    Air Pollution: Air Quality and Respiratory Problems in and Near
    the Great Smoky Mountains (25-MAY-01, GAO-01-658).

    There has been growing concern about the air quality, visibility,
    and certain respiratory illnesses in and near the Great Smoky
    Mountains National Park, which straddles the border between North
    Carolina and Tennessee. This report analyzes recent trends in and
    contributing factors to (1) visibility impairments, (2)
    ground-level ozone, and (3) respiratory illnesses. In addition,
    this report 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 three types of emissions (1) sulfur dioxide, (2)
    nitrogen oxides, and (3)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 associated with 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 40 percent and
    its ''ozone-season'' emissions of nitrogen oxides by 70 percent
    between 1999 and 2005.
    -------------------------Indexing Terms-------------------------
    REPORTNUM:   GAO-01-658
        ACCNO:   A01015
      TITLE:     Air Pollution: Air Quality and Respiratory Problems in
                 and Near the Great Smoky Mountains
         DATE:   05/25/2001
      SUBJECT:   Air pollution control
    	     Electric power generation
    	     Environmental law
    	     Environmental monitoring
    	     National parks
    	     Respiratory diseases
    	     Great Smoky Mountains National Park
    	     North Carolina
    	     Tennessee

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    GAO-01-658

    Briefing Report to Congressional Committees

    United States General Accounting Office

    GAO

    May 2001 AIR POLLUTION Air Quality and Respiratory Problems in and Near the
    Great Smoky Mountains

    GAO- 01- 658

    Page i GAO- 01- 658 Air Pollution Letter 1

    Briefing Section I Overview 10

    Briefing Section II Visibility 12

    Briefing Section III Ozone 18

    Briefing Section IV Respiratory Illnesses 24

    Briefing Section V TVA?s Emissions 34

    Appendix I Comments From the Department of the Interior 40

    Appendix II Comments From the Environmental Protection Agency 41

    Appendix III Comments From the Tennessee Valley Authority 43 Contents

    Page 1 GAO- 01- 658 Air Pollution

    May 25, 2001 The Honorable Charles H. Taylor Chairman The Honorable James P.
    Moran Ranking Minority Member Subcommittee on Legislative Committee on
    Appropriations House of Representatives

    The Honorable Robert F. Bennett Chairman The Honorable Richard J. Durbin
    Ranking Member Subcommittee on Legislative Branch Committee on
    Appropriations United States Senate

    Although air quality has generally been improving throughout much of the
    United States in the past 20 years, there is growing concern about
    visibility, air quality, and certain respiratory illnesses in and near Great
    Smoky Mountains National Park, which straddles the border between North
    Carolina and Tennessee. In light of these concerns about the park and
    adjacent areas, we were directed to analyze recent trends in and
    contributing factors to (1) visibility impairments, (2) ground- level ozone,
    1 and (3) respiratory illnesses. In addition, we were directed to examine
    the Tennessee Valley Authority?s (TVA) plans to reduce its emissions of
    regulated pollutants from generating electricity. We generally focused our
    review on the period from 1990 to 1999 or 2000, depending on data
    availability. (See H. Rept. 106- 1033, Conference Report to Accompany H. R.
    4577, Making Omnibus Consolidated and Emergency Supplemental Appropriations
    for Fiscal Year 2001.)

    The results of our work are summarized in this letter. Briefing Sections I
    through V contain the charts that we used to brief Chairman Taylor and his
    staff on March 1 and 22, 2001, along with explanatory notes.

    1 Ozone is a colorless gas that occurs both in the earth?s upper atmosphere
    and at ground level. In this report, we use the term ozone to refer to
    ground- level ozone.

    United States General Accounting Office Washington, DC 20548

    Page 2 GAO- 01- 658 Air Pollution

    Reduced visibility, high ozone levels, and respiratory illnesses in and near
    Great Smoky Mountains National Park are continuing concerns. Visibility
    remained poor throughout the 1990s. The number of days when ozone levels
    exceeded a health- based standard generally rose during the decade but fell
    in 2000. Visibility impairment and ozone are largely attributable to three
    types of emissions.

     Sulfur dioxide, which is generated primarily from coal- fired power plants
    north and west of the park, can be transformed into sulfate particles, which
    are the main contributor to reduced visibility.  Nitrogen oxides, which are
    generated largely from motor vehicles, as well

    as coal- fired power plants, participate in ozone formation.  Volatile
    organic compounds, which result from both natural sources (such

    as isoprene from trees) and human actions (including a wide range of
    compounds resulting from such activities as the incomplete combustion of
    gasoline), also participate in ozone formation.

    The sulfate particles and ozone gas formed from these emissions are
    associated with respiratory illnesses. Relative to the entire states of
    North Carolina and Tennessee, the counties that border the park generally
    have slightly higher death rates from two types of respiratory illness, even
    though they have substantially lower death rates from all causes. Research
    is continuing on why and how air pollution leads to adverse health effects.

    In response to federal laws and other factors, the Tennessee Valley
    Authority is making substantial environment- related investments and expects
    to reduce its annual emissions of sulfur dioxide by 36 percent and its
    ?ozone- season? (primarily summer time) emissions of nitrogen oxides by 68
    percent between 1999 and 2005.

    Great Smoky Mountains National Park encompasses 800 square miles in North
    Carolina and Tennessee. Designated a national park in 1934, it is 95 percent
    forested and is renowned for the diversity of its plant and animal resources
    and the beauty of its ancient mountains. Elevations in the park range from
    800 feet to 6, 643 feet.

