    [Senate Hearing 109-1048]
    [From the U.S. Government Publishing Office]

                                                           S. Hrg. 109-1048

    THE SCIENCE AND RISK ASSESSMENT BEHIND EPA'S PROPOSED REVISIONS TO THE
                    PARTICULATE MATTER AIR QUALITY STANDARDS

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

                                    HEARING

                                   BEFORE THE

                                  COMMITTEE ON
                          ENVIRONMENT AND PUBLIC WORKS
                              UNITED STATES SENATE

                           ONE HUNDRED NINTH CONGRESS

                                 SECOND SESSION

                                   __________

                                 July 19, 2006

                                   __________

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

    Available via the World Wide Web: http://access.gpo.gov/congress.senate

                                   __________

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                   COMMITTEE ON ENVIRONMENT AND PUBLIC WORKS

                           ONE HUNDRED NINTH CONGRESS
                                 SECOND SESSION

                      JAMES M. INHOFE, Oklahoma, Chairman
    JOHN W. WARNER, Virginia             JAMES M. JEFFORDS, Vermont
    CHRISTOPHER S. BOND, Missouri        MAX BAUCUS, Montana
    GEORGE V. VOINOVICH, Ohio            JOSEPH I. LIEBERMAN, Connecticut
    LINCOLN CHAFEE, Rhode Island         BARBARA BOXER, California
    LISA MURKOWSKI, Alaska               THOMAS R. CARPER, Delaware
    JOHN THUNE, South Dakota             HILLARY RODHAM CLINTON, New York
    JIM DeMINT, South Carolina           FRANK R. LAUTENBERG, New Jersey
    JOHNNY ISAKSON, Georgia              BARACK OBAMA, Illinois
    DAVID VITTER, Louisiana
                    Andrew Wheeler, Majority Staff Director
                     Ken Connolly, Minority Staff Director

                                      (ii)

                                C O N T E N T S

                                  ----------
                                                                       Page

                                 July 19, 2006
                               OPENING STATEMENTS

    Boxer, Hon. Barbara, U.S. Senator from the State of California...     6
    Carper, Hon. Thomas R., U.S. Senator from the State of Delaware..    10
    Clinton, Hon. Hillary Rodham, U.S. Senator from the State of New
      York...........................................................     9
    DeMint, Hon. Jim, U.S. Senator from the State of South Carolina..     7
    Inhofe, Hon. James M., U.S. Senator from the State of Oklahoma...     1
    Jeffords, Hon. James M., U.S. Senator from the State of Vermont..     3
    Lautenberg, Hon. Frank R., U.S. Senator from the State of New
      Jersey.........................................................     8
    Voinovich, Hon. George V., U.S. Senator from the State of Ohio...     4

                                   WITNESSES

    Lieberman, Hon. Joseph, U.S. Senator from the State of
      Connecticut, prepared statement................................    47
    Gray, George, Assistant Administrator for Research and
      Development, U.S. Environmental Protection Agency..............    11
        Prepared statement...........................................    47
        Responses to additional questions from:
            Senator Inhofe...........................................    50
            Senator Voinovich........................................    51
    Greenbaum, Daniel, President, Health Effects Institute...........    33
        Prepared statement...........................................    54
        Responses to additional questions from Senator Voinovich.....    58
    McClellan, Roger, Advisor, Toxicology and Human Health Risk
      Analysis.......................................................    28
        Prepared statement...........................................    60
        Responses to additional questions from Senator Voinovich.....    66
    Smith, Anne, Vice President, CRA International...................    32
        Prepared statement...........................................    68
        Responses to additional questions from Senator Voinovich.....    81
    Stephenson, John, Director, Natural Resources and Environment,
      U.S. General Accountability Office.............................    13
        Prepared statement...........................................    86
        Responses to additional questions from Senator Voinovich.....    90
    Thurston, George, Associate Professor, New York University,
      School of Medicine, Department of Environmental Medicine.......    30
        Prepared statement...........................................    92
        Responses to additional questions from Senator Voinovich.....    95

                              ADDITIONAL MATERIAL

    Letters:
        Children's Health Protection Advisory Committee..............   163
        Undersigned by Bart Ostro and Michael Lipsett (regarding
          support for revising particulate matter standards).........   188
        Undersigned by National, Regional, State, and Local
          Organizations
          (regarding supprt for revising particulate matter
          standards).................................................   193
        Undersigned by Senators (regarding funding for the State and
          Local Air Quality Management Program)......................   202
    Statements:
        CRA International............................................96-162
        Fran Pavley, Assembly California Legislature................191-192
        Jonathan Borak & Company Inc................................171-187

    THE SCIENCE AND RISK ASSESSMENT BEHIND EPA'S PROPOSED REVISIONS TO THE
                    PARTICULATE MATTER AIR QUALITY STANDARDS

                                  ----------

                            Wednesday, July 19, 2006

                                           U.S. Senate,
                     Committee on Environment and Public Works,
                                                        Washington, DC.
        The committee met, pursuant to notice, at 9 o'clock a.m. in
    room 628, Dirksen Senate Office Building, Hon. James Inhofe
    (chairman of the committee) presiding.
        Present: Senators Inhofe, Voinovich, Chafee, DeMint,
    Isakson, Jeffords, Boxer, Carper, Clinton, and Lautenberg.
        Senator Inhofe. Consistent with our policy of starting on
    time, we will call this meeting to order.

     OPENING STATEMENT OF HON. JAMES M. INHOFE, U.S. SENATOR FROM
                         THE STATE OF OKLAHOMA

        I would like to tell our members, since we have quite a
    number of people here and of course we have the WRDA bill on
    the floor, which I have to manage so I am not going to be able
    to stay very long, we are going to try to keep everyone to
    about 3 minutes. I think we put a notice out if we could
    encourage both sides to do that, and then anyone who arrives
    after the conclusion of our opening statements would have to
    just submit the statements for the record, if that is
    acceptable.
        I am managing the WRDA bill, along with my colleague
    Senator Jeffords, on the floor so I am going to have to go down
    and prepare for that and won't be able to stay here very long.
    I am going to ask that Senator Voinovich, who is kind of the
    master of all air issues anyway, would handle chairing this
    committee.
        Last week, the Air Subcommittee examined the impacts of
    tightening particulate matter standards on our Nation. Although
    EPA failed to analyze the regulatory impact on the Nation,
    these impacts will be enormous. I was particularly struck by
    the testimony of Harry Alford, president of the National Black
    Chamber of Commerce, who testified that the greatest health
    threat to minorities is access to health care and a tightened
    standard which would threaten the paychecks that cure that
    threat.
        Today, we are examining the science underlying the
    particulate matter review. The estimated risk today is less
    than it was estimated in 1997 under Carol Browner when the
    current standard was set. So while I feel EPA's proposal to
    tighten the daily standard to 35 micrograms is overly
    stringent, I am pleased EPA proposed to retain the existing
    annual standard.
        The rationale to tighten this standard is weak. The EPA
    cherry-picked what studies it was relying on, downplaying many
    key studies that shed light on the health effect of particulate
    matter, some of which are listed on this chart which is
    difficult even for me to read this close. But anyway, these are
    the studies.
        It also cherry-picked what information it provided to the
    Clean Air Science Advisory Committee, an important document
    that seriously skewed the review. A lot of times, CASAC is not
    given their assigned task. CASAC, the Clean Air Scientific
    Advisory Committee, is one of a set of some 21 scientists that
    are supposed to be giving advice and we are supposed to be
    listening to that advice. They were never told by the EPA that
    the estimated risk from PM exposure is now considered lower
    than the risk level estimated during the last review.
        EPA's process for this review is also radically different
    from every previous scientific assessment, calling into
    question the credibility of the entire review. CASAC is
    supposed to review relevant science and the public is supposed
    to provide input. This time, EPA had a cutoff date of April,
    2002 which meant that CASAC's assessment does not include
    almost 4 1/2 years of new studies. Only after I asked EPA to
    collect the newer studies did it do so. Now, it plans to issue
    a final rule without an opportunity for public review of how it
    is assessing those studies.
        Worse, the General Accounting Office report being released
    today shows EPA has failed to follow the National Academy of
    Sciences recommendations to examine the health effect
    associated with different kinds of particulates and to
    incorporate the range of particulate toxicity assumptions into
    its uncertainty analysis. If we don't know the types of
    particles causing the health effects, we can't really
    accurately assess those.
        The system that is in place today only considers the size
    of the particulate matter. I think we all know that the health
    effects of a molecule of asbestos is much more dangerous than
    would be a molecule of dust. These things should be considered.
        Senator Jeffords.
        [The prepared statement of Senator Inhofe follows:]

             Statement of Hon. James M. Inhofe, U.S. Senator from
                             the State of Oklahoma
        Last week, the Air Subcommittee examined the impacts of tightening
    particulate matter standards on our nation. Although EPA failed to
    analyze the regulatory impact on the Nation, these impacts will be
    enormous. I was particularly struck by the testimony of Harry Alford,
    President of the National Black Chamber of Commerce, who testified that
    the greatest health threat to minorities is access to health care and a
    tightened standard would threaten the paychecks that cure that threat.
        Today, we are examining the science underlying the particulate
    matter review. The estimated risk today is less than what was estimated
    in 1997 under Carol Browner when the current standard was set. So while
    I feel EPA's proposal to tighten the daily standard to 35 micrograms is
    overly stringent, I am pleased EPA proposed to retain the existing
    annual standard.
        The rationale to tighten the standard is weak. EPA cherry-picked
    what studies it relied on, downplaying many key studies that shed light
    on the health effect of PM, some of which are listed on this chart.
        It also cherry-picked what information it provided to the Clean Air
    Science Advisory Committee in important documents, seriously skewing
    the review. For instance, CASAC was never told by EPA that the
    estimated risks from PM exposure is now considered lower than the risk
    level estimated during the last review.
        EPA's process for this review is also radically different from
    every previous scientific assessment, calling into question the
    credibility of the entire review. CASAC is supposed to review relevant
    science and the public is supposed to provide input. This time, EPA had
    a cut-off date of April 2002, which meant CASAC's assessment doesn't
    include almost 4 1/2 years of new studies. Only after I asked EPA to
    collect the newer studies did it do so, and now it plans to issue the
    final rule without an opportunity for public review of how it is
    assessing those studies.
        Worse, as the General Accountability Office report being released
    today shows, EPA has failed to follow the National Academy of Science's
    recommendations to examine the health effect associated with different
    kinds of particles and to incorporate a range of particle toxicity
    assumptions into its uncertainty analyses. If we don't know what types
    of particle cause health effects, we may well spend billions of dollars
    on pollution controls while doing little to improve health.
        Thank you.

        Senator Jeffords. Mr. Chairman, thank you.
        Senator Inhofe. Let me just repeat what we said earlier to
    our new arrivals here. We are going to try to adhere to 3
    minutes in opening statements, and then cutoff statements after
    those who are present have concluded.
        Senator Jeffords.

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

        Senator Jeffords. Mr. Chairman, thank you for having this
    hearing on the EPA's proposed standards for particulate matter.
    There is perhaps no more important environmental standard than
    the national ambient air quality standard for particulate
    matter. Tens of thousands of Americans die prematurely each
    year from particulate matter.
        The NAAQS are the cornerstone of the entire Clean Air Act.
    Their fundamental purpose is to tell us when the air is safe to
    breathe. For more than 30 years, these standards have been set
    solely on health considerations, using the latest scientific
    evidence. Congress specifically chose not to allow
    consideration of cost when setting these standards.
        Those who call for a cost-benefit analysis would have us
    set a standard that fails to protect the health of all
    Americans. We cannot afford the human costs of such an
    approach.
        Consider this, if the cost-benefit analysis was used to set
    the NAAQS and the compliance costs of the standards are
    estimated at $1 billion, the EPA would be required to set a
    standard that would allow up to $1 billion worth of people to
    die from air pollution. So just how do we measure $1 billion in
    human life. Setting the NAAQS in that way was unconscionable.
    Telling people their air is safe to breathe when it is actually
    not safe is unacceptable public policy.
        We need to revise the existing standards set in 1997.
    Although the EPA itself has recognized this fact, EPA's
    proposal falls short of what the scientific evidence requires.
    The Clean Air Scientific Advisory Committee recommended the EPA
    revise both the annual standard and the daily standard, but the
    EPA disregarded this advice, forcing the Scientific Advisory
    Committee to reconvene and reiterate its advice to the EPA.
        The committee has made it clear that the EPA's proposal for
    the coarse particle standard was outside the bounds of
    scientific evidence. If the EPA were to listen to the advice of
    its science advisors, tens of thousands of lives could be
    saved. The standard proposed by the EPA would result in a 22
    percent reduction in deaths. Standards set within the range
    recommended by the Scientific Advisory Committee would save up
    to 48 percent more lives.
        Particulate matter kills more people than HIV/AIDS and more
    people than drunk driving. It is a big killer and we need to
    reduce it as soon as possible. That is what the science shows.
        Thank you. I look forward to hearing from the witnesses.
        [The prepared statement of Senator Jeffords follows:]

            Statement of Hon. James M. Jeffords, U.S. Senator from
                              the State of Vermont
        Mr. Chairman, thank you for having this hearing on the EPA's
    proposed standards for Particulate Matter.
        There is perhaps no more important environmental standard than the
    National Ambient Air Quality Standard for Particulate Matter. Tens of
    thousands of Americans die prematurely each year from particulate
    matter.
        The NAAAQS are the cornerstone of the entire Clean Air Act. Their
    fundamental purpose is to tell us when the air is safe to breathe. For
    more than 30 years, these standards have been set based solely on
    health considerations, using the latest scientific evidence. Congress
    specifically chose to not allow consideration of costs when setting
    these standards.
        Those who call for a cost-benefit analysis would have us set a
    standard that fails to protect the health of all Americans. We cannot
    afford the human cost of such an approach.
        Consider this: If cost benefit analysis is used to set the NAAAQS
    and the compliance costs of a standard are estimated at $1 billion, the
    EPA would be required to set a standard that would allow up to $1
    billion worth of people to die from air pollution. So just how do we
    measure $1 billion in human life? Setting the NAAAQS in that way is
    unconscionable. Telling people their air is safe to breathe, when it is
    actually not safe, is unacceptable public policy.
        We need to revise the existing standard set in 1997. Although the
    EPA itself has recognized that fact, the EPA's proposal falls far short
    of what the scientific evidence requires. The Clean Air Scientific
    Advisory Committee recommended that the EPA revise both the annual
    standard and the daily standard. But the EPA disregarded that advice,
    forcing the scientific advisory committee to reconvene and reiterate
    its advice to the EPA.
        The Committee also made it clear that the EPA's proposal for the
    coarse particle standard was outside the bounds of the scientific
    evidence. If the EPA were to listen to the advice of its science
    advisors, tens of thousands of lives could be saved.
        The standard proposed by EPA would result in a 22 percent reduction
    in deaths, but a standard set within the range recommended by the
    scientific advisory committee could save up to 48 percent more lives.
    Particulate matter kills more people than HIV/AIDS and more people than
    drunk driving. It is a big killer and we need to reduce it as soon as
    possible. That is what the science shows.
        Thank you, and I look forward to hearing from our witnesses.

        Senator Inhofe. Thank you, Senator Jeffords.
        Senator Voinovich.

      OPENING STATEMENT OF HON. GEORGE V. VOINOVICH, U.S. SENATOR
                         FROM THE STATE OF OHIO

        Senator Voinovich. Thank you, Mr. Chairman. I appreciate
    the fact that you bumped this hearing from my subcommittee to
    the full committee. It shows how important this matter is. To
    sum up last week's hearing, we do not know the impact of
    revising the particulate matter standards, and let's review
    what we do know.
        We know that the air is significantly cleaner; that the EPA
    has proposed to move the goal posts in the States as they
    implement the current standards. We believe that the Agency is
    underestimating the number of non-attainment counties. We know
    that the current non-attainment designations threaten highway
    funding and jobs and increase energy prices and that revised
    standards would exacerbate the situation.
        We also know this decision has a profound impact on the
    health and well being of many, as the National Black Chamber of
    Commerce President Harry Alford stated, ``The biggest health
    risk to African Americans anywhere is poverty.'' I will never
    forget when Tom Mullen from the Catholic Charities came here
    several years ago and testified that in setting ambient air
    standards and environmental policy, that we should take into
    consideration its impact on the poor and the elderly, and the
    Clean Air Trust named him villain of the month because he had
    the audacity to raise the issue.
        Today's hearing focuses on the science and risk assessment
    behind the standards. I make three points. First, according to
    the recent proposal and risk assessment, we will hear today the
    EPA's estimates, the risk from exposure to fine particulate
    matter has declined from the level of risk estimated in setting
    the last standards.
        Second, the health benefits of EPA's proposal are not fully
    understood. A 2002 National Academy of Sciences report made 34
    recommendations to improve our understanding of the estimation
    of the public health benefits. According to GAO that we asked
    for, EPA has fully implemented less than 25 percent of
    recommendations made back in 2002 by the National Academy of
    Sciences. For example, the NAS, along with the Office of
    Management and Budget and EPA's Inspector General, has urged
    the Agency not to assume that all fine particulate constituents
    have the same potency. As stated in the IG's report, otherwise
    some facilities may install unneeded controls, while some
    needed controls may go uninstalled. Ultimately, compliance may
    be further delayed and more costly.
        Unfortunately, the EPA has largely not implemented the
    recommendations. The standards should not be revised until we
    have adequate information that tells us with greater certainty
    the health benefits and whether we are targeting the most
    harmful constituents of particulate matter, especially
    considering the negative impacts on this country's economy. Air
    quality will continue to improve through implementation of the
    current standards and the Federal clean air rules.
        I know you want me to cut this short. I will just basically
    say, Mr. Chairman, it is important that everyone understand
    that science can only take us so far, but ultimately it is a
    policy decision whether or not to change a standard. That is
    why the Clean Air Act states the air quality standards are to
    be set in the judgment of the Administrator. Given this
    judgment discretion, how can EPA revise the particulate matter
    standards when the public health benefit is not fully
    understood?
        Thank you, Mr. Chairman.
        [The prepared statement of Senator Voinovich follows:]

           Statement of Hon. George V. Voinovich, U.S. Senator from
                               the State of Ohio
        Mr. Chairman, after our hearing in the subcommittee, I appreciate
    this important issue being elevated to the full committee.
        To sum up last week's hearing, we do not know the impact of
    revising the particulate matter standards. Let's review what we do
    know:

         We know that the air is significantly cleaner and that EPA has
    proposed to move the goal posts on States as they implement the current
    standards.
          We believe that the Agency is underestimating the number of
    nonattainment counties and that Federal clean air rules will only
    mitigate this problem.
         We know that the current nonattainment designations threaten
    highway funding and jobs and increase energy prices and that revised
    standards would exacerbate the situation.
         We also know that this decision has a profound impact on the
    health and well-being of many, as National Black Chamber of Commerce
    President Harry Alford stated: ``the biggest health risk to African
    Americans anywhere is poverty.''

        Today's hearing focuses on the science and risk assessment behind
    the proposed standards. I will make three points.
        First, according to the recent proposal and risk assessment, we
    will hear today that EPA's estimate of the risk from exposure to fine
    particulate matter has declined from the level of risk estimated in
    setting the 1997 standards.
        Second, the health benefits of EPA's proposal are not fully
    understood. A 2002 National Academy of Sciences (NAS) report made 34
    recommendations to improve our understanding of the estimation of the
    public health benefits. According to the Government Accountability
    Office report that Chairman Inhofe and I requested, EPA has fully
    implemented less than 25 percent of them.
        For example, the NAS along with the Office of Management and Budget
    and EPA's Inspector General has urged the Agency not to assume that all
    fine particle constituents have the same potency. As stated by the IG:
    ``Otherwise, some facilities may install unneeded controls, while some
    needed controls may go uninstalled; ultimately, compliance may be
    further delayed and more costly.''
        Unfortunately, EPA has largely not implemented the recommendations.
    The standards should not be revised until we have adequate information
    that tells us with greater certainty the health benefits and whether we
    are targeting the most harmful constituents of particulate matter--
    especially considering the negative impacts on our economy. Air quality
    will continue to improve through implementation of the current
    standards and the Federal clean air rules.
        EPA claims that they will address more of the NAS recommendations
    when the final rule is issued. At this time, we are told that there
    will also be a more complete Regulatory Impact Analysis and new science
    will be considered. It is unacceptable for the public and this
    committee to get critical information only after the final decision has
    already been made.
        Third, testimony that we will hear today indicates that EPA
    selectively used study results in developing the proposal.
        In conclusion, it is important that everyone understand that
    science can only take us so far, but ultimately, it is a policy
    decision whether or not to change a standard. That is why the Clean Air
    Act states that air quality standards are to be set ``in the judgment
    of the Administrator.'' Given this judgment discretion, how can EPA
    revise the particulate matter standards when the public health benefit
    is not fully understood?
        Mr. Chairman, I again thank you for holding this hearing and look
    forward to hearing from the witnesses. Thank you.	_

        Senator Inhofe. Thank you, Senator Voinovich.
        Senator Boxer.

