[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

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                                                                   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

    1. Air Pollution and Health. Holgate ST, Samet JM, Koren HS, 
Maynard RL (eds). San Diego: Academic Press, 1999.
    2. American Thoracic Society, Committee of the Environmental and 
Occupational Health Assembly. Health effects of outdoor air pollution. 
Part 1. Am J Resp Crit Care Med 1996; 153: 3-50.
    3. American Thoracic Society, Committee of the Environmental and 
Occupational Health Assembly, Bascom R, Bromberg PA, Costa DA, Devlin 
R, et al. Health effects of outdoor air pollution. Part 2. Am J Resp 
Crit Care Med 1996; 153: 477-498.
    4. Samet JM, Zeger S, Dominici F, Curriero F, Coursac I, Dockery D, 
et al. The National Morbidity, Mortality, and Air Pollution Study 
(NMMAPS). Part 2. Morbidity and mortality from air pollution in the 
United States. 2000. Cambridge, MA: Health Effects Institute.
    5. Samet JM, Zeger S, Dominici F, Dockery D, Schwartz J. The 
National Morbidity, Mortality, and Air Pollution Study (NMMAPS). Part 
I. Methods and methodological issues. 2000. Cambridge, MA: Health 
Effects Institute.
    6. Anderson HR, Spix C, Medina S, Schouten J, Castellsague J, Rossi 
G, et al. Air pollution and daily admissions for chronic obstructive 
pulmonary disease in 6 European cities: results from the APHEA project. 
Eur Respir J 1997; 10: 1064-1071.
    7. Katsouyanni K, Schwartz J, Spix C, Touloumi G, Zmirou D, 
Zanobetti A, et al. Short-term effects of air pollution on health: A 
European approach using epidemiologic time series data: The APHEA 
protocol. J Epidemiol Community Health 1995; 50 (Suppl 1): S12-S18.
    8. Katsouyanni K, Touloumi G, Spix C, Schwartz J, Balducci F, 
Medina S, et al. Short-term effects of ambient sulphur dioxide and 
particulate matter on mortality in 12 European cities: results from the 
APHEA project. Br Med J 1997; 314: 1658-1663.
    9. Katsouyanni K, Touloumi G, Samoli E, Gryparis A, Le Tertre A, 
Monopolis Y, et al. Confounding and effect modification in the short-
term effects of ambient particles on total mortality: results from 29 
European cities within the APHEA2 project. Epidemiol 2001; 12: 521-531.
    10. Spix C, Anderson R, Schwartz J, Vigotti M, Le Tertre A, Vonk 
JM, et al. Short-term effects of air pollution on hospital admissions 
of respiratory diseases in Europe. A quantitative summary of the APHEA 
study results. Arch Environ Health 1997; 53: 54-64.
    11. Sunyer J, Spix C, Quenel P, Ponce de Leon A, Ponka A, 
Barumamdzadeh T, et al. Urban air pollution and emergency admissions 
for asthma in four European cities: The APHEA project. Thorax 1997; 52: 
760-765.
    12. Touloumi G, Samoli E, Katsouyanni K. Daily mortality and 
``winter type'' air pollution in Athens, Greece--a time series analysis 
within the APHEA project. J Epidemiol Community Health 1996; 50 (Suppl 
1): S47-S51.
    13. Touloumi G, Katsouyanni K, Zmirou D, Schwartz J, Spix C, Ponce 
de Leon A, et al. Short-term effects of ambient oxidant exposure on 
mortality: a combined analysis within the APHEA project. Am J Epidemiol 
1997; 146: 177-185.
    14. Zmirou D, Schwartz J, Saez M, Zanobetti A, Wojtyniak B, 
Touloumi G, et al. Time-series analysis of air pollution and cause-
specific mortality. Epidemiol 1998; 9 (5): 495-503.

                               __________
  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.
      
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    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.
      
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    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)
      
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    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).
      
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    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.
      
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    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).
    Dockery DW, Pope CA III, Xu X, Spengler JD, Ware JH, Fay ME, Ferris 
BG. Jr., Speizer FE. An association between air pollution and mortality 
in six U.S. cities. N Engl J Med 329: 1753-1759 (1993).
    Klemm RJ, Mason RM Jr. Aerosol research and inhalation 
epidemiological study (ARIES): air quality and daily mortality 
statistical modeling--interim results. J Air Waste Manage Assoc 50: 
1433-1439 (2000).
    Krewski D, Burnett RT, Goldberg MS, Hoover K, Siemiatycki J, 
Jerrett M, Abrahamowicz M, White WH. Reanalysis of the Harvard Six 
Cities Study and the American Cancer Society Study of Particulate Air 
Pollution and Mortality. Cambridge, MA: Health Effects Institute 
(2000).
    Laden F, Neas LM, Dockery DW, Schwartz J. Association of fine 
particulate matter from different sources with daily mortality in six 
U.S. cities. Environ Health Perspect 108: 941-947 (2000).
    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).
    Mar TF, Norris GA, Koenig JQ, Larson TV. Associations between air 
pollution and mortality in Phoenix, 1995-1997. Environ Health Perspect 
108: 347-353 (2000).
    McDonnell WF, Nishino-Ishikawa N, Petersen FF, Chen LH, Abbey DE. 
Relationships of mortality with the fine and coarse fractions of long-
term ambient PM10 concentrations in nonsmokers. J Exposure 
Anal Environ Epidemiol 10: 427-436 (2000).
    Ozkaynak H, Thurston GD. Associations between 1980 U.S. mortality 
rates and alternative measures of airborne particle concentration. Risk 
Anal. 7: 449-461 (1987).
    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).

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