    Areas adjacent to the park are growing in population and economic activity.
    For example, between 1990 and 2000, while the U. S. population grew 13
    percent, the population of North Carolina and Tennessee grew 21 percent and
    17 percent, respectively, and the population grew 18 percent in Buncombe
    County, the most populous county in western North Carolina. Recreational
    visits to the park increased from 8.2 million Results in Brief

    Background

    Page 3 GAO- 01- 658 Air Pollution

    in 1990 to 10. 2 million in 2000, and non- recreational visits to the Park
    increased from 9.4 million to 10. 9 million during the same period.

    The burning of coal, gasoline, and other fossil fuels- by electric
    utilities, motor vehicles, manufacturing facilities, and other sources-
    generates sulfur dioxide and nitrogen oxide gases. When emitted into the
    air, these gases, and the substances, into which they can be transformed,
    may be transported hundreds of miles away. In the atmosphere, these gases
    may be transformed into tiny particles or may react with other chemicals.
    Visibility is impaired when light encounters these tiny airborne particles
    and is absorbed or scattered before reaching the observer. Humidity
    magnifies the problem because the particles may attract water and grow in
    size, thereby scattering more light. In addition to reducing visibility,
    these tiny particles, which can be inhaled deeply into the lungs, have been
    consistently associated in epidemiological studies with hospital admissions
    and premature deaths.

    Ozone is not emitted; it forms when nitrogen oxides react with volatile
    organic compounds in the presence of sunlight. Repeated exposure to ozone
    may permanently damage lungs or trigger symptoms, such as chest pains or
    coughing. It may also interfere with plants? ability to produce and store
    food, making them more susceptible to pathogens, pests, and other
    pollutants. (By contrast, in the upper atmosphere, ozone forms a protective
    layer that shields the earth from harmful ultraviolet rays.)

    The Clean Air Act 2 requires the Environmental Protection Agency (EPA), in
    concert with state and local air pollution agencies, to regulate mobile and
    stationary source emissions of certain air pollutants. In addition, for
    pollutants it determines to be harmful to human health, EPA is responsible
    for setting standards for concentrations of those pollutants in the air that
    people breathe. It has designated six such principal pollutants, including
    sulfur dioxide, nitrogen dioxide, particulate matter, and ozone. Finally,
    certain provisions of the act specifically address visibility impairments.

    Although the 1977 amendments to the Clean Air Act established tougher
    requirements for new power plants and certain other facilities, existing
    facilities- including those operated by TVA and many other electric
    utilities- were exempted from these requirements, so long as they did not

    2 It was enacted in its present statutory format in 1970 and has been
    amended since then, most recently in 1990.

    Page 4 GAO- 01- 658 Air Pollution

    make physical changes to the plants that resulted in increased emissions.
    EPA alleged in 1999 that TVA and several privately owned utilities had
    violated the Clean Air Act provisions by making physical changes to their
    units that had resulted in emissions increases. EPA?s lawsuit against TVA is
    pending.

    Despite the progress over the past 20 years in reducing the emissions of
    most principal pollutants and improving air quality, ozone concentrations in
    many counties in the United States exceed national standards, and visibility
    in many otherwise pristine areas remains a problem. Over the same time
    period, the prevalence of asthma- the most common chronic disease of
    children in the United States and other developed countries- has increased
    by more than half.

    Visibility in Great Smoky Mountains National Park remained poor throughout
    the 1990s. On the worst days (those ranked in the bottom onefifth of all
    days in terms of visibility- usually hot and humid summer days), visibility
    ranged between 12 and 15 miles from 1989 through 1999, according to the
    latest available data from the National Park Service. On average days (the
    middle one- fifth of all days), visibility stayed at about 27 miles during
    the decade and, on the best days (those ranked in the top one- fifth of all
    days), it stayed at about 51 miles.

    Reduced visibility is primarily caused by airborne particles that either
    scatter or absorb light. In the eastern states generally, and in the park
    specifically, during the summer, these particles are predominantly fine
    sulfate particles formed from sulfur dioxide gas, a product of burning coal
    and other fossil fuels. The electric utility sector accounted for 67 percent
    of the nation?s sulfur dioxide emissions in 1999 (latest available data);
    the transportation sector, 7 percent; and other sources, the remaining 26
    percent.

    Because sulfur dioxide gas and the sulfate particles, into which it can be
    transformed, can travel hundreds of miles on wind currents, the particles
    that degrade visibility in the park may originate from emissions released
    over a large area. According to a recent National Park Service analysis of
    the air masses that reached the park on low- visibility days (that is, days
    with high levels of particulates), the majority started, or spent
    considerable time, over the industrial Midwest, which allowed them to
    accumulate substantial quantities of sulfur dioxide. Air masses arrived from
    the west on a lesser, but still significant, portion of the low- visibility
    days, while few air masses arrived from the east and south on such days.
    Visibility

    Page 5 GAO- 01- 658 Air Pollution

    In 1994, the year before the provisions of the Clean Air Act Amendments of
    1990 limiting sulfur dioxide emissions took effect, the nation?s electric
    utilities emitted 14. 9 million tons of sulfur dioxide. In 1999, the level
    fell to 12.7 million tons, and it is projected to decrease to just under 9
    million tons in 2010.

    The number of days when ozone levels in the park exceeded a health- based
    threshold set by EPA, called ?exceedances,? generally increased during the
    1990s, according to data from EPA and the National Park Service. However,
    the number fell sharply in 2000. It is believed that the decline is related
    to the cooler summer temperatures in 2000.

