Air Pollution: Air Quality and Respiratory Problems in and Near
the Great Smoky Mountains (25-MAY-01, GAO-01-790T).
Concerns have been growing about the air quality, visibility, and
respiratory illnesses around the Great Smoky Mountains National
Park, which straddles the border between North Carolina and
Tennessee. This testimony analyzes recent trends in and
contributing factors to (1) visibility impairments, (2)
ground-level ozone, and (3) respiratory illnesses. This testimony
also examines the Tennessee Valley Authority's (TVA) plans to
reduce its emission of regulated pollutants from generating
electricity. Visibility impairments and ozone are largely
attributable to the following three types of emissions: sulfur
dioxide, nitrogen oxides, and volatile organic compounds. The
counties that border the park generally have slightly higher
mortality rates from two types of respiratory illness. The three
types of emissions interact in the atmosphere to form ozone gas
and sulfate particles, which are linked to respiratory illnesses.
In response to federal laws and other factors, TVA is making
substantial environment-related investments and expects to reduce
its annual emissions of sulfur dioxide by 36 percent and its
''ozone-season'' emissions of nitrogen oxides by 68 percent
between 1999 and 2005. This testimony summarizes the May report,
GAO-01-658.
-------------------------Indexing Terms-------------------------
REPORTNUM: GAO-01-790T
ACCNO: A01063
TITLE: Air Pollution: Air Quality and Respiratory Problems in
and Near the Great Smoky Mountains
DATE: 05/25/2001
SUBJECT: Air pollution control
Respiratory diseases
Electric power generation
National parks
Environmental monitoring
Great Smoky Mountains National Park
North Carolina
Tennessee
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GAO-01-790T
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 TVA?s 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 TVA?s Emissions
Page 17 GAO- 01- 790T
That concludes my prepared statement, Mr. Chairman. I would be happy to
address your questions.
(360099)
*** End of document. ***