Testimony

Before the Subcommittee on Legislative, Committee on

Appropriations, House of Representatives

United States General Accounting Office

GAO

For Release on Delivery

Expected at 2:00 p.m.,

Friday, May 25, 2001 AIR POLLUTION

Air Quality and

Respiratory Problems in

and Near the Great Smoky

Mountains

Statement of David M. Walker

Comptroller General of the United States

GAO-01-790T
Page 1 GAO-01-790T

Mr. Chairman and Members of the Subcommittee:

Good afternoon. It is a pleasure to be here in beautiful Asheville today to

speak with you about the air we breathe. Western North Carolina has a

well-justified reputation for beautiful mountains and diverse species of

plants and animals. But air quality remains a concern.

For about the past 6 months, we have been working with Chairman

Charles H. Taylor on a study of air quality in this area. Today, we are

releasing the results of that study.1

 But, before we get into the results, let

me tell you a little bit about who we are. As the Comptroller General, I

head the U.S. General Accounting Office or GAO. GAO is part of the

legislative branch of government, and we help the Members of Congress

carry out their constitutional responsibilities. We perform audits,

investigations, evaluations, and policy analyses, and we provide a range of

legal services that span the entire scope and reach of the federal

government—from Social Security issues to national security issues.

Simply stated, our mission is to help the Congress make government work

better for all Americans.

For the purposes of our study of air quality in and near Great Smoky

Mountains National Park, we were charged with answering four questions:

(1) What is the trend in visibility in the park and what are the causes of

reduced visibility? It is difficult to appreciate the beauty of the mountains

if we cannot see them. (2) What is the trend in ozone in the park and what

are its causes? Ozone, specifically ground-level ozone, is a potential threat

to human health, (3) What is the trend in lung diseases for the people who

live in the North Carolina and Tennessee counties that border the park?

and (4) What are the plans of the Tennessee Valley Authority (TVA), the

largest electric utility in this area, to reduce its emissions of two key air

pollutants? In developing the information for our study, we collected data

from five federal agencies—the Environmental Protection Agency, the

Forest Service, the National Park Service, Department of Health and

Human Services, and the Tennessee Valley Authority. In addition, we

gathered information from state agencies in North Carolina and

Tennessee, and from other academic, research, and special interest

groups.

 1

Air Pollution: Air Quality and Respiratory Problems in and Near the Great Smoky

Mountains (GAO-01-658, May 25, 2001).
Page 2 GAO-01-790T

To put our study results in context, some background on Great Smoky

Mountains National Park and air quality is probably in order. The park

encompasses 800 square miles in North Carolina and Tennessee.

Designated a national park in 1934, it is 95 percent forested, and elevations

in the park extend from 800 to more than 6,600 feet.

Areas adjacent to the park are growing in population and economic

activity. Between 1990 and 2000, the nation’s population grew 13 percent.

During this same period, North Carolina’s population grew 21 percent, and

Buncombe County—the most populous county in Western North

Carolina—grew 18 percent. Moreover, over the past 10 years, annual

recreational and non-recreational visits to Smoky Mountains National Park

have increased from 18 million to 21 million visitors. Unfortunately, this

growth has a cost. More people usually mean higher demand for

electricity, more cars, and more goods transported by truck.

Burning coal to generate electricity and burning gasoline to power our

cars and trucks results in emissions of many gases that can harm the

environment. This isn’t going to be Chemistry 101, but understanding two

chemicals is particularly important to our air quality discussion today.

First, sulfur dioxide (SO2)—which is generated mostly from coal-fired

plants located to the north and west of the park—is closely associated

with decreased visibility. Second, nitrogen oxides (NOx)—which come

primarily from motor vehicles, but also from power plants—are linked to

the formation of potentially health-threatening ozone. Now, for the

specifics of our study.

Study Background
Page 3 GAO-01-790T

Our first question related to visibility trends in the park and the causes of

reduced visibility. In general, visibility was poor at the beginning of the

1990s and remained poor through 1999 (the latest data available),

according to the National Park Service. For the days with the worst

visibility (those ranked in the bottom one-fifth of all days for each year),

visibility ranged from between 12 and 15 miles during that decade.

Visibility

1

Visibility in the Park on the Worst Days

Remained Poor During the 1990s

Source: National Park Service

Visibility
Page 4 GAO-01-790T

On the best-visibility days in the park, visibility averaged around 51 miles

during the 1990s. By contrast, it is estimated that typical visibility in the

park—before industrialization—was on the order of 60 to 90 miles. In

analyzing visibility, we focused on the worst days—typically hot, humid

summer days—because it is on those days that reduced visibility is the

most detrimental to enjoyment of the park.

Reduced visibility is caused by small particles in the air that either scatter

or absorb light. In the Eastern United States generally, and the park

specifically, most of these particles are sulfates. These particles are widely

believed to have adverse health effects, and research is underway to more

clearly understand how they harm health and which particles are most

harmful.

Sulfate particles are formed in the air from emissions of sulfur dioxide gas.