    Because sunlight is necessary to the formation of ozone and heat accelerates
    chemical reactions, ozone levels tend to peak in the summer months. The two
    principal precursors of ozone- nitrogen oxides and volatile organic
    compounds- have diverse sources. Motor vehicles and other transportation
    sources produced 55. 5 percent of the nation?s nitrogen oxide emissions in
    1999 (latest available data); electric utilities produced 22. 5 percent; and
    other sources produced the remaining 22 percent. Volatile organic compounds
    include isoprene, which trees produce, and various hydrocarbons, such as
    those emitted when gasoline evaporates or is burned incompletely. In North
    Carolina, Tennessee, and other southeastern states, trees and other natural
    sources produce relatively high levels of isoprene. Thus, there is an
    abundance of naturally occurring volatile organic compounds in these areas
    to react with nitrogen oxides to form ozone.

    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 after passing through the industrial Midwest. Fewer air
    masses arrived from the west and south and very few arrived from the east.

    The Clean Air Act Amendments of 1990 are expected to reduce national
    nitrogen oxide emissions by 2 million tons a year by 2010, relative to the
    level without these provisions. Other EPA policy initiatives are intended to
    make further cuts in emissions. Ozone

    Page 6 GAO- 01- 658 Air Pollution

    Throughout the 1990s, death rates from two respiratory illnesses- (1)
    chronic lung disease 3 and (2) pneumonia/ influenza- in North Carolina and
    Tennessee were consistently higher than the comparable national rates.
    Moreover, death rates from these illnesses in the North Carolina and
    Tennessee counties adjacent to the park were generally higher than the
    comparable rates for these states as a whole throughout the 1990s, even
    though these counties had substantially lower death rates from all causes.
    (These rates are age- adjusted to allow comparability between states and
    over time; however they were not adjusted for other influences, such as
    rates of smoking and socioeconomic levels.)

    In the past 50 years, studies conducted in the United States and abroad have
    consistently shown that people who breathe polluted air are more likely to
    suffer adverse health effects. These effects may be reflected in increases
    in breathing problems, hospital admissions, and premature mortality from
    lung and heart conditions. People over the age of 65 and those with pre-
    existing chronic heart and lung conditions, such as heart disease and
    asthma, are more likely than others to experience adverse health effects
    from exposure to air pollutants. However, scientists do not clearly
    understand why and how air pollution leads to adverse health effects, and
    many other factors, notably cigarette smoking, also affect the development
    and severity of lung and heart diseases.

    TVA?s decision on how to meet its customers? demands for electricity is
    constrained by federal environmental laws and regulations, as well as
    internal policies. In recent years, TVA relied on coal to generate 62
    percent of its electricity and on nuclear power, hydropower, and other
    sources, in that order, to generate the remaining 38 percent. In 2000, TVA?s
    peak capacity to generate electricity was 29.5 gigawatts (a gigawatt is a
    million kilowatts). TVA estimates that its peak demand for electricity will
    grow about 1. 7 percent each year between 2001 and 2010. To meet this level,
    TVA will have to plan for an additional one- half a gigawatt increase each
    year- the equivalent of building an average- sized power plant every year.
    TVA can do so by purchasing power, constructing new plants, and providing
    incentives to its customers to reduce their peak demand.

    3 In this report we use the term ?chronic lung disease? to refer to chronic
    obstructive pulmonary disease, an umbrella term that includes asthma,
    bronchitis, emphysema, and other chronic lung diseases. Respiratory
    Illnesses

    TVA?s Plans to Reduce Emissions

    Page 7 GAO- 01- 658 Air Pollution

    Although TVA?s coal consumption increased from 34 million tons in 1990 to 40
    million tons in 1999, its emissions of sulfur dioxide (which can be
    transformed into visibility- reducing sulfate particles) declined 30
    percent. To achieve this reduction, TVA, among other actions, switched to
    coals with lower sulfur contents and installed equipment called ?scrubbers?
    to remove sulfur dioxide from exhaust gases. TVA estimates that such
    emissions will decline 36 percent between 1999 and 2005. TVA?s emissions of
    nitrogen oxide (an ozone precursor) were relatively stable during the 1990s;
    however, it estimates that its emissions of nitrogen oxides- during the
    warm- weather months when ozone levels peak- will decline 70 percent between
    1999 and 2005. To achieve this reduction, TVA is, among other actions,
    spending about $1 billion to install ?selective catalytic reduction?
    devices- which remove nitrogen oxides from the exhaust gases- at some of its
    coal units.

    We provided a draft of this report for review and comment to the Departments
    of Agriculture, Health and Human Services, and the Interior; EPA; and TVA.
    We received letters from the Department of the Interior, EPA, and TVA, which
    are reprinted, along with our comments, as appendixes I through III,
    respectively. Those three agencies, as well as the Department of Agriculture
    and the Centers for Disease Control and Prevention (part of the Department
    of Health and Human Services) provided technical and clarifying comments,
    which we incorporated where appropriate. We did not receive comments from
    the National Institutes of Health (another part of the Department of Health
    and Human Services).

    The agencies generally agreed with the facts and analysis we presented. The
    Department of the Interior said that our narrative description of visibility
    conditions is accurate. However, it also said that the methodology it uses
    to calculate visibility conditions is currently under review and that some
    of the data we presented may be affected by this review. EPA also told us
    about this review.

