    [Senate Hearing 107-1011]
    [From the U.S. Government Publishing Office]

                                                           S. Hrg. 107-1011

         HEALTH IMPACTS OF PM-2.5 ASSOCIATED WITH POWER PLANT EMISSIONS

    =======================================================================

                                    HEARING

                                   before the

                   COMMITTEE ON ENVIRONMENT AND PUBLIC WORKS
                              UNITED STATES SENATE

                          ONE HUNDRED SEVENTH CONGRESS

                                 SECOND SESSION

                                   __________

                                OCTOBER 2, 2002

                                   __________

      Printed for the use of the Committee on Environment and Public Works

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                   COMMITTEE ON ENVIRONMENT AND PUBLIC WORKS

                          ONE HUNDRED SEVENTH CONGRESS
                                 SECOND SESSION
                      JAMES M. JEFFORDS, Vermont, Chairman
    MAX BAUCUS, Montana                  BOB SMITH, New Hampshire
    HARRY REID, Nevada                   JOHN W. WARNER, Virginia
    BOB GRAHAM, Florida                  JAMES M. INHOFE, Oklahoma
    JOSEPH I. LIEBERMAN, Connecticut     CHRISTOPHER S. BOND, Missouri
    BARBARA BOXER, California            GEORGE V. VOINOVICH, Ohio
    RON WYDEN, Oregon                    MICHAEL D. CRAPO, Idaho
    THOMAS R. CARPER, Delaware           LINCOLN CHAFEE, Rhode Island
    HILLARY RODHAM CLINTON, New York     ARLEN SPECTER, Pennsylvania
    JON CORZINE, New Jersey              PETE V. DOMENICI, New Mexico
                     Ken Connolly, Majority Staff Director
                     Dave Conover, Minority Staff Director

                                C O N T E N T S

                                  ----------
                                                                       Page

                                OCTOBER 2, 2002
                               OPENING STATEMENTS

    Bond, Hon. Christopher S., U.S. Senator from the State of
      Missouri.......................................................     4
    Jeffords, Hon. James M., U.S. Senator from the State of Vermont..     1

                                   WITNESSES

    Levy, Jonathan, assistant professor, Environmental Health and
      Risk Assessment, Department of Environmental Health, Harvard
      School of Public Health........................................    19
        Prepared statement...........................................    59
    O'Keefe, Robert, vice president, Health Effects Institute........    13
        Prepared statement...........................................    54
    Rose, Ben, executive director, The Green Mountain Club, Inc......    17
        Prepared statement...........................................    41
    Samet, Jonathan M., M.D., professor and chairman, Department of
      Epidemiology, Bloomberg School of Public Health, Johns Hopkins
      University.....................................................    11
        Prepared statement...........................................    29
    Wyzga, Ronald E., technical executive and program manager,
      Electric Power Research Institute..............................    15
        Prepared statement...........................................    43

                              ADDITIONAL MATERIAL

    Articles:
        Lung Cancer, Cardiopulmonary Mortality, and Long-term
          Exposure to Fine Particulate Air Pollution................139-148
        The Concentration--Response Relation between PM2.5
          and Daily Deaths..........................................149-153
    Charts:
        American Thoracic Society, 1996..............................    33
        Attributes of Epidemiological Studies of Coal-Fired Power
          Plant (CPP) Emissions...................................... 34-39
        Human Health Benefits of Reducing Fine Particulate Matter:
          Mortality-Related Benefits.................................     9
        Human Health Benefits of Reducing Fine Particulate Matter:
          Non-Mortality-Related Benefits.............................    10
        PM2.5 and 8-hour Ozone Standards Attainment
          (current data).............................................     7
        PM2.5 and 8-hour Ozone Standards Attainment (2020)     8
        Unnecessary Deaths, Lives Saved..............................     3
    Fact Sheet, Aries: Aerosol Research Inhalation Epidemiology Study 49-53
    Reports:
        Environmental Health Perspectives, in press, The Importance
          of Population Susceptibility for Air Pollution Risk
          Assessment: A Case Study of Power Plants Near Washington,
          DC.........................................................87-124
        Review of Particulate-Related Health Impacts of Eight
          Electric Utility Systems, Jonathan Levy, June 2002......... 65-86
    Technical Paper, Modeling the Benefits of Power Plant Emission
      Controls in Massachusetts, Jonathan I. Levy and John D.
      Spengler, Department of Environmental Health, Harvard School of
      Public Health, Boston, MA.....................................125-138

         HEALTH IMPACTS OF PM-2.5 ASSOCIATED WITH POWER PLANT EMISSIONS

                                  ----------

                           WEDNESDAY, OCTOBER 2, 2002

                                   U.S. Senate,
             Committee on Environment and Public Works,
                                                Washington, DC.
        The committee met, pursuant to notice, at 2:02 p.m. in room
    406, Senate Dirksen Building, Hon. Jim Jeffords (chairman of
    the committee) presiding.
        Present: Senators Jeffords and Bond.

    OPENING STATEMENT OF HON. JAMES M. JEFFORDS, U.S. SENATOR FROM
                          THE STATE OF VERMONT

        Senator Jeffords. The hearing will come to order.
        Good afternoon, everyone. Thank you all for being here
    today. I'm glad to have this chance to come together to learn
    more about the health impacts of air pollution.
        Not long ago, I was shocked to hear that as many as 50,000
    people or more may be dying prematurely every year from the
    exposure to fine particulate matter, also known as
    PM2.5 or sometimes as soot. This chart which we have
    up is based on the work done by many researchers, illustrating
    this terrible situation. More people are dying from the dirty
    air than are killed in auto accidents, from breast cancer and
    other causes. Most of this pollution comes from the burning of
    fossil fuel. This combustion creates tiny, almost microscopic
    particles from solid matter and gases. Then the wind spreads
    them afar and wide, sometimes thousands of miles. A few years
    ago, researchers documented fine particles coming from China
    and being deposited in the Pacific Northwest. More recently,
    Asian brown cloud has been in the news because of the
    continent-sized nature of this smog, soot and air toxics
    phenomenon.
        Luckily, our problems are not on the scale of the Asian
    brown cloud any more. We can thank the Clean Air Act for that.
    The Act has been very effective in reducing pollution to date,
    and the Act provides for even greater reduction in the future
    if it is fully, faithfully and swiftly implemented. I hope that
    it will be, but the signs haven't been too promising as of
    late. Since the 1990 amendments, information on the health
    effects of fine particulate pollution have increased
    dramatically. Unfortunately, most of the news is bad.
        In March, the Journal of the American Medical Association
    reported on a study which found that for increasing levels of
    fine particulate matter, there is a corresponding increased
    risk of mortality from all causes. There was an even greater
    risk associated with cardiopulmonary and lung cancer mortality.
    These findings mean that there are practically 130 million
    people who live in areas polluted by fine particles who have
    about the same increased risk of dying from heart or lung
    disease as people who live with cigar or cigarette smokers and
    regularly experience second-hand smoke.
        That's just the tip of the iceberg when it comes to the bad
    news. There is substantial and mounting evidence that besides
    death, heart disease or lung cancer, fine particles also cause
    decreased lung function, chronic bronchitis and aggravated
    asthma. Exactly how these particles cause such damage and
    destruction once they get deep down into the lungs is not
    entirely known. But what we do know with some certainty angers
    me. A report from the Clean Air Task Force found that fine
    particle pollution from power plants is responsible for as many
    as 30,000 deaths annually. As you can see from the chart on the
    left side, that's more than people who die from homicide or
    drunk driving accidents every year. On the right side, the
    chart shows how many people we could save by drastically
    cutting pollution from power plants. Coincidentally, those are
    the lives saved annually by the reductions in the Clean Air
    Act.
    [GRAPHIC] [TIFF OMITTED] T3723.001

        Most of that fine particle pollution appears to be coming
    from older, grandfathered power plants. Those are the ones
    built before 1972 that were largely exempt from applying new
    source performance standards. These are the same plants that
    are opposing the Government's efforts to make them apply new,
    cleaner technology when they make changes to their facilities.
    The Administration is now thinking of making their loophole
    even larger through changes in the new source review
    regulations. That is exactly the wrong direction. We cannot
    afford to increase pollution in that way. We certainly cannot
    afford to continue wasting the lives of people every year
    because of pollution that is controllable and coming from
    obvious sources in our own back yard.
        We the Congress, the Administration, elected officials,
    have a responsibility to act to prevent harm to the American
    public when we have evidence that the threat exists. The
    terrible attacks of 9/11 took the lives of 2,824 innocent
    people in the World Trade Center. There could not be a clearer
    or more tangible threat to our national security. Our rapid
    response has reached every corner of the world and almost every
    facet of American life. Now it may lead us to an expanded war
    that could be expensive in dollars and lives.
        What troubles me is that we have equal, clear evidence of
    the threat of death and damage occurring annually from fine
    particulate pollution and yet there is no huge call to action
    from most in Congress or the Administration. Every year New
    York City power plant pollution causes 2,290 lives, according
    to the studies we will be discussing today. Saving these lives
    doesn't require war, and it won't cost that much. It just
    requires a commitment to swift action.
        Perhaps our witnesses will give us good news. Maybe the
    threat of the fine particulate pollution is not as bad as the
    headlines and the studies suggest. I hope there's a slim chance
    that's right, because knowingly throwing away lives when we
    know how to save them just doesn't make any sense.
        Senator Bond.

      OPENING STATEMENT OF HON. CHRISTOPHER S. BOND, U.S. SENATOR
                       FROM THE STATE OF MISSOURI

        Senator Bond. Mr. Chairman, thank you very much for calling
    this hearing to examine the health risks associated with fine
    particle air emissions. I appreciate the opportunity to come
    and join you with the chart presentation, because I'm going to
    have some charts myself. I thought we might as well keep it
    visual as well as audible.
        My real regret is that this committee will end the session
    by refusing to pass three pollutant legislation that would save
    lives by addressing this very problem. According to EPA and
    information you have given, Mr. Chairman, fine particles of
    soot and smoke pose the greatest public health risk of any
    regulated air pollutant. Fine particulates are associated with
    tens of thousands of premature deaths per year in people with
    heart and lung diseases. Such emissions also lead to increased
    hospitalizations, emergency room and doctor visits, medication
    use and delays, numerous days, of missed school and work.
        One major source of fine particulates is the coal-fired
    electric utility industry. Indeed, reports show that full
    implementation by electric utilities of the Federal
    Government's acid rain and smog reduction program in 2007 would
    annually save 5,900 premature deaths and tens of thousands of
    respiratory illnesses associated with just 8 major coal-fired
    utilities. The question for us becomes why is this committee
    passing up the opportunity to mandate further reductions from
    electric utilities of the pollutants that produce particulate
    matter?
        This year, President Bush proposed his Clear Skies
    Initiative to reduce emissions of nitrogen oxides, sulfur
    dioxides, and mercury from electric utilities. Reducing
    emissions of these three pollutants by over two-thirds, as the
    President has called for, would also produce significant fine
    particulate emissions reductions.
        While we have made great strides in reducing air pollution
    since passage of the Clean Air Act in 1970, and the amendments
    in 1990, in which I played a role, we still have further to go.
    Based on the latest data, 173 counties nationwide are likely to
    exceed EPA's PM2.5 fine particle health standard.
    The chart here behind me shows where these counties are. As you
    can see, 157 counties in the East and in California, well
    represented on this committee, and we in Missouri and Illinois
    in the center of the Nation have some as well.
        Passage and implementation of President Bush's Clear Skies
    Initiative would bring 54 additional counties above and beyond
    what will be achieved with existing programs into compliance
    with the fine particle standard. This chart here shows the
    improvement the Clear Skies Initiative would bring to over 21
    million people. You can see that only a handful of counties
    would remain out of compliance with the PM2.5 health
    standard. These are the ozone non-
    attainment counties, the orange are the particulate matter 2.5
    non-attainment. Red are both non-attainment counties. This is
    the base case for 2020. This is what the Clear Skies Initiative
    would do, and reduce the number of areas out of compliance with
    either or both by a significant number by 2020.
        The mortality-related benefits from reducing fine particles
    under President Bush's plan are equally striking. This chart
    describes the number of lives saved under two different
    assumptions analyzing the President's plan. By 2010, Clear
    Skies would prevent annually between 3,800 and 6,000 premature
    deaths related to fine particles. By 2020, President Bush's
    plan would prevent annually between 7,000 and 12,000 premature
    deaths. Mr. Chairman, the health of my constituents in Missouri
    would clearly benefit under the Clear Skies initiative.
    Beginning in 2020, over $2 billion of annual benefits of Clear
    Skies would occur. Missourians would face 300 fewer premature
    deaths, approximately 200 fewer cases of chronic bronchitis,
    approximately 11,000 fewer days with asthma attacks.
    Missourians would suffer 300 fewer hospital days and emergency
    stays and emergency visits, 46,000 fewer days of work lost,
    360,000 fewer total days with respiratory-related symptoms.
        This is legislation that should be passed. We're not taking
    advantage, we're not seeking an agreement to reduce NOx, SOx
    and mercury. The committee is failing to take action on this
    legislation that would address the very health risks this
    hearing will examine for an unrelated reason. Some people want
    to hold up work on reducing the particle pollution in order to
    make a political point about climate change, global warming and
    carbon dioxide. Count me on the health side of that equation.
        Some want to preserve the global warming issue for future
    elections, including the election in 2004. I urge my
    colleagues, as we listen to today's testimony on the health
    risks, to think of ways we can move forward on the three
    pollutant legislation. The President has put forward a plan
    that will save and benefit thousands. The chairman has his own
    plan. The opportunity exists for compromise, and I hope that we
    will do so next year, and I thank the chair.
        Senator Jeffords. Thank you for your excellent statement.
        Our first witness is Dr. Jonathan M. Samet, co-director of
    the Risk Sciences and Public Policy Institute, and professor
    and chair of the Department of Epidemiology, Johns Hopkins
    Bloomberg School of Public Health, Baltimore, MD. Please
    proceed. Nice to have you here.