Electric utility power plants produce about two-thirds of the nation’s

sulfur dioxide emissions.
Page 5 GAO-01-790T

In fact, dozens of power plants are located within the states surrounding

the park.

2

Electric Utilities Produce Two-Thirds of

National Sulfur Dioxide Emissions

Source: EPA

Visibility
Page 6 GAO-01-790T

We know that many power plants are located in the states near the park,

but what do we know about the sources of the sulfates reaching the park?

National Park Service analysts recently traced the paths of the air masses

that delivered sulfate particles to the park for the 3 days before they

reached the park. Their analysis covered May through September in the

years 1995 through 1999.

3

Many Power Plants Are Close to the Park

Source: EPA

Visibility

Note: Purple denotes power plants that became subject to new Clean Air Act

requirements beginning in 1995. Blue

denotes power plants that became subject to

these requirements in 2000.
Page 7 GAO-01-790T

The analysts found that on low-visibility days (that is, days with high levels

of particles), the air masses generally started their 3-day journey just a few

hundred miles from the park and often followed a roundabout trajectory

to get there. The majority of the air masses started over the industrial

Midwest, or spent considerable time there, where they could have

accumulated substantial quantities of sulfur dioxide from this highemissions area. A significant minority of high-sulfur air masses arrived

from west of the park. Few air masses arrived from the east and south on

these low-visibility days.

Our second question related to the trend in ozone levels in the park and its

causes. Ozone is considered a potential threat to human health, and the

Environmental Protection Agency has established a public health standard

for the concentration of ozone in the air that we breathe. In addition,

exposure to ozone can harm plants, although this was not the focus of our

study.

Ozone is not emitted. It is formed from nitrogen oxides and volatile

organic compounds in reactions initiated by sunlight. Heat accelerates the

chemical processes through which ozone is formed.

We concentrated on days when the ozone level in the park exceeded the

federal standard— the standard which is also used by the state of North

Carolina. An “exceedance” is recorded on any day when a monitor

measures ozone levels that exceed this threshold. The number of

“exceedances” in the park varied greatly during the decade.

Ozone
Page 8 GAO-01-790T

During the early 1990s, the number of exceedances in the park gradually

rose—to 8 days in 1996. Then there was a strong rise in the number of

exceedances to 37 in 1999. Last year, the number fell sharply to 12 days.

This decline is believed to be related to last summer’s cooler temperatures.

4

Exceedances of the Ozone Standard in

the Park Increased in the 1990s, but Fell

Sharply in 2000

Ozone

Source: National Park Service for Great Smoky Mountains and Shenandoah for 1999 and 2000; otherwise, EPA

Note: Data for Great

Smoky Mountains National

Park are for Look Rock
Page 9 GAO-01-790T

The two chemicals involved in forming ozone stem from diverse sources.

More than 50 percent of the nation’s nitrogen oxides are produced by the

transportation sector—including cars, trucks, farm equipment—and even

your gas-powered lawn mower. Nearly another 25 percent come from the

electric utility sector.

Volatile organic compounds come from both natural and human sources.

Trees release isoprene—the most important natural organic compound for

5

The Transportation Sector Produces

Over Half of National Nitrogen Oxide

Emissions

Ozone

Source: EPA
Page 10 GAO-01-790T

producing ozone in this area—and North Carolina and the other heavily

forested southeastern states are particularly rich in isoprene. Human

sources of volatile organic compounds include the wide variety of

hydrocarbons that result both from fuel evaporating from cars and trucks

and from incompletely burned fuel.

According to a recent National Park Service analysis, on high-ozone days,

most of the air masses reaching the park arrived from the north and

northwest—generally from the industrial Midwest. Fewer air masses

arrived from the west and the south, and very few arrived from the east.

Our third question related to respiratory health in the areas surrounding

the park. We made three choices to keep our analysis manageable:

• First, of the many indicators of health conditions, such as hospitalizations,

illnesses, and deaths, we chose to focus on deaths because, of all the

indicators, only mortality data are available at the county level.

• Second, of the various specific health conditions we could have chosen to

analyze, we chose two groups of respiratory illnesses because they have

most often been linked to air quality. The two groups are

pneumonia/influenza and chronic obstructive pulmonary disease (which

we will refer to as chronic lung disease), a term that includes asthma,

bronchitis, emphysema, and other chronic lung diseases.

• Third, to specify the areas of North Carolina and Tennessee that are

adjacent to the park, we chose the groupings already used by those states.

Thus, we used the definition of North Carolina’s Department of

Environment and Natural Resources for the 19 counties that we label

Western North Carolina and Tennessee’s Department of Environment and

Conservation definition for the 16 counties that we label Eastern

Tennessee.

We completed several sets of comparisons, and I’ll highlight three of them

for you. First, we compared overall death rates for the period from 1991 to

1998 in the states of North Carolina and Tennessee with the overall death

rate in the United States as a whole. We found that the rates in each state

were somewhat higher than the national rate.

