air quality standards

are set by EPA to protect against adverse health

effects. “Secondary” standards are established to

protect against adverse impacts on human comfort

and welfare, including impacts on visibility, vegetation, animals, wildlife, materials, and property. The

States, together with EPA, are responsible for

ensuring that the primary air quality standards are

met “as expeditiously as practicable,” within the

deadlines specified in the Act. The secondary

standards are to be attained in a‘ ‘reasonable” period

of time.

The secondary standard for ozone is currently set

as a one-hour average concentration of 0.12 ppm,

i.e., identical to the primary standard set to protect

human health. The standard is under review by EPA,

as it is generally thought to be poorly designed for

protecting vegetation.

To date, definition of an appropriate secondary

standard for ozone has been hampered by: 1) the

preliminary status of assessment of its impact on

forests; and 2) uncertainty about whether peak or

long-term concentrations are most important in

determining impacts on vegetation. Implementation

of secondary standards for all of the criteria pollutants has been neglected, as evidenced by the scarcity

of air quality monitors located in rural areas.

Congress could direct EPA to put more effort into

developing and enforcing a secondary standard for

ozone.

Option 2: Congressionally specified NOx controls.

We estimate that imposing more stringent lightduty vehicle exhaust standards nationwide would

reduce NOX emissions by a total of 1.3 million tons

(7 percent of 1985 levels) in 2004, at a cost of $2.9

billion (for both NOX and VOC controls).

Nationwide imposition of RACT-level standards

for utility boilers in both attainment and nonattainment areas would result in NOX emissions reductions

of 3.7 million tons (about 20 percent of the

nationwide 1985 total) in 2004. Nationwide RACT

for other stationary sources would reduce emissions

in 2004 by about 800,000 tons (4 percent) .19

Long-Term Control Strategies for

Chronic Nonattainment Areas

Discussion

About half of the current nonattainment cities

may require greater emissions reductions to attain

the standard than are achievable with near-term

control methods. Figure 6-12 displays our estimate

of VOC emissions in 1994, after all of the controls

discussed in chapter 6 have been applied. Note that

emissions from solvents—surface coatings and many

other sources of organic solvent evaporation-will

account for about 35 percent of the remaining

inventory. Highway vehicles and the gas stations

that fill them will account for an additional 35

percent.

Longer term strategies to bring the remaining

nonattainment areas into compliance with the standard will have to include one or both of these

emissions categories-and in some cities, progress

in other categories as well. Within this section we

consider three possible targets of opportunity for

post-2000 emission reductions. These include: ways

to lower organic solvent emissions, long-term transportation control measures, and use of alternative

motor vehicle fuels such as methanol and compressed natural gas (CNG). Each of these was

discussed in detail in chapter 7.

Options

Option 1: Lowering emissions from solvents.

As described in chapter 7, organic solvents are

used in a myriad of products and manufacturing

processes. They are used to clean many types of

products, from decreasing metals to drycleaning fine

l~e majority of ~e~ r~uctions (56 percent) would occur in the South; 17 percent would occur in the Midwest; and 9 Wrcent would Occw in tie

Northeast.
Chapter 8—Policy Options . 229

clothing; to deliver surface coatings, including

house paints, printing inks, and coatings on many

manufactured products from cans to furniture to

magnetic tape; and in consumer products such as

pesticides and deodorants.

Solvent emissions can be lowered in many ways.

In some instances it is possible to switch to

alternative products that use no solvent (for example, using water-based rather than oil-based paints).

Products can be reformulated so that less solvent is

used or solvents that are not photochemically

reactive are substituted for those that are involved in

ozone formation. Manufacturing methods can be

changed so that less solvent is emitted per unit

manufactured. And finally, emissions can be captured or destroyed through control methods such as

incineration, preventing release to the atmosphere.