    OPENING STATEMENT OF HON. BARBARA BOXER, U.S. SENATOR FROM THE
                          STATE OF CALIFORNIA

        Senator Boxer. Thank you, Mr. Chairman, for holding this
    hearing. I ask that my full statement be placed in the record.
        Senator Inhofe. Without objection, so ordered.
        Senator Boxer. I will read part of it.
        This hearing is important because protecting the air that
    Americans breathe is important. It is a critical responsibility
    of this committee. We have made great strides in this country,
    but unfortunately EPA's proposed standards for controlling
    toxic soot and dust drastically depart from this path.
        Now, I won't get into politicizing science, but what I want
    to say here is EPA has rejected advice from its own Clean Air
    Science Advisory Committee on health-based standards for toxic
    soot and dust. This, despite the fact that the American Lung
    Association and other public health groups say the children,
    the elderly and people with heart disease, diabetes or
    respiratory diseases are especially vulnerable to the adverse
    impacts of such pollution.
        Let me be more specific. Particulate pollution causes
    premature death, whether you are in Oklahoma, New York, New
    Jersey, Vermont, California or Ohio. Particulate pollution
    causes premature death. It exacerbates asthma, cardiovascular
    disease, including heart attacks and strokes, and it increases
    hospital admissions.
        I have to say, sometimes in this committee we talk about
    things as if they were very interesting scientific issues. But
    the bottom line is what we are talking about here is the
    longevity or lack of such of the American people and the
    quality of their lives, be they children or adults. More than
    160 national, State, local, environmental, religious groups,
    and I want to point out religious groups are getting involved
    in this, and public interest groups have urged EPA to increase
    these clean air protections. EPA's Children's Health Advisory
    Committee also urged EPA to revise these standards to protect
    children.
        I would ask unanimous consent that these letters be placed
    in the record at this time. Mr. Chairman, I would like to place
    these letters from the religious groups and others into the
    record at this time.
        Senator Inhofe. Without objection.
        [The referenced letters can be found on pages 193-201.]
        Senator Boxer. EPA has also proposed a protective standard
    for coarse particulate matter. The Agency proposal ignores
    pollution by exempting some industries, exempting them,
    industries such as mining. In addition, EPA proposes such a
    limited amount of monitoring that pollution will go undetected
    in many of our medium size and small cities.
        So EPA must stop this politicizing. They are politicizing
    scientific decisions, and I resent it as a U.S. Senator from
    the largest State in the union, where we are deeply affected by
    this. A particularly egregious example was identified by Mr.
    Bart Ostro, chief of California's Office of Environmental
    Health, regarding the particulate pollution rule. On February
    3, 2006, Mr. Ostro testified before EPA's Science Committee
    that ``last minute additions of edits and opinions by OMB and
    others circumvented the entire peer review process.'' That is a
    condemning statement.
        The Clean Air Act has it right. Sound science and the
    protection of public health should guide the establishment of
    Clean Air Act standards and sadly, Mr. Chairman, I am very
    worried about the fact that we seem to be veering away from
    science and making politics the key ingredient in these
    decisions.
        Thank you.
        Senator Inhofe. Thank you, Senator Boxer.
        Senator DeMint.

      OPENING STATEMENT OF HON. JIM DEMINT, U.S. SENATOR FROM THE
                        STATE OF SOUTH CAROLINA

        Senator DeMint. Thank you, Mr. Chairman. I am very
    interested in the results today. I appreciate our witnesses.
        Last week, we looked at the possibility of a rule change.
    As we all know, the Clean Air Science Advisory Committee has
    recommended that EPA lower its annual standard for particulate
    matter. What I find interesting is that the air today is
    significantly cleaner than it was years ago, and even more
    intriguing is the risk assessment of health complications due
    to long-term exposure, PM2.5 ambient air, have been
    reduced.
        Studies have shown that the risk assessment for
    PM2.5 have either stayed the same or been reduced.
    Then why is the EPA receiving a recommendation from the
    committee to tighten the standard? Obviously, I am very
    interested in clean air. I just want to make sure that we find
    the source and really do something that cleans the air, not
    just do something to do something.
        The mechanisms that were used to direct the committee to
    recommend more stringent annual standards are actually
    disturbing. The EPA staff memo directed the committee to study
    three specific scientific studies. One of the studies gave
    mixed results of the human risk of high levels of
    PM2.5; another was nullified by the scientists who
    performed the study because the data constantly changed based
    on their assumptions; and the third one was based on cities
    outside the United States over a 6-year process that showed a
    drop in ambient air quality.
        So I am very interested in the testimony today. We want to
    know about good science. We want to know how to clean the air.
    I am just afraid we are looking at doing something just to look
    like we are doing something. We will end up costing this
    country a lot of jobs and prosperity, and not leave the air any
    cleaner.
        So I am here to learn, and I thank you, Mr. Chairman.
        Senator Inhofe. Thank you, Senator DeMint.
        Senator Lautenberg.

      OPENING STATEMENT OF HON. FRANK R. LAUTENBERG, U.S. SENATOR
                      FROM THE STATE OF NEW JERSEY

        Senator Lautenberg. Thanks, Mr. Chairman, for giving us
    another opportunity to examine the need to protect our air.
        This week gives us an urgent reminder about what we have to
    do. The red air days are oppressive. I felt it myself, not
    enough to make me ill, but enough to make me realize that that
    air wasn't particularly clean.
        Parents are warned not to let children play outdoors if
    they have respiratory problems because of increased danger of
    asthma attack or other complications. We know that particulate
    matter pollution triggers asthma attacks and affects the health
    of people with other respiratory and lung conditions.
        Today, we are going to hear how it also poses threats to
    people with heart conditions. But we will hear a lot of talk
    about uncertainty. We are not sure. It is like saying, well,
    the fire is only in the basement; let's not get excited
    upstairs.
        I heard the same thing 20 years ago when I wrote the law to
    ban smoking on airplanes. The tobacco industry said there was
    too much uncertainty about the effects of secondhand smoke.
    There is no doubt anymore about it. Today, we know that there
    is real danger from secondhand smoke and we are so grateful
    that we did something when we did it.
        We have heard the same excuse about uncertainty for years
    in the discussion of global warming. Look outside; feel it. The
    claim of uncertainty is the smokescreen that diverts attention
    from real problems. It is merely an excuse to avoid taking any
    action that might cost an extra few bucks to accommodate our
    need.
        We are here to represent the 25 million American adults
    with heart disease and 6 million children with asthma, one of
    whom is my grandson, Alexander. There is no uncertainty about
    whether they deserve clean, healthy air. This week, we learned
    of a report on particulate matter which had been requested by
    OMB. That report suggests that particulate matter is actually a
    worse problem than we previously thought. So much for
    uncertainty.
        So we ought not to let a handful of particular interests
    pressure us into doing anything that will permit more harm to
    millions of Americans. I think that this is a matter of urgency
    and I think we have to get on to making sure that the standards
    that we have are the highest and are the toughest than we get
    to meet.
        And not without consideration for either jobs or
    investment. But I will tell you, when we talk about jobs and I
    read the reports about what is happening, where things are
    being made today, they are not being made in India and other
    places, or Bangladesh because of environmental issues. They are
    being taken away because of cost issues. So we shouldn't
    confuse the facts.
        I thank you, Mr. Chairman, once again, for the opportunity
    to air this problem.
        Senator Inhofe. OK. Senator Clinton.

    OPENING STATEMENT OF HON. HILLARY RODHAM CLINTON, U.S. SENATOR
                       FROM THE STATE OF NEW YORK

        Senator Clinton. Thank you, Mr. Chairman.
        Although we are making opening remarks, I want to begin by
    welcoming someone whom I have a great deal of regard for, Dr.
    George Thurston, to the committee. Dr. Thurston is on the
    faculty at New York University School of Medicine, where he
    conducts investigations into the human health effects of air
    pollution. He is truly one of the leading scientists in this
    field. I am pleased that he will be testifying on the second
    panel.
        I have particular regard for Dr. Thurston because when I
    was raising questions about the quality of air after 9/11 and
    the Administration was assuring everyone that there were no
    problems in the air, and in fact everything was fine, Dr.
    Thurston was one of those who said this is just not squaring
    with the scientific work I have done.
        Well, now nearly 5 years later, we have hundreds and
    hundreds of firefighters, police officers, construction
    workers, residents and others who are suffering from
    respiratory distress. Now, that was an intense experience
    because the air was so contaminated with everything that came
    from the World Trade Center. We can look at that and we can
    draw some conclusions about the impact of such a horrible
    event.
        But it is also true that after 9/11 when all the planes
    were grounded, there are a lot of pictures showing how clean
    the air was. We are facing a very serious question here. This
    is an important issue, not just in New York, but across our
    country. Since the 1997 revisions to the particulate matter
    standards, numerous scientific studies have been published.
    These have not been partisan studies. These have not been
    ideological studies. They have ranged from scholarly academic
    studies like Dr. Thurston, to the American Lung Association.
        These studies have overwhelmingly strengthened the links
    between particulate pollution and a range of adverse health
    outcomes, including asthma, heart attacks, hospital admissions,
    adverse birth outcomes, and premature death. Some recent
    studies have even linked long-term particulate matter exposure
    to increased risk of lung cancer.
        In addition, our understanding of the biological mechanisms
    at work helps explain these links better than we understood
    back in 1997. So I was dismayed when the EPA disregarded the
    advice of its Clean Air Science Advisory Committee.
        You know, when CASAC recommended what it thought needed to
    be done, the EPA decided not to lower the annual PM standard in
    its proposed revisions. This action prompted a letter back to
    the EPA from CASAC, which I think is unprecedented. That letter
    reiterated the CASAC's finding. All of these scientists who
    have no particular ax to grind, ``the epidemiological evidence
    supported by emerging mechanistic understanding indicates
    adverse PM2.5 health effects below 15 micrograms per
    cubic meter.''
        Now, I think the science is clear. One of the reasons the
    air is cleaner today is that for more than 30 years we have
    been cleaning it up. So we have a little bit in the bank, but
    that is not going to stand.
        So Mr. Chairman, I hope that we will go with the lower
    standard, and I ask unanimous consent to submit the full
    statement to the record.
        Senator Inhofe. Without objection, so ordered.
        Senator Inhofe. Senator Carper.

     OPENING STATEMENT OF HON. THOMAS R. CARPER, U.S. SENATOR FROM
                         THE STATE OF DELAWARE

        Senator Carper. Thanks, Mr. Chairman.
        I want to follow up on what Senator Clinton has said, if I
    may, and also just kind of respond to what Senator DeMint has
    said. EPA doesn't come up with these recommendations out of
    thin air. They have this CASAC committee that Senator Clinton
    just referred to. They made their recommendations for advising
    the annual and the daily limits on this particulate matter.
        Good people, they are all scientists. They have no ax to
    grind. What they try to do is to use good science and to give
    us their best recommendations, and also to give those
    recommendations to EPA. EPA has reviewed, I am told, over 2,000
    scientific studies I believe since 1997, and they found an
    association between particulates in ambient air and all kinds
    of health problems. We have heard a couple of them, a
    recitation of them from Senator Clinton. I want to mention them
    again: aggravated asthma, chronic bronchitis, reduced lung
    function, irregular heartbeat, heart attacks, and premature
    death in people with heart or lung diseases.
        In just nine cities that EPA looked at, particulates would
    cause an estimated almost 5,000 premature deaths unless current
    standards are strengthened. EPA could have come in and frankly
    followed the advice of CASAC. They didn't. They erred the other
    way. For some of us on this committee, we were disappointed
    with that result.
        I do want to commend Administrator Johnson for
    acknowledging that the science does support strengthening the
    current particulate matter standards. I am concerned that the
    proposed standard is higher than the range recommended by EPA's
    CASAC. I look forward to hearing today EPA's justification for
    that decision.
        Finally, I would like to follow on a point made during last
    week's hearing by a number of Senators, as well as Bill Wehrum
    of EPA. To do so, let me just quote Mr. Wehrum's testimony from
    last week. Here is what he said: ``between 1970 and 2005, gross
    domestic product increased by 195 percent. Vehicle miles
    traveled increased 178 percent. Energy consumption increased 48
    percent. The U.S. population grew by 42 percent. During the
    same time period, total emissions of the six principle air
    pollutants dropped by 53 percent.''
        In other words, since the inception of the Clean Air Act,
    our country has made significant increases in our energy usage,
    mobility and an ever-growing economy, and at the same time we
    have seen our air pollution decrease. Our Nation's air has not
    become cleaner on its own. The improvements are a direct result
    of specific air regulations and the implementation of the
    National Ambient Air Quality Standards. The arguments we are
    hearing today that claim that tighter air regs will hurt our
    economy and cost people jobs are not new. We have heard these
    claims every time EPA has proposed a new regulation over the
    past 30 years.
        However, as Mr. Wehrum and others on the committee
    correctly pointed out last week, those claims have not proven
    to be true. We can have cleaner air. We can grow our economy
    and we can do those things today, as we have in the last 30
    years.
        Thank you, Mr. Chairman.
        Senator Inhofe. Thank you, Senator Carper.
        That will conclude our opening statements. We have on our
    first panel Dr. George Gray, Assistant Administrator for
    Research and Development for the EPA; and John Stephenson,
    Director, Natural Resources and Environment for the United
    States GAO.
        We will start with you, and try to confine your remarks to
    5 minutes, if you could. Dr. Gray, you are recognized.

    STATEMENT OF GEORGE GRAY, ASSISTANT ADMINISTRATOR FOR RESEARCH
         AND DEVELOPMENT, U.S. ENVIRONMENTAL PROTECTION AGENCY

        Mr. Gray. Thank you, Mr. Chairman, members of the
    committee. I am George Gray, the Assistant Administrator for
    the Office of Research and Development at the Environmental
    Protection Agency.
        I want to thank you for the opportunity to discuss EPA's
    evaluation of the scientific evidence for potential health
    effects of airborne particulate matter known as PM. Last week,
    the subcommittee heard from my colleague Bill Wehrum, the
    Acting Assistant Administrator for Air and Radiation and the
    EPA's review of the National Ambient Air Quality Standards, we
    call them the NAAQS.
        During the testimony, he explained to you the crucial role
    that science plays in helping to inform our decisions about the
    NAAQS. Today, what I would like to talk to you about in more
    detail is the science, how it is prioritized, how it is
    developed, and how it is synthesized and integrated.
        As the Assistant Administrator for the Office of Research
    and Development, I am responsible for both the development of
    new scientific information targeted at specific Agency needs,
    and for the evaluation, synthesis and integration of the
    world's peer reviewed literature and to a document that informs
    EPA decisionmakers.
        As we characterize the current state of our collective
    scientific knowledge, we are careful to point out the strengths
    and weaknesses of this large body of information so that
    informed decisions can be made. It is clear that scientists and
    staff of EPA play a crucial role in the development and
    evaluation of the world's scientific information to inform
    their review of the NAAQS.
        A very important function of EPA is the synthesis and
    integration of these thousands of individual acts of science to
    provide a clear characterization of our knowledge and the
    degree to which we are still uncertain about some aspects of PM
    health and environmental effects.
        We have a scientifically rigorous process by which we
    evaluate and interpret this important body of knowledge and we
    ensure that our interpretation of them is complete,
    transparent, unbiased, and consistent with an array of views in
    the scientific community.
        A fundamental step in the review of the NAAQS is the
    evaluation of scientific evidence in the preparation of
    scientific assessments known as criteria documents by the
    National Center for Environmental Assessment, which is part of
    the Office of Research and Development. The development of
    criteria documents involves a review of thousands of peer-
    reviewed research publications, evaluation of those studies
    that are most relevant to the review of air quality standards
    and the integration of scientific information across
    disciplines.
        The body of evidence must be reviewed, evaluated, weighed
    and then accurately and objectively described to help inform
    our decisions about National Ambient Air Quality Standards. For
    the current PM review, EPA evaluated research studies that
    addressed a wide range of issues, including PM toxicology,
    epidemiology, atmospheric chemistry, human exposure and other
    areas of environmental effects. Thousands of studies were
    reviewed and over 2,000 were referenced in the final criteria
    document, many of which were conducted or funded by EPA's
    Office of Research and Development.
        Considered together, these new studies significantly
    advanced our understanding of PM's potential effects on public
    health and welfare and reduced the uncertainties associated
    with some important aspects of the science. Drawing on the
    evaluation of studies reviewed in the PM criteria document
    about health effects and dose response, as well as information
    about exposures to PM, EPA also completed a risk assessment to
    estimate the degree to which various approaches for revising
    the standards would potentially affect the public health risks
    that are posed by PM.
        Further, the Agency prepared a document known as a staff
    paper that utilized the evaluation and characterization of
    scientific evidence in the criteria document, together with the
    results of the risk assessment, to help inform policy judgments
    that are required in making decisions about the NAAQS.
        In summary, the Bush administration is committed to the
    development and use of the highest quality scientific
    information to inform decisionmaking. The mission of the Office
    of Research and Development is to develop, evaluate and
    communicate relevant scientific information to the
    Administrator and to assure that the Administrator is well
    informed of the nature, the strengths, and the limitations of
    this information. EPA has sponsored a targeted and effective
    research program on particulate matter, and I am pleased to
    convey to you and others the value of this investment.
        We have made a great effort to evaluate and characterize
    the existing and new scientific results available on
    particulate matter and I am personally pleased to share with
    you my views on this work. I look forward to addressing any
    questions that you may have, and I respectfully request that my
    full written testimony, as submitted, be inserted into the
    record.
        Senator Voinovich. [Presiding] Thank you, Mr. Gray.
        Mr. Stephenson, before you give your testimony to the
    committee, I am going to ask that this report by the GAO be
    made a part of the record. I look forward to your testimony.
        [The referenced document can be found on pages 86-90.]