    [GRAPHIC] [TIFF OMITTED] T3723.002

    [GRAPHIC] [TIFF OMITTED] T3723.003

    [GRAPHIC] [TIFF OMITTED] T3723.004

    [GRAPHIC] [TIFF OMITTED] T3723.005

        STATEMENT OF DR. JONATHAN M. SAMET, M.D., PROFESSOR AND
       CHAIRMAN, DEPARTMENT OF EPIDEMIOLOGY, BLOOMBERG SCHOOL OF
                PUBLIC HEALTH, JOHNS HOPKINS UNIVERSITY

        Dr. Samet. Thank you, Chairman Jeffords, Senator Bond,
    ladies and gentlemen. Thank you for the opportunity to speak
    with you today about the health effects of particulate matter,
    and particularly fine particulate matter in the air arising
    from power plant emissions.
        Just briefly as background, my training includes
    specialization in internal medicine and pulmonary diseases,
    quite relevant to the topic we're discussing, as well as
    epidemiology. I've been involved in the studies of the health
    effects of air pollution for more than 20 years, initially
    doing work in Steubenville, OH, and then in western
    Pennsylvania, where we carried out a series of studies to
    assess the effects of large coal-fired power plants on the
    respiratory health of women and children in the surrounding
    communities.
        More recently, I've been involved in a project funded by
    the Health Effects Institute known as the National Morbidity,
    Mortality and Air Pollution Study. We've been using publicly
    available data to try and provide a national picture of the
    health effects of air pollution.
        I've served as a consultant member of the Clean Air
    Scientific Advisory Committee, or CASAC, of the EPA on the
    particulate matter issue. Presently, I chair the National
    Research Council's Committee on Research Priorities for
    Airborne Particulate Matter. I'll be speaking, as does my
    testimony, to the question of, is there a hazard from fine
    particles? I know that others who will follow will talk about
    the actual magnitude of the hazard posed by particulate matter
    in the air.
        This is a substantial research challenge, but one that the
    scientific community has now been addressing for decades. Part
    of the challenge is that the particles in air exist in a
    complex mixture that includes other pollutants, like ozone, and
    they themselves are a mixture coming from different sources.
    Particles are described by their size. This is important,
    because size is a determinant of how long particles will remain
    suspended in the air, whether they will reach the lung, and
    where they will deposit once inside the lung.
        These characteristics are relevant to health, and
    appropriately the Environmental Protection Agency has now
    focused in on measuring and setting a standard for the finest
    particles, PM2.5, which are in a size range that can
    reach into the lung. I would point out that while
    PM2.5 measurements, as part of our national
    monitoring, are recent, PM10, which has been
    monitored nationally since 1987 and which is the basis for much
    of our research, includes these smaller particles, so that
    studies of PM10 are relevant to PM2.5.
        I would also point out that we breathe particles wherever
    we are, including this room today, I'm sure. But the particles
    we breathe indoors have not only indoor sources, but they
    include particles that have outdoor sources. Particles and
    other air pollutants are important potentially to our health,
    because even though concentrations may sometimes be portrayed
    as low, we breathe in large quantities of air, 10,000 liters of
    air a day, approximately. We call on our lungs to handle all
    those particles. At times, because of the numbers of particles
    or because of the toxicity of those particles, injury may
    result. We think that key to the action of particles is some
    form of inducement or stimulation of inflammation within the
    lung.
        We know that the deposition of particles within the lung
    can cause adverse health effects. We can look back 50 years to
    the air pollution disasters in Donora, PA and in London. There
    was no need for complicated statistical methods to count those
    who died from the air pollution. The excess numbers were
    substantial.
        Now, as levels have dropped, fortunately, researchers have
    faced a challenge to continue to track the health effects of
    air pollution and to sort out the effects of the different
    pollutants present in air. For this purpose, we use many
    different kinds of science. We use epidemiological studies like
    those that I carry out. We look to toxicologic evidence that
    tells us how particles or other pollutants cause their injury.
    We put all of this evidence together, so that our decisions
    about the health effects of particles or other pollutants do
    not rest on any particular study or any particular line of
    evidence, but on the whole body of evidence.
        That body of evidence is now large, with literally
    thousands of studies published on particles. My written
    testimony includes some general references that provide access
    to those studies. Of course, they are cataloged by the
    Environmental Protection Agency in its now massive Criteria
    Document most recently on particles. But just to summarize a
    few of the things that we know at present, the numbers of
    deaths per day. Here we know that if we look to the numbers of
    deaths per day and examine the association or correlation with
    air pollution on the same or recent days, something that we've
    done in our NMMAPS project, we do find an association. Although
    we've recently needed to revise our estimates downward because
    of technical issues, we find nationally that an increase in
    PM10 is associated with an increment in the number
    of total deaths and an even steeper increment in the number of
    deaths for cardiovascular and respiratory or lung conditions
    each day.
        You already mentioned the recent report in March in the
    Journal of the American Medical Association. This is one of
    several studies showing that in fact, for the longer term, air
    pollution, particulate air pollution in particular, is
    associated with increased risk of dying. We would take the
    daily studies and these longer term studies as evidence that
    particulate air pollution is contributing to sufficient life
    shortening to be a public health concern.
        There are other health indicators. Hospitalization and
    emergency care, again, with the numbers of visits to emergency
    rooms or the number of people on Medicare coming to hospitals
    increased as the levels of particles increased from day to day.
    We have further evidence that people with cardiovascular
    diseases may be adversely affected. This is one of these areas
    of emerging research with a number of studies going on. But the
    first indications from this research provide warnings.
        Asthma, an all too common condition in our country, rising
    in children for reasons unknown, with prevalence rates of 10
    percent or more. This is a susceptible group, again with
    evidence showing that there are adverse effects on this
    important and large population.
        In my testimony, I've also summarized a group of
    epidemiological studies, some quite old now, that address the
    health effects of power plants directly in communities, such as
    those we did 20 years ago in the Chestnut Ridge region in
    western Pennsylvania. While these studies are quite different
    in their methods, my overall interpretation of this evidence is
    again a warning of adverse effects of coal-fired power plants
    on public health in surrounding communities.
        So in summary, the health effects of air pollution have
    been a focus of research for nearly a half century. There's no
    doubt, there's clear evidence from the past that high levels
    can have direct and evident adverse effects on health. While
    air pollution constitutes a complex mixture with many toxic
    components, the evidence consistently indicates that airborne
    particles in our outdoor environments and urban environments
    have adverse effects on health associated with premature
    morbidity and mortality.
        Based on our knowledge of how particles penetrate in the
    lung, these effects likely reflect the deposition of smaller
    particles in the size range encompassed by PM2.5.
    These particles have many man-made sources, vehicles, industry
    and electric power generation by coal-fired power plants.
    Epidemiological studies of communities located adjacent to such
    plants show that the health of community residents can be
    harmed, although links to specific products of combustion
    cannot be readily made.
        I would note that risk assessment approaches that build on
    these epidemiological studies have proved quite useful for the
    purpose of estimating the burden of disease and ill health
    associated with power generation in coal-fired power plants. So
    I will say that while research is ongoing, as it should be and
    as it always will, the indications at this time provide a clear
    warning of a threat to public health.
        Thank you.
        Senator Jeffords. Thank you.
        Our next witness is Robert M. O'Keefe, vice president of
    Health Effects Institute, in Boston, MA. Please proceed.

             STATEMENT OF ROBERT O'KEEFE, VICE PRESIDENT,
                        HEALTH EFFECTS INSTITUTE

        Mr. O'Keefe. Thank you, Mr. Chairman. It is a pleasure to
    appear before you and other members of the committee to share
    the perspective of the Health Effects Institute on what we have
    learned and what we still need to learn about the health
    effects of particulate matter.
        For the record, I am Robert O'Keefe, vice president of HEI.
    HEI is an independent, not-for-profit research institute funded
    jointly and equally by the U.S. Environmental Protection Agency
    and industry. We provide impartial, high quality science on the
    health effects of air pollution.
        In 1997, the U.S. EPA promulgated a new set of National
    Ambient Air Quality Standards for fine particulate matter. At
    that time, there were nearly 40 short-term studies that found a
    link between daily changes in air pollution and daily increases
    in death and illness. There were two long-term studies, the
    Harvard Six Cities Study and the American Cancer Society study,
    which found that those who lived in the most polluted cities
    had between a 17 percent and a 26 percent increase in the risk
    of premature death relative to those who lived in the least
    polluted cities.
        At the same time, there were a number of outstanding
    questions about these studies, including the individual short-
    term studies that were done by diverse investigators using
    different methods. Would a more systematic study find the same
    results? Could other pollutants, which occur along with PM, be
    responsible for the increased mortality? And importantly, could
    the Harvard Six Cities study and the American Cancer Society
    study stand up to intensive scrutiny and analysis from new
    independent investigators?
        Since 1997, substantial new research has been undertaken to
    advance our understanding. HEI alone has invested in some 40
    epidemiology, exposure and toxicology studies to test the
    validity of these original assumptions. Key among HEI's work
    have been two efforts, the National Morbidity, Mortality and
    Air Pollution Study, or NMMAPS, which Dr. Samet alluded to, and
    the re-analysis of the landmark Six Cities and the American
    Cancer Society studies.
        NMMAPS is a systematic study of air pollution, weather and
    mortality in the 90 largest cities across the United States
    conducted under HEI oversight by John Samet and his colleagues
    at Johns Hopkins University. It found a consistent relationship
    between PM and mortality in these 90 large cities, and it was
    not affected when other pollutants were added to the model. At
    the same time, this first nationwide analysis found what may be
    differences in levels of effects across regions of the United
    States that really remain to be understood.
        Recently, NMMAPS investigators identified an issue with the
    statistical software package used by air pollution and other
    investigators to analyze data. In NMMAPS, this result modified
    the study effect estimates. With HEI peer-reviewed alternative
    approaches employed, they found that the mean effect estimate
    in the studies shifted from a .4 percent increase in mortality
    for every 10 micrograms of PM10 to a .2 percent
    increase. Importantly, these results remain statistically
    significant, and the PM effect still does not appear to be
    affected by other pollutants. A further report of these efforts
    will be provided in January.
        Looking to the long-term side, in response to requests from
    Congress, the U.S. EPA and industry, HEI convened a detailed
    re-analysis of the Six City Study and the American Cancer
    Society studies. Given full access to all data, HEI's expert
    panel selected an entirely new team of investigators who
    assured the quality of the original data by conducting a
    thorough data quality audit, and tested the results against
    alternative analytic approaches suggested by scientists and
    critics alike, without substantively altering the original
    findings of an association between mortality and fine particles
    and sulfates (a form of particles created in the atmosphere
    primary from coal combustion).
        At the same time, the re-analysis found that the effects on
    mortality appeared to increase for those with less education
    and lower socioeconomic status. Also that there was an
    increase, or an association between sulfur dioxide and
    mortality that persisted when other variables were included.
        As we look ahead over the longer term, it will be important
    to understand whether some particles and some sources can
    contribute higher toxicity and should be more stringently
    controlled. To address questions of particle characteristics,
    the HEI review committee in April 2002 issued the second in its
    HEI perspectives series titled, ``Understanding the Health
    Effects of Components of the Particulate Mix--Progress and Next
    Steps.'' This review, which I have provided to your staff,
    summarizes recent HEI and other research and lays out
    recommended future approaches to understand the differential
    effects of particles and sources.
        In conclusion, we've made much progress over the last 5
    years, especially in testing the validity of the short-term and
    the long-term epidemiology studies. We have tested a number of
    possible confounding factors and alternative explanations. In
    reviewing the latest evidence, the HEI review committee
    concluded ``Epidemiologic evidence of PM's effects on mortality
    and morbidity persist, even when alternative explanations have
    been largely addressed.''
        At the same time, some new questions have arisen. In the
    near term, it's necessary to complete the re-assessment of
    NMMAPS and identify, reassess and provide peer review for other
    key studies. Over the longer term, important questions remain
    concerning the comparative toxicity of different components and
    sources of the PM mixture. Only through a systematic effort to
    test and compare the toxicity of these diverse pollutants will
    we be able to have the best chance of targeting future
    strategies to control emissions that are the most toxic.
        Thank you.
        Senator Jeffords. Thank you. Very helpful testimony.
        Dr. Wyzga is the technical executive and manager of Air
    Quality, Health and Risk, Electric Power Research Institute,
    Palo Alto, CA. Please proceed.

     STATEMENT OF RONALD E. WYZGA, TECHNICAL EXECUTIVE AND PROGRAM
                   MANAGER, ELECTRIC POWER RESEARCH
                               INSTITUTE

        Mr. Wyzga. Thank you, Mr. Chairman. Thank you very much for
    inviting me.
        Let me introduce myself a little bit by saying that I work
    for EPRI, which is a non-profit, tax-exempt organization that
    performs scientific research for the public benefit. I have
    worked in environmental health research for over 30 years,
    published over 50 peer reviewed papers on the topic of air
    pollution and health, and served on numerous EPA and other
    scientific panels. The comments that I present today reflect my
    personal views and judgments as a scientist.
        It was suggested that I highlight some of EPRI's most
    important research findings on the health effects of air
    pollution. I will summarize these in my oral comments, but my
    written comments provide further detail.
        There are a large number of scientific studies that report
    a link between air pollution and health. From this literature,
    I conclude that there is a clear association between air
    pollution and health in the United States at current pollution
    levels. Among the various pollutants examined, the strongest
    associations between air pollution and health are for
    particulate matter, or PM. However, as yet there is no accepted
    biological explanation for the link between the pollution found
    in the United States today and observed health responses.
        Particulate matter is made up of thousands of different
    components from a wide variety of sources. There are limited
    data on the toxicity of the different components of particulate
    matter. Few toxicology experiments have been undertaken
    examining the different fractions of PM. But those that have
    been undertaken have found significant difference in the
    toxicity for different components.
        The EPRI ARIES, or Aerosol Research Inhalation Epidemiology
    Study project was designed specifically to examine the toxicity
    of the various components of PM and air pollution. This study,
    conducted in metropolitan Atlanta, in conjunction with U.S.
    DOE, several universities and others, is unique in terms of the
    number of air quality parameters measured and the number of
    health effects examined. In the study, we're looking at both
    potential death and disease associations with air quality. For
    mortality of people over 65 years old, results today show a
    statistically significant association for several pollutants.
    These include PM2.5, PM10, carbon
    monoxide and oxygenated hydrocarbons, which are carbon
    containing compounds largely in gaseous form. Indeed, when we
    look at several analyses, the latter, the oxygenated
    hydrocarbons, appear to be most consistently associated with
    death.
        The results for disease show that in general, different
    components of air pollution are associated with respiratory
    effects than with cardiovascular effects. The respiratory
    effects appear to be associated with PM10 and the
    gaseous pollutants, carbon monoxide, ozone, and nitrogen
    dioxide. On the other hand, cardiovascular effects appear to be
    associated with fine particles, carbon monoxide and nitrogen
    dioxide. However, the only fractions of PM2.5 that
    show any statistically significant associations with
    cardiovascular effects are particles that contain organic and/
    or elemental carbon. There is little evidence of any health
    effects tied to acid aerosols, and no significant associations
    have been found between any health effect and total soluble
    metals, ultra fine particles or sulfates.
        Recent concerns have been raised about some of the past
    applications of statistical tools to understand the air
    pollution-health relationship. In fact, EPA has delayed its
    current review of particulate matter effects until the matter
    is more fully understood. Our research suggests that
    differences and yet other statistical methods can lead to
    different results. It is important to understand the influence
    of the different statistical methods on the results of the
    analyses of this air pollution-health relationship.
        We now have a better understanding of the relationship
    between average outdoor levels of pollution and personal
    exposure. We see, however, that there can be short periods of
    time when these exposures to pollution can be extremely high.
    We need to identify these time periods and determine whether
    these short periods of exposure, a very high exposure, can
    impact health.
        There is also a great need for additional studies that
    focus upon the specific components of particulate matter and
    the relationship to human health. I would urge others, such as
    the EPA, to consider studies similar to ARIES in other
    geographic areas. We also need laboratory studies to examine
    the toxic effects of specific components and the sources of PM,
    so that we can identify the pollution components and sources
    that most impact public health. We need to develop a better
    biological understanding of the link between pollution found in
    the United States today and health effects.
        Finally, statistics is a wonderful tool, and has allowed us
    to make considerable progress in understanding the relationship
    between pollution and health. But it is important that we fully
    understand the implications and potential weaknesses associated
    with the tools that we use.
        To recap, my main points are as follows. No. 1, air
    pollution likely impacts the health of individuals in the
    United States today. No. 2, particulate matter is a likely
    candidate to explain these impacts. No. 3, in our studies, when
    health effects are associated with fine particles, our research
    points strongly to particles that contain carbons as the agents
    of concern. In most United States cities, carbon containing
    particles are the largest component by weight. Gaseous
    pollutants may still, however, be of health concern. There is a
    great need to apply alternative statistical methods in
    analyzing data and to understand the influence of these
    methods. There is a strong need to identify with more certainty
    those specific components of air pollution that cause health
    effects. Finally, decreasing the non-toxic part of particulate
    matter will not necessarily reduce health effects.
        In summary, our latest results show that when health
    effects of fine particles are seen, these effects are most
    strongly associated with specific particle constituents. This
    may be an important factor in designing control strategies.
    Further research is needed to replicate and extend these human
    health studies in other geographic areas. Laboratory toxicology
    studies are also needed to gain a better biological
    understanding of the observed effects.
        I would like to thank the committee for the opportunity to
    present my views, and would be pleased to respond to questions.
        Senator Jeffords. Thank you very much.
        Mr. Rose, you're next. executive director of the Green
    Mountain Club in guess where--Waterbury Center, VT. Nice to
    have you here.

              STATEMENT OF BEN ROSE, EXECUTIVE DIRECTOR,
                     THE GREEN MOUNTAIN CLUB, INC.