However, for many products and processes, low

or no-solvent alternatives are not available and

alternative manufacturing methods may not deliver

the desired quality end product. Thus, unlike for

many other source categories for which significant

reductions can be achieved by applying “reasonably

available control methods” or “best available control methods,” the problem of solvent emission

reduction faced by Congress, EPA, and the States is

to force the development of new products, manufacturing processes and control methods.

This problem is not without precedent. When

Congress directed EPA in 1970 to develop regulations that lowered motor vehicle emissions by 90

percent, the technology to achieve this was not

available. Congress decided to force development of

technology by choosing a percentage reduction

target and a date by which it was to be reached, and

by adopting penalties to provide additional incentives for manufacturers to develop technologies that

would comply with the new law. Deadlines were

slipped many times and several have yet to be

reached, but tailpipe emissions of VOC, nitrogen

oxides, and carbon monoxide have been lowered

considerably.

We have identified three basic approaches that

Congress can take to facilitate reductions in solventrelated emissions and promote innovative approaches

to achieve these reductions:

1) Direct EPA to issue “reasonably available

control measures” for specified solvent uses and

source sizes. Some categories for which Federal

guidance or regulations could be issued in the near

future were discussed in earlier sections of this

chapter. Under this option, EPA would be directed

to continue developing control technique guidelines

(CTGs) for new categories of sources or develop

Federal regulations that apply nationwide. In some

instances, size cutoffs could be lowered from current

levels or eliminated altogether.

2) Direct EPA or the States to issue regulations to

lower solvent-related emissions by a specified percentage by a certain date. Rather than specifying

particular solvent uses, Congress could specify the

desired emissions reduction schedule and leave the

choice of solvent uses to be regulated to either EPA

or the States.

3) Provide clear authority in the Clean Air Act for

EPA or the States to use a market-based approach

for controlling emissions and, in the latter case,

direct EPA to provide model regulations as guidance for the States. Two basic approaches would

either: 1) impose fees or surcharges on emissions or

products with high solvent content, making the fees

high enough so that it is cheaper to control emissions

or find substitutes than to pay them; or 2) distribute

permits to producers or users that allow them to emit

a specified amount of VOCs, and then cut back

gradually on the permitted levels. Trades would be

allowed among sources so that those who could

reduce emissions at the least cost could reduce more

than required, and “sell” their extra reductions to

others for whom reductions were more expensive.

Of the three options listed above, the marketbased strategy deviates most from traditional control

approaches. We did not evaluate whether fees or

permits or some variation of these approaches would

be best suited to VOC or solvent regulation. Nor did

we analyze in detail the advantages and disadvantages of market-based approaches compared to more

traditional regulatory systems in which EPA or State

engineers identify available control technology for

specific source categories and require those sources

either to use them or match the reductions obtained

with them by using other measures. However,

market-based approaches seem to offer enough

promise for cutting costs and promoting develop-
230 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

ment of new ways to reduce emissions that Congress

might choose to direct EPA to seriously evaluate

their use for lowering solvent-related emissions.

Though the Clean Air Act does not preclude the

use of market incentives, most of the Act is devoted

to establishing a regulatory system based on the

traditional “engineering” approach. By clearly

stating its intent that market-based approaches are

acceptable, Congress could at least allow them to be

considered on their merits. If Congress decides that

a market-based strategy is the preferred approach,

then EPA could be required to develop model

regulations for the States to adopt.

Option 2: Long-term transportation control measures.

The 1988 Air Quality Maintenance Plan for Los

Angeles estimates that by 2010, highway vehicle

emissions could be reduced by 30 percent below

where they otherwise are projected to be, by using a

suite of complementary transportation control measures ranging from parking management to highway

expansion to telecommuting. Total daily reductions

anticipated in 2010 are 10 times higher than those

expected from the program in 1994, as measures

focused on new businesses or developments take

effect, and as freeway expansion projects are completed. Growth management measures aimed at

matching new jobs with nearby housing account for

about 40 percent of the reductions projected for

2010, but have negligible impact in 1994. These

measures entail assessing development fees, modifying zoning rules, and policies for location of new

public facilities and infrastructure. An additional 15

percent of the expected reductions would come from

freeway capacity enhancements to reduce congestion.