    Similarly, EPA provided additional data on changes in the amount of airborne
    sulfate particles, an indicator of visibility. EPA said that a 12 percent
    decrease in sulfate particles was measured at a site about 100 miles
    northeast of Great Smoky Mountains National Park between the periods of 1990
    through 1992 and 1998 through 2000. EPA did not provide comparable data for
    Great Smoky Mountains National Park. Agency Comments

    Page 8 GAO- 01- 658 Air Pollution

    EPA noted the overall appropriateness of how we presented the current
    understanding of the health risks from the pollutants that we examined. EPA
    and TVA commented that our location- specific analysis of death rates should
    be viewed with caution because of the many factors that influence the
    development and severity of respiratory illness. We agree.

    To analyze trends in visibility and ozone, we interviewed officials from,
    and reviewed studies and other documents prepared by, the Department of the
    Interior?s National Park Service, the Department of Agriculture?s Forest
    Service, EPA, and TVA, as well as recent scientific literature. We also
    interviewed representatives of, and reviewed studies and other documents
    prepared by, state officials in North Carolina and Tennessee and the
    Southern Appalachian Mountains Initiative- a voluntary partnership of
    federal and state agencies, industry, academia, environmental groups, and
    interested public participants.

    To analyze trends in respiratory illnesses, we reviewed recent scientific
    literature and contacted the Centers for Disease Control and Prevention, a
    unit within the Department of Health and Human Services, and EPA health
    researchers to ascertain the availability of data on health outcomes
    associated with exposure to air pollution. We focused our analysis on
    mortality data because they were available for the nation as a whole and for
    the counties in North Carolina and Tennessee- the two states that border the
    park. We also focused on death from all causes and on death from pneumonia/
    influenza and chronic lung disease, two sets of illnesses that many studies
    associate with exposure to air pollution. We obtained national data from the
    Department?s National Center for Health Statistics and state and county data
    from the North Carolina and Tennessee health agencies.

    To describe trends in areas near the park, we divided counties in each state
    into regions used by the state agencies responsible for air quality
    monitoring and selected the region in each state that borders the park. To
    analyze the data for deaths from all causes and from selected respiratory
    illnesses, we used the same statistical procedures and significance tests
    that the National Center for Health Statistics uses to develop national
    death rates. To calculate death rates for comparison between the two states
    and the nation we used the 1940 standard population, the current practice of
    the National Center for Health Statistics. For the comparison between county
    clusters and the states, we used the 2000 standard population, the current
    practice of the North Carolina State Center for Health Statistics. Scope and

    Methodology

    Page 9 GAO- 01- 658 Air Pollution

    Although we did not independently verify the data obtained from the federal
    agencies and other sources, we used the same emissions and mortality data
    that federal and state agencies and other analysts generally use. We
    performed our work from October 2000 through May 2001 in accordance with
    generally accepted government auditing standards.

    We are sending copies of this report to the Chairman and Ranking Member,
    Committee on Appropriations, United States Senate; the Chairman and Ranking
    Minority Member, Committee on Appropriations, House of Representatives; the
    Chairman and Ranking Member, Committee on Governmental Affairs, United
    States Senate; the Chairman and Ranking Minority Member, Committee on
    Government Reform, House of Representatives; Representative Zach Wamp and
    other interested Members of Congress; the Honorable Ann M. Veneman,
    Secretary of Agriculture; the Honorable Tommy G. Thompson, Secretary of
    Health and Human Services; the Honorable Gale A. Norton, Secretary of the
    Interior; the Honorable Christine Todd Whitman, Administrator, EPA; the
    Honorable Skila Harris and the Honorable Glenn L. McCullough, Jr., Members
    of the Board, TVA; and other interested parties. We will also make copies
    available to others upon request.

    Questions about this report should be directed to me or David Marwick at
    (202) 512- 3841. Key contributors to this report were Gene M. Barnes,
    Richard A. Frankel, and Cheryl A. Williams.

    John B. Stephenson Director, Natural Resources and Environment

    Briefing Section I: Overview Page 10 GAO- 01- 658 Air Pollution

    Briefing Section I: Overview

    Air Pollution and Respiratory Illnesses in and Near the Great Smoky
    Mountains National Park

    Briefings for Chairman Charles H. Taylor Subcommittee on Legislative House
    of Representatives March 1 and 22, 2001

    Briefing Section I: Overview Page 11 GAO- 01- 658 Air Pollution

    As directed by House Report 106- 1033 and as discussed with Chairman Charles
    H. Taylor, we focused on four issues:

     visibility, which is important to people who live near the park, visitors
    from other areas who travel to enjoy the park?s vistas, and others;  ozone,
    which can harm people, animals, and plants;  respiratory illnesses, a
    manifestation of the harm from ozone and other

    causes; and  Tennessee Valley Authority?s (TVA) plans to reduce its
    emissions of sulfur

    dioxide and nitrogen oxides. To do this work we interviewed officials from,
    and reviewed studies and other documents prepared by, the following five
    federal agencies:

     the Department of Agriculture?s Forest Service,  the Department of Health
    and Human Services? Centers for Disease

    Control and Prevention and National Institutes of Health,  the Department
    of the Interior?s National Park Service,  the Environmental Protection
    Agency (EPA), and  TVA.

    We also collected information from North Carolina and Tennessee state
    agencies, non- profit groups, and others.