        Mr. Rose. Chairman Jeffords, thank you for the opportunity
    to testify.
        My name is Ben Rose, I'm not a scientist. The Green
    Mountain Club is a 93-year-old, member-supported, not-for-
    profit hiking club in Waterbury Center, VT, headquartered
    there. The mission of the club is to make the Vermont Mountains
    play a larger part in the life of the people by protecting and
    maintaining the Long Trail, which is as you know a hiking trail
    which runs the length of Vermont from Massachusetts to Quebec.
    The southern 100 miles of the Long Trail are part of the
    Appalachian National Scenic Trail from Georgia to Maine, and
    the Green Mountain Club is one of 31 local volunteer-based
    clubs which maintain specific sections of the AT. The
    Appalachian Trail is also the longest linear national park in
    the world.
        Although most people do not associate scenic mountain
    ranges with smog, some of the dirtiest air in the United States
    is in our mountains. Mountain air contains fine particulate
    matter, largely sulfates derived from burning coal, as well as
    nitrates and ozone, by-products of power plant emissions. The
    air is often at its worst in the higher elevations. This is of
    concern to the Green Mountain Club and our sister hiking clubs
    as the Long Trail, the Appalachian Trail and thousands of miles
    of other trails beckon hikers up into the air, which we now
    know is of poor quality a significant amount of time.
        We are also concerned at The Green Mountain Club because we
    hire dozens of young people each summer as ridge line
    caretakers, to work on the trails and to protect the unique
    alpine plants that exist only on some of our highest summits.
    These folks spend months at high elevations. They see lots of
    haze, and they breathe it, too.
        In August 2002, during a stretch of severe haze,
    particulate matter and ozone smog in New England, three hikers
    were treated with oxygen near the summit of Mount Washington,
    New England's highest peak, only tens of miles from Waterbury,
    VT. Staff and hikers there reported nausea and shortness of
    breath. During the same period, vistas from New England
    mountaintops were shrouded in a thick, white haze. These are
    the same pollutants that are causing acid rain, forming
    sulfuric and nitric acids responsible for the high mortality
    rates in our high elevation spruce and fir forests.
        While many studies which will be referenced by the medical
    researchers on this panel have linked particulate matter to
    asthma, heart attacks and premature death, little attention has
    been paid to the health effects of fine particulate matter
    specifically on healthy people exercising outdoors, such as
    hikers. The most important study to date on the subject was
    conducted during the summers of 1990 to 1992, when scientists
    from the Harvard School of Public Health and the Appalachian
    Mountain Club studied the lung responses of hikers climbing
    Mount Washington in New Hampshire to fine particulate matter
    and ozone pollution.
        Hikers' lung functions were measured using spirometers
    before and after their hikes. At the same time, ozone and
    PM2.5 concentrations were measured in the air at the
    top and bottom of the mountain. Data was also collected
    regarding past respiratory history and fitness levels, current
    smokers were excluded from the study.
        In a nutshell, the results show that healthy hikers
    experienced measurable declines in short-term lung function
    related both to ozone and to PM2.5. Although the
    PM2.5 correlation did not meet the 95th percentile
    confidence level, the study provided credible evidence that
    both ozone and particulate matter independently impact hikers'
    lungs. It's important to note that the air quality during the
    study was only moderate, with 1-hour and 8-hour ozone levels
    and PM2.5 well below the Federal standards. This
    suggests that even moderate levels of these pollutants reduced
    the lung function of healthy people exercising outdoors.
        The study recommended ``Physicians, public health officials
    and the general public should be made aware of the potentially
    serious health effects of low-level air pollutants, not just in
    urban and industrial regions, but specifically on those who
    engage in outdoor recreation in various wilderness areas.''
        Currently, a similar study is being conducted in the Great
    Smoky Mountains National Park, in cooperation with the National
    Park Service and Emory University. Air quality in the Great
    Smoky Mountains is significantly worse than the air quality
    observed during the Mount Washington study. The Great Smokies
    have experienced 140 days of unsafe air quality over the past
    four summers.
        Senator Jeffords. Four summers totaling 140 days?
        Mr. Rose. Yes.
        Senator Jeffords. Thank you.
        Mr. Rose. Old, dirty power plants are the largest source of
    fine particulate air pollution in the region, accounting for
    half or more of the fine particulate matter and most of the
    sulfate deposition in the Appalachians. This means that these
    same plants are responsible for most of the haze and the acid
    rain as well.
        Many coal-burning plants in the region and upwind were
    exempted under the Clean Air Act, and have not yet installed
    sulfur dioxide scrubbers or NOx catalysts, even though the
    technology has been available for many years. Sulfur dioxide
    and nitrogen oxide from power plants form sulfates and nitrate
    particles that can be suspended in the air for weeks and
    transported hundreds of miles downwind into our wilderness
    areas, forests and parks.
        Grandfathered coal plants are endangering public health,
    not only to those living in cities and industrial areas, but
    also to those of us who exercise in and enjoy the outdoors. As
    a hiking club, we promote the benefits of outdoor exercise and
    fresh mountain air. Yet we know that those who recreate in the
    mountains are being exposed to unhealthy air. In conclusion,
    current air quality and national energy policy allow unsafe
    levels of fine particulate matter pollution in the air of
    Vermont, of northern New England and of the entire Appalachian
    Mountain chain that is harmful to our lungs and those of our
    children. People throughout the Eastern United States look to
    the mountains for clean, fresh air. If they can't find it in
    Vermont, where can they go?
        We respectfully ask the Senate of the United States to act
    in support of aggressive measures to clean up power plants as
    embodied in S. 556, and to reject measures that would weaken
    the Clean Air Act. Thank you.
        Senator Jeffords. Thank you for your excellent testimony.
        Our last witness is Dr. Jonathan Levy, assistant professor
    of Environmental Health and Risk Assessment, Department of
    Environmental Health, Harvard School of Public Health, Boston,
    MA.

           STATEMENT OF JONATHAN LEVY, ASSISTANT PROFESSOR,
        ENVIRONMENTAL HEALTH AND RISK ASSESSMENT, DEPARTMENT OF
         ENVIRONMENTAL HEALTH, HARVARD SCHOOL OF PUBLIC HEALTH