     STATEMENT OF JOHN STEPHENSON, DIRECTOR, NATURAL RESOURCES AND
            ENVIRONMENT, U.S. GENERAL ACCOUNTABILITY OFFICE

        Mr. Stephenson. Thank you, Mr. Chairman and other members
    of the committee. I am pleased to be here today as the
    committee considers the science and risk assessment supporting
    EPA's proposed revisions to the national air quality standards
    for particulate matter.
        A large body of scientific evidence over the past several
    years links exposure to particulate matter to serious health
    problems, including asthma, chronic bronchitis, heart attack
    and premature death. EPA, as part of its authority under the
    Clean Air Act to periodically review and revise as appropriate
    the air quality level at which to set national standards,
    proposed revisions to the particulate standards. It issued a
    draft regulatory impact analysis in January, 2006 of the
    revisions' expected costs and benefits.
        As you know, EPA's estimates of the expected benefits from
    its air pollution regulations have in the past often been
    controversial and the methods the Agency used to prepare these
    estimates have been questioned. As a result, at the direction
    of the Senate Appropriations Committee, the National Academy of
    Sciences evaluated EPA's overall methodology and approach for
    estimating the health benefits of all proposed air regulations,
    and in 2002 issued a report that made recommendations to EPA
    to, among other things, conduct more rigorous assessments of
    uncertainty, increase the transparency of how it estimates
    benefits, conduct more detailed analysis of exposure, and
    estimate the benefits of each regulatory option under
    consideration.
        Mr. Chairman, you asked GAO to determine the extent to
    which EPA has implemented the academy's recommendations and our
    report that you just mentioned being released today provides a
    detailed discussion of each recommendation and EPA's efforts to
    respond to them.
        In summary, we found that while the National Academy
    generally supported EPA's overall approach to estimating
    benefits, it made 34 specific recommendations for improvements.
    EPA is making progress in responding to the National Academy's
    recommendations, but in the case of its January, 2006 analysis,
    EPA had applied 8 of the recommendations, partially applied 14,
    and did not apply 12.
        For example, in response to the Academy's recommendations,
    EPA evaluated how benefits might change, given alternative
    assumptions, and discussed sources of uncertainty not included
    in the benefit estimates. Although EPA applied an alternative
    technique for evaluating one key uncertainty that concerning
    the causal link between exposure to particulate matter and
    premature death, the health benefits analysis did not assess
    how the benefit estimates would vary in light of other key
    uncertainties, as the Academy had recommended.
        Consequently, EPA's response represents a partial
    application of some of the recommendations. EPA told us that
    insufficient resources impeded its progress in applying some of
    the Academy's recommendations, citing in particular the limited
    availability of skilled staff, time and other resources to
    conduct the recommended analyses. EPA also stated that in some
    cases, it did not believe the state of the scientific knowledge
    was sufficient to implement other academy recommendations. One
    such area has been mentioned today, is for EPA to determine the
    relative toxicity of particulate matter components. EPA intends
    to pursue research and development so that additional academy
    recommendations such as that can be incorporated in future air
    regulations.
        We believe that continued commitment and dedication of
    resources will be needed if EPA is to fully implement the
    improvements recommended by the National Academy. In
    particular, EPA will need to ensure that it allocates resources
    to needed research on emerging issues such as the relative
    toxicity of particulate matter, and to assessing which sources
    of uncertainty have the greatest influence on the benefit
    estimates. EPA officials said that they expect the final rule,
    due September 27, will better address other academy
    recommendations pertaining to uncertainties associated with the
    health benefits estimates.
        We should all be closely examining EPA's final rule because
    a more robust analysis of the remaining uncertainties, not
    addressing the proposal, will be critical if decisionmakers and
    the public are to better understand the likelihood of actually
    attaining the health benefit estimates.
        Mr. Chairman, that concludes my summary. I will be happy to
    answer questions.
        Senator Voinovich. [Presiding.] Thank you very much.
        In our last hearing, we talked particularly about asthma. I
    would like to read a statement to both of you and have you
    comment on it in terms of what impact do you believe that
    increasing the particulate role would have on the issue of
    asthma.
        According to the Centers for Disease Control and
    Prevention, from 1980 to 2001, the number of Americans with
    asthma tripled to 20.3 million. From 1975 to 2000, the number
    of asthma attacks also tripled. At the same time, EPA data
    indicates the emissions of the six principal air pollutants
    dropped by 53 percent since 1970. Thus, while the number of
    people with asthma and the incidence of attacks have increased,
    air pollution has decreased substantially over the same time.
        Senator Lautenberg stated at the hearing, ``But during the
    summertime when most people are enjoying their vacation playing
    outside, children with asthma often have to stay indoors, and
    the reason that they have to stay indoors is the air is just
    too dangerous for them to breathe.''
        However, staying indoors is exactly the opposite of what
    children should be doing, according to a report on the indoor
    air pollution. EPA ``studies of human exposure to air
    pollutants indicate the indoor levels of many pollutants may be
    25 times and occasionally more than 100 times higher than
    outdoor levels. These levels of indoor air pollutants are of
    particular concern because it is estimated that most people
    spend as much as 90 percent of their time indoors. The poor
    quality of indoor air and the amount of time spent indoors
    seems to explain the increased incidence of asthma better than
    outdoor air which is greatly improved.''
        Furthermore, according to NIH, air pollution is one of the
    many things that can bring on asthma symptoms. They talk about
    animal dander, dust mites, cockroaches, pollen and mold,
    cigarette smoke, air pollution, cold air, strong odor, scented
    products, strong emotional expression and stress, medicines,
    sulfites in food, or beverages.
        Will you comment on how you think, if we improve this
    particulate matter, it is going to make a difference in terms
    of something like asthma, that is always the subject matter
    here before this committee?
        Mr. Gray. Senator, as many of you have stated, it is very
    clear that the issue of particulate matter and the ambient air
    quality standard is one of the most important decisions that
    EPA makes. Particulate matter is linked with a variety of
    adverse health outcomes, exacerbation of asthma being one of
    them. That is, no one is suggesting that in fact particulate
    matter causes asthma, but that it may be something that helps
    to trigger an attack or make them worse.
        That is part of the evidence, along with the other health
    effects that we can consider. They were part of the rationale
    behind our proposed rule that you can read about, where we
    suggested a particulate matter ambient air standard. We also
    asked for people's views. We asked for input from the
    scientific community and from the public about that. The
    information we are going to get is going to be an important
    part of the ultimate decision we make. We are trying to
    understand the range of scientific information on all of the
    health effects of particulate matter, and the role that that
    might play in the ultimate judgment of an appropriate standard.
        Senator Voinovich. Mr. Stephenson, the fact that your
    report says that the recommendations of the National Academy of
    Sciences in terms of the things that you need to do to measure
    whether or not particulate matter has an impact on health have
    not been carried out by the Environmental Protection Agency. Do
    you believe that they have enough information now that they can
    intelligently, objectively make a decision in terms of what
    this rule's impact will have on public health?
        Mr. Stephenson. Well, one of the problems is the rulemaking
    process doesn't lend itself to a broad picture of air quality
    in general. We are looking at particulate matter in this case.
    Our concern was that many of the uncertainty analyses were
    done, but they were never rolled up into a more robust analysis
    of all the uncertainties such that you could determine the
    ranges of exposure and project the health benefits in that way.
        So we think they have data. It is a question of how you
    analyze that data.
        Senator Voinovich. Do they have enough data to
    intelligently, objectively decide whether or not for public
    health, and I am not talking about weighing all the other sides
    of this. In other words, they are not supposed to weigh the
    impact on the economy and jobs and poor people's energy costs
    and all the rest of that. They close their eyes to that. But do
    they have enough information to intelligently, objectively make
    a decision in terms of what impact a new rulemaking it more
    stringent would have on public health?
        Mr. Stephenson. In some cases yes and in some cases no.
    They need more exposure data. They need more data to determine
    how particulate matter affects various populations, how people
    inhale the particulate matter, etc. There is another category,
    which you mentioned, on the components of particulate matter,
    what makes up particulate matter. As Chairman Inhofe mentioned,
    asbestos is certainly more dangerous than dust. There is more
    research that is needed in that area in order to determine if
    there is in fact a difference between different types of
    particulate matter.
        Senator Voinovich. Thank you.
        At the request of the Ranking Member of the subcommittee,
    he asked that Senator Boxer be next.
        Senator Boxer. Thank you very much. I appreciate that.
        I really have one question that I want to ask to both of
    you. Assistant Administrator Gray, EPA's proposal to reduce
    dangerous levels of coarse particulate matter or toxic dust
    relies on air pollution monitoring to detect potential
    violations. However, the President's proposed budget for fiscal
    year 2007 cuts these monitoring funds by $17 million. State and
    local Clean Air Act administrators believe this will severely
    weaken monitoring programs and likely result in significant
    staff cuts across the country, so we will not have the people
    necessary to tell us what this monitoring is showing us. And
    what the monitoring is showing us is very important because at
    certain levels, we know our most vulnerable populations, our
    children, our elderly, our sick, our weakest, are impacted.
        So I don't quite get why we see that kind of a cut, $17
    million is not a lot in the scheme of things, when you think of
    what we are spending in Iraq every week. It is in the billions.
    We need the $17 million to be restored. It just boggles the
    mind that would be gone.
        Let me tell you the impact of it that we are being told. We
    are being told that as a result of this, dangerous pollution
    will go undetected in rural areas and cities, such as
    California's San Joaquin Valley where we have our farms and
    workers, farm workers; Missoula, MT; Carson City, NV; the
    Raleigh-Durham metro area in North Carolina; the Fort Worth-
    Arlington area in Texas.
        I am just giving you examples of cities and regions that
    don't meet the population set out here. So I am wondering if
    you think that people in these areas deserve less protection
    than people in larger areas. To Mr. Stephenson, given the same
    set of facts, you have testified before that EPA fully or
    partially implemented only two thirds of the National Academy
    of Sciences' recommendations, but that Agency officials
    complained of a lack of funds hampered their ability to do so.
    Your testimony states that continued commitment and dedication
    of resources will be needed if EPA is to fully implement the
    improvements recommended by the National Academy.
        This is an Administration, and my colleagues on the other
    side and we join them in this. We want to do everything that is
    based on science, and the National Academy of Sciences puts
    forward the plans, and then we don't have the funding. So this
    $17 million cut that I am coming back to, and then there is $1
    million in cuts to EPA's budget for science and research for
    developing and implementing clean air standards.
        So I would like both of you to react to these budget cuts,
    and how do you, first of all defend them, if you do, Mr. Gray
    and Mr. Stephenson. Can you just give us some straight talk
    about what it really means to our people?
        Mr. Stephenson. Well, let me just say that we have in the
    past recommended in other reports on other air issues that more
    monitoring is needed. We are a data-based organization. We
    support the need for real monitoring data. That is the
    cornerstone of scientific research. So if there is a cutback in
    the amount of data you actually collect, we would see that as a
    problem.
        Senator Boxer. And Mr. Gray, I assume you don't think it is
    a problem?
        Mr. Gray. I want you to know that the EPA is committed to
    having the information that they need to make good science-
    based decisions. In fact, it is our network of thousands of
    monitors that we operate, together with our partners in the
    States, that helps give the public information Senator
    Lautenberg referred to, when there is a Code Red day. That
    information comes from monitors that are like those or even
    perhaps from those that are maintained by the Agency. But it
    also helps to support the research that we are talking about.
        Senator Boxer. Wait a minute. Excuse me for interrupting
    you.
        Mr. Gray. Yes.
        Senator Boxer. We agree that monitoring is important. I am
    asking you to tell me why, then, would you be cutting that
    budget?
        Mr. Gray. First of all, we have invested over $100 million
    since 1998 in monitoring and specifically in monitoring
    speciation, questions that we are being asked to address by the
    National Academy, by this committee and by others. In addition,
    we believe that we can find efficiencies. We can do our
    monitoring in better ways. We are all being asked to do things
    more efficiently and we are looking for efficiencies.
        Senator Boxer. So you don't believe that the local people
    who are telling us that as a result of these cuts there will be
    pollution undetected in rural areas and cities, including for
    example, San Joaquin Valley in California; Missoula, MT; Carson
    City, NV; Raleigh-Durham metro. We have a whole list of them.
    You think that is an overreaction and that these people will in
    fact have their air monitored? Is that what you are telling us?
        Mr. Gray. I am telling you that I am sure that they may be
    concerned, but that we are committed to making sure that we
    have the information that we need to monitor the air, to make
    sure that everyone has an adequate level of protection.
        Senator Boxer. So they may be concerned, but they shouldn't
    be concerned because you are going to monitor their air. Is
    that what you are saying?
        Mr. Gray. I am saying that.
        Senator Boxer. Yes or no? Are you going to monitor the air
    in those areas and those regions?
        Mr. Gray. Most of the monitoring that is done is not done
    by the Agency.
        Senator Boxer. Yes or no? Are you going to monitor the air
    in those regions?
        Mr. Gray. We are going to do what we need to do to make
    sure that we have the information.
        Senator Boxer. Mr. Chairman, they are not going to monitor
    the air in these areas. You can't get a yes or no answer. It is
    very disturbing. Yes or no, can't get it.
        Thank you.
        Senator Voinovich. Thank you, Senator Boxer.
        For the record, I would like insert a letter signed by 33
    members of the U.S. Senate to the Appropriations Committee
    asking that they restore this $33 million to your budget, $17
    million of which is to be used for monitoring. I think it is
    outrageous that some of the domestic budgets of this Government
    have not been given the dollars they need to get the job done
    that they are being asked to do. The non-defense discretionary
    budget is being clobbered, and we just stick our heads in the
    sand and ignore it.
        If we ask you to do a job, you ought to have the money to
    get the job done and we are not giving you the money and the
    Administration should wake up to the fact that we have a
    problem not only in the EPA, but across the board. I am sorry.
        Senator Isakson.
        Senator Isakson. Thank you, Mr. Chairman.
        On that subject, just to help educate me, this is a
    prospective cut that is being discussed based on last year's
    funding and this year's appropriation. Do you feel like you
    have sufficient funding at this year's level to do the
    monitoring necessary to make a reasonably informed
    determination on your standards?
        Mr. Gray. The information that we use to make judgments
    about our standards is based on a range of scientific
    information. It includes not only this monitoring.
        Senator Isakson. No, no, no. Excuse me for interrupting.
    But in terms of funding for monitors, which was the question, I
    am just wondering if you think you have enough funding at
    current levels, not contemplating the future proposed cut, to
    make reasonable determinations?
        Mr. Gray. We believe that we have the information that we
    need to make the determinations that we need to make.
        Senator Isakson. OK. Second, the GAO report, and excuse me,
    but I will read this so I will get it correct, in referring to
    the unexecuted 12 recommendations where you all cited
    insufficient resources, the GAO report says, the Agency will
    need to ensure that it allocates resources to needed research
    on emerging issues such as the relative toxicity of particulate
    matter components and to assessing which sources of uncertainty
    have the greatest influence on benefits.
        This portends that you have some discretion in allocation
    that you could use to move moneys to complete all the 34
    recommendations that GAO recommended. Is that correct?
        Mr. Gray. We take the recommendations from the National
    Academy of Sciences very seriously. Characterizing the science
    well in a balanced way and characterizing uncertainty are very
    important to the Agency. I, in fact, take some comfort in the
    fact that we have achieved, at least partially two thirds of
    those, and when our final RIA comes out in September, I think
    you will find we have made even more progress.
        Some of the recommendations will require additional work.
    They will require us to do methods development. They will
    require us to do research. At this point, for example, we have
    committed over $150 million for research to help address the
    question of speciation, one of the very highest priorities that
    we have in addressing National Ambient Air Quality Standards.
    So we are setting our priorities to help to meet many of those
    recommendations that came from the National Academy.
        Senator Isakson. Should you implement a rule before you
    have reached all the conclusions you need to reach based on the
    studies of the science?
        Mr. Gray. I think that the recommendations from the
    National Academy are important for us in the way we do our
    Regulatory Impact Analyses. Those are very important documents
    that help the Nation, that help you understand the costs and
    benefits of the actions that we take. We cannot consider those
    in setting our National Ambient Air Quality Standard.
        Senator Isakson. You cannot consider them?
        Mr. Gray. We cannot consider the costs in setting our
    National Ambient Air Quality Standard. For that reason, we
    evaluate the scientific evidence. We consult with the
    scientific community. We have our panel of experts that we use,
    and that is the information that goes into the setting of the
    National Ambient Air Quality Standard.
        Senator Isakson. One final question, and I want to thank
    the Chairman for holding this hearing and the hearing we held I
    guess last week, wasn't it?
        At the hearing last week, we had a county commissioner from
    Georgia, Walker County, GA, that is in non-attainment; entered
    into a compact with EPA; has from what I can understand from
    EPA and them, done everything that was asked of them within
    their control. But they find themselves the recipient of
    pollution from other continents, as well as larger cities near
    them, and also Mother Nature with the Bermuda High which over
    the southeast traps so much of this stuff for about 5 months
    out of the year.
        I know everybody has heard this before, but just one more
    time. It seems to me like the restrictions and the punishment,
    if you will, that somebody who has done everything admittedly
    within their control to do, that we are punishing the wrong
    person. There ought to be some attention to the unintended
    consequences of them receiving this pollution without any
    ability to stop or divert it after they have taken care of all
    of the things at the local level they need to do.
        So I know there was some testimony by one of the gentlemen
    testifying that there is a way out through appeal to EPA? I
    want to just perfect the record from last week. Walker County,
    at their own expense, did extensive studies to do that, and
    demonstrate the point source of this pollution, but still was
    unable to get any breathing room from the EPA restrictions.
        So I think we do, I am very much for clean and cleaner air,
    and I am very much for doing everything we can in terms of
    standards to implement that. But I also am for reasonable
    common sense on the application, particularly of these non-
    attainment standards when there is no control by the people who
    are being restricted, and in my case it is 63 percent of my
    State.
        Thank you, Mr. Chairman.
        Senator Voinovich. Thank you, Senator.
        Senator Lautenberg.
        Senator Lautenberg. Yes, thanks, Mr. Chairman.
        Mr. Gray, the EPA is proposing to attain an annual health
    standard of particulates that is much less protective than that
    which California has adopted. Can you explain why?
        Mr. Gray. In the case of our proposed rule, first, it is
    important to note that we are committed to making sure that our
    National Ambient Air Quality Standards fulfill the Clean Air
    Act goal of protecting human health. Setting a standard, as we
    have already discussed, is a judgment of the Administrator. The
    job of my office, and a job that I think we have done very
    well, is to present the Administrator with a picture, a
    complete picture of the science, its strengths and its
    limitations, and the uncertainties of what we know and don't
    know, and to help inform that judgment.
        In our proposed rule, we did describe the basis for the
    level of 15 that we proposed, but we did ask for comments on
    other levels. I want you to know that those comments are going
    to be taken seriously and they will be an important factor in
    the Administrator's decision. We are in the middle of an open-
    ended, deliberative process that is going to result in a final
    standard in September. It will fulfill that goal of protecting
    human health, taking into account the science that is
    available, the advice of our advisory committees like CASAC,
    and public comment.
        Senator Lautenberg. Do you think that we are at a point in
    time where we think that there ought to be any making the
    standards more rigid, to raise the standards for particulate
    matter that we ought to move on with? Have we done enough
    research, in your judgment, Mr. Gray, to say that there are
    significant problems with the ambient air quality as we know
    it? We ought to, particularly as it affects particulate matter,
    should we strengthen those standards, make them more rigid than
    they are? Or should we reduce them?
        Mr. Gray. Again, this is an important judgment that has to
    be made. National Ambient Air Quality Standards for particulate
    matter are some of the most important decisions that are made
    by the Environmental Protection Agency and the decisions are
    not made lightly. They are made with as much scientific
    information, as much scientific advice, as much scientific
    input as we can muster. That information is put before the
    Administrator in a balanced way, in a careful way, describing
    the strengths and limitations to help inform the judgment about
    whether the standard needs to be retained, needs to be raised,
    or needs to be lowered.
        Senator Lautenberg. Do you make recommendations when you
    submit it to the Administrator as to the direction that EPA
    ought to take? Or is this simply, I've done my job and here it
    is? Or do you do all the decisionmaking as to the
    Administrator?
        Mr. Gray. My office does not do that. We prepare what we
    call the criteria document, thousands of pages of scientific
    information summarizing what we know and don't know. There are
    recommendations that come from the staff in the Office of Air
    and Radiation in EPA that make suggestions to the
    Administrator. CASAC makes suggestions to the Administrator.
    All of that informs their judgment.
        Senator Lautenberg. You are aware of those recommendations?
        Mr. Gray. I am very aware of them, yes.
        Senator Lautenberg. What is the conclusion that you would
    come to, hearing their recommendations? Do you think that the
    standards ought to be reduced, lowered?
        Mr. Gray. I think that when we put out our proposed rule
    and our proposed standards, we very clearly articulated the
    thinking behind them, the science behind them. We asked for
    public comment, scientific information that might be out there
    that we might find useful. All of that will inform our
    judgments.
        Senator Lautenberg. I understand the mechanics, but there
    must be some conclusions out of this that say we could do
    better. We certainly ought not to do worse. The Chairman talked
    about a statement I made about keeping kids indoors. So I think
    I can come up with a conclusion that you have to choose your
    poison. In other words, if a mother unwittingly says, well, I
    am going to bring my child inside, or keep my child indoors
    because I think that the air quality is better. Here we come up
    with a conclusion that no, that there is more danger indoors
    than there is outside.
        So that is quite a dilemma. I think that what we ought to
    do is understand people's emotion, and understand what people's
    thinking is. In the house, air conditioned, etc., and you think
    that the air quality is better. I know it's easier to breathe
    when you are in a house that has some air quality action going
    on.
        So maybe we ought to meet outside in the interest of safety
    for the Senators and the visitors.
        [Laughter.]
        Senator Voinovich. Thank you, Senator.
        Senator Chafee.
        Senator Chafee. Thank you, Mr. Chairman.
        Senator Isakson was talking about his county in Georgia,
    Walker County, and he mentioned particulate matter coming from
    other continents. In your studies, are there any other
    countries that are similar to us in our research? I don't want
    to put you on the spot, but that we can work with as we try and
    wrestle with reconciling the health benefits toward some of the
    regulations on particulate matter?
        Mr. Gray. There are two parts here. One is that we, as EPA,
    review the scientific information that is available to us to
    help us understand the appropriate levels that inform the
    judgments about the appropriate levels of air quality
    standards, we use information from around the globe. We use
    research that is done in the United States, Europe, and North
    America. We tend to focus on certain areas, partly for
    technical reasons. There is better monitoring data in the
    United States than in Canada, or monitoring is done differently
    than it is in other parts of the world and interpretation can
    become a little tricky.
        We work with international experts. We work with
    international data to try to inform our decisions, to bring the
    best information to bear. In implementation, we do have to
    think about the fact that some of these pollutants can travel a
    very long way, when we think about how we control them.
        Senator Chafee. Any countries in particular really leading
    the way, that we work more closely with? Or are we more on the
    forefront?
        Mr. Gray. Well, I don't know that I can speak to that very
    authoritatively, though I will say that in many cases we do
    think about international transport of pollutants, and we have
    efforts under way in EPA to help reduce the pollution that
    comes out of power plants in China because we know that that
    can affect air quality in the United States. So we are thinking
    about the global environment and trying to transfer some of the
    practices that we have to other countries not only to benefit
    them but to benefit us.
        Senator Chafee. Again, I don't want to put you on the spot,
    but I am just curious. Are there any other countries that have
    stricter standards than we do?
        Mr. Gray. There are countries that have mixes of standards
    some parts of which are stricter than ours, and some they are
    not. In some parts of the world, even in some parts of this
    country, they may have standards that are very strict, but the
    rules for implementation are not as strict. When we set a rule,
    we mean it and it is going to mean something. That is not
    always the case; for example, the World Health Organization has
    set a standard that is stricter than ours, but it is completely
    aspirational and has no teeth to it.
        Senator Chafee. Can we learn from some of the economic
    impacts from those stricter standards?
        Mr. Gray. Again, because many of them are not being
    implemented, because they are aspirational, it is hard to
    learn. If there are opportunities to learn, we will use them.
    As I said, we take our requirement for doing a Regulatory
    Impact Analysis very seriously. We want to make sure that we
    inform the Nation and you and anyone else who is interested in
    it, of the costs and the benefits of these actions that we
    take.
        Senator Chafee. OK, thank you.
        On another subject, does the science dictate that the
    Administrator, I think this is following up on Senator
    Lautenberg's question, dictate that the Administrator choose a
    specific number in setting the particulate matter standards?
    Does the Administrator have some leeway?
        Mr. Gray. It is my understanding--and again I am a
    toxicologist, not a lawyer--that in the Clean Air Act
    recognizes that in fact, setting a National Ambient Air Quality
    Standard is a judgment on the part of the Administrator that
    considers the science, scientific advice, and a variety of
    other factors. So in fact setting a national ambient air
    quality standard is a judgment. In the Office of Research and
    Development, we do our very best to make sure that he has an
    accurate, unbiased characterization of the science to inform
    that judgment.
        Senator Chafee. Thank you, gentlemen.
        Thank you, Mr. Chairman.
        Senator Voinovich. Senator Clinton.
        Senator Clinton. Thank you, Mr. Chairman.
        Mr. Gray, in your testimony you said that EPA has spent
    $500 million since 1997 to improve our scientific understanding
    of the health impacts of particulate matter. Now, it is my
    understanding, based on all of this research that has been
    conducted since 1997 and the extensive review that the research
    has received from outside experts, as well as the public, that
    there is a consensus.
        Let me ask you, does EPA have significantly more confidence
    now that current levels of PM are responsible for very serious
    health effects, including premature death?
        Mr. Gray. When we look at the science that is available to
    us, especially that which has been developed since the last
    evaluation of the standard in the late 1990's, I can say that
    there is better causal evidence linking particulate matter to a
    range of adverse health effects. The understanding of the
    levels at which that happens is much less clear.
        Senator Clinton. Right, but we actually know more today
    about the causal effects than we did in 1997. Is that correct?
        Mr. Gray. Based on what we have learned from epidemiology,
    from studies in people, from toxicology, it is believed we have
    a better understanding of the causal relationship, yes.
        Senator Clinton. What I am confused about is that given our
    understanding of the causal effects, which is greater than it
    was in 1997, given the recommendations from CASAC and others,
    in your proposed rule, EPA itself said that risk assessment was
    too uncertain for standard-setting purposes. What is the basis
    for that assertion?
        I know that we are searching for the best way to implement
    a rule that does take into account the scientific evidence,
    particularly the causal connections, so how did EPA reach a
    different conclusion than all of the other experts who have
    reviewed this matter?
        Mr. Gray. I think an important point is that EPA doesn't
    come to a different conclusion on this issue of causality, is
    there a relationship between particulate matter and adverse
    health effects. Where there is uncertainty and where the Agency
    felt there was too much uncertainty to rely upon the risk
    assessment for setting a standard is in the ultimate
    understanding of the strength of those relationships and the
    levels at which the effects occur.
        Senator Clinton. Well, then may I ask you, because we are
    limited, this is a very frustrating experience asking difficult
    question in 5 minutes, but may I ask you then, why wouldn't our
    Government err on the side of health? If there is an
    uncertainty of the mechanism, why wouldn't we go with the
    stricter standard as recommended by the weight of scientific
    evidence?
        Mr. Gray. I think I would echo your final sentence, that is
    the importance of the weight of scientific evidence. What we
    have done in our proposed rule is lay out what we think the
    scientific evidence is for the standards that we proposed. We
    asked for further comments, recognizing that others, reasonable
    minds can differ on this very large and very complex body of
    information. We have asked for comments. We have asked for
    further information, and that is all going to play a role in
    the final judgment of the Administrator for the final standard
    that will be coming out in September.
        Senator Clinton. Mr. Gray, may I also ask you, have you or
    anyone on your staff had contact with or from anyone in the
    White House concerning this proposed rule?
        Mr. Gray. In the preparation of the science here, the work
    that we do in the Office of Research and Development has been
    done in a completely public and open way through the CASAC
    process. All of our CASAC meetings are open to the public. All
    of their deliberations are public.
        Senator Clinton. I know, but have you or anyone on your
    staff had any contact with or from anyone in the White House
    with respect to this proposed rule?
        Mr. Gray. I can speak for myself and say that I have not.
    In terms of the science here, I cannot speak for my staff. I
    don't know.
        Senator Clinton. OK. But when you say in terms of the
    science that is a blanket denial of any contact whatsoever from
    or through the White House?
        Mr. Gray. It is important to recognize, and I have said
    this----
        Senator Clinton. Can you answer that yes or no?
        Mr. Gray. These are very important standards and that there
    are interagency reviews.
        Senator Clinton. Mr. Gray, I just want a yes or no answer.
        Mr. Gray. Our scientific information is in our hands.
        Senator Clinton. I know, but you haven't answered my
    question. Have you or anyone on your staff had any kind of
    contact with from or through the White House with respect to
    this proposed rule?
        Mr. Gray. In respect to the proposed rule, yes, of course
    we have.
        Senator Clinton. OK.
        Mr. Chairman, could we get further information about this?
    I asked because, again, I go back to the very difficult
    experience I had after 9/11 when it became clear that the White
    House was directly interfering with the EPA scientific
    assessments and the public information provided to my
    constituents. I think that this committee deserves to know
    what, if any, kind of contact, pressure or other relationship
    exists between the White House and the EPA with respect to this
    proposed rule.
        Senator Voinovich. I would like to comment that I was just
    concerned about that as you are. I would really like to discuss
    that because I was not aware of the fact that the White House
    had had anything to do with whatever they came out with after
    that. I know one thing, that when Joe Albaugh came before this
    committee, no one seemed to know what was going on, and that
    was one of the things that disturbed me. That is why our
    legislation is so important. The President can move in and
    immediately determine what folks are exposed to.
        I do not see that there is any problem with it, that we
    look into that. I would be surprised if there wasn't. I suspect
    once you are done with this, don't you have to submit it to
    OIRA to look at the cost-benefit analysis at OMB?
        Mr. Gray. As I said, with our proposed rule, there is
    clearly contact with the other parts of the executive branch.
        Senator Voinovich. I think if you talk about the official
    contact, I think it is reasonable that we get an answer to that
    question.
        Mr. Gray. There is an interagency process that we use with
    all of our rulemakings.
        Senator Voinovich. Why don't you share it with us, OK? Then
    I think we will feel a lot better about it.
        Mr. Gray. Certainly.
        Senator Voinovich. Respond to Senator Clinton's concerns.
        Senator Carper.
        Senator Carper. Thanks, Mr. Chairman. Mr. Chairman, let me
    ask a first question of you. Do you recall several years ago
    when, maybe 3 or 4 years ago when Governor Whitman was EPA
    Administrator that you and I collaborated on a proposal calling
    for the establishment of a position within EPA?
        Senator Voinovich. Here it is.
        Senator Carper. The Deputy Administrator for Science and
    Technology. There you go. You may have been talking about this
    when I was out of the room.
        Senator Voinovich. No, we didn't talk about it. Why don't
    you talk about it?
        [Laughter.]
        Senator Carper. We had this notion, silly notion that maybe
    we ought to have somebody who was pretty senior within EPA who
    would be part of the top dog for science and technology. It is
    an idea that was not warmly embraced by EPA and maybe by the
    Administration. We introduced it as legislation and not a whole
    lot has come of it, but I am still interested. I know Senator
    Voinovich is still interested in making sure that we are making
    decisions that are based on good science.
        Let me just follow it up by asking you to talk a little bit
    more with us about CASAC, this Clean Air Scientific Advisory
    Committee. Just start out by saying, who are these people?
        Mr. Gray. CASAC is actually called for in the Clean Air
    Act, and its base is a seven member panel of experts with the
    requirement for one member to be a physician, one member to be
    from the National Academy of Sciences, and one member to be
    from a State pollution control Agency. Then it is filled in
    with nationally recognized experts to help to provide advice to
    the Agency on ambient air quality standards.
        On any specific standard, whether it is particulate matter,
    ozone, lead or something else, the base group of CASAC is
    augmented by topic-specific experts, again to help us in our
    evaluation, characterization, and presentation of the science.
        Senator Carper. Who selects or appoints these folks?
        Mr. Gray. They are selected by the Administrator.
        Senator Carper. What is the criteria used, just roughly?
        Mr. Gray. Roughly, it is relevant expertise and knowledge.
        Senator Carper. They serve a period of several years?
        Mr. Gray. I don't know the exact period. Yes, they serve
    for several years.
        Senator Carper. OK, thank you.
        Why should EPA, why should the Congress, frankly why should
    anybody else heed the recommendations of the CASAC?
        Mr. Gray. Well, the EPA certainly values the advice of the
    CASAC. It is very, very important to us. The current proposal
    on National Ambient Air Quality Standards for particulate
    matter, for example, our proposal for a daily standard is
    something that reflects very clearly the advice of CASAC.
    Advice from CASAC, again, is one of the important factors that
    are weighed by the Administrator in making the sort judgments
    that are made.
        Senator Carper. What are the other factors?
        Mr. Gray. There are a range of other factors, comments from
    outside scientists, comments from others, the range of science
    that is presented to the Administrator. All of these are going
    to be before the Administrator. When we proposed our standards
    in every case, whether we were matching the recommendation of
    CASAC or not, we asked for comment. We asked people to advise
    us on levels that included everything that CASAC had
    recommended across a wide range of different potential
    standards. All of those comments and all of that information
    will be an important part of the factors that are weighed by
    the Administrator in making a final judgment.
        Senator Carper. Just to understand this, the current
    standards that exist are for annual, and there is a standard
    for daily exposures. If my life depended on it, I don't know
    that I could well explain what a microgram is, but I understand
    that the current PM standard on an annual basis is 15
    micrograms per cubic meter. On a daily basis, it is 65.
        Just explain that. As a toxicologist, I am glad that you
    aren't a lawyer for this question, but as a toxicologist and
    someone who studied some science himself, explain that so that
    the lay person can understand it.
        Mr. Gray. The numbers you are citing are the concentration
    of particles that are in the air. These are particles that are
    all around us right now. We can't see them. In our monitoring
    system, we suck air into a collector, put it on a filter, and
    measure it, and that is how we learn about how much is there.
    That information plays a role in our doing epidemiology,
    comparing the health effects in populations with higher levels
    of exposure to those with lower levels of exposure. It helps us
    to understand what happens when we give animals exposure to
    this, to help us understand the mechanisms by which adverse
    effects might occur.
        So these standards, these numbers are simply ways of
    identifying a certain amount of this particulate matter that is
    in the air.
        Senator Carper. Again, drawing on your own expertise and
    training as a toxicologist, could you describe for us how these
    small, tiny pieces of matter, how they actually contribute to
    asthma, how they contribute to chronic bronchitis, how they
    contribute to heart disease or irregular heartbeat? How does it
    actually happen?
        Mr. Gray. That is one of the areas that we have learned
    much more about in the last 10 years, partially through
    research that has been funded by the Environmental Protection
    Agency. We know that at certain levels of exposure, for
    example, levels that are frankly higher than what we have in
    the air today, it can increase the thickness of atherosclerotic
    plaques.
        Senator Carper. Say that again?
        Mr. Gray. Atherosclerotic plaques, atherosclerosis, the
    stuff you worry about with cholesterol building up and making
    your arteries get small. That can happen in mice. They are
    sensitive mice. They are bred to be sensitive, but that can
    happen to them if they are exposed to high levels of
    particulate air pollution. It is one example of a study that
    has been done to help us understand how these particles may
    have their adverse effects.
        Senator Carper. My last question, Mr. Chairman, would be
    this, we have our current standard, and I think you said the
    annual standard is 15 micrograms. The CASAC had recommended I
    think going down to anywhere from 12 to 14. EPA chose to stay
    at 15. With respect to the daily standard, the current standard
    is 65. The CASAC had suggested going anywhere from 25 to 40,
    and you have come in at EPA at 35 micrograms.
        You chose not to adopt or move toward the annual standard,
    and you chose, or adjusted the daily standard. You went to the
    high end of the CASAC recommendation. Could I ask why?
        Mr. Gray. Again, these are judgments on behalf of the
    Administrator and they are laid out very nicely in our proposed
    rule with the scientific reasoning behind each of the choices
    that were made. But the important thing, and I want to
    emphasize this again, I have said it a lot of times, we asked
    for comments about a range of other potential standards to get
    information from the outside community, from scientists, from
    the interested public about other potential levels, and that is
    all going to play a role in setting the final standard, and it
    will happen in September.
        Senator Carper. All right. Thanks very much.
        Mr. Stephenson, sorry I didn't get to you, but another day.
    Thank you.
        Senator Voinovich. I would like to thank both of you for
    your testimony before the committee. Mr. Gray, I want to thank
    you for your fine testimony here today, not an enviable
    position if you are getting shot at from both sides on this
    one. So maybe that is good. Thank you very much.
        Our next panel will come forward: Dr. Roger McClellan who
    is the Advisor for Toxicology and Human Health Risk Analysis,
    and also is a CASAC, Clean Air Science Advisory Committee
    member; Dr. George Thurston from New York University; Dr. Anne
    Smith from CRA International; and Mr. Dan Greenbaum from the
    Health Effects Institute, which is jointly funded by EPA and
    the industry.
        I would like to urge the witnesses to limit their testimony
    to no more than 5 minutes. Your entire testimony has been
    inserted into the record. We really appreciate your being here
    today. We look forward to hearing what you have to say.
        Dr. McClellan, we are going to start with you.