Second, we compared death rates in Western North Carolina and Eastern

Tennessee against the comparable rates in each state. For overall deaths,

we found that Western North Carolina and Eastern Tennessee had

substantially lower rates than their respective states, for the period 1991

through 1998.

Respiratory Illnesses
Page 11 GAO-01-790T

Third, for deaths from respiratory illnesses during the same period, we

found that these two regions had slightly higher rates than their respective

states.

6

Death Rates for All Causes Were Lower

in Areas Adjacent to the Park Than in

Those States as a Whole

Note: Differences in death rates are statistically significant

Source: GAO analysis of unpublished North Carolina and Tennessee data

Respiratory Illnesses
Page 12 GAO-01-790T

Many factors influence the development and severity of respiratory

illnesses, including smoking behavior and exposure to pollutants or

allergens. Research is currently ongoing to increase our understanding of

the link between exposure to air pollution and respiratory illnesses.

7

Death Rates for Chronic Lung Disease

Increased in North Carolina and

Tennessee Between 1991 and 1998

Note: Differences in death rates are statistically significant

Source: GAO analysis of unpublished North Carolina and Tennessee data

Respiratory Illnesses
Page 13 GAO-01-790T

Our fourth question related to TVA’s plans to reduce its emissions of two

key air pollutants. As you know, TVA is the largest electric utility in the

southeast, serving customers in seven states, including some in North

Carolina.

Like other electric utilities, TVA is subject to a range of federal and state

laws and regulations. Of particular significance—for TVA and all other

utilities that burn coal to generate electricity—is Title IV of the 1990

amendments to the Clean Air Act.

These amendments mandated substantial reductions in emissions of sulfur

dioxide (which is linked to reduced visibility, as I discussed earlier) and

modest reductions in emissions of nitrogen oxides (which is linked to

ozone, as I also discussed).

To generate electricity, TVA relies primarily on burning coal—which

accounted for 62 percent of TVA’s total generation over the last 5 years.

The remaining electricity was generated by nuclear power (28 percent),

hydroelectric power (9 percent), and other sources (1 percent).

TVA’s total generation of electricity grew about 10 percent between 1992

and 1999. During that period, TVA’s consumption of coal increased 18

percent. TVA estimates that the generation trend will continue, with peak

generating capacity requirements expected to grow 1.7 percent per year

between 1999 and 2010. This is equivalent of adding one new average-sized

power plant every year. To meet this challenge, TVA plans to use a

combination of strategies, such as purchasing power, constructing new

plants, and providing incentives to customers to reduce their peak

demand.

TVA’s total emissions of sulfur dioxide declined 30 percent between 1989

and 1999. TVA estimates that, as a result of additional steps underway and

being planned for the next decade, these emissions will decline an

additional 36 percent between 1999 and 2005. Mr. Chairman, your

proposed legislation would require a substantially greater reduction in

sulfur dioxide emissions by 2005, as shown in the chart.

TVA’s Plans to Reduce

Its Emissions
Page 14 GAO-01-790T

TVA has taken and plans to take to a number of steps to reduce these

emissions. For example,

• TVA will continue to burn coals with lower sulfur content at 51 of its

59 units and

• TVA has installed equipment called “scrubbers” at its three largest plants.

8

TVA Cut Its Sulfur Dioxide Emissions

During the 1990s and Expects to Cut

More by 2005

Source: TVA

TVAís Emissions
Page 15 GAO-01-790T

Scrubbers can remove more than 90 percent of the sulfur dioxide from a

plant’s emissions and are considered the best currently available

technology for reducing such emissions.

In looking at TVA’s emissions of nitrogen oxides, we focused on the

5-month “ozone season” (May through September) when ozone levels tend

to be relatively high and when exceedances tend to occur. TVA’s total

nitrogen oxide emissions in the 1999 ozone season were about the same as

in the 1989 season. TVA projects that its ozone season emissions will

decline about 68 percent between 1999 and 2005.

This reduction reflects, among other things, the results of TVA’s plans,

announced in 1998, to invest nearly $1 billion in pollution-control

equipment. Such equipment includes “selective catalytic reduction”

devices for nearly one-half of its coal-fired units. These devices transform

nitrogen oxide emissions into harmless nitrogen and water vapor. Again,

Mr. Chairman, your bill would require a substantial reduction of nitrogen

oxides from TVA’s current projections for the year 2005.
Page 16 GAO-01-790T

In summary, let me just say that you should be commended for your

concern about the quality of your air, and for wanting to do something

about it. Many Americans in other areas of the country share your

concern. The solutions to air pollution, however, are not simple. Balancing

our ever-increasing demand for energy with our need to protect the

environment for future generations is at the heart of the policy debates

now raging in the Congress. We at GAO will continue to work with the

Congress to help find solutions for this complex problem.

9

TVA Expects to Cut Its “Ozone-Season”

Emissions of Nitrogen Oxides Sharply

by 2005

Note: The ozone season is May 1 to September 30

Source: TVA

TVAís Emissions
Page 17 GAO-01-790T

That concludes my prepared statement, Mr. Chairman. I would be happy

to address your questions.

(360099)