        Mr. Levy. Thank you, Mr. Chairman, and thank you for giving
    me the opportunity to speak before you today. As you mentioned,
    I am an assistant professor of environmental health and risk
    assessment, and I am a member of the environmental science and
    engineering program, as well as the Harvard Center for Risk
    Analysis.
        I appear before you today as a risk assessor who has
    evaluated the current evidence about the health impacts of
    power plant emissions in multiple recent analyses. My comments
    will focus on the implications of the health literature for
    risk calculations, with more detail provided in my written
    materials.
        As a risk assessor, I believe that decisions about
    alternative policies for controlling power plant pollution
    should be based in part on a comparison of the benefits and
    costs of those policies, considering the magnitude and
    distribution of both benefits and costs. In quantifying
    benefits, premature mortality associate with fine particles
    invariably contributes a large portion of the benefits, so I
    focus on this literature today.
        I believe that there are three crucial questions that must
    be considered. No. 1, Is there a threshold below which no
    health effects of PM2.5 are found, and if so, where
    is that threshold? No. 2, Do all types of particulate matter
    have similar health impacts, or are some particles more toxic
    than others? No. 3, Which is related to one and two, would
    alternative control strategies have significant impacts on the
    magnitude or distribution of particulate matter health impacts?
        On the first point, multiple recent studies have addressed
    this question and have found no evidence of a threshold to
    date. For example, the American Cancer Society cohort study
    found that mortality risks decreased as PM2.5 levels
    decreased, down to levels below 10 micrograms per cubic meter.
    Similarly, multiple investigations of time series data found no
    evidence of thresholds for daily changes in PM levels down to
    extremely low concentrations. The observational evidence
    therefore supports the assertion that mortality risks will
    continue to decrease as PM2.5 levels decreased.
        The question of relative toxicity is far more difficult to
    answer from a quantitative perspective. When considering power
    plant emissions, this is essentially a question about sulfate
    toxicity. In the American Cancer Society and Six Cities cohort
    mortality studies, the two most comprehensive and
    representative studies to date, sulfates show a similar
    association with mortality as PM2.5 with an
    association also seen with sulfur dioxide.
        When considering the time series mortality literature,
    sulfate has been associated with premature mortality in the
    majority of studies. I would therefore conclude that while it
    would be anticipated that different types of particles would
    have different effects, there is not sufficient information to
    conclude that sulfates differ from average particles in either
    direction. It should be noted that this is not the same as
    concluding that all particles are identical, but rather that
    the best quantitative risk estimate at present is that sulfates
    have similar effects as PM2.5 in general.
        I address the distribution question in greater detail in my
    written materials, but it is worth noting that there are
    spatial gradients in particulate matter impacts from power
    plants, and that when the health literature regarding
    susceptible subpopulations is taken into account, these spatial
    variations increased. At the same time, particulate matter from
    power plants is transported a long distance. This makes the
    exposure question national rather than local in scope.
        The general conclusion I would draw is that different
    policy structures will lead to different distributions and
    exposures in health risks, and that careful consideration of
    these distributions should be incorporated into any comparison
    of control strategies.
        Now, what does the health literature imply for the
    magnitude of benefits from alternative controls? That PM
    contributes to premature mortality and current concentrations
    are above any population threshold, and any reductions in PM
    concentrations will provide corresponding benefits. This means
    that benefits can be quantified for benefit cost comparisons as
    done in research studies by our research team, Abt Associates,
    EPA and others. Combining the cohort mortality evidence cited
    above with atmospheric models that we have analyzed and found
    to be appropriate, Abt Associates estimated that power plant
    emissions contribute to 30,000 premature deaths each year.
        The EPA has estimated that the Clear Skies Initiative would
    reduce this burden by about 12,000 deaths per year, with an
    alternative straw proposal yielding benefits of 19,000 fewer
    deaths per year. While these estimates are clearly uncertain, I
    view the calculations as reasonable central estimates that
    provide a crucial foundation for policy comparisons. Thus, it
    is reasonable to assume that the Clear Skies Initiative would
    provide substantial public health benefits, but that the EPA
    straw proposal, which is similar to the Clean Power Act, would
    increase those benefits on the order of 7,000 fewer premature
    deaths per year.
        Despite the quantitative uncertainties, the qualitative
    conclusion that greater controls will lead to greater health
    benefits appears robust, implying that choices between
    alternative control strategies should depend on the incremental
    cost and benefits of increased stringencies.
        In conclusion, I thank you once again for allowing me to
    speak here today, and I would be happy to answer any questions.
        Senator Jeffords. Thank you again, for very, very helpful
    testimony. I can't thank you all enough for helping us to
    really get a better idea as to where we stand and what we must
    and should do to help make our country more habitable and
    safer.
        I will now have some questions for you. Dr. Samet, how do
    scientists determine that premature mortality and heart or lung
    ailments are associated with air pollution and not other
    factors, like diet or lifestyle?
        Dr. Samet. Clearly, other factors do influence longevity
    and health. But in the epidemiological studies, either the
    daily studies, where such factors as lifestyle don't vary day
    to day, just implicitly takes such factors into account. In the
    Harvard Six Cities and the American Cancer Society studies, the
    longer term studies, there was an effort to take account of
    such lifestyle factors as smoking, obesity and some other
    measures and that is done by collecting information about those
    characteristics and then controlling for it in the analytical
    approach used by the investigators.
        Senator Jeffords. Mr. O'Keefe, I know you have another
    engagement. So I will go to you next. What do you think are
    some of the remaining gaps in knowledge regarding the health
    effects of particulate matter pollution?
        Mr. O'Keefe. Thank you. I think one of those has been
    raised, and that's the important question of whether or not
    there is a threshold below which particle effects exist or not.
    As Dr. Levy pointed out, evidence presented in both time series
    and studies of long-term effects have not demonstrated that
    there is a threshold below which we see effects. That's an
    important area of new work to follow up on, No. 1.
        No. 2, that I alluded to earlier, as we look ahead to the
    next generation of particulate matter research, is there an
    ability to tie sources of particles and types of particles with
    particular health impacts? This type of analysis, which won't
    be done soon, and is not something we need to do before taking
    action during the regular course of events, if current
    understanding leads us to that, would really allow us over the
    longer term, looking forward to best target control measures,
    to focus on sources that may be most responsive, to focus on
    sensitive subpopulations that might be most toxic, and perhaps
    to do so in a very cost-effective manner.
        Senator Jeffords. Thank you.
        Dr. Levy, in your testimony you cite several studies that
    distinguish the health effects of power plant emissions from
    natural causes like wind-blown dust. Could you please elaborate
    on those findings?
        Mr. Levy. There are a number of studies in which it was
    tried to determine which species of particulate matter have
    greater health effects. Some of those, like the ones that Dr.
    Wyzga mentioned, measure a number of different constituents,
    sulfates, elemental organic carbon, dust and other elements,
    and try to look at the effects of those. Others try to take
    elemental data and combine them to try to attribute them to
    certain sources.
        So one example of the latter study was based on the Harvard
    Six Cities data, where they looked at a number of different
    elements and then combined them to look at, to attribute them
    to coal sources, to residual fuel oil, to automobiles, to dust
    and so forth. What they found is particles from motor vehicles
    and from coal were significantly associated with premature
    death, whereas crustal particles were not. That's consistent
    with what a number of different studies have found, really
    indicating that the combustion-based fine particles seem to
    have greater health implications than crustal particles.
        Senator Jeffords. Thank you. Mr. Rose, have you found that
    visitors to the Green Mountains express concern over pollution
    haze and reduced vistas? Do they feel robbed of their
    opportunity to see what they wanted to see?
        Mr. Rose. Yes. This is anecdotal, of course, but I do talk
    to a lot of hikers and visitors. I hear a lot of people express
    disappointment at hazy vistas. I was out quite a bit this
    summer and I saw some days that were clear days with a lot of
    haze. Other people, especially people who have been coming to
    the Green Mountains for a long time, comment on the same thing,
    that generally, visibility, even on clear days, is reduced.
    There is a general sense that air quality in the mountains is
    being impacted.
        Senator Jeffords. Thank you.
        Mr. Wyzga, your testimony on the ARIES study relies heavily
    on draft results but does not reference published peer-reviewed
    articles. When will the final results of the ARIES study be
    published?
        Mr. Wyzga. The results based on 1 year's data have been
    published, and they are attachment A that I submitted to my
    testimony. Final results on 2 years' worth of data, manuscripts
    are in preparation. They will be submitted to peer review
    publications, I'm guessing, within the next month. I am asking
    the investigators to get them in as soon as possible and I
    think it's imminent.
        Senator Jeffords. Thank you.
        Dr. Samet, you and your colleagues performed a new analysis
    of the NMMAPS study. What are the important conclusions of the
    study that remain unchanged by re-analysis?
        Dr. Samet. Qualitatively, the conclusions are unchanged. I
    think Bob O'Keefe already alluded to the quantitative change in
    our sort of national average estimate, which dropped by half
    when we made some changes in the statistical tools used. The
    same patterns were there, seemingly a higher effect of
    particles in the northeast region of the United States. The
    greater effect for deaths from cardiovascular and respiratory
    diseases presumably reflect in the greater susceptibility or
    vulnerability of people with heart and lung disease to
    particles than for other causes. Again, an association with
    particles that was robust to control for other pollutants. I
    think those would be the principal findings.
        Senator Jeffords. Dr. Levy, the NAS recently issued a
    report concluding that EPA's mortality estimates appropriately
    referenced long-term cumulative studies. What are the mortality
    estimates from the power plant risk assessments based?
        Mr. Levy. The ones that I referenced by Abt Associates and
    by EPA and by our research team were based on the long-term
    cohort mortality studies. There are a few of those studies
    available. What is generally used by myself, Abt Associates and
    others are estimates from the American Cancer Society study in
    part because it's the largest, most scrutinized study to date.
    It also has risk estimates that are slightly lower than those
    found from the Harvard Six Cities study, so it reflects a
    somewhat conservative interpretation of the literature.
        Senator Jeffords. Mr. Rose, with environmental effects
    aside for the moment, could you tell us a little more about how
    severe pollution days affect the ability of volunteers to
    maintain trails, and how pollution might affect your business,
    tourism and the local economy as well?
        Mr. Rose. Well, again I would say, ``yes, that we can
    foresee a day when many of our volunteers won't go out.'' In
    point of fact, in the last few years we've seen hiker days flat
    or declining in many parts of the State. We speculate as to why
    that's happening. Part of it is weather related, and it
    fluctuates from year to year. Part of it is because it's been
    so hot in southern New England that people are probably home in
    front of their air conditioners.
        We actually saw a big slug of hikers come out over Labor
    Day weekend this year, I believe because people had stayed home
    all summer and said, ``Wow, the summer got away from us, it was
    really hot.'' What's true for hikers is true for volunteers.
        I should note that the average age of Green Mountain Club
    members and logically, of the volunteers who are a subset of
    those members, is 52. It makes sense that at that point in
    people's lives they have some time to give back to the trail,
    and are able to participate as volunteers. We see a lot of our
    best trail maintainers are people in their 60's and 70's. We
    have a lot of people who are models of good, healthy aging in
    the Green Mountain Club and in other hiking clubs. Those folks
    breathe hard when they're going up the trail.
        So when we see that air quality is having an impact on
    people when they hike, the same is certainly true for
    volunteers, and it would have an impact on the long-term health
    of the trails that give people access, sure.
        Senator Jeffords. Mr. O'Keefe, you mentioned a number of
    factors causing particulate matter toxicity. Would you tell us,
    in your opinion, which of these is being addressed rigorously
    by current regulations and which need further regulatory
    attention or research?
        Mr. O'Keefe. Well, you really raised the key question that
    the scientific community is working very hard to answer. The
    current National Ambient Air Quality Standards are mass based
    standards. By taking that approach, they act to reduce
    particles more broadly across the large spectrum with
    PM10, PM2.5 and smaller.
        Within that, there are numbers of questions about which
    type of particle within that range could be most toxic or not.
    There are carbon particles, there are sulfate particles. There
    are biogenic particles, there are different metals that travel
    with particles. This area is very much an active area of
    research. I alluded to an understanding of the active agents in
    particulate health effects. They could help protect public
    health in the most cost-effective manner.
        I will add that a mass-based standard, although it doesn't
    necessarily fire the bullet with ultimate precision, does have
    measurable effects in reducing health impacts.
        Senator Jeffords. Mr. Wyzga, despite the clear linkage
    between particulate pollution from utilities and adverse health
    effects and death, you are recommending that this committee
    consider the culpability of power plant emissions. Would all
    the ARIES study researchers agree with your policy?
        Mr. Wyzga. I really can't speak for the researchers. I
    think that what we're finding in the area that is important is
    we're finding that there are health effects at contemporary
    levels of pollution in the United States. I think that's
    something that's being widely found. We're seeing that the
    gases are important, as well as particles. That means we can't
    ignore the gases. We're seeing that different particles have
    different toxicities. I think it's important to really
    basically replicate this study in lots of other areas and see
    whether or not we find similar results.
        I think when we look at that, we're going to be able to
    target specifically those pollutants that are causing our
    health problems. I think it's clear, and I would agree with
    what others have said, if we look at the data, there doesn't
    appear to be any threshold. It looks as if we're seeing health
    effects down to background and zero levels of pollution. People
    are dying. It's a potentially very serious--looks like a
    serious public health problem. To get the results, we've got a
    lot more work to do in terms of targeting those specific
    sources and pollutants that are going to give us the biggest
    bang for the buck. I would urge that everybody work together to
    resolve this issue.
        Senator Jeffords. Thank you. Dr. Samet, isn't it true that
    long-term studies examining the combined effects of chronic and
    acute exposure would generally yield estimates on an order of
    magnitude higher than the short-term studies, such as NMMAPS?
        Dr. Samet. I think one of the difficult areas where we have
    a signal from the long-term studies that, in terms of the
    effect of particles on mortality, it's about 10 times that we
    see in the daily time series. I would again--both estimates are
    in the wrong direction, that is, they're signaling an effect of
    air pollution on mortality, either short term or long term. We
    haven't quite been able to rationalize why we're seeing a
    seemingly larger effect on the longer term than on the shorter
    term. Actually, I think there will be further research, there's
    certainly further research on this. This is an area of research
    need, but it's hard to harmonize these two pieces of evidence
    at present.
        Senator Jeffords. Dr. Levy, you completed new research this
    year that for the first time ever shows the disproportionate
    health impacts from power plant pollution on poor minority
    populations. Would you elaborate on your findings?
        Mr. Levy. Sure. This is a study that we did based on the
    Washington, DC. area, looking at five power plants in and
    around, in about a 50-mile radius around Washington, DC. What
    we did is look to the health literature, to the existing
    epidemiological studies that focused on susceptible
    subpopulations. So as was alluded to earlier, the American
    Cancer Society cohort study looked at the effect of educational
    attainment on the risk of mortality from air pollution, and
    found that those with less than high school education were much
    more affected than those with higher education. Similarly, it's
    well known that asthma prevalence, for example, and asthma
    emergency room visit rates are much higher in African American
    populations.
        So they took that as a foundation for our analysis to
    quantify the magnitude and distribution of health benefits that
    would accrue if emission controls were placed on these five
    power plants, and found essentially that when you take the
    susceptibility into account--what's been documented in the
    health literature--that the picture changes somewhat. So if you
    look at the example of mortality, the method that is usually
    used is to assume that everyone implicitly is equally at risk.
    The reason, we looked at 25 percent of people had less than
    high school education, so normally you would assume that, well,
    25 percent of benefits would accrue in that population. In
    fact, when we took account of the information about
    susceptibility, more than half of the benefits accrued in that
    group. You can tell a similar story for cardiovascular hospital
    admissions among diabetics and asthma emergency room visits as
    a function of race.
        So we were building on the epidemiology, so clearly, more
    epidemiology, more studies of this type are needed to be able
    to provide a more robust picture. But we think this is an
    important direction to consider to better target who are the
    susceptible subpopulations, that are their characteristics.
    That can potentially help us guide our control strategies.
        Senator Jeffords. This is a question for all of you. As you
    know, I have been deeply concerned to learn about the health
    studies that show tens of thousands of lives are ended
    prematurely each year due to air pollution, especially from
    power plants. Do any of you know of other peer reviewed studies
    that would dispute these findings? We'll start with Dr. Samet.
        Dr. Samet. Not really, no. I think there is substantial
    literature, that I think have just voiced a consensus on what
    it shows now.
        Mr. O'Keefe. I would agree.
        Mr. Wyzga. I think there are lots of studies out there that
    show relationship between air pollution at levels of experience
    today and health effects.
        Senator Jeffords. Mr. Rose.
        Mr. Rose. I guess I would say that there is a large and
    growing literature in any literature where there's hundreds or
    thousands of studies, there are going to be some studies with
    negative findings. But I think the vast majority of studies are
    pointing to the direction that power plant air pollution leads
    to the premature mortality you described.
        Senator Jeffords. Next question for everyone. Will reducing
    SOx and NOx by about 75 percent make progress in reducing the
    problem of particulate matter? Do you have any ideas for other
    ways that Congress can help minimize this public health threat?
        Dr. Samet.
        Dr. Samet. I guess the first part is the easier one.
    Clearly, SOx and NOx contribute to the formation of secondary
    particles, and we think in fact these particles that have been
    discussed are possibly critically important to health effects.
    The second question, you know, what else can be controlled and
    how we should control it, I don't think lends itself to a quick
    answer. I think in fact you mentioned the gains that we've made
    in cleaning up the air with the Clean Air Act, and actually
    1970, 1990 and prior attempts to clean the air.
        I think the remainder of controls beyond what we've
    discussed, we'll have to take a look at what are the other
    contributors to particles. I think in line with what some of
    the other commenters said, are there particular sources that
    are associated with particles having particular toxicity that
    we should hone in on? I think the scientific community is
    probably not quite ready yet to say what those other sources
    might be.
        Mr. O'Keefe. I might answer that there are things that have
    been done recently in other areas. Being from a health effects
    institution, I won't delve too deeply into this area. But I
    would observe EPA's heavy duty diesel rule that was put into
    place and will significantly reduce particulate emissions from
    heavy duty diesel vehicles through the reduction in sulfur
    content in fuels and through innovative new technologies, which
    include traps and NOx absorbers.
        So there do seem to be opportunities here for moving
    forward.
        Senator Jeffords. Thank you.
        Mr. Wyzga.
        Mr. Wyzga. First of all, I think that clearly, both SOx and
    NOx form particulates, sulfates and nitrates. I think that one
    of the things that is--particularly, some of the work we've
    seen--NO2 itself is a pollutant that may still have
    concerns. But don't forget the gas. That's one message I have.
        Second, in our work, we don't see health effects per se of
    nitrates and sulfates. We see a stronger signal for some of the
    carbon containing particles. We don't really know what the
    sources are. One very interesting thing in Atlanta is that we
    see a very strong link between carbon containing particles and
    cardiovascular effects, emergency room admissions to the
    hospital.
        These effects are only occurring in the winter. They're not
    occurring in the summer. We'd love to see what are the sources
    of carbon containing particles in Atlanta in the winter, and to
    our surprise, the No. 1 source was actually wood burning. The
    No. 2 source were diesel. Diesel contributes in the summer, but
    we're not seeing health effects in the summer.
        I don't know if we're seeing this because of differences in
    pollution sources or differences in behavior, people may spend
    more time indoors in the winter in Atlanta. I don't think we
    have the answer yet, and I think we have to look a lot further
    into it.
        But I think we really have to do a lot more work to sort of
    hone in on these things. There are a lot of studies out there.
    Another important source that sort of surprised me a lot in
    that area, in the summer months in Atlanta, whether it's
    causing health effects or not, is meat burning. There are a lot
    of fast food restaurants out there, and they don't have big
    chimneys. They're in our city.
        Senator Jeffords. Mr. Rose.
        Mr. Rose. I understand the question to be, Is there
    anything else we can do? Of course, there's a lot that we can
    do in national energy policy and transportation policy. We need
    more stringent, in my opinion, vehicle efficiency standards. We
    need alternative fuels. We need renewables. People understand
    that it's all part of the same policy problem. The Clean Air
    Act exempted existing coal plants from requirements to retrofit
    with best available technology. Here it is, decades later, and
    the status quo is costing lives. I coach soccer on Sunday
    mornings, just like a lot of your other constituents. The
    parents on the sidelines agree that there's a lot of asthma,
    and people understand that the Clean Air Act hasn't realized
    its potential and that you're here fighting a much bigger game.
        Senator Jeffords. Mr. Levy.
        Mr. Levy. I think my comments will echo what a lot of the
    other presenters have said. I think it's clear that these
    SO2 and NOx controls from power plants, both because
    of the fine particle benefits, the ozone benefits, even the
    gaseous pollutant benefits, will clearly confer a major public
    health benefit. It's an important direction to head in. I think
    in terms of another direction, there isn't as obvious of a low
    hanging fruit, in my mind, but I think Bob was right to talk
    about heavy duty diesel on the transportation side as one of
    the other major contributors to combustion-related particles,
    to ozone, to a lot of urban air pollution. I think there's a
    lot of room for improvement in that direction as well.
        Senator Jeffords. Last question. In your opinion, would the
    current particulate matter standards be sufficiently able to
    meet the Clean Air Act mandate of protecting sensitive
    populations with an adequate margin of safety? If not, do you
    think EPA should consider a stricter standard?
        Mr. O'Keefe. I have to leave now.
        [Laughter.]
        Dr. Samet. I have to leave before him.
        [Laughter.]
        Dr. Samet. I'll just comment. This language is very
    difficult to interpret. In fact, I have chaired a committee of
    the American Thoracic Society, which wrote a statement on what
    constitutes an adverse health effect of air pollution, where we
    grappled with some of the complexity of the language of the
    Clean Air Act, in part around the issue that you raised. I
    think in terms of achieving an adequate margin of safety, that
    implies that we can identify a level below which effects don't
    occur. We can then build in the margin of safety and say, ``set
    a standard here.''
        What I think you've heard from myself and others along the
    table today is that we can't yet identify such a point, that
    the evidence, we're finding a signal of an adverse effect, even
    as we go down to the lower levels we have today.
        So the answer right now is, we haven't identified a
    ``safe'' level of effect that would allow us to meet that
    margin of safety statement in the Clean Air Act.
        Senator Jeffords. Mr. O'Keefe.
        Mr. O'Keefe. I think the threshold issue is a tough one for
    this particular pollutant. I know, and appreciate the nature of
    your question. I will say that almost as we speak, EPA, its
    Clean Air Act Scientific Advisory Committee and many others are
    sifting through the weight of the evidence that's emerged over
    the last 5 years to draw exactly, to make exactly this
    determination. That process is about two-thirds of the way
    through, and I will wait to hear what they say, actually.
        Senator Jeffords. Mr. Wyzga.
        Mr. Wyzga. I guess first of all, I'm going to get in
    trouble if I make a policy statement with my employer. So this
    isn't a policy statement. But I think one of the premises of
    the Clean Air Act is that there is some threshold below which
    there are no health effects. We're having difficulty basically
    identifying such a threshold. So I think we might have to sort
    of think, are there new ways to set standards.
        Senator Jeffords. Interesting.
        Mr. Rose.
        Mr. Rose. Sorry, but I don't know.
        Senator Jeffords. Mr. Levy.
        Mr. Levy. Batting cleanup, I have to once again echo some
    of the other comments. I agree that what the health literature
    is showing, seemingly no threshold, or at least that we have
    not yet gotten down to a threshold, the concept of trying to
    then set a threshold that adequately protects sensitive
    subpopulations seems a bit contradictory. I agree with Ron's
    statement that maybe we need to start thinking of alternative
    ways of formulating these standards.
        Senator Jeffords. Well, thank you all very much. This has
    been extremely helpful to the committee. I appreciate all the
    work that went into being here today. That concludes our
    session. Thank you.
        [Whereupon, at 3:16 p.m., the committee was adjourned, to
    reconvene at the call of the chair.]
        [Additional statements submitted for the record follow:]

      Statement of Jonathan M. Samet, M.D., M.S., Professor and Chairman,
     Department of Epidemiology, Bloomberg School of Public Health, Johns
                               Hopkins University

                                  INTRODUCTION

        Senator Jeffords and members of the Senate Committee on Environment
    and Public Works, thank you for the opportunity to speak with you today
    concerning the health effects of particulate matter and particularly
    fine particulate matter arising from power plant emissions. This topic
    has been a focus of my research for several decades. As background, my
    training includes medicine with specialization in internal medicine and
    subspecialization in pulmonary diseases. I also have a Masters degree
    in epidemiology from the Harvard School of Public Health and my career
    has been spent in the settings of academic medicine, largely at the
    University of New Mexico School of Medicine, and of academic public
    health, now at the Johns Hopkins Bloomberg School of Public Health
    where I am professor and chair of the Department of Epidemiology.
        Over 20 years ago, I first carried out research directed at the
    health effects of particulate matter. These studies were carried out in
    Steubenville, Ohio, where we assessed how air pollution affected the
    numbers of persons needing care for respiratory and other diseases in
    the emergency room of the community hospital, and in western
    Pennsylvania, where we carried out a series of studies to assess the
    effects of large, coal-fired power plants on the respiratory health of
    women and children in the surrounding communities. With colleagues at
    Harvard and Marshall University, I participated in an extensive study
    of the respiratory health of children in Kanawha County, West Virginia,
    following the Bhopal episode. Since 1994, with colleagues at Johns
    Hopkins, my research has focused on the effect of airborne particles
    and other pollutants on mortality. Our most recent work, the National
    Morbidity, Mortality, and Air Pollution Study (NMMAPS) uses publicly
    available data from the 90 largest cities in the United States to
    provide a national picture of the effect of particles on mortality,
    both total and from cardiac and respiratory causes of death. I have
    also conducted large studies directed at indoor air pollutants, such as
    tobacco smoke and nitrogen dioxide.
        Because of my research interest in particulate air pollution, I
    have served as a consultant member of the Clean Air Scientific Advisory
    Committee (CASAC) of the Environmental Protection Agency's Science
    Advisory Board for the mid-1990s review of the Particulate Matter (PM)
    National Ambient Air Quality Standard (NAAQS) and again for the review
    now in progress. I also chair the National Research Council's Committee
    on Research Priorities for Airborne Particulate Matter, which set out a
    national plan for research on particulate matter in its first report in
    1998. The committee is now evaluating progress since 1998 in reducing
    scientific uncertainties concerning particulate matter.

            WHAT IS PARTICULATE MATTER AND HOW ARE WE EXPOSED TO IT?