      STATEMENT OF ROGER McCLELLAN, ADVISOR, TOXICOLOGY AND HUMAN
                          HEALTH RISK ANALYSIS

        Dr. McClellan. Thank you very much. Good morning, Mr.
    Chairman and members of the committee. I appreciate this
    invitation to present my views on EPA's current review of the
    national ambient air quality standard for particulate matter.
        Since 1999, I have served as an advisor on issues related
    to air quality, drawing on my more than 45 years of experience
    in comparative medicine, toxicology, and aerosol science and
    risk analysis. In particular, my testimony draws on my
    experience serving on the Clean Air Scientific Advisory
    Committee, which I chaired from 1988 to 1992, and service on
    all of the CASAC PM panels from the late 1970's to the most
    recent PM panel, as we moved from consideration of total
    suspended particulates to PM10 to PM2.5,
    and now consideration of a PM10-2.5 standard.
        I would like to make several points. First, I want to
    emphasize there is no scientific methodology which can
    determine a specific indicator, precise averaging time,
    numerical level, or statistical form that will be adequate to
    protect public health. The available scientific information can
    inform those decisions, however the Administrator must
    ultimately use policy judgments in making decisions on each of
    those four elements of the standard, drawing on an array of
    scientifically acceptable options.
        Two, I personally find acceptable the Administrator's
    policy choices for the PM standard as were published in the
    Federal Register. Specifically, I find acceptable a proposal to
    reduce the 24-hour standard from 65 to 35 micrograms per cubic
    meter, with a 98th percentile form. I found it acceptable in
    terms of science for him to propose retention of the
    PM2.5 annual standard at 15 micrograms per cubic
    meter. With reluctance, I concurred scientifically with the
    setting of a PM10-2.5 indicator for the 24 hour
    averaging time concentration set at 70 micrograms per cubic
    meter, within a 98th percentile form.
        I say with reluctance because the science base for that is
    extremely weak and uncertain. I would have preferred retention
    of the PM10 standard.
        Third, it is important to recognize that although the
    criteria document is hundreds of pages in length and compiling
    the results of what we know in terms of the world of science
    about PM, at the end of the day the key information for setting
    the standards are the results of the epidemiological studies.
    That has been the basis for changes in standards from a total
    suspended particulates set in 1971, to the PM10
    standard set in 1987, PM2.5 in 1997, and now
    consideration of this new PM10-2.5 standard.
        So the current review focused on the PM2.5
    indicator. Now, some might have said, well, why didn't we look
    at sulfates or elemental carbon or some particular chemical
    species? The fact of the matter is we are chained to the
    ``regulatory compliance lamppost'' in terms of monitoring data.
    You cannot conduct epidemiological studies unless you have the
    monitoring data. Our past obsession with monitoring that which
    is regulated has precluded the development of the richer
    science base that really need to consider these options in
    terms of speciation.
        I am not optimistic that that is going to change. I can
    envision us sitting here 5 years, 7 years from now and
    discussing, well, why not for specific standards; why didn't we
    perhaps preclude or set outside of the standards on material,
    because it is very innocuous; or why didn't we focus on
    something in particular? In fact, we won't have the
    epidemiological data because I don't think we are developing
    adequate monitoring data.
        Fourth, we can then turn to the question of toxicology. I
    am a toxicologist. I am intellectually married to the subject,
    if you will. We have exciting new methods at hand, but at the
    end of the day, I have to say that our toxicology methods are
    simply too blunt and yield results that can only be
    qualitatively extrapolated to the human population. I know of
    no scientific method for using the results of the toxicology
    studies with PM, including those conducted with specific
    chemical constituents, to develop quantitative numerical
    standards that are the core of the PM NAAQS.
        Fifth, we have heard some discussion about the issue of
    uncertainty. I certainly, as a scientific colleague of Dr.
    Gray, am an enthusiast for trying to determine how we can bring
    our scientific information together and relate all of the
    uncertainties, so we can have better informed policy decisions.
        I want to comment on one aspect of that, and that is the
    use of expert elicitation. That was covered in the GAO report.
    I served as one of those five experts on the pilot expert
    elicitation. I hesitate to say whether it is expert advice or
    expert opinion. It is a challenge when you are asked to present
    information. The answers that are given can be heavily
    influenced not only by your knowledge of the science, but your
    personal choices. All of us want quality life. Well, how do we
    separate that from our judgment on the science?
        I am concerned about the use of that expert elicitation
    advice, and I certainly would urge the Administrator to use a
    high degree of caution in using that in the regulatory impact
    analysis and in making decisions on the standard.
        Senator Voinovich. Dr. McClellan, could you finish up?
        Dr. McClellan. I am going to just wrap up with that and
    emphasize that one of the challenges we have today is
    separating out people's views on the science versus their views
    on the science wrapped up with the policy and some desired
    outcome--the level of the standard. I think in some cases, as
    individuals and professional groups have weighed in, they are
    weighing in not just on the science, but the policy outcome
    they want.
        I do think it is important to have a distinction between
    the science and policy choices. In my comments on the
    acceptability of the Administrator's choices, I viewed the
    science options laid out in the staff paper as acceptable, and
    he used his judgment in selecting from among those options. I
    think that was appropriate.
        Thank you.
        Senator Voinovich. Thank you very much for being here.
        Dr. Thurston.