Of the remaining measures, about 30 percent of

the reductions come from a series of measures aimed

at lowering highway vehicle usage. These are

primarily strategies to reduce the number of singleoccupancy car trips, including employer ride share

and mass transit incentives, parking management

(increase parking meter fees, eliminate peak-period

on-street parking, eliminate employer-subsidized

parking, etc.), van pool purchase incentives, auto use

restrictions, and high-occupancy vehicle (HOV)

lanes. About 15 percent of the reductions come from

measures that do not lower vehicle usage but rather

reduce congestion. Reducing congestion decreases

the number of hours that vehicles are on the road and

thus lowers emissions. These include such measures

as traffic flow improvements (e.g., metering on

highway ramps, synchronized traffic signals, and

intersection improvements) and rescheduling and

rerouting of truck deliveries away from congested

areas during peak commute hours.

For Los Angeles, such reductions would occur at

a crucial period. Highway vehicle emissions are

forecast to drop over the next 10 years due to the

replacement of older cars and trucks with more

stringently controlled ones. After 2000, however,

emissions are forecast to rise again due to population

growth. The hoped for 30-percent reduction due to

transportation control measures is enough to more

than offset the expected emissions growth between

2000 and 2010, keeping highway vehicle emissions

on a slight downward trend.

The potential for reducing emissions appears

greatest if TCMs are viewed as long-term programs.

To guide SIP revisions likely to be required in the

interim, areas could be required to develop TCM

programs over 15- to 20-year time horizons and

include them in urban transportation and land-use

plans. Periodic updates would accommodate

changes in development patterns and transportation

requirements, etc.

In addition to requiring that States use TCMs,

Congress may want to require that air quality

objectives are given higher priority in federally

funded urban transportation projects. Section 176(c)

of the 1977 Amendments was an attempt to provide

a check on the air quality impacts of all projects

supported by Federal highway and mass transit

funds by requiring that federally funded projects

“conform” to State Implementation Plans. However, DOT, which distributes Federal highway and

mass transit assistance, has sought to equate ‘‘conformance” with a narrow finding that a transportation plan or project does not interfere with transportation control measures included in SIPs [19]. EPA

has suggested a broader requirement that transportation plans and projects “should not cause or

contribute to existing or new standard violations, or

delay attainment” [3]. Congress could clarify or

strengthen the conformance requirements of section

176(c) to support EPA’s interpretation.
Chapter 8—Policy Options ● 231

Option 3: Requirements for widespread use of

alternative fuels in nonattainment areas that are far

from meeting the standard.

We estimate that for every 25 percent of light-duty

vehicles using alternative fuels in 2004, VOC

emissions would effectively be reduced by 1.5 to 4

percent, compared to 1985 levels. The lower level of

reductions is our best estimate. Achieving greater

reductions from alternative fuels would require

exclusive use of methanol or compressed natural gas

in each vehicle, as opposed to use of methanol/

gasoline blends or vehicles that could run on

gasoline or alternative fuels. Achieving the greater

reduction levels would also require significant

advances in vehicle technology, and vehicle designs

and operating parameter adjustments to ensure

minimal emissions.

Assuming that methanol blended with 15 percent

gasoline is used, and the lower levels of reductions

cited above are achieved, we estimate that costs

would be $8,700 to $66,000 per ton of VOCs

reduced. Assuming use of CNG 75 percent of the

time and use of gasoline for the remaining 25

percent, cost-effectiveness would fall in the range of

$3,900 to $22,000 per ton. If the upper bound level

of reductions can be achieved, the cost of using

straight methanol could be as low as $3,200 to

$22,000 per ton. Exclusive use of CNG could result

in costs between $1,600 to $14,000 per ton. In each

case, costs are extremely sensitive to fuel prices.