        The air that we breathe contains myriad particles that come from
    numerous sources that are both natural, e.g., the abrasive action of
    wind, and are generated by human activity, e.g., the burning of coal in
    a power plant. There are both outdoor and indoor sources, such as
    cigarette smoking and cooking. The particles in air are a complex
    mixture reflecting the diversity of these sources; they vary in
    chemical composition, shape, and size. The particles include sand,
    pollen and other biological materials, carbonaceous material from
    combustion, and particles formed secondarily from chemical and physical
    transformations of gaseous emissions from combustion and other sources.
        Particles are often described by their size, which is a key
    determinant of how long they remain suspended in the air and also of
    whether they will reach the lung when inhaled and where they will
    deposit in the lung. The size of particles is described by their
    aerodynamic diameter in microns, a measure that is based on equivalence
    to a particle having a standard size and mass. Typically, in urban air,
    the distribution of particles by size is trimodal. The largest size
    mode, generally above about 5 microns in aerodynamic diameter,
    primarily contains dust and other particles that have been resuspended
    by wind and mechanical action, e.g., motor vehicles, and also some
    large biological particles, such as pollens. The intermediate size
    mode, centered below one micron contains primarily products formed by
    combustion including primary particles emitted directly by the sources,
    such as diesel soot, and particles formed secondarily. There may be a
    third size mode of very tiny particles that are the immediate
    consequence of combustion.
        These size characteristics are quite relevant to health
    considerations since larger particles tend to be filtered out by
    defense mechanisms in the nose and upper airway, and only the smaller
    particles, less than approximately 3.5 microns reach the lung. The
    sites of deposition within the lung also depend on size; the smaller
    particles tend to penetrate more deeply, reaching the smallest airways
    and the lung's alveoli or air sacs. Thus, injury to the lungs and other
    organ systems from particulate air pollution is thought to result
    primarily from the smaller particles. There is also concern, however,
    that persons with asthma may be adversely affected by responses to the
    larger particles that reach the upper airway.
        The Environmental Protection Agency has set NAAQS for progressively
    smaller size fractions of particles, reflecting evolving understanding
    of how particles affect health and also measurement capability. The
    first particle standard was for Total Suspended Particles (TSP), which
    encompassed nearly all airborne particles. That standard was replaced
    in 1987 by a standard for PM10 and the new standard for
    PM2.5 was added with the 1997 NAAQS revisions. The shift
    towards measuring and regulating smaller size fractions is well
    justified by scientific knowledge of the behavior of particles in the
    respiratory system. The size fractions for PM are inclusive: that is
    PM2.5 includes all particles below the 2.5 micron diameter
    cut-point and PM10 does include the PM2.5 size
    fraction. Consequently, studies of PM10 can inform
    understanding of the health effects of PM2.5.
        We are exposed to particles in all places where we spend time, both
    indoors and outdoors. While we spend relatively little time outdoors,
    particles in outdoor air, particularly the finer particles, do
    penetrate indoors. Consequently, the doses of particles from outdoor
    sources like power plants are received not only while we are outdoors,
    but also while we are indoors.

                        HOW DO PARTICLES AFFECT HEALTH?

         We inhale about 10,000 liters of air per day containing countless
    particles. Fortunately, the lung does have mechanisms for removing
    particles and for detoxifying them but these mechanisms may not be
    sufficient if the particles are too numerous or have high toxicity. The
    general mechanisms of particle toxicity appear to reflect the
    inflammatory responses that they evoke in the lung following
    deposition. There may be more specific mechanisms at play as well,
    reflecting immune responses to antigens or the actions of carcinogens
    in particles. While scientific understanding of these mechanisms is
    still evolving, we have evidence that particles stimulate the lung's
    inflammatory cells, leading to the release of various mediators that
    continue the inflammatory process. Particles are thought to possibly
    affect the heart by release of mediators into the circulation. The
    severity of the response to particles and perhaps the nature of the
    response itself are likely to vary with key characteristics of the
    particles, such as metal content, acidity, or the various organics that
    are adsorbed on the surfaces of particles. Better understanding of the
    toxicity--determining characteristics of particles is one of the
    research priorities set by the National Research Council's Committee.

        WHAT DO WE KNOW ABOUT THE HEALTH EFFECTS OF PARTICULATE MATTER?

        The health effects of air pollution have been investigated for
    about half-century, following the extraordinary air pollution disasters
    in Donora, Pennsylvania in 1948 and in London in 1952. These and other
    episodes of evident excess mortality and morbidity showed that high
    levels of air pollution could quickly damage the public's health. Over
    the 50 years that the health effects of air pollution have been
    investigated, we have carried out many studies in communities using
    epidemiological approaches to assess the health effects of air
    pollution, including particulate matter. One challenge faced by
    researchers in investigating the health effects of air pollution is to
    attempt to separate the effects of one pollutant from the others that
    co-exist in the pollutant mixture that is present in the air that we
    breathe. Nonetheless, substantial evidence has now accumulated, much of
    it summarized in the references that I have cited in the bibliography
    for this testimony.
        I will focus on summarizing the more recent literature, as the
    earlier studies were generally carried out at levels of air pollution
    that are higher than measured today and the characteristics of the air
    pollution mixture have changed over time, as sources have changed both
    in their numbers and characteristics. Because researchers often use the
    monitoring data collected for regulatory purposes, most of the recent
    evidence on PM draws on measures of PM10, rather than
    PM2.5 as a national monitoring network for PM2.5
    has only recently been implemented.
        A 1996 review by the American Thoracic Society offered a summary of
    literature to that time, synthesizing the information concerning major
    pollutants and listing health effects among the populations at greatest
    risk (Table 1). The more recent scientific literature includes
    thousands of papers on particles, so that I can only offer a general
    summary of the findings. The following general conclusions can be
    offered based on the now available evidence:
         Daily Mortality: Beginning in the early 1990s, many
    studies carried out in the United States and other countries have
    linked daily mortality counts to levels of air pollutants, and
    specifically to particles, on the same or recent days. More recently,
    several multi-city studies, including our NMMAPS project, have
    confirmed the association of particulate air pollution with mortality
    from all causes and from cardiovascular and respiratory causes. As
    anticipated, based on the concept that persons with chronic
    cardiovascular and respiratory diseases are vulnerable to air
    pollution, the effect of particles is stronger for cardiac and
    respiratory causes than for total mortality. In the multi-city
    approach, we are able to take better control for other pollutants in
    assessing effects of particles than with the single city approach. In
    NMMAPS, we estimate that the effect of PM10 on mortality is
    an increment of about 0.2% for each 10 microgram per cubic meter
    increase in concentration. Chicago, for example, has about 100 deaths
    daily; with a 20 microgram increment in concentration, about 0.5
    additional deaths are projected on average. While we and others have
    recently needed to update our findings because of a previously
    unidentified statistical issue, the findings are proving robust in
    showing increased daily mortality associated with air pollution.
         Long-Term Mortality: The daily time-series studies
    indicate an effect of particles on mortality rates, but the data do not
    provide an indication of longer-term consequences. Longer-term follow-
    up or cohort studies provide information relevant to the question of
    the extent of life-shortening resulting from particulate air pollution.
    The strongest evidence on this question comes from two studies: the
    Harvard Six Cities Study and the American Cancer Society's Cancer
    Prevention Study II (CPS II). Both studies show that persons living in
    more polluted communities tend to have higher mortality rates over the
    approximately two decades that the participants in these studies have
    been observed. These analyses take into account factors that might
    artificially introduce an apparent association with air pollution, such
    as smoking and socioeconomic status. The initial findings from the two
    studies were replicated with a re-analysis organized by the
    Environmental Protection Agency. The general pattern of findings
    suggests that the increased mortality observed in these studies is most
    strongly associated with particulate air pollution. Several other
    studies have now been reported and others are in progress. Gaining a
    better understanding of the long-term effects of particulate air
    pollution is another of the research priorities of the National
    Research Council's committee.
         Hospitalization and Emergency Care: Using the time-series
    approach, a number of investigators have addressed associations of air
    pollution with daily counts of hospitalizations or emergency room
    visits. The files of the Medicare system have been used frequently for
    this purpose, as they provide nearly complete coverage of persons over
    65 years of age in most communities. For example, Drs. Joel Schwartz
    and Antonella Zanobetti at the Harvard School of Public Health and
    members of the NMMAPS team, analyzed Medicare data from 14 United
    States cities. They have found associations of PM10 with
    hospitalization for cardiovascular diseases and chronic obstructive
    pulmonary diseases. There have been similar findings from other
    investigators in the United States, Europe, and other countries.
         Cardiovascular Disease: Persons with chronic
    cardiovascular diseases, particularly coronary heart disease, have been
    considered as susceptible to air pollution exposure, including to
    particulate air pollution. A series of recent studies indicate possible
    adverse cardiac effects of particulate air pollution, although the
    evidence is still somewhat mixed and preliminary. Studies show that air
    pollution may adversely affect the heart's rhythm and even trigger
    potentially fatal rhythm disturbances in high-risk persons with
    implanted defibrillation devices. There are supporting experimental
    studies.
         Asthma: Persons with asthma are made susceptible to air
    pollution by the responsiveness of their lungs to environmental
    triggers. Studies that monitor the health status of persons with asthma
    on a day-to-day basis indicate that particulate air pollution can have
    adverse effects.
        In summary, there is now substantial epidemiological evidence
    linking particulate air pollution to adverse health effects, ranging
    from increased mortality and life-shortening to medical morbidity in
    people who are susceptible because they have a chronic heart or lung
    disease. While few of these studies have incorporated PM2.5
    as the primary exposure indicator, our understanding of particle
    dosimetry in the lungs implies that particles in the respirable size
    range are responsible for these effects. Emissions associated with
    power plants contribute to the PM2.5 mass in many locations
    in the U.S.

                     STUDIES OF THE IMPACT OF POWER PLANTS

        Studies have been carried out that directly address the health
    effects of coal-fired power plants on surrounding communities. In a
    recent review, a graduate student in the Department of Epidemiology of
    the Bloomberg School of Public health identified 16 publications (Table
    2) describing the findings of such studies. These source-directed
    studies considered the effects of multiple pollutants, including
    particulate matter. In general, their findings indicate adverse effects
    of coal-fired power plants on the public health in surrounding
    communities.

                            SUMMARY AND CONCLUSIONS

        The health effects of air pollution have been a focus of research
    for nearly a half century, giving clear evidence that the high levels
    of the past had obvious adverse effects on health and providing a
    warning that air pollution continues to adversely affect public health,
    even at the lower levels of outdoor air pollution today. While air
    pollution constitutes a complex mixture with many potentially toxic
    components, the evidence consistently indicates that airborne particles
    in urban environments have adverse effects on health, causing premature
    mortality and excess morbidity. Based on our knowledge of how particles
    penetrate into the lung, these effects likely reflect the deposition of
    smaller particles in the size range encompassed by PM2.5.
    These particles have many man-made sources, including vehicles,
    industry, and electric power generation by coal-fired power plants.
    Epidemiological studies of communities located adjacent to such plants
    show that the health of community residents can be harmed, although
    links to specific products of combustion cannot be made. Risk
    assessment approaches can be used for the purpose of estimating the
    burden of disease and ill health associated with power generation in
    coal-fired power plants.

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                                  BIBLIOGRAPHY

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    United States. 2000. Cambridge, MA: Health Effects Institute.
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                                   __________
      Statement of Ben Rose, Executive Director, The Green Mountain Club,
                                      Inc.

        Senator Jeffords, members of the committee, thank you for the
    opportunity to testify. My name is Ben Rose. I am the Executive
    Director of the Green Mountain Club, a 93-year-old member-supported
    not-for-profit hiking club headquartered in Waterbury Center, Vermont.
    The mission of the Green Mountain Club is to make the Vermont mountains
    play a larger part in the life of the people, by protecting and
    maintaining the Long Trail (a hiking trail which runs the length of
    Vermont from Massachusetts to Quebec) and by fostering, through
    education, the stewardship of Vermont's hiking trails and mountains.
    The southern 100 miles of the Long Trail are part of the Appalachian
    National Scenic Trail (AT) from Georgia to Maine, and the Green
    Mountain Club is one of 31 local clubs, which maintain specific
    sections of the AT. The Appalachian Trail is the longest linear
    national park in the world.
        Although most people do not associate scenic mountain ranges with
    smog, some of the dirtiest air in the United States is in our
    mountains.\1\ Mountain air is thick with fine particulate matter--
    largely sulfates derived from burning coal--as well as nitrates and
    ozone, byproducts of power plant nitrogen oxides emissions.
    Unfortunately, we know that the air is often at its worst in the higher
    elevations. This is of concern to the Green Mountain Club and sister
    organizations, as the Long Trail, Appalachian Trail and thousands of
    miles of other trails beckon hikers up into the poor quality air.
    ---------------------------------------------------------------------------
        \1\ ``Out of Sight: Haze in our National Parks: How Power Plants
    Cost Billions in Visitor enjoyment Clean Air Task Force for Clear the
    Air, September 2000. Available at: http://www.clnatf.org/publications/
    reports/out--of--sight.html. See also American Hiker, March/April
    2002).
    ---------------------------------------------------------------------------
        We also are concerned because we hire dozens of young people each
    summer as ridgeline caretakers, to work on the trails and to protect
    the unique alpine plants that exist only on our highest summits. These
    folks spend months at high elevations. They see lots of sulfate haze,
    and breathe it, too.
        In August 2002, during a stretch of severe haze, particulate matter
    and ozone smog in New England, three hikers were treated with oxygen
    near the summit of Mt. Washington, New Hampshire's highest peak, only
    tens of miles from the border with Vermont. Staff and hikers there
    reported nausea and shortness of breath.\2\ During the same period,
    vistas from New England mountaintops were shrouded in a thick white
    sulfur laden haze. These are the same pollutants that cause acid rain,
    forming sulfuric and nitric acids responsible for the high mortality
    rates in our high elevation spruce and fir forests.\3\
    ---------------------------------------------------------------------------
        \2\ Georgia Murray, Staff Scientist, Appalachian Mountain Club.
    Personal communication. September 2002.
        \3\ Dr. L. Bruce Hill, Senior Scientist, Clean Air Task Force.
    Personal communication. September 2002.
    ---------------------------------------------------------------------------
        While countless studies--many referred to by the medical
    researchers on this panel--have linked particulate matter to asthma
    attacks, heart attacks and premature death, little attention has been
    paid to the health affects of fine particulate matter on healthy people
    exercising outdoors, such as hikers.\4\
    ---------------------------------------------------------------------------
        \4\ ``Coal blamed for haze'', Atlanta Journal-Constitution. Friday,
    August 30, 2002
    ---------------------------------------------------------------------------
        The most important study to date on the subject was conducted
    during the summers of 1990 to 1992, when scientists from the Harvard
    School of Public Health and the Appalachian Mountain Club (AMC) studied
    the lung responses of hikers climbing Mount Washington in New Hampshire
    to fine particulate matter and ozone pollution.\5\
    ---------------------------------------------------------------------------
        \5\ ``Effects of Ozone and Other Pollutants on the Pulmonary
    Function of Adult Hikers'' by Korrick, Neas, Dockery, Gold, Allen,
    Hill, Kimball, Rosner, Speizer. Environmental Health Perspectives,
    Volume 106 Number 2, Feb. 1998. Conducted 1990-92, Pinkham Notch, New
    Hampshire, White Mountain National Forest by Harvard School of Public
    Health, Brigham and Women's Hospital and Appalachian Mountain Club.
    http://ehpnet1.niehs.nih.gov/docs/1998/106p93-99korrick/korrick-
    full.html
    ---------------------------------------------------------------------------
        Hikers' lung functions were measured using spirometers before and
    after their hikes. At the same time, ozone and PM2.5
    concentrations were measured in the air at the top and bottom of the
    mountain. Data was also collected regarding past respiratory history
    and fitness levels, and current smokers were excluded.\6\
    ---------------------------------------------------------------------------
        \6\ Ibid.
    ---------------------------------------------------------------------------
        In a nutshell, the results showed that healthy hikers experienced
    measurable declines in short-term lung function.\7\ related to ozone
    and as well as PM2.5.
    ---------------------------------------------------------------------------
        \7\ Ibid.
    ---------------------------------------------------------------------------
        Note that, although the PM2.5--correlation did not
    technically meet the 95th percentile confidence level, the study
    provides credible evidence that both ozone and particulate matter
    independently impact hiker's lungs. It is important to note that the
    air quality during the study was only moderate, with 1-hour and 8-hour
    ozone levels and PM2.5 well below the Federal standards.
    This means that even moderate levels of these pollutants reduce the
    lung function of healthy people exercising outdoors.
        The study recommended:

              ``Physicians, public health officials and the general public
            should be made aware of the potentially serious health affects
            of low-level air pollutants, not just in urban and industrial
            regions but specifically on those who engage in outdoor
            recreation in various wilderness areas.'' \8\
    ---------------------------------------------------------------------------
        \8\ Ibid.