      STATEMENT OF GEORGE THURSTON, ASSOCIATE PROFESSOR, NEW YORK
      UNIVERSITY, SCHOOL OF MEDICINE, DEPARTMENT OF ENVIRONMENTAL
                                MEDICINE

        Dr. Thurston. Good morning. I am George Thurston, a tenured
    Associate Professor of Environmental Medicine at the New York
    University School of Medicine, where my research involves the
    investigation of human health effects of air pollution.
        I first wish to present for inclusion in the record letters
    from many major medical societies and public health groups,
    including the American Medical Association, the American
    Thoracic Society, and the American College of Chest Physicians,
    the American Public Health Association, the American Lung
    Association, the American Heart Association, the American
    Cancer Society, and more. These letters show the unprecedented
    support that exists for PM standards that are much tighter than
    EPA has proposed.
        Especially note that they all agree that the science
    supports tightening annual standards to no more than 12
    micrograms per meter cubed. If this were to be done, many
    thousands of premature deaths could be avoided each year.
        I also present a copy of Dr. Rogene Henderson's letter from
    the EPA's Clean Air Science Committee, CASAC, urging that the
    Administrator comply with their recommendations, with CASAC's
    recommendations, to implement more stringent PM standards than
    now proposed by the EPA.
        Now, in my written testimony, I have addressed three
    factors that need to be considered in the EPA's proposed
    revisions to the particulate matter air quality standards.
    First, I address the fact that we are now far more certain, as
    discussed earlier, of the adverse impacts and biological
    mechanisms of PM health effects. The uncertainties raised at
    the time of the initial setting of the PM2.5
    standard are now greatly reduced.
        As outlined in figure one, if someone could put that up,
    from my testimony, the PM research funded since the setting of
    the last PM2.5 standard has collectively shown the
    existence of numerous biological pathways capable of causing
    damage to the human heart, the lung, the nervous system and the
    circulatory system. This is consistent with the health impacts
    found by the PM epidemiology studies upon which the
    PM2.5 standard was set.
        This has greatly reduced scientific uncertainty associated
    with the mechanisms by which PM has such severe effects on
    human health.
        Second, I documented reducing ambient PM levels can and do
    result in significant reductions in the mortality risk
    associated with this pollutant. Since the setting of the
    original PM2.5 standard, more recent follow-up
    analyses of the landmark Harvard Six Cities and ACS studies
    have now considered longer records of time and have confirmed
    and expanded the conclusions from these two major studies.
        As shown in figure two, an extended analysis of the Harvard
    Six City study through 1990 has now shown that reductions in
    long-term ambient PM pollution results in concomitant
    reductions in health risks associated with PM. Large reductions
    in PM at four of the Harvard cities have resulted in likewise
    large reductions in the relative risk of mortality in those
    cities. We see S, Steubenville, where the pollution levels have
    come down, and so has the risk of mortality from that
    pollution. In Harriman, TN, the pollution levels have come down
    and the risk of mortality in that city has diminished as a
    result of the lower pollution. St. Louis, the L, has come down
    similarly, and Watertown, right, Boston, has similarly come
    down.
        So the places where they have had improvements, we see that
    lower PM2.5 lowers mortality. But I think it is
    important to say we still have a long way to go, and a lot of
    improvement yet to be made and benefits to be reaped from
    lowering the PM standard.
        Finally, I show that the adverse health effects of PM air
    pollution extend below the PM2.5 standard of 15. A
    recent NIOSH-funded extension of the ACS study, of which I was
    a principal investigator, strengthens the original conclusions
    of the ACS study, and it importantly now links increased risk
    of lung cancer to long-term exposure to PM, as shown here. As
    the pollution level goes up, the risks of lung cancer rise, as
    do all cause and cardiopulmonary.
        As seen in this figure, the risks from PM2.5
    extend well below 15 micrograms per meter-cubed.
        In conclusion, since it was the level of uncertainty about
    PM biological mechanisms and effects at concentrations lower
    than 15 micrograms per meter-cubed that limited the standard to
    that level in 1997, and, I point out, not some specific
    acceptable level of health risk from PM, and since new sound
    scientific studies have greatly reduced or resolved those
    uncertainties, then concern about the health of the public
    clearly indicates that the long-term PM2.5 standard
    should now be reduced below 15, consistent with CASAC's advice.
        And finally, I just want to point out that I was involved
    with the actual expert elicitation that has just been finished.
    It is finishing up under EPA. It is clear from the expert
    elicitation; I was shown the results of all the experts at the
    final meeting in New Orleans a few weeks ago. It is clear that
    the experts are, there is a consensus that, the risk from fine
    particle is much higher than previously thought, and that
    expert elicitation gives us an estimate of somewhere on the
    order of 1 percent decline in mortality per microgram per
    meter-cubed of fine particles.
        So we are talking about a very large reduction in health
    risk, if you consider the fact that over two million people die
    every year in the United States, a reduction of 1 percent in
    that would be 20,000 deaths per year. So we are talking about
    many thousands of premature deaths that can be avoided by
    lowering this pollution.
        I did want to respond to the question that you raised about
    asthma, if I have a second. Do I have time to respond to that?
        Senator Voinovich. Why don't you bring it up in the
    question period.
        Dr. Thurston. OK, we will talk about it then.
        Well, thank you for this opportunity to testify.
        Senator Voinovich. Thank you.
        Dr. Smith.

       STATEMENT OF ANNE SMITH, VICE PRESIDENT, CRA INTERNATIONAL

        Dr. Smith. Mr. Chairman, thank you for inviting me to
    participate in today's hearing. I am Dr. Anne Smith. I am a
    Vice President, CRA International.
        I have been analyzing the risks and policy options
    associated with fine particle standards for over 10 years. The
    opinions I will present today are my own and not those of my
    company, CRA International.
        When EPA set the first ever national ambient air quality
    standards for PM2.5 back in 1997, in the face of
    substantial knowledge gaps at that time, it presumed that fine
    particles do have a causal relationship with public health. The
    law then required that standards be set for that
    PM2.5 at a level that would protect the public
    health with an adequate margin of safety.
        The courts ruled that the current standards they set did
    indeed provide that adequate margin of safety. EPA and the
    courts have also made it clear that that margin of safety does
    not eliminate estimated risk. Today, EPA is deciding whether
    new evidence accumulated since 1997 justifies tightening these
    standards. In both 1997 and now, EPA prepared a quantitative
    risk analysis using the available health studies. EPA says this
    is to help decide whether to tighten the standard. As I will
    show, it can help with this.
        However, if you take the position that the PM2.5
    standard has to be tightened just because the risk analysis
    produces a body count at the prevailing standard, you will find
    yourself having pre-decided to tighten the standard in every
    future review cycle, even if the evidence never changes in the
    interim. This cannot be what Congress intended.
        In thinking about whether to tighten the standard, the more
    appropriate question to ask is: Has anything changed in our
    knowledge that would undermine the Administrator's 1997
    judgment regarding the adequacy of the margin of safety? Having
    a large number of new studies today, having successfully
    reanalyzed the studies we had originally, and even having some
    evidence of a still elusive biological mechanism, all fail to
    provide a justification to tighten the standard. They merely
    confirm that a standard is needed in the first place, which was
    the judgment made in 1997.
        However, one could justify tightening the standard if the
    new evidence that I have just spoken of indicated that risks at
    the attainment level of the current standard have increased
    since 1997. To test this, I went back to my 1997 files to
    construct a comparison of EPA's estimates of mortality risks on
    a then and now sort of basis. I found that the estimates of
    mortality risk at the attainment level have actually fallen
    since they were first estimated in 1997.
        Risks due to long-term mortality have fallen in every
    location. The risks due to daily exposure, which vary by city,
    have fallen in six of the eight cities that are in EPA's risk
    analysis. This new information suggests that the margin of
    safety provided by the current standards is actually greater
    than we originally thought.
        What I have told you so far is based entirely on EPA's own
    point estimates of risk. However, it is worth looking more
    closely at those estimates and the basis for them. Every one of
    the new epidemiological studies actually contains multiple
    alternative risk estimates. Sometimes there are dozens of them
    within a single paper. Which one is best? Which one should be
    used in the risk analysis? The Health Effects Institute has
    pointed out in the face of this issue that there is no gold
    standard for deciding this.
        When I reviewed the full body of evidence in each paper
    that EPA used for its risk analysis, I went back to the
    original papers, I noticed that EPA had consistently selected
    the highest risk estimate or nearly the highest one from each
    of the papers. Therefore, EPA's risk estimates overstate what
    the full body of evidence supports today.
        The evidence on fine particle risks has weakened in a
    number of other ways. Several of EPA's own point estimates
    today of the risk are not statistically significant. What this
    means is that behind the purported body count that comes out
    the risk analysis there is also actually a rather large
    probability of no health impact at all associated with that
    very same estimate. I found that none of the risk estimates for
    any of the eight cities in EPA's risk analysis remains
    statistically significant across all of the reasonable
    estimates in those papers.
        This body of new evidence has also substantiated some of
    the concerns that were raised in 1997 that fine particles may
    be a scapegoat, while the real villain hides behind a veil of
    statistical uncertainty. The only clear trend in the new
    evidence has been that the estimated levels of risk that are
    being attributed to fine particles are lower than originally
    thought.
        I would like to conclude by saying that we still have no
    idea of which constituent of PM2.5, if any, is the
    culprit underlying this complex body of evidence. Even if the
    risk estimates are good, correct risk estimates, by regulating
    this generic mass of many compounds that is PM2.5,
    we may gain little if any public health benefit.
        Thank you for this opportunity to share my views on this
    important topic.
        Senator Voinovich. Thank you, Dr. Smith.
        Dr. Greenbaum.