Obviously, for vehicles in general use to operate

on CNG or methanol, both vehicles and fuel have to

be made available. Establishing fuel production

capacity, fuel distribution networks, and motor

vehicle production lines entails major investments,

and simultaneous and appropriately scaled commitments are needed in each area. Current estimates of

the economics of using alternative fuels, compared

to gasoline, suggest that either subsidies or mandates

from Federal or State government will be needed if

alternative fuels are to be used in general service in

the next 10 to 15 years.

Using California as an example, a fixed percentage of each major automobile manufacturer’s new

vehicle sales in the State might be required to be

either CNG or methanol fueled. Vehicle registration

fees or tax credits could be used to equalize the cost

of alternative and gasoline-fueled vehicles. Similarly, fuel retailers could be required to offer

alternative fuels at a fixed percentage of their

stations, and gasoline taxes could be set to about

$0.25 to $0.50 per gallon to allow methanol to

compete with gasoline on a cents per mile basis.

Flexibly fueled vehicles that can run on methanol

or gasoline or any combination of the two, and

dual-fueled CNG vehicles that can run on gasoline

or CNG, would be easier to introduce into general

service than vehicles operated exclusively on CNG

or methanol, because they could be operated out of

range of refueling stations that supplied the alternative fuels. Where improvements in air quality are the

major motivation for using alternative fuels, however, these vehicles have two disadvantages: low

emissions that might be possible with the alternative

fuels would be compromised to provide for satisfactory operation on multiple fuels; and consumers

might simply choose not to operate them on the

alternative fuel. The second problem could be

addressed by using taxes or subsidies to encourage

alternative fuel use. The first problem suggests that

flexibly or dual-fueled vehicles should only be

viewed as a transition measure.

In addition to developing the necessary infrastructure, government intervention may be needed to

increase the likelihood that low emission rates can

be realized, so that from an air quality standpoint,

alternative fuels will be worth the investment. This

could take the form of government-funded research

and development efforts. Alternatively, manufacturers could be required to produce a fixed percentage

of vehicles meeting new, technology forcing emissions standards, but be given the flexibility of

meeting them using any vehicle technology they

choose. EPA would be given the task of defining

equivalent emission rates—based on ozone forming

potential—of gasoline-, methanol- and CNG-fueled

vehicles.

The Los Angeles area Air Quality Management

District has already adopted the goal that by the year

2000, at least 15 to 30 percent of the motor vehicles

in the area should be “clean fuel” vehicles [12]. To

date, however, the district has not set forth its

strategy for meeting that goal.
232 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

REFERENCES FOR CHAPTER 8

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

Alson, J.A., “The Emission Characteristics of Methanol and Compressed Natural Gas in Light Vehicles, ”

paper 88-99.3, presented at the 81st Annual Meeting

of the Air Pollution Control Association (Dallas, TX:

June 19-24, 1988).

Bockh, L., U.S. Environmental Protection Agency,

personal communication, May 11, 1989

Clay, D.R., and Wilson, J.J., letter to R.E. Farris,

Nov. 8, 1988.

Croes, B., California Air Resources Board, personal

communication, December 1988.

Meiburg, M., U.S. Environmental Protection

Agency, personal communication, Apr. 10, 1989

Nazemi, M., South Coast Air Quality Maintenance

District, personal communication, December 12,

1988.

Princiotta, F., U.S. Environmental Protection

Agency, personal communication, Oct. 4, 1988

Principe, P., U.S. Environmental Protection Agency,

personal communication, April 1989

Pacific Environmental Services, Inc., Study of the

1979 State Implementation Plan Submittals (Washington, DC: National Commission on Air Quality,

December 1980).

Sierra Research, Inc., Evaluation of the Cal#ornia

Smog Check Program, Technical Appendix (April

1987).

Sierra Research, Inc., The Feasibility and Costs of

More Stringent Mobile Source Emission Controls,

contractor report prepared for the Office of Technology Assessmen4 Jan. 20, 1988.