        Currently a similar study is being conducted in the Great Smoky
    Mountains National Park in cooperation with the National Park Service
    and Emory University. Air quality in the Great Smoky Mountains is
    significantly worse than the air quality observed during the Mount
    Washington study. The Great Smokies have experienced 140 days of unsafe
    air quality over the past four summers.\9\
    ---------------------------------------------------------------------------
        \9\ Source: Jim Renfro, Air Quality Specialist, Great Smoky
    Mountains National Park, National Park Service.
    ---------------------------------------------------------------------------
        Old dirty power plants are the largest source of fine particulate
    air pollution in the region, accounting for half or more of the fine
    particulate matter and most of the sulfate deposition in the
    Appalachians.\10\ This means that these same plants are responsible for
    most of the haze and acid rain as well.\11\
    ---------------------------------------------------------------------------
        \10\ According to the National Park Service's ``Air Quality in
    National Parks'' 2nd edition, sulfate particles formed from sulfur
    dioxide emissions associated with fossil fuel combustion (mostly from
    electric generating facilities) accounts for up to 60%-80% of
    visibility impairment in eastern parks compared to only 30-40%
    visibility impairment in western states.
        \11\ Abt Associates (2000). Out of Sight: The Science and Economics
    of Visibility Impairment, Bethesda, MD. Available at: http://
    www.clnatf.org/publications.
    ---------------------------------------------------------------------------
        Many coal burning plants in the region and upwind were exempted
    under the Clean Air Act (CAA) and have not yet installed sulfur dioxide
    scrubbers or NOx catalysts,\12\ even though the technology has been
    available for many years.
    ---------------------------------------------------------------------------
        \12\ National Park and Conservation Assoc. (NPCA) Fact Sheet.
    ---------------------------------------------------------------------------
        Sulfur dioxide and nitrogen oxides from power plants form sulfates
    and nitrate particles that can be suspended in the air for weeks and
    can be transported hundreds of miles downwind into our wilderness
    areas, forests and parks.
        Grandfathered coal plants are endangering public health not only to
    those living in cities and industrial areas but also to those of us who
    exercise in and enjoy the outdoors.
        As a hiking club, we promote the benefits of outdoor exercise and
    fresh mountain air and yet we know that those who recreate in the
    mountains are being exposed to unhealthy air.
        Current air quality and national energy policy allow unsafe levels
    of fine particulate matter pollution in the air of Vermont, of Northern
    New England, and of the entire Appalachian Mountain chain that is
    harmful to our lungs and those of our children. People throughout the
    Eastern United States look to the mountains for clean fresh air. If
    they can't find it in Vermont, where can they go? We respectfully ask
    the Senate of the United States to act in support of aggressive
    measures to clean up power plants as embodied in S. 556 and reject
    measures that would weaken the Clean Air Act.
        Thank you.

                                   __________
               Statement Dr. Ronald E. Wyzga, EPRI, Palo Alto, CA

                                  INTRODUCTION

        I am Dr. Ronald E. Wyzga. I work for the Electric Power Research
    Institute (EPRI), in Palo Alto, California. EPRI, a voluntarily-funded
    501(c) (3) non-profit organization operating in the public interest, is
    almost 30 years old and has an annual budget of approximately $350
    million. EPRI's Environment Sector has an annual budget of
    approximately $50 million; this makes EPRI one of the largest
    privately-funded health and environmental research organizations in the
    world. Within the Environment Sector, I am responsible for air quality
    research, including research on the health effects of air pollution.
    The results of EPRI's health and environmental research is published
    and made publicly available, usually through the peer-reviewed
    scientific literature.
        I began my research career working on the relationship between
    health and air pollution (specifically particulate matter) while a
    graduate student at the Harvard School of Public Health, and my
    doctoral dissertation in biostatistics in 1971 addressed this topic.
    Since then I have been actively engaged in environmental health issues.
    I have co-authored a book and published over 50 peer-reviewed papers. I
    have served on and chaired subcommittees of the National Research
    Council (NRC), National Academy of Sciences. I currently serve on the
    NRC Committee on Research Priorities for Airborne Particulate Matter. I
    have also served on or chaired several EPA Science Advisory Board
    Committees, and I have been appointed a Fellow of the American
    Statistical Association. The comments that I present today reflect my
    personal views and judgments as a scientist who has worked in this area
    for over thirty years. These comments should not be construed to be the
    official opinion of my employer or of any associate.

                                    SUMMARY

        There are a large number of scientific studies that report a link
    between air pollution and human health. I have personally been involved
    in some, and EPRI has supported many more. The majority of these
    studies link particulate matter with health effects; however, some of
    these studies do not show an association with health, and other studies
    implicate gaseous pollutants in addition to, or in place of particulate
    matter. In any consideration of the health and air pollution issue, it
    is important to keep in mind that air pollution is a complex mixture of
    many different types of gases and particles. Discerning specific
    causative agents is a challenge we in the scientific community are
    working to address. Today I want to highlight some of the work that
    EPRI has recently been involved in to provide you with some of our
    latest results.
        There have been several major facets to our research:
        1. It is important to understand which specific components of air
    pollution are associated with health impacts. In studies undertaken to
    date, the strongest associations between air pollution and health are
    with particulate matter. In studies which include particulate matter
    (PM) and other pollutants, such as ozone and carbon monoxide (CO), in
    their analyses, PM is most consistently associated with health
    responses; there are, however, some exceptions where other pollutants,
    especially carbon monoxide, are most highly associated with health
    responses. Very few studies have considered a comprehensive set of the
    pollutants, especially the different chemical constituents of
    particulate matter, in their analyses. This is because monitoring
    programs currently only measure a small number of compounds.
        There are limited data on the toxicity of the different components
    of particulate matter. Few toxicology experiments have been undertaken
    examining the different fractions of PM, but those that have been done
    have found differences in toxicity for the different fractions. Other
    results show that the total quantity of PM by weight does not explain
    biological responses. Certain components in PM appear to explain the
    toxicity of PM more readily than total PM.
        2. The EPRI ARIES (Aerosol Research Inhalation Epidemiology Study)
    project was designed to examine the toxicity of the various components
    of PM and air pollution. This study is unique in terms of the number of
    air quality parameters measured and the number of health effects
    examined. This study, undertaken in Metropolitan Atlanta in conjunction
    with several universities, U.S. Department of Energy, and others,
    characterized the air quality on a daily or more frequent basis for
    over one hundred air quality variables. This characterization,
    accompanied by a suite of epidemiological studies, allowed us to
    examine the influence of the various components of air pollution on a
    variety of health outcomes.
        In general, the ARIES study is finding that different components of
    air pollution are associated with respiratory effects than are
    associated with cardiovascular effects (heart-related effects). More
    explanation of the preliminary results is given in the detailed
    testimony, but in summary, the respiratory effects appeared to be
    related to the gaseous pollutants (carbon monoxide, ozone, and nitrogen
    dioxide) and cardiovascular effects appeared to be associated with
    PM-2.5 (particles 2.5 microns in size and smaller) and
    carbon monoxide. However, the only fraction of PM-2.5 that
    showed any association with the cardiovascular effects were particles
    containing organic and elemental carbon. It is the PM-2.5
    fraction that has been at the center of attention as the potential
    cause of negative health impacts. For total mortality, the pollutants
    most consistently associated with premature death are oxygenated
    hydrocarbons, substances that to date have had limited study.
        3. EPRI has initiated smaller ARIES-like studies in Baltimore and
    St. Louis to determine whether the results from Atlanta can be
    replicated elsewhere. A major effort is also underway to launch a study
    very similar to ARIES in Chicago.
        4. A major toxicology effort will start soon in which the effects
    of coal combustion emissions will be investigated by exposing animals
    to diluted, aged emissions from power plants. This effort will provide
    important data to help evaluate different combinations of fuel type,
    control technologies, and burning configurations. The results of this
    work will be particularly useful to help inform and complement the
    research underway at the National Environmental Respiratory Center in
    Albuquerque, which is also evaluating the toxicity of emissions from
    diesel and gasoline engines, as well as wood smoke.
        5. EPRI has also been active in trying to understand the
    implications of alternative statistical methods used in the analyses of
    epidemiological data. Given the recent discovery that the applications
    of statistical software have led to erroneous results in some pollution
    health studies, the EPA is delaying its review of particulate matter
    health effects. Other statistical analyses require judgments that can
    impact their outcome. It is important to understand these potential
    impacts.
        6. EPRI has undertaken studies to understand the nature of exposure
    to the various constituents of air pollution, including particulate
    matter and its major constituents. We have found that there appears to
    be a better association between personal exposure to particulate matter
    and outdoor measured levels than there is for many of the gaseous
    pollutants.
        What is particularly important is that recent results suggest that
    there are short periods of time (in specific environments) when
    personal exposures to pollutants are much higher (by factors of 5 for
    PM and over 50 for carbonaceous particles) than the levels that we
    measure at our monitoring stations. We need to establish whether these
    short-term peak exposures are related to health responses.
        7. Our joint study with Washington University of some 50,000
    Veterans was designed to answer the question of whether there are long-
    term (chronic) effects associated with air pollution. In this study we
    found that after adjusting for many other factors Veterans who lived in
    cities with higher levels of nitrogen dioxide and very high ozone
    levels died earlier than those living in cleaner cities. We could find
    no such effect, however, when we examined particulate matter.

                               SCIENTIFIC ISSUES

        There is a clear association between air pollution and health in
    the U.S. at pollution levels we have experienced in the 1990s and
    earlier. Several different types of epidemiological studies, undertaken
    at a wide variety of locations, have found associations between air
    pollution and human health effects in the U.S.. Among the various
    pollutants examined, the strongest associations between air pollution
    and health are for particulate matter (PM). Many of the earlier studies
    (pre-1990s) considered just one or a limited number of pollutants; in
    these studies, PM was frequently studied and found to be associated
    with health effects. Later studies more frequently examined multiple
    pollutants. Most of these studies also found associations between PM
    and health effects, although a subset of the studies found greater
    associations between health effects and other pollutants, especially
    carbon monoxide (CO). In interpreting the results of these studies,
    several factors must be taken into account. First, the pollution
    measurements used in these studies were made at outdoor monitoring
    sites; these are not necessarily representative of personal exposures
    to these pollutants. We now have some limited data on the differences
    between personal exposures and outdoor measurements. These differences
    are not the same for every pollutant measured, leading to possible
    statistical impacts on the results of the analyses of the relationships
    between air pollution and health.
        Second, studies can only consider pollutants for which measurement
    data are available, and only a few pollutants/substances are generally
    measured. If the pollutant(s) that are truly responsible for health
    effects are not measured, then other pollutants that are measured and
    present at the same time as the responsible pollutants can be
    associated statistically with health effects. In such cases what we
    measure and use in our analyses could be a surrogate for something that
    is not measured. In all of our study results we need to keep this in
    mind. The only way to overcome this issue is to measure as many
    components of air pollution as possible, hopefully including the true
    culprit (or culprits), which only detailed analyses can reveal.
        There is as yet no accepted biological explanation for the link
    between the levels of pollution found in the U.S. today and observed
    health responses. Past research has focused on epidemiological
    studies--observational studies on humans going about their normal
    activities. Laboratory research, which has been limited to date, can
    focus on establishing the underlying biological mechanisms that can
    cause negative health effects. Several possible biological explanations
    have been put forth to explain the results from epidemiological
    studies, and recent laboratory results support some of these
    hypotheses. For example, one study appeared to show that blood clotting
    can increase with exposure to higher levels of fine particulates. If
    this occurs, it could be an explanation for why some heart disease
    effects are related to fine particulate levels in epidemiological
    studies. At this time, I believe that the most likely scenario is that
    a combination of explanations is responsible for the effects observed,
    with different mechanisms acting for different air pollution/PM
    components. Different mechanisms may also be acting in susceptible
    individuals, such as asthmatics or those with hypertension. Clearly,
    much more work is needed to gain insight into the mechanism(s) of PM
    action.
        Particulate matter is a complex mixture and its composition varies
    over time and place. Some of these major components (e.g., organic
    matter) contain hundreds of chemical compounds. The most important
    fractions of PM are carbon-containing particles and sulfate in the
    Eastern U.S., with carbon-containing particles being more important in
    urban areas. In the Western U.S., nitrates are more important and
    sulfates are generally less important.
        There are limited data on the toxicity of the different components
    of particulate matter. Several PM components have been hypothesized to
    play a role in toxic responses, including acid aerosols, metals,
    sulfates, nitrates, ultrafine particles (very tiny particles much
    smaller than the PM-2.5 particles), bioaerosols (including
    pollen and mold spores), diesel exhaust particles, and organic
    compounds. Toxicological and human exposure evidence suggests that acid
    aerosols do not contribute much to the adverse respiratory outcomes
    observed in epidemiological studies; however, acid components have not
    been assessed thoroughly with respect to potential cardiovascular
    effects. Metals have been shown in multiple studies to cause cell
    injury and other effects. Particle size, specifically the ultrafine
    fraction, may also be important in the development of health effects. A
    number of studies have investigated the effects of ultrafine particles
    and have found lung inflammation and other respiratory effects,
    although it appears that chemical composition may play a key role in
    the responses observed. Cardiovascular and systemic effects of
    ultrafine particles have been investigated to only a limited extent.
    Bioaerosols are not considered to account for the reported health
    effects of ambient PM as their concentrations are very low and health
    effects can occur at times when bioaerosol concentrations are low.
    Toxicological evidence is accumulating to suggest that diesel PM can
    exacerbate the allergic response to inhaled allergenic material.
        Finally, the organic compounds associated with PM have been little-
    studied from a toxicological perspective, although they represent a
    substantial portion of the mass of ambient PM (10-60% of total dry
    mass). Other fractions of PM, including sulfates and nitrates, appear
    to be of less concern.
        In a recent draft report, the Netherlands Aerosol Programme
    concluded: ``Based upon current toxicological and human clinical
    knowledge: water, sea salt, ammonium sulfate, ammonium nitrate, and
    probably non-crystalline crustal material too, can be considered an
    inert part of PM-10 at the ambient concentrations in the
    Netherlands.'' This report has not yet been finalized, and the
    conclusions are still under discussion.
        In order to more fully understand which components of PM are
    responsible for the health effects observed, additional toxicological
    studies must be conducted. Studies which examine the toxicity of
    emissions from various sources of pollution can be informative in
    identifying those pollutants (and sources) most highly associated with
    health effects.
        The EPRI ARIES study was designed to examine the toxicity of the
    various components of PM and air pollution. This study is unique in
    terms of the number of air quality constituents measured and the number
    of health effects examined. The best way to increase our understanding
    of the types of PM and air pollution that may be responsible for the
    health effects observed in other studies is to undertake a study in
    which all of the potentially relevant fractions of PM are measured.
    Traditionally we only measure what is required because of local, state
    or Federal regulations. On occasion a research study may measure a
    larger array of air pollutants, but it is rare to have a large number
    of constituents measured systematically over an extended period of
    time. ARIES addresses this need through detailed air quality
    characterization for a period of over two years and through undertaking
    several epidemiological studies to relate air quality characteristics
    to health effects. Appendix A provides further details about ARIES.
        Extensive daily--and in some cases continuous--measurements were
    made for all of the particle size fractions and constituents about
    which concerns have been raised. At the same time, several
    epidemiological studies were undertaken to examine the potential health
    effects of the various constituents. Initial results from the
    analytical team focused on the subset of air pollution measures tied to
    the major existing hypotheses about the pollution/health relationship.
    Results based upon the first year's data have been published in peer-
    reviewed journals; two years of data have now been analyzed and
    manuscripts based upon analyses of two years worth of data are now
    under preparation for peer review. The draft results are very
    informative, and I would like to share them with you.
        These results are complex and reflect a methodology that examined
    pollutants individually. Analyses which consider several pollutants
    simultaneously are planned and may help identify the pollution
    components that are of greatest concern.
         Several pollutants are statistically significantly
    associated with mortality of those over 65 years old; they include
    PM-2.5, PM-10, CO (carbon monoxide), and
    oxygenated hydrocarbons. When alternative statistical models were
    applied, the results were most consistent for oxygenated hydrocarbons,
    a pollutant that has not previously been considered in air pollution
    health studies.
        Results are available for several morbidity (disease) measures
    including emergency room admissions to Atlanta area hospitals,
    unscheduled physician visits to a health maintenance organization
    (HMO), and responses of defibrillator devices implanted in patients
    with erratic heart rhythms. Preliminary analyses of heart rate
    variability considered only PM-2.5 and not its components
    nor gases. Based on these limited data, PM-2.5 was found to
    be associated with statistically-significant changes in heart rate
    variability.
         Lung and respiratory problems were related to PM-10
    and to pollutant gases including ozone, nitrogen dioxide, and carbon
    monoxide.
         Heart disease responses were much more likely to be
    related to PM-2.5, carbon monoxide, and nitrogen dioxide.
         Organic compounds were associated with several
    cardiovascular effects.
         When the components of PM-2.5 were considered,
    the only ones found to be significant were elemental and organic
    carbon.
         There was little evidence of any health effects tied to
    acid aerosols.
         No associations were found between any health effect and
    total soluble metals; additional analyses are planned to look at
    individual metals.
         No associations were found with ultrafine particles. Since
    the concentrations of these particles appear to change so rapidly over
    time and space, it is doubtful that the ARIES study could shed much
    light on the effects of these particles. Nevertheless, their
    concentrations are unrelated to the concentrations of other particle
    fractions; hence it is unlikely that ultrafine particles can explain
    the association seen with other particles.
         No cardiovascular or respiratory effects were associated
    with sulfates.
        ARIES did not look at sources of pollution directly. We did,
    however, undertake a source-attribution analysis of the organic
    compounds in Atlanta. Cardiovascular effects were found in the winter
    months only in this study. In the winter months, organic compound
    concentrations were tied principally to wood smoke, although diesel
    emissions were also a contributor. Diesel emissions were also a major
    contributor to organic compounds in the summer months when no
    cardiovascular effects were related to these compounds.
        There is a great need for additional studies which focus upon the
    specific components of particulate matter and examine their
    relationship to human health. The ARIES study will provide an important
    piece of evidence in understanding which fractions of PM and of air
    pollution are the most important in affecting human health. ARIES
    results are from one metropolitan area, Atlanta. Atlanta is a logical
    place for a study; it has high pollution levels, many sources of
    pollution, and no unique sources of pollution that would yield a unique
    result. Nevertheless it is important to undertake similar studies in
    other metropolitan areas. We are now engaged in similar, although more
    limited, studies in St. Louis and Baltimore, where detailed monitoring
    is underway. Much of this monitoring is funded by EPA's supersites
    monitoring program. Undertaking such studies is expensive because the
    air quality monitoring itself is costly; hence, governmental resources
    to undertake such studies are critical.
        Secondly, more laboratory studies are needed which examine specific
    fractions of particulate matter and its toxicity. Since it would be
    very costly and time-consuming to test all specific compounds
    rigorously in laboratories, special protocols should be considered
    which examine the mixture of pollutants associated with specific
    sources. For example, studies are now underway at the National
    Environmental Respiratory Center to examine the toxicity of emissions
    from several sources. EPRI is planning some similar efforts, but
    clearly more research is needed. There are a large variety of emissions
    from different sources, and we need to learn how these emissions
    interact with other pollution elements once they enter the environment
    at large.
        An ongoing committee of the National Research Council, of which I
    am a member, will issue a report next year identifying the highest
    priority research needs to inform particulate matter-health policy
    issues.
        The implications of the statistical methods used to investigate the
    relationship between health and air pollution need to be fully
    understood. A recent announcement by researchers at Johns Hopkins
    University raised some issues about the past use of one particular
    statistical approach and its related software. Fortuitously, at a
    meeting of EPRI researchers with our advisors, it was decided to use
    alternative statistical methods in our research, and we have examined
    these methods thoroughly. We have found that, on occasion, ARIES
    results, especially in the mortality analyses, can be influenced by
    changes in the statistical approach even when the alternative
    approaches are judged reasonable by statisticians. For example, carbon
    monoxide (CO) was found to be statistically significantly associated
    with deaths of those over 65 years old with one approach but not with
    the other. Fortunately most results were similar across the various
    approaches, but because there are some differences, it is important to
    articulate and understand these differences.