       STATEMENT OF DANIEL GREENBAUM, PRESIDENT, HEALTH EFFECTS
                               INSTITUTE

        Mr. Greenbaum. Thank you, Mr. Chairman. It is a pleasure to
    be back in front of the committee. I thank you for the
    opportunity to testify.
        I am the President of the Health Effects Institute, which
    as you know is an independent research institute funded jointly
    by the EPA and industry to provide high quality, impartial
    science on the health effects of air pollution.
        I am going to focus today on the science progress we have
    made since 1997, the most recent findings on the relationships
    between different ambient concentrations of PM and health, and
    key science needs going forward.
        Since Congress identified the need for substantial enhanced
    research in 1997, much progress has been made. We know much
    more about the sources of fine particles and about personal
    exposure. We have conducted the first multi-city epidemiology
    studies and analyzed and reanalyzed many of these studies,
    finding that in general the earlier studies were well done.
        At the same time, there has been some evidence that the
    health effects we have seen in those earlier studies may in
    some cases be smaller. Unlike in 1997, we now have a number of
    toxicology studies that have begun to indicate potential
    biological mechanisms by which PM may cause health effects,
    although as always there is still much more to learn.
        Among the most important questions addressed in recent
    years is whether exposure to PM has health effects at all
    levels, or whether there is a threshold below which no effects
    are expected. This question is central to setting the level of
    the NAAQS. This has been looked at in both short-term and long-
    term studies. Perhaps the most rigorous short-term study
    conducted since 1997 is the National Morbidity, Mortality and
    Air Pollution Study, which was funded by HEI and led by Johns
    Hopkins. That study examined daily changes in air pollution and
    health in the 90 largest U.S. cities.
        As shown in figure one in my testimony, the study found
    that there appeared to be a linear relationship between
    mortality and air pollution for all causes of mortality and for
    deaths from heart and lung disease without an apparent
    threshold. Our review committee, which intensively peer-reviews
    all HEI research, advised caution in drawing conclusions from
    the apparent absence of a threshold, but noted that the
    reported associations in the study are at ambient
    concentrations well below the current U.S. daily standard.
        There were two principal long-term studies in 1997, the
    Harvard Six Cities and the American Cancer Society study, and
    there have been some additional studies since, but attention
    has primarily focused on HEI's reanalysis of these two and on
    extended analysis in the ACS population.
        For the reanalysis, we gained access to all underlying data
    in the studies and chose independent investigators who tested
    the original studies against a wide variety of alternative
    explanations. The investigators also conducted an analysis of
    the concentration response and figure two in my testimony
    presents the results, summarizing for each community the annual
    air pollution level and the risk of death due to heart and lung
    disease. As you can see, there is some scatter of effects. It
    is not all in a straight line, especially at the highest and
    lowest PM levels studied, but also an overall trend of
    increasing mortality risk with increases in pollution levels,
    starting at relatively low levels.
        Following the reanalysis, the original investigators for
    the ACS study conducted an extended analysis of the data, which
    Dr. Thurston has mentioned and participated in, and found
    similar results.
        While we have made much progress, there continue to be, as
    there always are in science, important questions. Two key areas
    are: First, we need continuous improvement in the statistics
    used in epidemiology to better test the sensitivity of the
    results, to quantify the uncertainty, and to communicate both
    the results and the uncertainties clearly.
        Second, no other question will have as much impact on
    future regulations than determining whether some components of
    the complex mixture of PM are more toxic than other components.
    Ultimately, this data will be essential to ensuring that
    regulations are targeted at reducing those emissions which will
    have the most public health benefit at the least cost.
        This has also become important in light of the current
    proposal for a PM NAAQS for coarse particles, which is proposed
    to exclude certain particles from regulation. There have been
    some individual city studies of this question, but no
    systematic national effort to compare results from both
    epidemiology and toxicology. To fill that gap in time to inform
    a next round of PM NAAQS review, HEI has launched, with support
    from both EPA and multiple industries, a set of systematic
    multidisciplinary national studies.
        As indicated in both the NRC review of PM research
    priorities and in today's GAO report, these PM component
    studies will be central to ensuring that future PM actions are
    the most effective possible.
        I might add that while I obviously have the utmost respect
    for Dr. McClellan and take his skepticism that we can answer
    this question as a true challenge, as a long-time Boston Red
    Sox fan and a hopeless optimist, I enter this challenge with
    the hope that we can, if we all put our minds to it, answer
    this question of which components much better 5 or 6 years from
    now than we can today.
        Thank you for this opportunity to testify. I would be
    pleased to answer any questions you might have.
        Senator Voinovich. I want to thank all the witnesses for
    your testimony this morning.
        Before I start the questioning, Chairman Inhofe asked that
    I insert testimony for the record from Dr. Borack on the issue
    of coarse particulate matter. Without objection, we will do
    that.
        [The referenced Testimony can be found on pages 171-187.]
        Senator Voinovich. Mr. Greenbaum, as you know, there is an
    ongoing debate about whether EPA must lower the annual
    standard. We talked about it last week, and this week we are
    trying to get some of you that are smarter than we are in the
    scientific area to give us your best thoughts.
        Your opinion is invaluable in this debate as an entity that
    sits squarely in the middle. You are funded by both industry
    and the EPA. Clearly, the statute says the standard shall be
    set, ``in the judgment of the Administrator.'' In your opinion,
    is it reasonable from a scientific and health perspective for
    the Administrator to retain the annual standard at 15 and not
    lower it?
        Mr. Greenbaum. Well, Mr. Chairman, I appreciate that that
    is the $64 million question at this hearing. I tried to present
    the best view of the science that we at HEI can give you on
    that question. While the dose response or the relationships
    going down to the lowest levels are very clear for why we are
    tightening the daily standard, they are strong, but not as
    clear, for the long-term studies, as shown in the data I
    presented.
        There is evidence with cities showing reduced effects as
    you go down below 15 micrograms per cubic meter. I think it is
    exactly in that area where there is some certainty about these
    results, but where the Administrator has to make a policy
    judgment about whether that is certain enough to require
    additional actions. As Dr. McClellan said, there is really no
    scientific method even that HEI has that could set that.
        I should add that we at HEI, since our inception, have
    never taken a position on a specific standard because of the
    clear concern that such a position would be viewed as therefore
    biasing any of our future science. So we don't take positions
    on this. We don't advocate. The science is definitely stronger
    on the concentration.
        Senator Voinovich. The question is, is it reasonable?
        Mr. Greenbaum. I think I am going to have to leave that to
    the Administrator to make that judgment. I think that there is
    evidence that we didn't have in 1997 of effects still
    continuing below 15. But whether that is enough evidence to
    make a call for a reduction in the standard is a public health
    policy judgment, not a scientific judgment.
        Senator Voinovich. Dr. Smith, what is your opinion?
        Dr. Smith. The way to think about setting the annual
    standard is to look at the chronic health studies. The chronic
    health studies have been the ones that have been found to have
    FE.
        Senator Voinovich. What studies again?
        Dr. Smith. I am sorry. Chronic health studies, which are
    studies of long-term exposure to PM2.5 so they are
    more relevant to measures like the annual standard and annual
    average, rather than to a day to day peak, which is the daily
    standard. So the studies that look at the long-term exposure of
    PM2.5 with mortality are the ones that are in
    question for whether we need to tighten the annual standard.
    Those studies are some of the most difficult ones to properly
    control for in statistical methods.
        What we found in the reanalysis that Dr. Greenbaum's
    organization performed is that in fact when reanalyzed with
    alternative methods of control, the estimate gets more and more
    insignificant as additional factors are brought into play such
    as SO2. SO2 when added into the analysis
    causes the PM2.5 health effect to become
    insignificant, issues that are complex statistical issues, and
    I will use a technical term, spatial autocorrelation, are
    problems if you have those in the analysis. They were found in
    the health effects studies for long-term standards and when
    controlled for, the effect becomes statistically insignificant,
    again meaning a very large probability that there may be no
    effect at all.
        So the evidence has weakened since the standard was set at
    15 micrograms per cubic meter based on that data set. I will
    also say, when that standard was set, there was evidence of
    effects below 15 in that data set. That hasn't changed. That is
    not new information. So while the analyses have held up to
    reanalysis and been confirmed that you can find this sort of
    correlation in the long-term studies, they are much weaker in
    terms of how well you can make a causal interpretation of them.
        Another very important finding that came out of the Health
    Effects Institute's reanalysis is that in fact if you break the
    population that the data, if you break the cohort that is being
    studied into three groups, different educational levels, and
    you look at the group that has even 1 year of education beyond
    high school, which is what good deal of our population has,
    there is no effect at all. It is gone. It is not in that
    analysis.
        So the effects are very dependent, the effects that are
    being purported and attributed to PM2.5 out of that
    study are now known to be very dependent on whether a person
    has had any education beyond high school or not. That
    relationship is found in all the studies.
        Senator Voinovich. What does that mean?
        Dr. Smith. It suggests that there is a missing variable in
    the equation, basically. We know that education does not in
    itself make somebody more or less susceptible to exposures to
    fine particles, but there may be something.
        Senator Voinovich. Does this mean that the people that are
    1 year in high school live out in the suburbs and others live
    in the urban area and are more impacted by this?
        Dr. Smith. It may have something to do with the poor
    evidence on what they are being exposed to. It may be something
    about lifestyle that actually creates risk for them that the
    PM2.5 is picking up on, but isn't really
    exacerbating. It is just serving as another thing, a scapegoat.
        Senator Voinovich. Let me ask you something. If I am a
    smoker, and please forgive me if these are elementary question,
    but if I am a smoker, am I more subject to fine particle PM
    than if I am a nonsmoker?
        Dr. Smith. I actually am not quite sure how that
    relationship works out in the study, but they have controlled
    for smoking in the relationship. Certainly, smoking is related
    to educational level, but smoking was controlled for when they
    did this analysis of whether there was an effect at different
    educational levels. So the correlation between smoking and
    educational level is not the education for what is going on
    there. It means there is something totally different at play.
        Until you find out what that problem is, through more
    study, more research, and it can be done, until you find out
    what that problem is that explains this unexpected and bizarre
    result, you don't have an unbiased estimate of what the risk
    is. It could be larger or it could vanish, the PM2.5
    risk, that is.
        Senator Voinovich. OK. In terms of the particulate matter,
    again, we are trying to reduce NOX and
    SOX, mercury. When they do the analysis of the
    particulate matter, they just segregate that out and you don't
    take into consideration the impact that NOX or
    SOX. Or does particulate matter have something to do
    with NOX and SOX?
        Dr. Smith. The results that are being used in the risk
    analysis do not account for SOX or NOX or
    any of the other pollutants and whether they may have an
    explanatory role, too. As I said a minute ago.
        Senator Voinovich. In other words, when you are doing the,
    I always have a tough time with that word, epidemiologist do
    the studies, OK, the fact is that they are just looking, they
    are trying to figure out just what the particulate matter is.
    They don't take into consideration that I am exposed as a
    person to both NOX, SOX, particulate
    matter, mercury and the rest of it, and somehow they are able
    to pull out and say these particulate matters are the things
    that are really contributing to morbidity.
        Dr. Smith. As I was saying, the mortality, as I was saying,
    the estimates that are being used right now to estimate risk
    from PM2.5 only consider PM2.5. However,
    the studies in the many, many other results that are in these
    papers look at other formulations, other methods of doing the
    estimate that put the other pollutants in to the model as well
    and try to understand which pollutant is it. Does one of them
    explain the effect that we are seeing for PM2.5 when
    that is the only one in the model? Is there another pollutant
    that could explain it better, when we put them both in the
    model?
        What is found in study after study after study when this is
    done is that the PM2.5 effect goes away, becomes
    statistically insignificant is what I mean. The other pollutant
    that is in the model that is being explained by the analysis at
    the same time retains its statistical significance. I looked at
    all the PM2.5 short-term studies that I could find
    that did this analysis, this type of two pollutant analysis. I
    found that the vast majority of them had the PM2.5
    effect that was statistically significant if it was the only
    one in the model, become statistically insignificant when one
    of the gaseous pollutants, and these included ozone,
    SO2, NOX, and carbon monoxide. The same
    thing is going on in the chronic studies for SO2.
        Senator Voinovich. To get back to the original question. If
    the Administrator, is it reasonable from a scientific and
    health perspective for him to retain the annual standard at 15
    and not lower it? Is it reasonable?
        Dr. Smith. Given the basis for the standard of 15, which
    was the same chronic studies that I have just described to you,
    but before we studied them and discovered some of the
    underlying uncertainties in them, and given that the risks are
    lower now based on the new evidence using their point
    estimates, it seems quite reasonable to say that we haven't
    learned anything that says that that standard has a smaller
    margin of safety than it had when the standard was set.
        Senator Voinovich. So you would say that if he did it, it
    would be reasonable.
        Dr. Smith. That could be reasonable.
        Senator Voinovich. May I ask another question? In terms of
    sulfur and NOX, in terms of public health, and
    particulate matter, which is the worst?
        Dr. Smith. Between sulfur and NOX SO2
    and NOX
        Senator Voinovich. Sulfur dioxide or NOX, if you
    were able to reduce those substantially, in terms of public
    health, which one of those is the worst?
        Dr. Smith. I really cannot say.
        Senator Voinovich. I would be interested in all of you.
        Dr. Smith. I just don't know. I have not actually done a
    relative analysis of SO2 and NOX.
        Senator Voinovich. Well, has anybody done an analysis at
    the table? Dr. Thurston, you have been around a long time. You
    have testified a lot of times before this committee. Do you
    have an opinion?
        Dr. Thurston. Well, yes, I would like to respond to a few
    things that were just said, including that.
        Mr. Greenbaum. Senator, I realize you are going to go
    through everybody, but I would like, since it was HEI who
    conducted the reanalysis I would like to have the opportunity
    to clarify for the record what we did conclude.
        Senator Voinovich. Get your mike there, please. Go ahead.
        Mr. Greenbaum. I'm sorry.
        Senator Voinovich. OK, go ahead.
        Mr. Greenbaum. I just want to, and I don't mean to take
    away from Dr. Thurston, but I did want to clarify what the HEI
    reanalysis of the long-term studies in effect did and didn't
    find, because there has been some degree of confusion just
    thrown into it unfortunately by Dr. Smith's comments.
        First of all, I think everybody can in this process pick
    their favorite study and their favorite result from the study
    and try to emphasize that, so they can emphasize the one that
    has multiple pollutants in it and say there is no effect, or
    they might emphasize the one that has no other pollutants but
    PM in it and say there is a big effect of PM.
        Our Review Committee, in our review of the reanalysis--this
    very intensive look these studies--had to look across all of
    the analyses to figure out which ones were the right ones,
    which ones were the wrong ones, which ones were statistically
    stronger or weaker. While, of course, that group of scientists
    identified continuing questions for those studies, we did find
    as strength of the evidence that the effects of PM were robust
    to a number of analyses that were done.
        We also found for the first time a strong effect of sulfur
    dioxide in that, although our committee, and this is in partial
    answer to your question, did not think that sulfur dioxide
    itself could be attributed to doing that, based on toxicology
    information, but that it might be a marker for something else
    in the air that would travel with it, but we are just not
    measuring that, and therefore we don't have information about
    that other substance.
        The reanalysis definitely found, after test after test
    after test, stronger results from those studies, with some
    continuing questions. We certainly had that.
        Second, on the question of education, and how education
    modifies the results, certainly there was a stronger result
    shown for those with the least education in terms of increased
    mortality. We do largely view educational levels as one marker
    for poverty or socioeconomic status. We know that poverty and
    socioeconomic status themselves can have effects on health.
    People can have less good medical care, less good nutrition,
    and a number of other things that shorten their lives. We know
    that and our reviewers certainly understood that as well.
        In that analysis, in the reanalysis, however, when you
    looked at heart and lung disease deaths, which is not what Dr.
    Smith put in her testimony, you still see some effect in
    everybody else in the population. That effect was marginally
    statistically significant, but still there. Our investigators,
    our reviewers felt two things, that: One, that there was a
    continued effect at these different levels, with the strongest
    effect being that those with the least education and probably
    least socioeconomic status, and that might be because of higher
    exposures, less access to air conditioning, and a number of
    other things that would increase the effect.
        Two, they also did note that no study is perfect, so there
    probably is still, somewhere in there, some continued
    confounding where the results are showing an effect of being
    poor, but they didn't suggest that that explained the whole
    effect. I just wanted to clarify that.
        And then they did test all of the pollutants in the
    reanalysis, including nitrogen oxides and sulfur dioxide and
    ozone. Sulfur dioxide was the only one that showed effects and
    had any effect on the PM results. As I said earlier, they
    thought that was important to understand. They understood that
    we need to do more work on that. They weren't sure that it was
    the sulfur dioxide. In fact, the sulfur dioxide might have been
    a marker for other types of particles that are coming along
    with the sulfur dioxide, not the gases themselves. There could,
    for example, be metals that come out of the same sources.
        So I thank you for the opportunity. I just wanted to
    clarify what our reanalysis did say, and obviously the full
    report was actually presented to you at an earlier hearing.
        Thanks.
        Senator Voinovich. Dr. Thurston.
        Dr. Thurston. Yes, thank you.
        Before we start out, you were noting that Dr. Greenbaum is
    between Government and industry. I just want to point out that
    I represent, I think, a disinterested party. I am a tenured
    professor at NYU. My salary is paid by NYU. I don't do
    consulting for the vested interests involved here. So I feel
    that my testimony should be viewed as a disinterested party,
    not an uninterested party, but a disinterested party.
        I have to agree with Dr. Greenbaum's discussion of the
    SO2 and the HEI reanalysis. SO2, it is
    clearly stated. You know, I think that unfortunately what Dr.
    Smith has done here is exactly what she accuses EPA of having
    done. She has cherry-picked certain results that support her
    position and unfortunately hasn't looked in a balanced unbiased
    way at this question.
        Senator Voinovich. Can I ask you something?
        Dr. Thurston. Yes.
        Senator Voinovich. What is it that contributes to the
    particles? You have coarse particles, you have fine particles.
    We are becoming more concerned about fine particles. I know I
    have been at the University of Cincinnati, the Children's
    Hospital down there. They are doing a study of diesel fumes on
    urban kids----
        Dr. Thurston. Yes, I have done that myself.
        Senator Voinovich [continuing]. The development and so
    forth. But we are talking about the things that cause the
    particles. Is it basically emissions from automobiles? What is
    it? What is the cause of this?
        Dr. Thurston. On that question, you made a good point, you
    know, that these are oftentimes markers. I think the
    SO2 being a marker of largely power plant pollution
    in the United States; NOX being largely a marker of
    traffic. It is very likely, actually, that that SO2
    in the ACS study, because I have done some of this analysis, of
    course, as being PI of the NIH-funded portion of that, that the
    SO2 is a marker for power plant pollution, and that
    contribution to mortality.
        It depends on the health outcome you are looking at and
    where you are.
        Senator Voinovich. The particulate matter we are talking
    about, you know, what is the biggest source of particulate
    matter?
        Dr. Thurston. Well, there are different types, and I think
    what we are wrestling with is: Which effects are caused by
    which types? But I think it is safe to say if you lower the
    fine particle levels, you are going to better protect health.
    So the standard is necessary. It is appropriate. As we learn
    more, we may be able to refine that further.
        Senator Voinovich. Just for example, we are trying to make
    things better, and we are going to set a standard. Well,
    somebody is going to have to meet a standard, but if you were
    going to meet the standard, do you do that by reducing diesel
    emissions? Or what is it that is going to have the biggest
    impact on, if you assume what you are saying, that fine
    particle matters are bad and if you set it at 12, everybody's
    going to live longer than if you have it at 15, what is it that
    you have to do in order to make sure that you don't expose
    people to these things?
        Dr. Thurston. Well, I think that is going to vary depending
    on where you are. If you are in Los Angeles, I think traffic
    would be a good thing to try, the pollution from traffic. If
    you are in the Northeastern United States, power plants are a
    big problem there, but not so much in Los Angeles.
        So I think that the States will implement controls on the
    pollution problems that are the largest. I think as we go on, I
    mean, this is going to take us 20 years before we are finished
    with this process, in reality, of meeting the standard that is
    set. So as we go through it in that time, we should be able to
    provide the kind of research that HEI is funding, that EPA is
    funding. In 5 years, I think we will be able to give you a
    better answer. As the States move to the implementation phase,
    they will have that information about the sources.
        Senator Voinovich. But the answer that they come up with is
    that at 12 it would have a major impact on the economy of this
    country and the environment in various places. There is just no
    question about it.
        Dr. Thurston. But it would have major benefits, health
    benefits of lowering it to 12. I agree with that. The past has
    shown that environmental controls are not a big problem
    economically. We have been able to. We have other problems with
    economics, as you are well aware.
        Senator Voinovich. Dr. Thurston, let me tell you something.
    I am a former Governor of Ohio, OK. The first thing I did was
    try to get my counties into compliance with the current ambient
    air standards because my businesses told me they weren't going
    to expand, and we knew from an economic development point of
    view that those counties that weren't in attainment wouldn't
    even get smelled by businesses that we were trying to bring to
    our State.
        Today, with the new rule, we have a number of counties
    throughout the United States that are not compliant with
    particulate matter. They have this stamp on them: don't expand,
    cost you more, don't go there, cost you more. If we reduce the
    standard from 15 to 12, and there are going to be a whole lot
    more of those throughout the country, it will have an impact on
    the economy of those respective communities.
        Now, that is not supposed to even be paid attention to, so
    they can't do it, but it seems to me that we have a lot of
    speculation going on whether it should be 15 or 12 or 14, that
    we ought to be pretty sure, pretty certain about some of the
    conclusions that we come to.
        I have a problem, that I am just wondering about, you know,
    the budget, the monitoring budget, the $17 million. Senator
    Carper and I have been trying to get them to have an Assistant
    Administrator for Science in the EPA. Does the EPA have the
    brains and the people to get the job done?
        Dr. Thurston. I can't answer that one. But you know, I
    think the last time we spoke, we both agreed that we as a
    country need to set a standard for the rest of the world, and
    we need to develop the technology to meet these standards and
    then sell it to the rest of the world.
        Look at China. The pollution problems there are huge. That
    is a huge market for the United States. If we develop the
    control technology here first, if we confront this problem
    first, we can then turn lemons into lemonade, if you want to
    view it that way. We can be first to clean the air, and sell
    that to the rest of the world. We agreed on that, as I recall,
    the last time. I think it is time we got on with that process.
        Now, to get back to the issues, this education question.
    Being one of the authors of this, we have looked into this. I
    agree with Mr. Greenbaum on this. I just would like to point
    out, one of the things we have looked at is the migration
    question, and that is that people of lower income tend to not
    move out of their MSA. They are not highly mobile. We looked at
    the data and they tend to stay exactly where they are year
    after year after year.
        Whereas higher educated people are much more mobile, and
    that makes it so that the exposure estimates that we are using
    in our studies are less reliable and therefore, some of them
    move to higher exposure areas, some move to lower, so that we
    are going to have greater difficulty finding an association in
    those places.
        That leads us to believe that the estimates of the lower
    income people are probably more accurate and yes, the higher
    income people, the higher educated people are having the
    effects, but they don't show up in a study because the studies'
    estimates of their exposures are not as good as for the less
    educated people.
        So I think what that says is that what we have reported is
    the average of all three. Probably the lower income people are
    giving us the most accurate estimates, which means they are
    much higher than we thought, and that is part of the equation
    why, in the expert elicitation, the various experts, a dozen
    experts, have come up with estimates much higher than the ACS
    study because they have adjusted for this factor and others
    that have come.
        So when you resolve uncertainties, we are not going to
    lower estimates of the pollution. We are resolving
    uncertainties and figuring out what is going on, and actually,
    the impacts are going up in terms of the long-term exposure
    which is, you know, that is what most of the deaths are
    associated with, the long-term exposure to this pollutant,
    which is pervasive year after year, day after day, for every
    American.
        Senator Voinovich. Thank you.
        Senator Carper, I didn't think you were coming back. I was
    taking everybody's questioning time.
        I think in fairness to Dr. McClellan, we have less than a
    minute, because Senator Carper is here.
        Dr. McClellan. I would like to respond to your question in
    terms of lowering the annual standard.
        Senator Voinovich. The question was reasonable, would it be
    reasonable?
        Dr. McClellan. Yes. I am on record as stating that I think
    that the staff paper laid out the science. It had a range of 12
    to 15 mg/m3. I felt that was the appropriate
    expression of the science, and, thus, the Administrator's
    policy judgment to go with 15 mg/m3 I thought was
    appropriate.
        I did not think, as a member of CASAC, that it was
    appropriate to narrow the range of 12 to 15 down to 13 to 14.
    In fact, I thought that was just one step away from saying,
    this is the standard that should be set. I thought that
    overstepped the bounds.
        I would like to use one of Dr. Thurston's graphs, if I
    could, to point out some of the difficulties here. This is the
    Harvard Six Cities study, started back in 1979 which I view as
    a platnium study. The late Dr. Ben Ferris was the guiding light
    that pulled together people in teams of six different
    communities. One of those happens to be in your State,
    Steubenville. OH. It started as an extensive study I think of
    about 8,000 people over time.
        Now, here are the results from this. I think it is
    important to look at the graph. Across the bottom we have
    PM2.5 micrograms per cubic meter, zero to 30. Now,
    we have a single number there on that. Now, you will note that
    each of the cities has changed over time. Steubenville was
    originally up close to 30 and now it is down just above 20. You
    can't express in this graph what it was in 1950? What was it in
    1940? Most of the deaths that are expressed in here are of the
    elderly. We know that. In the United States, people live long
    lives. So in any expression of death, they are going to be the
    individuals being counted.
        What we are not able to show on this graph is what these
    people were exposed to in those earlier years before we had the
    monitoring? We know that that was substantially higher, so we
    haven't captured that value in this data. What I am willing to
    say, looking at long-term data, is those values must have been
    substantially higher.
        Now, we look over here at the mortality relative risk of
    mortality related to PM exposive. I want to emphasize, we
    sometimes talk about excess deaths. It is important to
    recognize that when we conduct epidemiological studies we do
    not create extra deaths. What we do is try to take the deaths
    that have occurred and tease out what they may have been
    associated with.
        In terms of cardiopulmonary deaths, we know the biggest
    risk factor is cigarette smoking. If you go to the data of
    Engstrom, out of LA, his relative risk factors for the all
    cause mortality for smokers, about a pack a day, was 2.0. That
    would be way the heck up there on this graph. A value of 1.0
    means there are no deaths assignable to PM.
        So one of the things we do know if we look in terms of the
    baseline for this relative risk, death rates for
    cardiopulmonary deaths have been going down. For lung cancer,
    we have seen for the first time a decrease in lung cancer
    mortality. Why, because people quit smoking?
        So the data that Dr. Smith related to, I suspect, if I were
    able to examine her calculations, we would find that in all of
    the eight cities, there were improvements, and so the base for
    that relative risk factor is going down resulting in fewer
    calculated deaths related to PM in the air.
        What I am saying is when you look at all of this data, I
    think the Administrator was fully appropriate in his policy
    judgment to continue at 15 micrograms per cubic meter, and I
    think when that is ultimately met across the country, we will
    have I think some small improvement in total health.
        Senator Voinovich. I thank you very much for that. I will
    turn it over to Senator Carper. I just couldn't help, and I
    think you will understand this, I will never forget campaigning
    for Governor in 1990 in Steubenville, OH. I ran into a woman
    who was an immigrant, and we were talking about the air, and
    she said, ``Mr. Voinovich, I put the sheets out in the old days
    and there would be black stuff on it. Now I put it out, no
    black stuff. The sheets are clean, but nobody is working.''
        And that was it. We didn't get into the health or anything
    else, but the fact of the matter was that things were better
    for her environment, but the thing that she was concerned about
    is that nobody was working and wanted me to do something about
    bringing jobs to Steubenville, OH.
        Senator Carper. That was actually a pretty good segue,
    because I have just come from a hearing in the Banking
    Committee which is going on downstairs. Every 6 months, the
    Chairman of the Federal Reserve comes and testifies to brief
    the House and the Senate on monetary policy. He was just
    sharing with us how strong our GDP growth is, 5.6 percent I
    guess for the last quarter, how many new jobs are created thus
    far this year, and large growth in Federal revenues and that
    sort of thing.
        But the progress, the economic growth is uneven across the
    country. Frankly, the growth in incomes is uneven across our
    citizenry, as we know.
        I apologize for missing your testimony. Whenever the
    Chairman of the Federal Reserve comes and testifies, he doesn't
    do it often, I try to be there. I like to kid and say he won't
    go forward until I am there, but that is not really the case.
    But I wanted to be there to be able to offer a statement or two
    and maybe ask a question of him.
        I appreciate the fact that you are here. We appreciate your
    testimony, your input, and your willingness to respond to our
    questions. I have a couple of specific questions of Dr.
    Thurston. Before I do, I have sort of an unwritten rule that
    whenever one witness uses the charts of another witness to make
    a point, we always give the owner of the charts the opportunity
    to have the last word. Do you have any comment or any response
    you want to make to Dr. McClellan's comments?
        Dr. Thurston. Yes, I do. I thank you for that opportunity.
        Well, you know, I think that his reference to, well, first
    of all, his references to cigarette smoking, these studies have
    been controlled for cigarette smoking.
        Senator Carper. Say that again?
        Dr. Thurston. Have been controlled for, this study that is
    represented here has been controlled for cigarette smoking.
        Senator Carper. OK.
        Dr. Thurston. OK. So these reductions in relative risk have
    nothing at all to do with cigarette smoking and the fact that
    people are smoking less. This has to do with the reductions in
    air pollution after controlling for all these other factors
    that they studied. This is a cohort study where they had
    individual information about each of the people in the study.
        The other thing he is talking about, well, exposures long
    ago that could be responsible for these effects. There is
    recent research that indicates that it is really the exposure
    in the last 5, at most 10 years of your life, or up until the
    time of death that are the most important. Even if you look at
    cigarette smoking, when someone quits cigarette smoking, the
    Surgeon General's report points out, within 10 years their
    mortality risk is the same as the general public. It is similar
    with air pollution. The benefits are yielded very quickly,
    actually, after the exposure is reduced. We see that in this
    study and we see it in others.
        We are looking at the ACS study, looking at these windows
    of exposures, and we will be publishing on that as well. But I
    know there are papers out there, like Kunsley's recent paper
    pointing this out. So that is really my response to his
    comments.
        Senator Carper. Good. Well, thank for sharing that.
        Perhaps a couple of specific questions of Dr. Thurston. Dr.
    Smith and Mr. Greenbaum, I missed your testimony, as you know.
    What I am going to ask you to do is, take no more than a
    minute, but just give me my takeaways. It is impossible for us
    to remember everything you said or say, but just, if we
    remember nothing else, of a couple of key points that you made,
    what should we take away from here?
        Dr. Smith. Just a minute.
        I think the key takeaway is that if you want to understand
    whether to tighten the standard, rather than whether we need
    the standard that we have, then you need to look to the
    question of what is happening to the margin of safety that was
    deemed acceptable when that standard was set, and using the new
    evidence that we have today is that the margin of safety that
    is associated with the current standard has, if anything,
    grown, not narrowed.
        So while there is better information across the board,
    there does seem to be confirmation that there is some subtle
    effect going on with air pollution, that was assumed at the
    time the standard was set, and the standard at that time was
    set so that it provided a margin of safety, and that margin of
    safety remains today even in the face of all of this new
    evidence.
        Senator Carper. Thank you.
        Mr. Greenbaum.
        Mr. Greenbaum. Sure. Just three things. First, we have made
    tremendous progress since 1997 in understanding a whole series
    of questions we had then. In fact, they are not even on the
    table now in the same way because of research that was
    chartered by Congress and then put into place over the last 6
    to 7 years to answer those questions.
        Second, one part of that research has been to look at the
    so-called concentration response, what happens at higher and
    lower levels of pollution? Do we see more effects, less
    effects? Is there a point below which we don't see any effects?
    And there, we have seen, 0 with some uncertainty at both ends
    of the range, generally increasing effects with increasing
    levels of pollution, a generally linear relationship between
    those two.
        At the same time, and the third point, looking forward,
    there are still, as science always has, important continuing
    questions, probably most importantly, the one around
    understanding whether there is a different toxicity of
    different components of PM, really different sources of PM, to
    guide future regulatory decisions.
        Senator Carper. Good, thanks. My thanks to both of you.
        Dr. Thurston, a couple of questions, if I could. Do you
    believe that there is certain, I would underline the word
    certain, scientific evidence to justify lowering the annual
    standard?
        Dr. Thurston. Yes, I certainly do. The bulk of the
    evidence, as EPA has presented it, shows that we need to
    tighten these standards, that there are health effects below
    the present standards and that they need to be tightened.
        Senator Carper. OK. I think, and I didn't hear this issue,
    but Dr. Smith I believe you may have suggested that the risk of
    fine particles has actually decreased in your testimony. I
    would ask of Dr. Thurston if you want to comment on that. I
    don't want to mischaracterize what she said, but if I have that
    right, would you just comment on it?
        Dr. Thurston. Well, as I said in my testimony, I believe
    that, and I think the evidence supports, that the uncertainties
    associated with our estimates have actually decreased. We are
    more certain of the effects, the biological mechanism, and the
    size of the effects. So uncertainty has been diminished.
        I want to clarify the distinction between, I guess,
    uncertainty and doubt. There is no doubt that air pollution is
    causing these effects, and there is no doubt that lowering
    these pollution levels will reap huge health benefits. There is
    uncertainty exactly how much benefit for how much pollution. So
    that is uncertainty of the estimate. It could be higher. It
    could be lower. In the case of the long term, the scientific
    consensus is moving that the health effects of PM2.5
    long-term exposures are actually higher than we previously
    thought.
        So there is uncertainty around the estimates, but there is
    really no doubt here.
        Senator Carper. All right. My thanks to each of you. I am
    glad you were still here when I got back. Again, I appreciate
    very much your testimony and responding to our questions. Thank
    you.
        Senator Voinovich. Thank you much. I really believe that I
    have gotten some more clarity here, at least in terms of
    people's differences in terms of this standard. Hopefully, this
    will help the Administrator make the right decision.
        Thank you very, very much. The hearing is adjourned.
        [Whereupon, at 11:30 a.m. the committee was adjourned, to
    reconvene at the call of the Chair.]
        [Additional statements submitted for the record follows.]
             Statement of Hon. Joseph Lieberman, U.S. Senator from
                            the State of Connecticut
        Thank you, Mr. Chairman.
        In my view, EPA's most fundamental responsibility under the Clean
    Air Act is to tell Americans truthfully whether the concentrations of
    pollution in the air they breathe are at levels that endanger their
    health. If EPA knows that particulate matter hurts people at lower
    concentrations than those reflected in the agency's existing air-
    quality standards, then I believe the agency has a legal and a moral
    responsibility to tighten the standards.
        Following an exhaustive review of peer-reviewed studies on the
    subject, the scientists, doctors, and public servants on the
    congressionally chartered Clean Air Science Advisory Committee have
    told EPA that air-borne particulate matter is triggering large numbers
    of asthma attacks, heart attacks, and premature deaths in many areas of
    the country that meet EPA's existing air quality standards for
    particulate matter. That leads me directly to the conclusion that EPA
    must make those standards more stringent. An alternative risk analysis
    requested by the White House Office of Information and Regulatory
    Affairs has just come to the same conclusion.
        Unfortunately, EPA has proposed to not lower the annual particulate
    standard at all, and to lower the daily standard to a level that
    remains above the limit that the Science Advisory Committee has
    identified as necessary to protect public health.
        I do not believe that EPA can justify this disregard for the
    Science Advisory Committee's recommendations. Skeptics enjoyed
    representation on the Committee and ample opportunity to press their
    views. To me, it makes no sense to disregard the Committee's
    conclusions based on complaints that were not sufficiently compelling
    to convince that expert body. Here I note that only two of the twenty-
    two members of the Committee's panel on particulate matter dissented
    from the panel's conclusions, and that all seven members of the
    committee agreed with the panel's majority.
        Having reviewed the statements and testimony delivered at last
    week's hearing, it appears to me that the impetus behind the calls for
    EPA to disregard the Science Advisory Committee's recommendations is
    not dissatisfaction with the scientific work of the Committee, but
    rather concern over the cost of bringing air quality into line with
    more stringent standards.
        Clearly, achieving further reductions in particulate-forming
    emissions will cost money. That is why the Clean Air Act's system for
    implementing the health-based air-quality standards includes, at nearly
    every turn, generous regard for what is practicable and what is not.
    There is no need, then, to flout the Act by infecting the standard-
    setting process with considerations of implementation costs. I would
    point out, moreover, that by any reasonable measure, the economic
    benefit of the lives saved and illnesses averted by bringing
    particulate levels down to the levels recommended by the Science
    Advisory Committee would vastly outweigh the economic costs of the
    added pollution controls.
        The concentrations of particulate matter persisting in many parts
    of the country cause more than 45,000 premature deaths every year. The
    problem is too grave and too large to be concealed. We can solve this
    problem, and the first step is to level with the American people. That
    is why I urge EPA to set the revised particulate matter standards at
    the levels that the Science Advisory Committee has determined necessary
    to protect public health. Thank you, Mr. Chairman.
                                   __________
      Statement of George Gray, Assistant Administrator for Research and
               Development, U.S. Environmental Protection Agency
        Good morning, my name is George Gray, and I am the Assistant
    Administrator for the Office of Research and Development in EPA. I wish
    to thank you for the opportunity to discuss the EPA's evaluation of the
    scientific evidence for potential health effects of airborne
    particulate matter (PM). Last week the Subcommittee on Clean Air,
    Climate Change and Nuclear Safety heard from my colleague, William L.
    Wehrum, the Acting Assistant Administrator for Air and Radiation, on
    the EPA's review of the national ambient air quality standards (NAAQS)
    for PM. During that testimony he explained the crucial role of science
    in helping to inform decisions about the National Ambient Air Quality
    Standards.
        Today, I would like to talk with you in more detail about this
    science: how it is prioritized and developed, and how it is synthesized
    and integrated. As Assistant Administrator for EPA's Office of Research
    and Development (ORD), I am responsible both for the development of new
    scientific information targeted to address critical Agency research
    needs and for the evaluation, synthesis, and integration of the world's
    peer-reviewed science literature into a document that informs EPA
    decision-makers. As we characterize the current state of our collective
    scientific knowledge, we are careful to point out the strengths and
    weaknesses of this large body of information, so that informed
    decisions can be made. It is clear that the scientists and staff of ORD
    play a crucial role in the development and evaluation of the world's
    scientific information to inform the review of National Ambient Air
    Quality Standards.
        We all agree that environmental protection efforts must be based on
    high quality science. High quality science includes both the conduct of
    research--in the laboratory and in the field--and the careful
    evaluation of that body of research to inform policy making. High
    quality research is focused appropriately on generating new knowledge
    that addresses complex scientific issues and helps reduce important
    scientific uncertainties. It is carefully planned, well conducted, and
    thoroughly peer reviewed by independent scientific experts. The careful
    and balanced characterization of the body of knowledge created by high
    quality science requires an open process, interaction with appropriate
    subject matter experts, and serious consideration of the ways in which
    the results are communicated to decision makers. To me, an important
    component of high quality science is the characterization of the
    uncertainties related to individual studies and, more generally, the
    characterization of the weight of the scientific evidence.
        First, let me discuss EPA's efforts to develop new and relevant
    science on particulate matter. The Agency has a longstanding and strong
    program to develop and use new scientific knowledge on the health
    effects of airborne PM. After the last review of the PM NAAQS in 1997,
    EPA embarked on a very ambitious research effort to advance our
    knowledge and address important uncertainties in the science related to
    PM. Congress requested that we sponsor the National Academies of
    Science (NAS) to provide us advice. The NAS Committee on Research
    Priorities for Airborne Particulate Matter in the National Research
    Council completed four reports, published between 1998 and 2004, which
    provided the scientific basis EPA used to target its resources to
    address the highest priority PM research needs. These needs are being
    addressed by the Agency's particulate matter research program, with
    more than $500 million during the past 10 years committed by EPA in
    support of the highest priority research topics identified by the NAS.
    These funds have supported numerous research efforts by EPA's
    intramural laboratories, as well as extramural researchers funded
    through our competitively awarded Science to Achieve Results (STAR)
    program, our PM Research Centers, and interagency agreements with other
    federal agencies. EPA also coordinates closely with other federal
    agencies on PM research through the Committee on Environment and
    Natural Resources (CENR) Air Quality Research Subcommittee and its
    Interagency Working Group on Particulate Matter.
        We learn about the potential health effects of PM through several
    different types of research, especially epidemiology and toxicology.
    Guided by the NAS and other advisors, the Agency has funded research in
    all of these areas. Epidemiologic studies supported by EPA and others
    provide key information in our evaluation of PM. This research includes
    population-based studies that evaluate potential associations between
    human exposure to PM and health outcomes, including death,
    hospitalization, illness, and potential precursors to illness. We have
    sponsored research on populations of tens to hundreds of thousands of
    individuals in the United States that evaluates the effects of long-
    term exposure to PM on illness and death. These include both cohort
    studies and panel studies. Other research uses a different design--
    called time-series studies--in which air pollution levels are tracked
    on a day-to-day basis and compared with daily variations in health
    statistics to evaluate the effects of short-term exposures to PM on
    health. These time-series studies included hundreds of communities and
    databases that describe millions of residents. Other epidemiologic
    studies attempt to identify factors affecting people's susceptibility
    and the role of co-pollutant exposures.
        Toxicology studies, sponsored by EPA and others, provide both
    information to evaluate the strength and plausibility of the
    associations identified through epidemiology and hypotheses that form
    the basis of new epidemiological studies. Important studies include
    those that evaluate the components of PM that may be producing
    toxicity, and the mechanisms by which such toxicity might occur.
        These research efforts have resulted in literally thousands of
    published studies in the peer-reviewed literature over the past several
    years. In 2005, EPA prepared a report, Particulate Matter Research
    Program: Five Years of Progress, which highlighted the early results of
    EPA's substantial investment in PM. When it came time to prepare the
    science basis for the next evaluation of the PM standards (the 2004 Air
    Quality Criteria Document), more than 4000 articles from the peer-
    reviewed literature were reviewed--many of which came from research EPA
    had done in our laboratories or had funded through our STAR grants.
        A second, and equally important, function of EPA efforts is the
    synthesis and integration of these thousands of individual ``acts of
    science'' to provide a clear characterization of our knowledge and the
    degree to which we still are uncertain about aspects of PM health and
    environmental effects. We have a scientifically rigorous process by
    which we evaluate and interpret this important body of knowledge and
    ensure that our interpretation of them is complete, transparent,
    unbiased, and consistent with the array of views in the scientific
    community. A fundamental step in the review of the National Ambient Air
    Quality Standards is the evaluation of scientific evidence and the
    preparation of scientific assessments, by the National Center for
    Environmental Assessment of the Office of Research and Development,
    known as ``criteria documents.'' The development of criteria documents
    involves the review of thousands of peer-reviewed research
    publications, evaluation of those studies most relevant to the review
    of the air quality standards, and integration of the scientific
    evidence across disciplines. The body of evidence must be reviewed,
    evaluated, weighed and then accurately and objectively described to
    inform our decisions about National Ambient Air Quality Standards.
        For the current PM review, EPA evaluated research studies that
    addressed a wide range of issues including PM toxicology, epidemiology,
    atmospheric chemistry, human exposure, and other areas such as
    environmental effects. Thousands of studies were reviewed and over 2000
    studies were referenced in the criteria document, many of which were
    conducted or funded by EPA's Office of Research and Development.
    Considered together, these new studies significantly advanced our
    understanding of PM's potential effects on public health and welfare
    and reduced the uncertainty associated with some important aspects of
    the science. Drawing on the evaluation of studies reviewed in the PM
    criteria document about health effects and dose-response, as well as
    information about exposures to PM, EPA also completed a risk assessment
    to estimate the degree to which various approaches for revising the
    standards would potentially affect the public health risks posed by PM.
    Further, the Agency prepared a document known as a ``staff paper'' that
    utilized the evaluation and characterization of scientific evidence in
    the criteria document together with the results of the risk assessment
    to help inform the policy judgments required in making decisions on the
    NAAQS.
        Extensive independent external peer review was conducted on the
    criteria document, risk assessment, and staff paper by the Clean Air
    Scientific Advisory Committee (CASAC). CASAC, statutorily-mandated
    under the Clean Air Act, is a group of independent scientific and
    technical experts appointed by the Administrator to review EPA's
    evaluation and use of scientific and technical information related to
    air quality and make recommendations as appropriate. CASAC is made up
    of nationally-recognized scientists from a variety of relevant
    disciplines. For PM, CASAC was extensively involved in reviewing and
    commenting on several drafts of the PM criteria document, staff paper,
    and risk assessment. Their efforts, and those by EPA staff to address
    CASAC's comments, resulted in a PM science assessment that provides
    comprehensive, relevant information suitable to serve as the scientific
    basis for Administrator Johnson's decisions on the PM NAAQS.
        Let me briefly highlight some scientific information available on
    particulate matter. First, as a scientist, I know that all scientific
    research includes aspects of uncertainty. For example, we often do not
    understand the mechanisms by which pollutants such as particulate
    matter produce health effects in the population. We know our
    measurements of environmental conditions and biological response
    contain some uncertainty due both to our understanding and
    technological limits. To have uncertainty is normal. Uncertainty is a
    factor to be characterized and considered in the evaluation of studies
    and other data. We always consider the strengths and limitations of the
    available evidence when drawing conclusions about what that evidence
    means for decision making.
        For example, we highlighted the uncertainty in the evidence linking
    chronic exposure to PM2.5 with premature mortality in the
    1997 review of the PM NAAQS. In the next few years, EPA responded by
    funding a major reanalysis by independent investigators of two
    important long-term studies that used data from a Harvard Six Cities
    cohort and an American Cancer Society cohort. The quality of the data
    was evaluated, and an extensive series of sensitivity analyses were
    performed using various statistical models to test for the influence of
    many potential co-variables. The results duplicated the association
    between levels of chronic exposure to PM2.5 and premature
    mortality. These analyses were important in reducing our uncertainty
    about the consideration of these data in the standard-setting process.
    In addition, the analyses identified other avenues of research. For
    example, one study indicated that the estimated effects of fine
    particles appeared to vary with education level.
        In another example of our efforts to tackle uncertainty, EPA
    sponsored a number of multi-city epidemiologic studies designed to
    address the limitations inherent in single-city studies. Multi-city
    studies allow the assessment of risks of mortality or hospitalization
    across cities, thus reducing uncertainty regarding the effects of local
    features, such as differing mixes of pollutants and climates, on the
    interpretation of study findings. The results of these multi-city
    studies provide additional evidence that levels of exposure to
    PM2.5 are likely to be linked with serious health effects.
        Another major area of uncertainty remaining from the previous
    review was the lack of demonstrated biological mechanisms or pathways
    by which PM exposure could result in the effects observed in
    population-based studies. An important factor in evaluating the
    associations uncovered in epidemiologic investigations is biological
    plausibility, i.e., whether there is a coherent way in which the
    reported association could be expected to occur in the body. As noted
    in our 2005 report, EPA-funded research has provided crucial insights
    into numerous hypothesized mechanisms; including evidence that exposure
    to particles may contribute to atherosclerosis development and affect
    cardiac rhythm, thus linking the findings of mortality in the
    epidemiologic studies to plausible biological mechanisms of toxicity.
        Looking across the large landscape of study findings, our
    assessment of the research results for particulate matter finds
    evidence of a coherence of health effects associated with
    PM2.5 across many types of study designs, biological
    endpoints and time frames. The body of evidence--the thousands of
    studies from a wide variety of disciplines we have evaluated with the
    help of CASAC--demonstrates that PM2.5 exposure is likely
    causally associated with outcomes such as cardiovascular and
    respiratory morbidity and premature mortality from both epidemiologic
    and toxicology studies. Toxicology studies help us understand the
    mechanisms that provide some evidence of biological plausibility in the
    observations from epidemiological studies. We recognize that
    uncertainty exists, but uncertainty is not a barrier to decision-
    making; rather it is critical information to be factored into informed
    decisions.
        We also recognize that science is not static. New studies on PM are
    being published in the peer-reviewed literature all the time. As a
    continuation of the scientific review process, EPA recently conducted a
    survey of the evidence reported in the scientific literature since
    completion of the literature review reflected in the 2004 criteria
    document. This new survey includes some 700 additional studies and has
    emphasized the studies most relevant to the PM NAAQS decision. The
    provisional assessment of these new studies has only just been
    completed. To provide the public with an opportunity to review the
    survey results, we will provide notice of the completion of this survey
    and post the results on our Web sites. In brief, the provisional
    assessment concluded that taken in context, the new information and
    findings provide additional support regarding the health effects of PM
    exposure made in the 2004 PM Air Quality Criteria Document but do not
    materially change any of the broad scientific conclusions.
        In summary, the Bush Administration is committed to the development
    and use of the highest quality science to inform environmental decision
    making. The mission of the Office of Research and Development is to
    develop, evaluate, and communicate relevant scientific information to
    the Administrator, and to assure that the Administrator is well
    informed of the nature, strengths, and limitations of this information.
    EPA has sponsored a targeted and effective research program on
    particulate matter and I am pleased to convey to you and others the
    value of this investment. We have made a great effort to evaluate and
    characterize the existing and new scientific results available on
    particulate matter, and I am personally pleased to share with you my
    views on this work. I look forward to addressing any questions you may
    have.
        Thank you.
                                     ______