South Coast Air Quality Management District Board,

“Recommendation to Adopt a Five-Year Clean

Fuels Program,” December 1987.

Southern California Association of Governments,

Draft Air Quality Management Plan, 1988 Revision,

Appendix IV-G, “Transportation, Land Use, and

Energy Conservation Measures” (Los Angeles, CA:

September 1988).

Southern California Association of Governments,

Transportation Policy Recommendations: The Olympic Legacy, Let’s Keep It Moving (Los Angeles, CA:

January 1986).

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

State andT~“ Air Pollution Program AdministratomAssociation of Imcal Air Pollution Control Officials,

The STAPPA-ALAPCO National Ozone Control

Strategy, Executive Summary (May 1988).

Sullivan, M., Air Permit and Emissions Fees (Washington DC: State and Territorial Air Pollution Program Administrators/Association of I.acal Air Pollution Control Officials, April 1987).

Tesche, T, Radian Corp., personal communication,

Jdy 1986.

Twaddell, R., New York Department of Environmental Conservation, personal communication, August 1986.

U.S. Department of Transportation, Notice of Proposed Rulemaking, 53 FR 35178, Sept. 9, 1988.

U.S. Environmental Protection Agency, Guidance on

Estimating Motor Vehicle Emission Reductions from

the Use of Alternative Fuels and Fuel Blends, EPA

report number EPA-AA-TSS-PA-87-4 (Research

Triangle Park, NC: January 1988).

U.S. Environmental Protection Agency, Office of Air

Quality and Standards, Implications of Federal

Implementation Plans (FIPs) for Post-1987 Ozone

Nonattainment Areas (March 1987).

U.S. Environmental Protection Agency, Federal

Register, 52 F.R. 45044, Nov. 24, 1987.

U.S. Government Accounting Offke, Ozone Attainment Requires Long-Term Solutions to Solve Complex Problems, GAO/RCED-88-40 (Washington,

DC: January 1988).

U.S. Government Accounting Offke, EPA’s Ozone

Policy is a Positive Step but Needs More Legal

Authority, GAO/RCED-89-28 (Washington, DC:

November 1988).

Walsh, Michael P., Critical Analysis of the Federal

Motor Vehicle Control Program, report prepared for

the Northeast States for Coordinated Air Use Management, July 1988.

Wojcik, M., Wojcik, J., Bareford, P., Havelock, M.,

Geraghty, M., Haupt, S. E., “Cost Analyses of

Proposed Changes to the Air Quality Modeling

Guidelines,” EPA 450/4-82-014 (U.S. Environmental Protection Agency, February 1982).

Appendix A

Parameters Used To Calculate Volatile Organic Compound

Emissions Reduction Potential and Associated Costs of

Control for Stationary Sources

The equation used to calculated total annual cost is given by:

Annual cost = ( (A*CC*UCE) + (OC*UOE) -(RI + U*RS) }

where, A = annualization factor (assume 10% annual interest; incineration—15-year equipment life, others-10-year

life),

U = uncontrolled VOC emissions, and other parameters defined in the column headings below.

-235-
236 ● Catching Our Breath: Next Steps for Reducing Urban Ozone

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . -

. .

. .

. . . . . .

. . . . . .

. . . . . .

. . . . . .

. . . . . .

. . . . . .

. . . . . .

. . . . . .

.

. . . . . . . .

. . . . . . . .

. . . . .0..

. . . . . . . .

. . . . . . . .

. . . . . . . .

. . . . . . . .

. . . . . . . .

,... . . . .

. . . . . . . .

. . . . . . . .

..., . . . .

. . . . . . . .

. . . .

. . . .

. . . .

. . . .

. . . .

,.. .

. . . .

. . . .

. . . .

. . . .

. . . .

. . . .