    Briefing Section II: Visibility Page 12 GAO- 01- 658 Air Pollution

    Briefing Section II: Visibility

    Visibility Source: National Park Service

    Visibility in the Park on the Worst Days Remained Poor During the 1990s

    Briefing Section II: Visibility Page 13 GAO- 01- 658 Air Pollution

    Reduced visibility is caused by small particles in the air. In the east
    generally, and in the park specifically, most of these particles are
    sulfates, which are formed in the air from sulfur dioxide gas.

    In analyzing visibility, we focused on the worst days, typically summer
    days, because it is then that reduced visibility is the most detrimental to
    enjoyment of the park. We obtained data for visibility on the worst days in
    Great Smoky Mountains National Park and two others parks selected for
    comparison. The other parks are Shenandoah in Virginia and Acadia in Maine.

    On the worst- visibility days (those ranked in the lowest one- fifth of all
    days for each year), visibility in the park remained poor between 1989 and
    1999, ranging between 12 and 15 miles, according to data from the National
    Park Service. Visibility remained essentially unchanged on average days and
    on the best- visibility days. Between 1989 and 1999, visibility on the worst
    days in Shenandoah generally stayed at about 12 miles, while it improved in
    Acadia to 22 miles.

    Briefing Section II: Visibility Page 14 GAO- 01- 658 Air Pollution

    Visibility Source: EPA

    Electric Utilities Produce Two- Thirds of National Sulfur Dioxide Emissions

    Briefing Section II: Visibility Page 15 GAO- 01- 658 Air Pollution

    Sulfate particles, in turn, are formed primarily from sulfur dioxide gas.
    For the nation, the largest source of sulfur dioxide gas emissions in 1999
    was the electric utility industry, which accounted for about 67 percent of
    the total, according to EPA?s estimates. The transportation sector accounted
    for 7 percent and other sources accounted for the remaining 26 percent.

    The 1990 amendments to the Clean Air Act require that sulfur dioxide
    emissions by electric utilities be reduced between 1995 and 2010. Electric
    utility emissions of sulfur dioxide declined substantially during the 1990s-
    from 16. 2 million tons in 1989 to 12. 7 million tons in 1999.

    Under these amendments, these emissions are scheduled to decline to just
    under 9 million tons a year in 2010.

    Briefing Section II: Visibility Page 16 GAO- 01- 658 Air Pollution

    Visibility Note: Color differences denote different times at which plants
    must meet requirements under the Clean Air Act Amendments of 1990 Source:
    EPA

    Many Power Plants Are Close to the Park

    Briefing Section II: Visibility Page 17 GAO- 01- 658 Air Pollution

    Atmospheric studies have found that sulfate produced from power plant
    emissions can travel many hundreds of miles. Therefore, the
    visibilityreducing sulfates that reach the park can come from sources near
    and far. Dozens of power plants are located in the eastern states.

    National Park Service analysts recently traced the paths of the air masses
    that delivered sulfate particles to the park for the 3 days before reaching
    the park; they did this for both high- and low- visibility days, between May
    and September in the years 1995 through 1999. They found that on
    highvisibility days (that is, days with low levels of particulates), the air
    masses arrived from nearly all directions of the compass, although very few
    air masses arrived from the northeast. The air masses had often traveled
    many hundreds of miles, with some of them starting their 3- day journey as
    far away as Canada, the Gulf of Mexico, or the Atlantic Ocean. Because they
    traveled so quickly, they spent little time over any particular area,
    including the industrial Midwest and other areas with high levels of sulfur
    dioxide emissions.

    Conversely, they found that on low- visibility days (that is, days with high
    levels of particulates), the air masses generally had traveled shorter
    distances, with most of them starting their 3- day journey just a few
    hundred miles away from the park and often following more roundabout
    trajectories, which kept them over particular areas for longer times. The
    predominant majority of the air masses started over the industrial Midwest,
    or spent considerable time there, which allowed them to accumulate
    substantial quantities of sulfur dioxide. A lesser, but still significant,
    portion of the air masses on these low- visibility days arrived from the
    region west of the park, while few air masses arrived from the east and
    south on such days.

    Research continues on the sources of the air pollution that affects the
    park. The authors of a 1990 study told us that they are updating their study
    and hope to publish their results next year. Also, the Southern Appalachian
    Mountains Initiative- a voluntary partnership of federal and state agencies,
    industry, academia, environmental groups, and interested public
    participants- is analyzing the issue and also hopes to publish its results
    next year.

    Briefing Section III: Ozone Page 18 GAO- 01- 658 Air Pollution

    Briefing Section III: Ozone

    Ozone Note: Data for Great Smoky Mountains National Park are for Look Rock
    Source: National Park Service for Great Smoky Mountains and Shenandoah for
    1999 and 2000; otherwise, EPA

    Exceedances of the Proposed Ozone Standard in the Park Increased in the
    1990s, but Fell Sharply in 2000

    Briefing Section III: Ozone Page 19 GAO- 01- 658 Air Pollution

    Ground- level ozone is not emitted. It is produced from nitrogen oxides and
    volatile organic compounds in the presence of sunlight. Heat accelerates the
    chemical processes through which ground- level ozone is formed.

    Pursuant to the Clean Air Act, EPA establishes public health standards for
    various air pollutants. For ozone, EPA has established a threshold of 0.08
    parts per million, measured over an 8- hour period. An ?exceedance? is
    recorded on any day when a monitor measures ozone levels that exceed this
    threshold. (The state of North Carolina has adopted the federal standard.)

    We analyzed the number of exceedances during 1990 through 2000 for the Great
    Smoky Mountains and Shenandoah national parks and through 1999 for Acadia
    National Park. (Data for Acadia for 2000 were not available at the time of
    our review.).