            Responses by George Gray to an Additional Question from
                                 Senator Inhofe
        Question 1. The General Accountability Office found that EPA has
    fully implemented only 8 of the National Academy of Sciences' 34
    recommendations in conducting its PM air quality review. One of its
    recommendations was to include a cal culation of the total costs and
    benefits, including indirect benefits, in its regulatory impact
    analysis. It is well established that economic growth is associated
    with health, and conversely, economic costs and associated job losses
    is associated with increased mortality. In light of this, it is only
    possible to determine the net health benefit if these indirect costs
    are calculated. Does EPA intend to in the final RIA calculate the net
    benefits, including indirect disbenefits?
        Response. EPA believes there are indirect effects that should be
    considered when the measured costs and benefits are sufficiently large.
    However, quantifying these issues is very difficult. Until better
    methods are developed to assess these second-order effects, EPA has
    focused on assessing the primary benefits and costs that result from a
    partial equilibrium analysis.
        EPA uses a partial equilibrium analysis when assessing the benefits
    and costs of regulatory options. Partial equilibrium analysis, by
    definition, only looks at the direct effects of the regulation. It
    ignores the general equilibrium effects that may occur throughout the
    economy. Note that the partial equilibrium models ignore both the
    secondary benefits and the secondary costs that may occur. Partial
    equilibrium models are generally used when the costs and benefit
    impacts are small so that secondary impacts may be safely ignored.
        However, if the regulation has sufficient impacts on benefits and
    costs, these secondary costs may be significant. There are at least two
    effects that must be measured to do this correctly:
        The health-wealth tradeoff with costs: This literature suggests
    that costs of environmental regulation may be higher than the direct
    expenditures of a regulation. Specifically, raising costs also raises
    prices and reduces real wage income. This lower real wage reduces net
    income and may, therefore, reduce the overall health of workers. (The
    lower our income, the less health we can afford.) This is the effect
    mentioned in the question.
        The health-wealth tradeoff with benefits: When our environment
    improves, we reduce the sick loss days of workers, and improve the
    overall health of the population. These changes increase labor
    productivity, raising the real wage. As the real wage increases, the
    populations' health increases. (As our income increases, we can afford
    to buy better health care, etc.)
        In general, EPA assumes that these two effects roughly cancel. We
    have taken some exploratory looks at this issue and found this to be
    the case, though generalized conclusions cannot be made. These issues
    are also discussed in the context of EPA's analysis done under section
    812 of the Clean Air Act amendments.
        In addition to the above issues, it is our understanding that the
    NAS recommendation concerning indirect benefits focuses on whether any
    particular EPA analysis can and should try to capture potential
    indirect effects pertaining to changes in exposures. For example, the
    NAS gave as its first illustrative example of the indirect effects
    concept the possibility that air pollution regulations may change how
    fuels are made or how combustion devices are operated, which could in
    turn affect human health through other pathways.
                                     ______

             Responses by George Gray to Additional Questions from
                               Senator Voinovich&
        Question 1. Dr. Gray, please put yourself in our position as the
    oversight Committee or the publics position whether a regulated
    industry, environmental group, or just a concerned citizen. Last week,
    we discussed at length the fact that EPA has put together an incomplete
    Regulatory Impact Analysis. Basically, we do not know the impact of
    revising the standards. Let me remind EPA that this information is
    required by Section 108 of the Clean Air Act: Administrator shall. . .
    issue to the States. . .  information on air pollution control
    techniques, which information shall include data relating to the cost
    of installation and operation, energy requirements, emission reduction
    benefits, and environmental impact of the emission control technology.
        We are told that a more complete analysis will be addressed in the
    final rule.
        Today, we learn from GAO that EPA has implemented less than 25
    percent of the National Academies recommendations. We are told more of
    these recommendations will be addressed in the final rule.
        Chairman Inhofe has pushed EPA to consider the numerous new studies
    that have been completed since the criteria document was finished. We
    are told that this new science will be addressed in the final rule.
        Don't we have an oversight responsibility and doesn't the public
    have a right to know what EPA is doing behind closed doors on this
    rule?
        Response. EPA is committed to working with Members and committee
    staff to ensure the public is well-informed with regard to Agency
    rulemakings. EPA has been, and will continue to be, in regular contact
    with the committee regarding the PM2.5 NAAQS and the
    associated RIA, and we believe our final analysis will be
    comprehensive, useful, and robust.
        The Clean Air Act (Act) requires EPA to set a primary standard for
    each criteria pollutant that protects public health with an adequate
    margin of safety. As interpreted by the Agency and the courts, the Act
    requires EPA to base this decision on health considerations and forbids
    consideration of economic factors. Thus, while the final RIA can
    provide important insights into the costs and human health benefits
    associated with attaining a revised PM2.5 NAAQS, EPA cannot
    use estimates of attainment cost to inform the NAAQS decision.
        This prohibition against the consideration of cost in the setting
    of the primary air quality standard, however, does not mean that costs
    or other economic considerations are unimportant or should be ignored.
    The Agency believes that consideration of cost is an essential
    decision-making tool for the cost-effective implementation of these
    standards. Under the Clean Air Act, the impact of cost and efficiency
    are considered by the States during this process, when States are
    making decisions regarding what timelines, strategies, and policies
    make the most sense. The PM NAAQS final RIA is intended to inform the
    public about the potential costs and benefits that may result when any
    revised PM standards are implemented.
        With regard to the new studies cited in your question, EPA's Office
    of Research and Development has conducted a survey and provisional
    assessment of relevant scientific information that became available
    since the completion of the 2004 Criteria Document, as discussed in
    EPA's notice of proposed rulemaking on the PM NAAQS. In summary, our
    provisional assessment concluded that the new studies do not materially
    change the broad conclusions of the 2004 document.