,,. .
control (cc) (CE) (OC) (OE) (RI) (RS)

Efficiency Capital Cost: O&M Cost: Recovery Credit:

Control Strategy/Source Description Control Technique (percent) Constant Expon. Constant Expon. Intercept slope

Paper surface coating: large source

small source

Miscellaneous surface coating

Pharmaceutical manufactureb

Synthetic fiber manufacture

Crude oil/natural gas production

Cutback asphalt

Misc. (includes: industrial solvent use and

miscellaneous surface coating)a

New CTG’s;

Plastic parts coatingb

Wood furniture Coatingb

Coke-oven by-product plants Incinerator

Automobile refinishing

Publicly-owned treatment WOrkS

b

Bakeries b

Hazardous waste treatment, storage,

and disposal facilitiesb

Architectural surface coating

Stage II.b

Incinerator . . . . . . . . . . . . . . . . . . . . .

Incinerator . . . . . . . . . . . . . . . . . . . . .

Incinerator . . . . . . . . . . . . . . . . . . . . . .

Equipment & maintenance . . . . . . . .

Carbon adsorber . . . . . . . . . . . . . . . .

Equipment & maintenance . . . . . . . .

Emulsified asphalt . . . . . . . . . . . . . . .

Incinerator . . . . . . . . . . . . . . . . . . . . . .

Incinerator . . . . . . . . . . . . . . . . . . . . .

lncinerator . . . . . . . . . . . . . . . . . . . . . ,

Incinerator , . . . . . . . . . . . . . . . . . . . .

Afterburner . . . . . . . . . . . . . . . . . . . . .

Covers, carbon absorber. . . . . . . . . .

Water-base coating . . . . . . . . . . . . . .

Vapor balance . . . . . . . . . . . . . . . . . .

90 31,532

91 4,334

90 117,482

37 424

54 4,501

37 549

100 0

75 31,911

90

90

90

75 31,911

90

90 0

90

25 0

79

0.406 2,164.0 0.654 (5,914.0)

1.000 3,664.0 1.00 0 0.0

0.539 2,371.0 0.877 0.0

1.000 220.0 1.000 0.0

1.000 526.0 1.000 0.0

1.000 264.0 1.000 0.0

1.000 0.0 1.000 0.0

1.000 1,595.0 1.000 0.0

(No cost coefficients used. Assumed $2,000/ton)c

(No cost coefficients used. Assumed $2,000/ton)c

(No cost coefficients used. Assumed $2,000/ton)c

(No cost coefficients used. Assumed $2,000/ton)c

1.000 1,150.0 1.000 0.0

(No cost coefficients used. Assumed $900/ton)c

0.000 287.0 1.000 0.0

(No cost coefficients used. Assumed $1,OOO/ton)c

325

0

159

320

196

0

0

0

0

0

NOTES:

a=~w ~rms. ~m~ ~Om tinw t=ppar of VOC. all SWcefr emit less tfm 50 km par year of VOC. Urdess otherwise specified, ail categories atmm am for sour= emi~ more ~~ tons *r WW.

Q30uroes that emit less than 50 tons per year of VOC.

‘Cost4fectivaness assumed by OTA

Derived from:

(1) Sattye, W. H., M.G. Smith, and M. Deasa, Cost Assessment of Alternative National Ambknt Air OualityStandards For Ozone, Draft Report, prepared by Alliance Technology Corporation, Contrac# No. 66-02-4317 (Research Triangb

Park, NC: U.S. Emironmental Protadon Agency, October 19S7).

(2) E.H. Wchan and Associates, Inc., Natkmal Asaeaarne nt of VOC, CO, and NOx Contr~ Emissions, and Costs, Contract No. 6s-W841t13S (Washington, D.C.:Office of Policy, Planning and Standards, U.S. Environmental Protection

AWncy. September 19SS).
Related OTA Report

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

OTA-O-204, 6/84; 324 pages. GPO stock #052-O03-O0956-l; $9.50.

NTIS order #PB 84-222 967/AS.

NOTE: Reports are available from the U.S. Government Printing Office, Superintendent of Documents, Washington, D.C. 20402-9325 (202-783-3238);

and the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161 -O(X) I (703-4874650).