     In the early and mid- 1990s, the number of exceedances rose moderately in
    the park and was generally stable for the other two locations.  In 1997-
    99, the number of exceedances was much higher for the Great

    Smoky Mountains and Shenandoah but remained level for Acadia.  In 2000, the
    number of exceedances for the Great Smoky Mountains and

    Shenandoah fell sharply to about the 1996 level. It is believed that this
    decline in the number of exceedances is related to the cooler summer
    temperatures in 2000.

    Briefing Section III: Ozone Page 20 GAO- 01- 658 Air Pollution

    Source: EPA Ozone

    The Transportation Sector Produces Over Half of National Nitrogen Oxide
    Emissions

    Briefing Section III: Ozone Page 21 GAO- 01- 658 Air Pollution

    In 1999, the transportation sector emitted 55.5 percent of nitrogen oxides
    nationwide, according to EPA?s estimates. This includes cars and trucks
    (called on- road vehicles), as well as farm equipment and other engines
    (called non- road sources). Electric utilities accounted for 22. 5 percent
    and other sources, the remaining 22 percent.

    The transportation sector?s emissions of nitrogen oxides increased from 12.2
    million tons in 1989 to 14. 1 million tons in 1999- a rise of 16 percent.
    This increase is less than the 28- percent increase during that same period
    in the number of miles traveled by cars, trucks, and other vehicles,
    according to the Federal Highway Administration.

    Within the transportation sector, cars, trucks, and other on- road vehicles
    emitted 8.6 million tons in 1999, according to EPA. Farm equipment, lawn and
    garden equipment, and other non- road sources emitted the remaining 5. 5
    million tons.

    National Park Service analysts recently traced the paths of the air masses
    that arrived at the park on the lowest and highest ozone days from 1995
    through 1999; specifically, they traced the masses for the 3 days before
    they reached the park. On the low- ozone days (those ranked among the 15
    percent with the lowest concentrations during the 5- year period), the air
    masses arrived from all directions, with a slight preponderance from the
    south and relatively few traveling over the northeast (New England to
    Pennsylvania). A substantial proportion of the air masses traveled long
    distances within 3 days; many traveled from the Atlantic Ocean and Gulf of
    Mexico, and a few traveled from the west (the Plains states) and the north
    (Canada).

    On the high- ozone days (every day when an exceedance of the 8- hour
    standard was recorded in the park), the air masses traveled substantially
    shorter distances within 3 days. Virtually none of the paths extended back
    to the Atlantic Ocean or Gulf of Mexico. Even on land, the air masses
    traveled substantially shorter distances within 3 days than on low- ozone
    days, but they still traveled hundreds of miles, and a much smaller
    proportion arrived from south of the park. Thus, on high- ozone days, most
    air masses arrived in the park from the north and northwest- generally the
    industrial Midwest- with fewer air masses arriving from the west and south
    and very few arriving from the east.

    Briefing Section III: Ozone Page 22 GAO- 01- 658 Air Pollution

    Note: Data presented for the 15 states with the largest volume of natural
    Volatile Organic Compounds Source: GAO analysis of EPA data

    Ozone Southeastern States Produced Abundant Natural Volatile Organic
    Compounds per Square Mile, 1997

    Briefing Section III: Ozone Page 23 GAO- 01- 658 Air Pollution

    Volatile organic compounds, which are another ozone precursor, originate
    from:

     human activities, such as various hydrocarbons that are emitted when
    gasoline and other fuels evaporate or are burned incompletely, and  natural
    sources, such as isoprene from trees.

    In 1997, the amount of naturally emitted volatile organic compounds (28
    million tons) nationwide was greater than the amount released through human
    activities (19 million tons), according to EPA.

    The Southeast, because of its forests, is particularly rich in the naturally
    produced compounds. Of the 15 states with the largest total amount of these
    compounds, the 8 states with the greatest concentrations- pounds per square
    mile of land area- are all located in the Southeast. Thus, there is an
    abundance of naturally occurring volatile organic compounds in these areas
    to react with whatever nitrogen oxides are produced to form ozone. Because
    the formation of ozone in such a geographic area is constrained by the
    available amount of nitrogen oxides (called NOx), such an area is described
    as being ?NOx limited.?

    Briefing Section IV: Respiratory Illnesses Page 24 GAO- 01- 658 Air
    Pollution

    Briefing Section IV: Respiratory Illnesses

    Respiratory Illnesses 50 Years of Research Associates Health Problems With
    Air Pollution

    * Increasing evidence associates air particles and ozone with respiratory
    problems.

     Small particles seem to be particularly harmful to human health.

     Air quality is one of many factors that influence the development and
    severity of disease.

     Research continues to try to better understand the causal link.

    Briefing Section IV: Respiratory Illnesses Page 25 GAO- 01- 658 Air
    Pollution

    Over the past 50 years, epidemiological and other studies both here and
    abroad have consistently found that exposure to fine air particles and ozone
    is associated with respiratory and other health problems. Specifically,
    health effects- such as hospital admissions and premature mortality-
    increase as concentrations of ozone or airborne particles increase. These
    effects are seen most strongly in people with existing heart and lung
    conditions. Small particles seem to be particularly harmful to human health,
    in part because they can be inhaled deeply into the lungs and may carry
    other pollutants on their surfaces.

    A range of factors influences the development and severity of lung and heart
    conditions, including exposure to allergens or pollutants, genetics, and
    behavior. For example, cigarette smoking is a primary cause of chronic lung
    disease, other than asthma, and lung cancer.