                                  CONCLUSIONS

        1. Air pollution likely impacts the health of individuals in the
    U.S. today.
        2. Particulate matter is a likely candidate to explain these
    impacts.
        3. Not all fractions of particulate matter appear to be equally
    toxic.
        4. When health effects are associated with fine particles, our
    research points strongly to carbon-containing particles as the agents
    of concern; in most U.S. cities, carbon-containing particles are also
    the largest particle component by weight.
        5. Gaseous pollutants are still of concern and cannot be ignored.
        6. There is a strong need to identify with more certainty those
    specific components of air pollution which cause health effects.
        7. We need to understand in more detail the personal exposure of
    susceptible individuals to the various air pollution components. In
    particular, we need to identify when and where peak exposures occur and
    whether these peaks are important to health.
        8. There is a great need to apply alternative statistical methods
    in analyzing data and to understand the influence of a specific method.
        9. Decreasing the non-toxic part of particulate matter will not
    reduce health risks.

                                   Appendix A

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     Statement of Robert O'Keefe, Vice President, Health Effects Institute
        Mr. Chairman, members of the committee, it is a pleasure to have
    this chance to appear before you to share the perspective of the Health
    Effects Institute on what we have learned and what we still need to
    learn about the health effects of particulate matter. For the record, I
    am Robert O'Keefe, Vice President of the Health Effects Institute, an
    independent research institute funded jointly and equally by the US EPA
    and industry to provide impartial and high quality science on the
    health effects of air pollution.

           THE DATA WE HAD IN 1997--SHORT AND LONG TERM EPIDEMIOLOGY

        In 1997, the US EPA promulgated a new set of National Ambient Air
    Quality Standards (NAAQS) for fine particulate matter
    (PM2.5). In large measure, that action was based on two
    types of epidemiology studies:
         There were nearly 40 short-term studies that found a
    statistical relationship between daily changes in air pollution and
    daily small but relatively consistent increases in daily levels of
    death, hospitalization, and illness (e.g. 1% to 2% increases in
    mortality for every 10 microgram/cubic meter increase in
    PM10);
         Two long-term ``cohort'' studies--the Harvard Six Cities
    Study and the Pope/American Cancer Society Study--that tracked selected
    populations of people in a series of more- and less-polluted cities,
    and found that those who lived in the most polluted cities had between
    a 17% and 26% higher risk of premature death than those who lived in
    the least polluted cities.
        These studies suggested that a measurable portion of mortality and
    respiratory and cardiac illness in the United States might be
    attributable to fine particle air pollution, and based on them, EPA set
    the new, more stringent NAAQS for PM2.5. At the same time,
    there were a number of questions about these studies, key among them:
         The individual short-term studies were done by diverse
    investigators using somewhat different methods--would a more systematic
    study find the same results?
         Could other pollutants, which occur along with
    PM2.5, be more likely to be responsible for the increased
    mortality?
         Did the deaths measured in these short-term studies
    represent substantial losses of life years, or the advancing of death
    for critically ill people by a few days?
         Did the exposures measured in these studies--at central
    air pollution monitors--accurately represent the exposures of people
    who in general spend most of their time indoors?
         Could the Harvard Six Cities Study and the American Cancer
    Society Study, whose data had only been analyzed by the original
    investigators, stand up to intensive scrutiny and analysis from new,
    independent investigators? Could there be other differences between the
    cities (e.g. differences in socioeconomic status or health care) that
    would also explain the differences in mortality?
        In addition to these questions about the epidemiology, there were
    also questions about the relative toxicity of the many different
    components of the complex PM mixture, and about the possible biological
    mechanisms that might explain the epidemiology results, questions that
    were laid out in a 1998 priority research agenda by the National
    Academy of Sciences Committee on Research Priorities for Airborne
    Particulate Matter.

                        WHAT HAVE WE LEARNED SINCE 1997?

        Since 1997, substantial new research has been undertaken to advance
    our understanding of the health effects of PM. As one part of the
    larger effort undertaken, HEI has invested in some 40 epidemiology,
    exposure, and toxicology studies to test the validity of the original
    studies, and to begin to answer the remaining questions.
        Key among HEI's work have been two efforts to determine the
    validity of the short- and long-term epidemiology studies--the National
    Morbidity, Mortality, and Air Pollution Study (or NMMAPS), and the
    Reanalysis of the Harvard Six Cities and American Cancer Society
    studies.
    The National Morbidity, Mortality, and Air Pollution Study (or NMMAPS)
        NMMAPS is a systematic study of air pollution, weather and
    mortality in the 90 largest cities in the United States, conducted--
    under the oversight, quality assurance procedures, and review of HEI--
    by investigators at Johns Hopkins University. NMMAPS also included
    similar analyses of air pollution and elderly hospitalization,
    conducted in 14 U.S. cities by investigators at Harvard University.
        In brief, this systematic and rigorous study found a consistent
    relationship between PM10 and mortality in the 90 largest
    cities of an approximately 0.4% increase in mortality for every 10
    micrograms increase in PM10. This level of effect was about
    half the size of that found in the earlier study, but as the graph in
    my testimony illustrates, this effect was not substantially affected by
    any of the other gaseous air pollutants. (See Figure 1) The NMMAPS
    investigators also found that at least a portion of the mortality was
    not solely frail people dying a few days early, but deaths advanced 30
    days or more, and conducted analyses that suggested that errors from
    using centrally-monitored air pollution to estimate exposure were not
    likely to change the basic results.

        [GRAPHIC] [TIFF OMITTED] T3723.019

        At the same time, this first nationwide analysis found differences
    in levels of effect across the U.S., suggesting that other factors,
    perhaps different mixes of pollution, could contribute along with
    particles to the effect. (See Figure 2) Overall, the NMMAPS analyses
    provided greater confidence in the results of the short-term
    epidemiology.

        [GRAPHIC] [TIFF OMITTED] T3723.020

        NMMAPS Update: This past Spring, members of the original team of
    investigators from the Johns Hopkins School of Public Health were
    conducting additional analysis on their findings of an association
    between daily changes in air pollution and mortality. In the course of
    testing these analyses against different assumptions and examining the
    methods used, they identified a generally unknown aspect of S-Plus, a
    statistical software package widely used by air pollution and other
    investigators to fit general additive models (GAMs) to data. In NMMAPS
    the investigators found that the result of using this approach was to
    overstate the effect estimates in this study. Upon notification of
    these new findings, HEI mobilized its NMMAPS Review Panel, Chaired by
    Dr. Sverre Vedal of the National Jewish Medical and Research Center in
    Denver. The panel provided initial peer review of the work of the
    investigators to apply alternative analytic techniques to the data to
    correct for this effect. In brief the Panel found that:
         most of the raw, unadjusted individual city estimates
    changed, with an increased number of estimates that were negative or
    zero;
         the mean effect estimate shifted from .41 increase in
    mortality for every 10 micrograms increase in PM10 (in the
    original study) to .21 percent (in the revised analysis);
         in the revised results, PM10 effect estimates
    are unaffected by the addition of co-pollutants such as ozone. (see
    Figure 3 below)

        [GRAPHIC] [TIFF OMITTED] T3723.021

        The HEI Panel continues to review the work of the investigator
    teams from both Johns Hopkins and Harvard to recalculate key analyses
    in the studies and provide comprehensive HEI peer review and
    commentary. A final report is expected in January. In addition, a
    number of other studies cited in EPA's current draft Criteria Document
    for Particulate Matter also use this software and may be affected in
    similar or different ways. To assess the nature and extent of this
    effect, US EPA and its Clean Air Scientific Advisory Committee (CASAC)
    at its July meeting set out a multi-step process to identify studies
    central to the NAAQS and recalculate key analyses in these studies.
    HEI, at the request of EPA and CASAC will play a central role in the
    review of these analyses.
    The Reanalysis of the Harvard Six Cities and American Cancer Society
            Studies
        In addition to NMMAPS, and in response to requests from Congress,
    US EPA, industry and others, HEI convened a detailed reanalysis of the
    Harvard Six Cities and American Cancer Society studies. Given full
    access to the entire medical and air pollution data base from the
    original investigators, HEI's Expert Panel selected an entirely new
    team of investigators, conducted a detailed quality assurance audit of
    the data and replication analyses, and then implemented a large number
    of sensitivity analyses to test whether some other difference between
    the most and least polluted cities (e.g. differences in the quality of
    medical care) could explain the increased mortality risk.
        In brief, the reanalysis assured the quality of the data,
    replicated the original results, and tested those results against
    alternative risk models and analytical approaches without substantively
    altering the original findings of an association between sulfates (a
    form of particles created in the atmosphere from coal combustion and
    other emissions) and fine particles (PM2.5) and mortality
    (see Table 1 below).

     Table 1.--Relative Risk of Mortality for Those Living in Most Polluted
             City in ACS Study for Original Analysis and Reanalyses
     [E.G., in original analysis those living in city with the highest PM2.5
                       had a 17% higher risk of mortality]
    ------------------------------------------------------------------------
                Analysis                     PM2.5             Sulfates
    ------------------------------------------------------------------------
    Original........................    1.17 (1.08,1.27)    1.15 (1.08,1.22)
    Full............................    1.18 (1.09,1.26)    1.15 (1.09,1.21)
    Extended........................    1.18 (1.09,1.26)    1.15 (1.09,1.21)
    ------------------------------------------------------------------------

        At the same time, the reanalyses extended and challenged our
    understanding of the original results:
         the effects on mortality appeared to increase for those
    with less education (and likely therefore of lower socioeconomic
    status;
         when the correlations among cities near one another were
    considered, the effects of fine particles remained but were diminished;
    and
         an association between sulfur dioxide (SO2) and
    mortality (but not other pollutants) was observed and persisted when
    other variables were included.
        In conclusion: the reanalysis identified relatively robust
    associations of mortality with fine particles, sulfate, and sulfur
    dioxide, and tested those associations in nearly every possible manner
    within the limitations of the data sets.
       key question for the longer term: are all particles created equal?
        To date, most analyses of the effects of particulate matter have
    focused on the mass of PM. Particles are, however, a complex mixture of
    pollutants, and over the longer term, it will be important to
    understand whether all particles have similar levels of toxicity, or
    whether some particles, and therefore some sources, contribute higher
    toxicity, and should be more stringently controlled. While there are
    many actions underway already to reduce overall particle levels--for
    example to control diesel vehicle PM emissions and nitrogen oxide
    emissions (a precursor of nitrates) from power plants--in the years to
    come, it will be especially important to develop the most cost-
    effective control strategies aimed at the most toxic sources, or at the
    most toxic components of those sources' emissions. This will be a
    critical area for new research.
        There are a number of components of PM that could cause toxicity.
    At a multi-disciplinary NARSTO/EPA workshop in July, 1998, the
    following key PM characteristics and components were identified:
         PM mass
         PM particle size, surface area
         Ultra fine PM
         Reactive transition metals
         Organic compounds (e.g. diesel PM)
         Acids
         Biogenic particles
         Sulfates and nitrates (e.g. from SO2 and NOx)
         Peroxides
         Soot
         Co-pollutants--SO2, CO, Ozone, etc.
        Research studies are now underway at EPA, HEI, EPRI, NIEHS, and
    other research institutions to begin to identify the relative toxicity
    of some of these components. Initial indication of the potency of some
    of these elements (e.g. the metals attached to PM) are beginning to
    emerge. In some cases, studies have looked at effects of emissions from
    power plants. Some studies have not found effects from exposure to
    sulfates; however other studies, including the reanalysis and
    toxicology studies, have found effects of sulfates and other potential
    emissions such as fly ash. Ultimately, identifying whether one or more
    of these components is especially toxic will require a systematic,
    multidisciplinary effort.
        To address these questions, the HEI Review Committee, in April
    2002, issued the second in its HEI Perspectives series entitled,
    ``Understanding the Health Effects of Components of the Particulate
    Matter Mix: Progress and Next Steps.'' This review, which I have
    provided to your staff and is available on the HEI web site at http://
    www.healtheffects.org/Pubs/Perspectives-2.pdf, summarizes recent HEI
    and other research on the effects of different components of the mix.
    It also lays out a systematic effort necessary to achieve a better
    understanding, including:
         Parallel epidemiology studies in carefully selected,
    representative cities throughout the U.S., with detailed daily
    characterization of the particle mixture;
         Companion toxicology studies using concentrated ambient
    particles, source-
    specific particles, and model particles to test the full range of
    health endpoints and mechanisms for each particle type.
        Many elements of such an effort are currently underway in the EPA
    research program and other efforts. A more systematic approach will
    require substantial resources dedicated over the next decade. However,
    the result of such an effort could be a better-focused and more cost-
    effective path to improved public health.