    Epidemiological studies alone are limited in their ability to prove
    causality. However, they can suggest relationships for further scientific
    research, as in the case of cigarette smoking and heart disease. The exact
    causal link between exposure to air pollution and adverse health effects is
    not completely understood and research continues to try to learn the
    mechanisms by which pollutants harm human health and which kinds of airborne
    particles are the most harmful.

    Briefing Section IV: Respiratory Illnesses Page 26 GAO- 01- 658 Air
    Pollution

    Respiratory Illnesses Note: Differences in death rates are statistically
    significant Source: National Center for Health Statistics, and GAO analysis
    of unpublished data Death Rates for All Causes Were Higher in North

    Carolina and Tennessee Than in the United States

    Briefing Section IV: Respiratory Illnesses Page 27 GAO- 01- 658 Air
    Pollution

    To analyze trends in health, we used data on mortality- deaths- because
    comparable state- specific and national data on other health outcomes, such
    as hospitalizations, were not available. We adjusted all death rates for age
    to control for differences in the age distribution of the different
    populations. Age adjustment allows comparisons of rates over time and
    between groups; however, the rates are not adjusted for other influences,
    such as rates of smoking and socioeconomic levels.

    We made three sets of comparisons for death rates from all causes and for
    deaths from chronic lung disease from 1991 through 1998:

    1. We compared the nation as a whole to the states of North Carolina and
    Tennessee.

    2. We compared the entire state of North Carolina with the 19 counties that
    constitute western North Carolina, as categorized by the state?s Department
    of Environment and Natural Resources.

    3. We compared the entire state of Tennessee with the 16 counties in eastern
    Tennessee, as categorized by the state?s Department of Environment and
    Conservation.

    In the first set of comparisons, we found that from 1991 through 1998
    overall death rates were consistently higher in North Carolina than in the

    United States as a whole, and higher in Tennessee than in North Carolina.
    overall deaths rates declined by 8 percent for the United States as a whole

    and by 5 percent for North Carolina, and essentially stayed the same for
    Tennessee.

    Briefing Section IV: Respiratory Illnesses Page 28 GAO- 01- 658 Air
    Pollution

    Respiratory Illnesses Note: Differences in death rates are statistically
    significant Source: National Center for Health Statistics, and GAO analysis
    of unpublished data

    Death Rates for Chronic Lung Disease Were Higher in North Carolina and
    Tennessee Than in the United States

    Briefing Section IV: Respiratory Illnesses Page 29 GAO- 01- 658 Air
    Pollution

    Two sets of respiratory illnesses- chronic lung disease (a term applied to
    several related conditions including asthma, chronic bronchitis, and
    emphysema) and pneumonia/ influenza- have consistently been associated with
    exposure to ozone and airborne particles. In the United States, these two
    sets of respiratory illnesses have been the fourth and sixth leading causes
    of death since 1991. Each year they together account for about 9 percent of
    all deaths.

    For chronic lung disease, we found that between 1991 and 1998  the rates
    for North Carolina were usually higher than the rate for the

    United States as a whole, and the rates for Tennessee were always higher
    than the rates for North Carolina;  during the time period, these rates
    generally increased, which is counter to

    the general decline in death rates; and  the increases in rates varied- 6
    percent for the United States but about

    19 percent for North Carolina and 20 percent for Tennessee. The trends for
    pneumonia/ influenza followed similar patterns. Death rates in North
    Carolina and Tennessee were higher than the national rates, and the rates in
    Tennessee were usually higher than the rates in North Carolina. Moreover,
    death rates increased in each state by about 10 percent, but decreased
    slightly for the nation.

    Briefing Section IV: Respiratory Illnesses Page 30 GAO- 01- 658 Air
    Pollution

    Respiratory Illnesses Note: Differences in death rates are statistically
    significant Source: GAO analysis of unpublished North Carolina and Tennessee
    data

    Death Rates for All Causes Were Lower in Areas Adjacent to the Park Than in
    Those States as a Whole

    Briefing Section IV: Respiratory Illnesses Page 31 GAO- 01- 658 Air
    Pollution

    To analyze trends in health problems within each state, we compared age-
    adjusted death rates for the states of North Carolina and Tennessee with
    death rates for clusters of counties that border the park. In analyzing
    death rates for the entire state of North Carolina versus the 19 counties in
    western North Carolina, we found that

     overall death rates were consistently higher for the state than for
    western North Carolina  during the period, death rates dropped by 3 percent
    for the state and

    2 percent for western North Carolina. Results for the entire state of
    Tennessee versus the 16 counties in eastern Tennessee were similar, except
    that death rates rose slightly from 1991 through 1998. We found that

     overall death rates were consistently higher for the state than for
    eastern Tennessee and  during the period, death rates increased by 3
    percent for the state and

    4 percent for eastern Tennessee. To enhance the soundness of our analysis,
    we compared deaths occurring over 2- year periods, rather than single years.

    Briefing Section IV: Respiratory Illnesses Page 32 GAO- 01- 658 Air
    Pollution

    Respiratory Illnesses Note: Differences in death rates are statistically
    significant Source: GAO analysis of unpublished North Carolina and Tennessee
    data

    Death Rates for Chronic Lung Disease Increased in North Carolina and
    Tennessee Between 1991 and 1998

    Briefing Section IV: Respiratory Illnesses Page 33 GAO- 01- 658 Air
    Pollution

    Finally, we focused on the two respiratory illnesses- chronic lung disease
    and pneumonia/ influenza- in the states and county clusters. For chronic
    lung disease:

     there were increases in age- adjusted mortality during this period in both
    states- about 19 percent in North Carolina and about 20 percent in
    Tennessee,  the rate per 100, 000 deaths increased slightly faster in
    western North

    Carolina than in the state as whole, and  the rate in eastern Tennessee
    increased more slowly than did the rate for

    the entire state. The death rates for pneumonia/ influenza (not shown here)
    were lower than the rates for chronic lung disease but increased in both
    states about 10 percent. The rate in western North Carolina increased more
    slowly than did the state rate and the rate in eastern Tennessee increased
    somewhat more rapidly.

    Research is ongoing, in this country and abroad, to address the scientific
    uncertainties of the causal links between exposure to air pollution and harm
    to human health.

    Briefing Section V: TVA?s Emissions Page 34 GAO- 01- 658 Air Pollution

    Briefing Section V: TVA?s Emissions

    TVA?s Emissions Source: TVA

    TVA Relied on Coal to Generate 62 Percent of Its Electricity, 1996- 2000

    Briefing Section V: TVA?s Emissions Page 35 GAO- 01- 658 Air Pollution

    TVA?s choices in generating power are constrained by laws, regulations, and
    internal policies. For example,

     The Clean Air Act limits certain emissions from coal- fired power plants.
     The TVA Act provides that the generation of power from hydroelectric

    units is a lower priority than navigation and flood control.  An internal
    TVA policy limits the time period when TVA can draw down

    the lakes (reservoirs) that it manages for flood control and in the process
    generate hydropower.

    The longer the time frame, the more TVA must and can do to comply with laws,
    regulations, and policies. Because of the multiple purposes in the TVA Act
    and elsewhere, and because of other laws, regulations, and policies, TVA
    faces a difficult balancing act between its operating priorities and the
    often conflicting or competing user needs.

    To generate electricity TVA relies primarily on coal. Between 1990 and 1999
    TVA?s coal consumption increased 18 percent. In the most recent 5year period
    from 1996 through2000, coal accounted for 62 percent, nuclear power
    accounted for 28 percent, hydroelectric power accounted for 9 percent, and
    other sources accounted for the remaining 1 percent.

    During that 5- year period, the amount of nuclear power increased from 35.4
    to 46. 9 million kilowatt- hours, and its share of the total increased from
    24 percent in 1996 to 31 percent in 2000. In the same period, the amount of
    hydroelectric power fluctuated, largely because of changes in water levels;
    it generally declined from 16. 1 to 8. 8 million kilowatt- hours, and its
    share of the total declined from 11 percent in 1996 to 6 percent in 2000.

    Briefing Section V: TVA?s Emissions Page 36 GAO- 01- 658 Air Pollution

    TVA Cut Its Sulfur Dioxide Emissions During the 1990s and Expects to Cut
    More by 2005

    Source: TVA TVA?s Emissions

    Briefing Section V: TVA?s Emissions Page 37 GAO- 01- 658 Air Pollution

    TVA?s emissions of sulfur dioxide declined 30 percent from 1989- 99. It
    estimates that, as a result of additional steps under way and planned for
    the next decade, its sulfur dioxide emissions will decline an additional 36
    percent between 1999 and 2005. (The percentage reduction reflects TVA?s most
    recent estimate of 2005 emissions, which is not reflected in the figure.)

    Among the steps TVA has taken and plans to take to reduce these emissions
    are:

     burning coals with lower sulfur contents at 51 of its 59 units and
    installing equipment called ?scrubbers? in two units each at the

    Cumberland, Paradise, and Widows Creek plants. 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.

    Briefing Section V: TVA?s Emissions Page 38 GAO- 01- 658 Air Pollution

    TVA?s Emissions Note: The ozone season is May 1 to September 30 Source: TVA

    TVA Expects to Cut Its ?Ozone- Season? Emissions of Nitrogen Oxides Sharply
    by 2005

    Briefing Section V: TVA?s Emissions Page 39 GAO- 01- 658 Air Pollution

    In looking at emissions of nitrogen oxides, we focused on the 5- month
    ?ozone season? (May 1 through Sept. 30) when ozone levels tend to be
    relatively high.

    TVA?s emissions of nitrogen oxide in 1999 were about the same as in 1989. In
    1998, TVA announced plans to invest nearly $1 billion in pollutioncontrol
    equipment. It projects that its ozone- season nitrogen oxide emissions will
    decline about 68 percent between 1999 and 2005. (The percentage reduction
    reflects TVA?s most recent estimate of 2005 emissions, which is not
    reflected in the figure.)

    The planned equipment includes selective catalytic reduction devices for 25
    of its 59 coal- fired units. These devices transform nitrogen oxide
    emissions into harmless nitrogen and water vapor.

    Appendix I: Comments From the Department of the Interior

    Page 40 GAO- 01- 658 Air Pollution

    Appendix I: Comments From the Department of the Interior

    Appendix II: Comments From the Environmental Protection Agency

    Page 41 GAO- 01- 658 Air Pollution

    Appendix II: Comments From the Environmental Protection Agency

    Appendix II: Comments From the Environmental Protection Agency

    Page 42 GAO- 01- 658 Air Pollution

    Appendix III: Comments From the Tennessee Valley Authority

    Page 43 GAO- 01- 658 Air Pollution

    Appendix III: Comments From the Tennessee Valley Authority

    (360077)

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