                      CONCLUSION: PROGRESS AND NEXT STEPS

        In conclusion, we have made much progress in the last five years,
    especially in testing the validity of the short- and long-term
    epidemiology studies which served as the primary basis for the setting
    of the 1997 NAAQS for particulate matter. We have tested a number of
    possible confounding factors, explored whether errors in measuring
    exposure might explain the relationships between PM and health, and
    analyzed whether different statistical techniques could change the
    results. In reviewing the latest evidence, the HEI Review Committee
    concluded ``epidemiologic evidence of PM's effects on mortality and
    morbidity persists even when alternative explanations have been largely
    addressed''. Based on this evidence, a number of initial control
    measures are now moving forward.
        At the same time, important new questions have arisen. In the near
    term it is necessary to complete the reassessment of NMMAPS and
    identify, reassess and provide peer review for other key studies that
    use GAM. Over the longer term, other important questions also remain,
    especially concerning the comparative toxicity of different components
    and sources of the PM mixture. Much research is underway to understand
    this important question and to inform and target future strategies for
    control of those emissions that may be most responsible. Only through a
    systematic effort to test and compare the toxicity of these diverse
    particles will we be able to have the best chance of answering these
    key questions for the future.
        Thank you again for the opportunity to present this testimony. I
    would be pleased to answer any questions you might have.

                                   __________
     Statement of Jonathan Levy, Assistant Professor, Environmental Health
    and Risk Assesment, Department of Environmental Health, Harvard School
                                of Public Health

        The materials included in this written testimony provide support
    for my oral presentation regarding the implications of the PM2.5
    health literature for power plant risk calculations.
        In my oral testimony, I focused on the evidence for mortality risks
    from particulate matter, given the important role that mortality has
    played in past benefits assessments of air pollution controls (such as
    the EPA's benefit-cost analysis of the Clean Air Act). I also asserted
    that there are three crucial questions that must be answered to
    quantify the public health benefits of power plant pollution controls:
        1. Is there a threshold below which no health effects of PM2.5
    are found, and if so, where is that threshold?
        2. Do all types of particulate matter have similar health impacts,
    or are some particles more toxic than others?
        3. Would alternative control strategies have significant impacts on
    the magnitude or distribution of particulate matter health impacts?
        Within this document, I address these three questions in greater
    detail, summarizing the key studies that inform my answers to these
    questions. Along with this summary document, I have included copies of
    selected documents that provide even more information about the core
    issues.

                             IS THERE A THRESHOLD?

        An initial point that is important to emphasize is that this is not
    the same question as whether PM2.5 concentrations are above
    or below National Ambient Air Quality Standards. Quoting directly from
    the US EPA in their Final Rule for the PM2.5 NAAQS, ``The
    Act does not require the Administrator to establish a primary NAAQS at
    a zero-risk level, but rather at a level that reduces risk sufficiently
    so as to protect public health with an adequate margin of safety.'' (p.
    3). The question is therefore whether the health literature provides
    evidence of a threshold above current ambient concentrations.
        First considering time-series studies, which evaluate the effects
    of changes in daily concentrations of PM on daily mortality risks, two
    major studies illustrate the nature of the literature (Daniels et al.,
    2000; Schwartz et al., 2002). The first of these studies used
    information from the National Morbidity, Mortality, and Air Pollution
    Study (NMMAPS) to evaluate whether a threshold existed for short-term
    exposure to PM10, either for total mortality or
    cardiovascular/respiratory mortality. The authors showed that for daily
    changes in PM10, linear models without thresholds were most
    appropriate for total or cardiovascular/respiratory mortality. When
    considered probabilistically, the threshold for total daily mortality
    appeared to be definitely below 30  g/m3 and was most likely
    below 15  g/m3. The second study used information from the
    Six Cities Study, considering daily mortality risks from changes in
    PM2.5 concentrations. As with the NMMAPS study, the authors
    concluded that a linear no-threshold model was most appropriate.
        Thresholds have also been examined in the cohort mortality
    literature, with the most recent evidence provided in the follow-up to
    the American Cancer Society cohort study (Pope et al., 2002). Within
    the range of concentrations in the study, there was no evidence of a
    threshold, and the relationship appeared approximately linear. The
    lowest concentrations reported in the study (averaged across the study
    period) were less than 10  g/m3.
        Thus, the epidemiological literature shows no evidence of a
    threshold for mortality risks at current ambient concentrations.
    Although this may be counter-intuitive, given the normal assumptions
    regarding thresholds for non-carcinogens, this relationship is
    biologically plausible. As explained in Schwartz et al. (2002),
    individuals will likely have thresholds, but if those thresholds differ
    widely across individuals based on numerous factors, then the
    distribution of thresholds across the population should be normally
    distributed. This would imply that the population concentration-
    response curve would approximately a cumulative normal curve, which is
    linear at low concentrations. In other words, if current particle
    levels were below the mortality threshold for most (but not all)
    people, then linearity with no population threshold would be expected.

             DO ALL TYPES OF PARTICLES HAVE SIMILAR HEALTH EFFECTS?

        Prior to evaluating the literature, it is important to frame this
    question appropriately. Because most of the epidemiological evidence
    available to date has been based on monitors that measure total
    particulate mass in various size ranges, it has been established that
    particulate matter concentrations are associated with mortality and
    morbidity. However, little information has been available about the
    relative toxicity of different types of particles, so the default
    assumption has been that all pollutants have equal toxicity.
        While that is unlikely to be the case, to deviate from this
    assumption, one must be able to quantify relative toxicities and defend
    these quantifications. Explicitly, for the case of power plant
    emissions, we would need to be able to estimate how toxic a sulfate or
    nitrate particle is relative to average particles. Clearly, this is not
    a question that can be answered with certainty, nor is it one that will
    be definitively solved in the near term.
        Focusing on epidemiological evidence, there are two types of
    studies available: studies that directly measured at least one of the
    constituents of interest (often sulfates) and studies that used
    statistical methods to try to determine source-specific differential
    toxicity. Each approach has advantages and limitations, and each can
    add to the body of evidence.
        In cohort mortality investigations, the primary evidence arises
    through the analysis of sulfates along with particulate mass in various
    size fractions. In the Harvard Six Cities Study (Dockey et al., 1993)
    and American Cancer Society study (Pope et al., 2002), long-term
    exposure to sulfates displayed a consistent positive association with
    premature mortality. In the latter publication, as well as in the
    Health Effects Institute reanalysis (Krewski et al., 2000), the authors
    concluded that some combination of PM2.5, sulfates, and
    possibly SO2 were associated with mortality. In a third
    cohort study (McDonnell et al., 2000), sulfates were not statistically
    significant, although the central estimate for mortality for male
    nonsmokers from sulfates was between the values from the Six Cities and
    American Cancer Society studies.
        In terms of the relative effect of sulfate versus general
    PM2.5, our power plant risk assessment in Massachusetts
    (Levy and Spengler, 2002) found that impacts were greater if either the
    reported sulfate-mortality or SO2-mortality relationship
    were applied rather than the PM2.5-mortality relationship.
    Thus, the cohort mortality literature generally shows sulfate effects
    that are significant, with a concentration-
    response function slightly greater than general PM2.5
    effects and no direct information available on other particulate
    species.
        In the time-series literature, much of the speciation data come
    from studies looking at sulfates. These studies have generally found
    positive associations, as indicated in the following figure (taken from
    the second external review draft of the Particulate Matter Criteria
    Document).

        [GRAPHIC] [TIFF OMITTED] T3723.022

        As indicated in the above figure, there has been preliminary
    evidence available from the supersite in Atlanta, which measures
    numerous chemical species (Klemm and Mason, 2000). This study found no
    statistically significant relationship for any particulate measures
    using one year of time-series data. Per unit concentration, the central
    estimates were higher for elemental carbon and sulfates than for
    PM2.5 as a whole, with lower central estimates for organic
    carbon and nitrates (although no values were statistically
    significant). In interpreting these results, it is important to realize
    that lack of statistical significance could be related to either a lack
    of an effect or a lack of statistical power to find an effect, given a
    relatively small sample size. If we look at the body of sulfate time-
    series studies in the above figure, we see that the Klemm and Mason
    findings in fact have a central estimate in line with much of the
    previous literature, but with substantially wider confidence intervals.
    Once this study is completed, it should be combined with other
    available studies to determine a best estimate for the time-series
    relationship between sulfates and mortality, taking into account
    relevant site and population characteristics (e.g., air conditioning
    prevalence) to generalize to the U.S. at large.
        Looking at studies of source-specific effects, a study by Laden and
    colleagues (2000) applied statistical methods to elemental data from
    the Six Cities study to determine source-specific particulate matter
    factors. Across all six cities, they found that the motor vehicle and
    coal factors had statistically significant effects on premature
    mortality, with the motor vehicle factor approximately a factor of
    three greater than the coal factor (per unit concentration). A crustal
    factor was not significant. Although the confidence intervals were
    wide, there was some evidence that cardiovascular deaths were more
    closely related to motor vehicle particles and respiratory deaths were
    more closely related to coal-derived particles.
        Additional factor--analytic studies include Ozkaynak and Thurston
    (1987) and Mar (2000). In the former study, based on cross--sectional
    mortality data across the U.S., particles from industrial sources and
    coal combustion had greater coefficients than those from motor vehicles
    or crustal sources. In the latter study in Phoenix, combustion-related
    pollutants (from motor vehicles and vegetative sources) and secondary
    sulfates were associated with cardiovascular mortality. A soil-related
    factor had a negative association with mortality. Thus, the findings
    from factor analytic studies appear to show lower toxicity of crustal
    particles, with significant effects from motor vehicles, power plants,
    and other combustion sources. However, the studies do not provide
    consistent quantitative evidence for greater toxicity of one combustion
    source category over another.
        In conclusion, while it is difficult to assign specific
    differential toxicities to different particle types, it does appear
    likely that combustion particles are more toxic than crustal particles.
    In studies looking at both sulfates and PM, the effect per unit
    concentration of sulfates is generally slightly higher, but the
    relatively small difference and the lack of substantial toxicological
    evidence makes a conclusion of equal toxicity reasonable as a central
    estimate for risk calculations.

         WHAT ARE THE MAGNITUDE AND DISTRIBUTION OF PM HEALTH EFFECTS
                               FROM POWER PLANTS?

        First considering the distributional question, it is clear that the
    impacts from a single power plant will vary spatially (since the
    concentrations associated with that plant will not be uniform across
    the country). The crucial question is whether populations near the
    power plants are disproportionately at risk or whether the impacts
    occur at longer distances, as this will influence the formulation of
    optimal control strategies.
        In our initial power plant analysis in Massachusetts (Levy and
    Spengler, 2002), we concluded that the answer to this question depended
    largely on how the question was framed. We distinguished between
    individual risk (the mortality risk to a given individual at a given
    location) and aggregate risk (the total public health impact associated
    with the facility). When we look at individual risk, the maximum occurs
    relatively close to the power plants--approximately 25-40 km away for
    the two plants studied in Massachusetts. However, because of the long-
    range transport of particulate matter and the number of people who are
    impacted at long range, most of the aggregate risk occurs at long
    range--more than half beyond 100 km, as illustrated in the figure below
    from Levy and Spengler (2002). Thus, we can conclude that individuals
    who live closer to a power plant are more impacted by that plant than
    individuals living further away, but that local populations contribute
    a relatively small fraction of aggregate risk.

        [GRAPHIC] [TIFF OMITTED] T3723.023

        Although this captures broad distributional trends related to
    distance from the source, another aspect of the distributional question
    is whether selected demographic groups are disproportionately affected
    by power plant air pollution. If this is the case, then a greater
    amount of the population risk occurs in a smaller set of individuals,
    which increases the importance of considering distributional issues.
        In a recent power plant risk assessment focused on the Washington,
    DC area (Levy et al., in press), we identified high-risk populations
    for selected health outcomes and evaluated the implications for the
    magnitude and distribution of health benefits. For the case of
    premature mortality, we considered the influence of educational
    attainment on mortality risk, as documented in Pope et al. (2002). We
    concluded that if the observational evidence from the American Cancer
    Society cohort study were correct, then more than half of the health
    benefits accrued among the 25% of the population with less than high
    school education. Furthermore, we showed that small-scale spatial
    variations were significantly influenced by the incorporation of
    population patterns, as illustrated by Figure 4 from Levy et al. (in
    press), a portion of which is reproduced on this page.

        [GRAPHIC] [TIFF OMITTED] T3723.024

        Finally, I turn to the question of estimating the magnitude of
    health impacts from power plant emissions. Making this estimate
    requires a multi-step process. First, the emissions of SO2
    and NOx are quantified (given the structure of multi-pollutant
    regulations and the focus on particulate matter impacts). Second,
    atmospheric dispersion models are used to evaluate the influence of
    these emissions on concentrations of PM2.5 across a large
    region. These concentration changes are then combined with
    epidemiological evidence to quantify the public health implications.
        As an example of this sort of analysis, Abt Associates (2000) used
    an economic model to estimate the distribution of SO2 and
    NOx emissions from the power sector given proposed emission controls,
    applied two atmospheric dispersion models to evaluate the national
    PM2.5 implications of these proposals, and linked the
    concentration changes with health evidence, including the mortality
    risk derived from the American Cancer Society cohort study. They
    concluded that current power plant emissions were associated with
    approximately 30,000 premature deaths per year, with a 75% reduction
    scenario yielding benefits of approximately 19,000 fewer premature
    deaths per year.
        A critical question is whether these estimates represent reasonable
    central estimates or are biased in either direction. In a recent
    investigation (Levy, 2002), I reviewed the methodology used by Abt
    Associates in a similar analysis, focusing on the question of bias. I
    considered separately the atmospheric model and the health evidence. I
    concluded that the atmospheric model yielded health impact estimates
    that were essentially identical to those using a different model, and
    that the concentration-response function chosen for premature mortality
    was a reasonable central estimate. Thus, it appeared equally likely
    that the Abt Associates methodology yielded an underestimate as an
    overestimate, making their findings a reasonable foundation for policy
    decisions.
        A similar methodology was used by the EPA to estimate the benefits
    of alternative power plant control policies. For example, the EPA
    estimated that the Clear Skies Act would reduce premature deaths by
    about 12,000 per year, by combining the results of atmospheric models
    and epidemiological studies (see www.epa.gov/clearskies). Similarly, an
    earlier straw proposal from the EPA (which had more stringent caps on
    both SO2 and NOx) was associated with a reduction of 19,000
    premature deaths per year. Again, this was based on a similar
    methodology as used by Abt Associates, implying that the estimate is a
    reasonable central estimate.
        From the above discussion, it is qualitatively clear that increased
    reductions of SO2 and NOx are likely to lead to increased
    public health benefits. While the above public health estimates are
    clearly uncertain, they appear just as likely to be underestimates as
    overestimates. Thus, it is reasonable to assume that the Clear Skies
    Act would provide substantial public health benefits, but that the EPA
    straw proposal (which is similar to the Clean Power Act) would increase
    those benefits by perhaps 7,000 fewer premature deaths per year. This
    implies that choices between status quo emissions, the Clear Skies Act,
    the Clean Power Act, and other alternative formulations should depend
    on a comparison of the incremental costs and benefits of increased
    stringency.

                               Attached Documents

        I have attached a subset of the studies cited above, which either
    expand on the arguments in this testimony or are not yet publicly
    available. Attached documents include:
         Levy J. Evaluation of Methodology in ``Particulate-Related
    Health Impacts of Eight Electric Utility Systems''. Prepared for
    Rockefeller Family Fund, June 2002.
         Levy JI, Greco SL, Spengler JD. The importance of
    population susceptibility for air pollution risk assessment: A case
    study of power plants near Washington, DC. Environ Health Perspect, in
    press, December 2002 expected.
         Levy JI, Spengler JD. Modeling the benefits of power plant
    emission controls in Massachusetts. J Air Waste Manage Assoc 52: 5-18
    (2002).
         Pope CA III, Burnett RT, Thun MJ, Calle EE, Krewski D, Ito
    K, Thurston GD. Lung cancer, cardiopulmonary mortality, and long-term
    exposure to fine particulate air pollution. JAMA 287:1132-1141 (2002).
         Schwartz J, Laden F, Zanobetti A. The concentration-
    response relationship between PM2.5 and daily deaths.
    Environ Health Perspect 110: 1025-1029 (2002).

                                   References

        Abt Associates, ICF Consulting, E.H. Pechan Associates. The
    Particulate-Related Health Benefits of Reducing Power Plant Emissions.
    Available: http://www.cleartheair.org/fact/mortality/mortalityabt.pdf,
    2000.
        Daniels MJ, Dominici F, Samet JM, Zeger SL. Estimating particulate
    matter-
    mortality dose-response curves and threshold levels: an analysis of
    daily time-series for the 20 largest U.S. cities. Am J Epidemiol 52:
    397-406 (2000).
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