        Question 2. Dr. Gray, Congress established the Clean Air Act to
    protect human health. Last week:
        Georgia Commissioner Heiskell stated: As an elected official, I
    fear the lost tax revenues and increased stresses on local health
    services that lay-offs associated with our non-attainment status bring.
        National Black Chamber of Commerce President Harry Alford stated: .
    . .  the biggest health risk to African Americans anywhere. . .  is
    poverty.
        Now, I understand that EPA cannot consider costs. However,
    according to the GAO report:
        Another recommendation (from NAS) that EPA. . .  did not apply to
    the draft regulatory impact analysis concerns whether the proposed
    revisions to the particulate matter standards would have important
    indirect impacts on human health and the environment.
        This is a health based standard and there are indirect, negative
    impacts on health from nonattainment designations that reduce jobs and
    increase energy prices. Why isn't EPA following the NAS recommendations
    and considering these impacts?
        Response. Please see our answer to Question 1.

        Question 3. Dr. Gray, does science dictate a particular number for
    the air quality standards?
        Response. Uncertainty is inherent in science. As new data become
    available, our understanding of the health protectiveness of a given
    air quality standard grows, as does our understanding of the extent of
    uncertainties. That is why rarely, if ever, it is the case that a body
    of scientific evidence has the potential to dictate a particular number
    for an air quality standard. Science does provide the basic information
    used in setting air quality standards, and our analysis of the science
    includes consideration of the strengths and uncertainties in the
    available evidence. We know that our measurements of environmental
    conditions and biological responses contain some uncertainty due both
    to the limits of our understanding of the underlying process and
    available technology. EPA recognizes the importance of characterizing
    the implications of this scientific uncertainty.
        In the review of the PM air quality standards, the scientific
    evidence has provided strong support that PM exposures can have adverse
    effects on public health and the environment. The science summarized in
    EPA's Criteria Document and used in EPA's risk assessment provided the
    scientific basis for the range of options recommended in EPA's staff
    paper. There is uncertainty even within this range of options. The
    strength of the scientific evidence as well as the uncertainties are
    necessarily considered by the EPA Administrator in proposing and
    promulgating final PM NAAQS.

        Question 4. Dr. Gray, as I stated in my opening statement, I do not
    understand how EPA can revise the particulate matter standards when the
    public health benefit is not fully understood. For example, there are
    areas of the country, namely Southern California, that will never be
    able to meet the Agency's proposal, not to mention even tighter
    standards. When EPA estimates health benefits, how do you take into
    account that this area will never attain the standards? Basically, does
    the Agency estimate real benefits?
        Response. This Nation has an excellent record of rising to the
    challenge of reducing air pollution in a cost effective fashion. All
    areas have made significant progress in reducing air pollution even if
    some areas are still not yet in attainment of the current standards.
    The regulatory impact analysis that will accompany EPA's decision
    reflects the need to develop new ways and ideas for some areas to
    attain the proposed standard. To the extent that known controls are not
    sufficient to bring an area like Southern California into attainment by
    2020, EPA has relied on information from a variety of sources on the
    effectiveness of new control strategies under development to project
    what the costs and benefits of attainment might be. While these
    estimates have additional uncertainty associated with them, they give
    the public an idea of the likely magnitude of the potential costs and
    benefits of attainment.
        Because of its severe air pollution problems, Southern California
    has been one of the leaders in the development of creative ways to
    reduce air pollution by harnessing the free market. For example, the
    RECLAIM (Regional Clean Air Incentives Market) program has been in
    place since 1994 to harness market forces to reduce air pollution. See
    http://www.aqmd.gov/reclaim/reclaim.html for more information. Also,
    the California Air Resource Board (CARB) is now aggressively pursuing
    options for continuing to reduce air pollution. On April 20, 2006, CARB
    announced a new program for reducing air pollution from its ports which
    includes economic incentive elements. See http://www.arb.ca.gov/gmp/
    gmp.htm for more information.

        Question 5. Dr. Gray, the GAO report states that the Agency has
    implemented less than 25 percent of the National Academies'
    recommendations for estimating health benefits. Does the Agency have a
    plan to implement all of the recommendations?
        Response. EPA is committed to showing further progress in the final
    RIA, which will be published when the NAAQS is finalized this
    September. As noted in the GAO report ``Particulate Matter: EPA Has
    Started to Address the National Academies' Recommendations on
    Estimating Health Benefits, But More Progress is Needed,'' EPA
    expressed to GAO that the Agency is committed ``to further enhancing
    the transparency of the analysis by presenting clear and accurate
    references to the supporting technical documents, which detail the
    analytical assumptions and describe the data supporting the estimates
    [of our Regulatory Impact Analyses.]'' GAO found that of the 34
    detailed recommendations in the NAS report, the draft RIA implemented
    (in full or in part) 22 of them. Some of the remaining 12
    recommendations will be addressed in the final RIA to accompany the
    final rule in September; others require further research or
    development. For example, over the past few years, EPA ran an expert
    elicitation designed to characterize uncertainty in the estimation of
    PM-related mortality resulting from both short-term and long-term
    exposure. This work has recently been completed and peer reviewed. The
    results from this expert elicitation are being applied to the benefits
    analysis in the RIA. However, it has not been possible to address all
    the NAS recommendations since the September 2002 publication of the
    report. In its report and its recommendations, the NAS recognized that
    additional research and resources were going to be needed to address
    some of its recommendations. And, in some cases, the recommendations
    were in fact conditioned on the availability of improved scientific
    data. EPA is committed to addressing these recommendations, including
    those on PM speciation, and improving its analyses as new research
    becomes available.
        In its July 19, 2006, report, GAO acknowledged the progress EPA has
    made on implementing the recommendations while also noting that EPA
    needs to make more progress in addressing the National Academies'
    recommendations on estimating health benefits.

        Question 6. Dr. Gray, how does EPA decide which studies to rely on
    and which ones to ignore? Do CASAC or EPA have any written criteria for
    determining which studies are more important than others? Any intention
    of developing this so that the NAAQS review process is more objective
    and transparent?
        Response. We believe that the consideration of scientific evidence
    in the NAAQS review process is comprehensive, objective, and
    transparent. EPA conducts an extensive literature search to identify
    potential studies for inclusion in its science assessments. For
    example, EPA uses standard searches of systems such as MEDLINE in the
    National Library of Medicine, independent table of content searches by
    EPA staff, and input from the public and independent scientists outside
    EPA. These search methods are summarized in the Criteria Document. The
    selection of studies for consideration in a NAAQS review, the strengths
    and uncertainties of individual studies, and the subsequent
    determination of studies to be given greatest weight are outlined and
    discussed in the science assessment. These selections and
    determinations are evaluated by the public and by CASAC at public
    meetings. The inputs from the public and CASAC are documented,
    considered, and incorporated as needed.

        Question 7. What role did the White House and other Federal
    Agencies play in setting the NAAQS proposal?
        Response. Under Executive Order No. 12866, ``Regulatory Planning
    and Review,'' signed by President Clinton in September 1993, the
    Administrator of the Office of Information and Regulatory Affairs
    (OIRA) carries out a regulatory review process on behalf of the
    President. The objectives of this Executive order are to enhance
    planning and coordination with respect to both new and existing
    regulations; to reaffirm the primacy of Federal agencies in the
    regulatory decision-making process; to restore the integrity and
    legitimacy of regulatory review and oversight; and to make the process
    more accessible and open to the public. In general, involvement by
    other Federal agencies or the White House offices occurs during the
    routine interagency review process, when the Agency is developing its
    proposal and before making a final regulatory decision. Following this
    procedure, the proposal package for the PM NAAQS went through the
    interagency review process, which was managed by the OIRA and included
    input from various agencies and offices throughout the executive
    branch.
        Once EPA has issued a proposal to the NAAQS, the Agency evaluates
    public comments received on the proposal and develops a draft final
    rule. The draft will then be subject to the interagency review process,
    per Executive Order 12866, which includes input from across the
    executive branch.
                                   __________
       Statement of Daniel Greenbaum, President, Health Effects Institute
        Mr. Chairman and members of the committee, thank you for the
    opportunity to testify before you today on the health effects of
    particulate matter (PM). I come before you as the President of the
    Health Effects Institute, a non-profit, independent research institute
    funded jointly and equally by the U.S. EPA and industry to provide
    high-quality, impartial science on the health effects of air pollution.
    For over 25 years we have conducted targeted research on a variety of
    pollutants and health effects, and I am pleased to summarize our
    understanding concerning PM and health for you today.
        I also had the privilege to serve from 1998 until 2004, as a member
    of the National-Research Council Committee on Research Priorities for
    Airborne Particulate Matter, a congressionally chartered panel that
    both set priorities for national PM research, and monitored the
    progress in implementing those priorities by U.S. EPA and other public
    and private agencies.
        I would like today to briefly highlight three topics of direct
    relevance to the current discussion of U.S. EPA's proposal for
    revisions to the National Ambient Air Quality Standards for PM (the
    ``PMNAAQS''):

         Science progress we have made since 1997,
         The most recent findings on the relationships between different
    levels of ambient PM and health effects (so-called ``concentration-
    response''), and
         Keyscience needs going forward.
                              progress since 1997
        Since Congress identified the need for substantial enhanced
    research on PM in the wake of the 1997 PM2.5 NAAQS decision,
    established the NRC Committee, and appropriated substantial new funds
    for PM research, much progress has been made in answering key questions
    for the current NAAQS review process, and for future ones.
        Specifically:

         We know much more about the sources and transport of fine
    particles, and about personal exposure to those particles, especially
    for sensitive groups like the elderly and children.
         We have conducted the first multi-city epidemiology studies of
    effects, and analyzed and reanalyzed many of the major studies of human
    effects, finding that in general the earlier studies were well done and
    could be confirmed. At the same time there has been some evidence that
    the population health effects we had seen in those earlier studies may
    in some cases be smaller than previously thought.
         Unlike in 1997, we now have numerous laboratory, animal, and
    human toxicology studies that have begun to indicate potential
    biological mechanisms by which PM may cause health effects, especially
    new findings of effects on the heart and circulatory system. Although
    we have made progress, most science observers would agree that there is
    still much to learn about the mechanisms by which PM may cause these
    effects.

        Although there continue to be, as there always are, important
    questions about PM that need further research, I think Congress, the
    Federal Government, and the scientific community can take tremendous
    pride in the substantial progress that has been made.
    The ``Concentration-Response'' Relationship: Ambient PM Levels and
            Health Effects
        Among the most important questions addressed over the past few
    years is the question of whether exposure to PM has been shown to have
    health effects at.all levels of pollution--ie. down to zero--or whether
    there is a ``threshold'' below which no effects are expected. This
    question is, of course, central to deciding at what level to set a
    NAAQS. There are two major types of epidemiologic studies that have
    been done--of short term effects and long term effects--and I would
    like to briefly review what these studies have shown us.
                Short Term Effects
        In 1997, there were studies of daily changes in air pollution and
    health effects in a number of individual cities (so-called ``daily time
    series studies''). Since then, scientists have conducted much more
    rigorous multi-city studies of daily air pollution and health, most
    notably the National Morbidity Mortality and Air Pollution Study
    (NMMAPS) funded by HEI and led by investigators at the Johns Hopkins
    Bloomberg School of Public Health. That study examined daily changes in
    air pollution and health in the 90 largest U.S. cities. To answer the
    question of whether there is a threshold for effects, the investigators
    analyzed mortality and pollution levels across the 20 largest cities
    and the 90 largest.
        In brief, as shown in Figure 1, they found that there appeared to
    be a linear relationship between mortality and air pollution down to
    the lowest measured levels for all causes of mortality, and for deaths
    from heart and lung disease, without an apparent threshold. There did
    appear, however, to be a threshold for the effect of PM on ``other''
    causes of mortality (e.g. non-respiratory cancer, liver disease). The
    HEI Review Committee, which intensively peer reviews all HEI research,
    advised ``caution in drawing conclusions from the apparent absence of a
    threshold'' for all-cause and cardiopulmonary mortality, for a number
    of statistical and analytic reasons. They noted however that ``the
    reported associations are at ambient concentrations well below the
    current U.S. daily standard . . . thus the ambient concentration level
    at which any threshold might exist is likely to be correspondingly
    low.''

    [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

                Long-Term Effects
        In 1997, there were two principle studies of the effects of longer
    term exposure on mortality, the Harvard Six Cities Study and the
    American Cancer Society Study (ACS), which examined death rates among
    thousands of individuals living in cities with varying levels of
    pollution. Since that time, although there have been other long-term
    studies published there are still very few, and much attention has
    focused on HEI's Reanalysis of these two studies and on extended
    analyses in the American Cancer Society Study population (which still
    covers the broadest national population). In both of these efforts,
    initial analyses have examined the ``concentration-response''
    relationship between levels of pollution in each community and levels
    of health effects.
        HEIReanalysis--At the request of Congress (in the FY 1998
    Appropriations Bill), U.S. EPA, and others, HEI gained access to all
    underlying data in the two studies and selected an independent
    investigator--Dr. Daniel Krewski--and his team to conduct a detailed
    audit and reanalysis. Their work, which was also intensively peer
    reviewed by the HEI Review Committee, tested the original studies
    against a wide variety of alternative explanations about why people in
    the most polluted cities would have higher rates of premature
    mortality. In the end, the investigators and HEI's Review Committee
    agreed that these alternative analyses did not change the original
    findings of associations between PM and premature mortality, although
    there were new findings as well about an association of mortality with
    sulfur dioxide.
        Dr. Krewski and his team also conducted an initial analysis of the
    ``concentrationresponse'' relationship between PM levels in each of the
    cities and relative risks of mortality. Figure 2 presents the results,
    summarizing for each community (signified by a point on the graph) the
    annual air pollution level and the risk of death due to heart and, lung
    disease. They then attempted to estimate the ``average'' relationship
    across all of the communities (the solid line) and the range of
    uncertainty around that average (the ``95 percent confidence
    intervals'' indicated by the dashed lines). As you can see there is
    some ``scatter'' in the data, especially at the highest and lowest PM
    levels studied, but also an overall trend of increasing mortality risk
    with increases in pollution levels starting at relatively low levels.
    In reviewing this initial analysis, the HEI Review Committee found that
    ``for all-cause and cardiopulmonary mortality, the results show an
    increasing effect across the entire range of fine particles or sulfate
    but no clear evidence either for or against overall linearity.''

    [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

        Extended Analyses in the American Cancer society Cohort Following
    the reanalysis, the original investigators for the ACS study led a
    broad team of experts in an extended analysis of the data, including
    additional follow-up of more recent deaths among the study population,
    and using new PM2.5 data from monitors installed since 1997.
    That study found results similar to those found in the Reanalysis and
    also conducted analyses of the ``concentration-response'' relationship
    (shown in Figure 3). This also shows a general, though less steep,
    upward trend in mortality with increasing pollution levels, with the
    largest uncertainty being found at the very lowest and very highest
    levels where there are fewer cities. The Investigators concluded that:
    ``Within the range of pollution observed in this analysis, the
    concentration response function appears to be monotonic and nearly
    linear. This does not preclude a leveling off (or even steepening) at
    much higher levels of air pollution.''

    [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

                Summary: PM-Mortality Concentration-Response
        In sum, recent analyses of the relationship between ambient levels
    of pollution and mortality have found a generally increasing trend of
    mortality with increases in pollution across a wide range of locations.
    The strongest evidence that there is not a threshold for these effects
    comes from studies of short-term effects, where any threshold is likely
    to be well below the current ambient standards. The initial analyses of
    these relationships in long term studies also shows this general
    pattern, albeit with somewhat greater uncertainty at the lowest and
    highest levels.
                       key research needs looking forward
        While we have made much progress in understanding PM exposure and
    health effects over the past decade, there continue to be, as there
    always are in science, important questions to be answered to help
    inform future decisions about ambient air quality standards and
    protecting public health. Two key areas needing continued attention
    are:
                Continuous Improvement in the Statistics Used in
                        Epidemiology
        The analysis and reanalysis of studies on population health, air
    pollution and weather over the last decade have enhanced our ability to
    determine whether health effects can be tied to certain air pollutants.
    However, those same analyses have shown that the results can be
    significantly affected by the choices of statistical techniques and the
    assumptions made in each analysis. Looking forward, we need to pay
    continued attention to understanding the sensitivity of the results to
    different assumptions, quantifying the uncertainty of the results, and
    communicating clearly for each analysis both the results and the
    continuing uncertainties around those results.
                Systematic Analyses of which PM Components and Sources May
                        Contribute the Most to Toxicity
        Perhaps no other question will need as much attention, and will
    have as much implication for future regulations, than determining
    whether some components of the complex mixture of PM are more toxic
    than other components. Ultimately, this data will be essential to
    ensuring that regulations and control strategies are targeted at
    reducing those emissions which will have the most public health benefit
    at the least cost. This has also become important in light of the
    current proposal for a PMNAAQS for ``coarse particles'' which has
    proposed to exclude certain particles from consideration even before
    the needed studies are complete.
        To date, there have been some individual city analyses of toxicity
    of different components supported by U.S. EPA and others; but no
    systematic national effort to compare results from across the country
    and from epidemiology and toxicology studies. To fill that gap in time
    to inform a next round of PMNAAQS review, HEI has launched, with
    support from EPA and multiple industries, a sysatematic, multi-
    disciplinary effort which will:

         Conduct comprehensive, multi-city analyses of PM components and
    health
         Combine and compare epidemiology and toxicology across the
    country, and
         Provide the first-ever analyses of long-term effects of different
    PM components (all studies to date have looked only at daily changes in
    air pollution and health)

        As indicated in both the NRC review of priorities for future PM and
    health research (NRC 2004), and in today's report of the Government
    Accountability Office concerning data needed for future PM benefits
    analysis, these studies will be central to ensuring that future PM
    actions are the most effective possible.
                   summary: progress made and more to be done
        In sum, we have made much progress since 1997 in answering key
    questions about whether and how PM can affect public health. Initial
    analyses have also helped us better understand the ``concentration-
    response'' relationship between levels of ambient air pollution and
    health effects and the generally increasing effects with increasing
    levels of pollution. At the same, looking forward there continue to be
    important issues to be addressed to inform future NAAQS and regulatory
    decisions, especially around the toxicity of different component and
    sources of PM.
        Thank you for this opportunity to testify; I would be pleased to
    answer any questions you might have.
                                     ______

          Responses by Daniel Greenbaum to Additional Questions from
                               Senator Voinovich
        Question 1. Mr. Greenbaum, as you know, there is an ongoing debate
    about whether EPA must lower the annual standard. Your opinion is
    invaluable in this debate as an entity that sits squarely in the middle
    -funded by both industry and EPA. Clearly, the statute says that
    standards shall be set " in the judgment of the Administrator." In your
    opinion, is it reasonable from a scientific and health perspective for
    the Administrator to retain the annual standard at 15 and not lower it,
    does science dictate a particular number for the air quality standards?
        Response. This is of course one of the major questions facing the
    Administrator as he makes final decisions on the NAAQS. As I noted in
    my testimony, the Health Effects Institute has not, since its inception
    over 25 years ago, taken a position advocating either changing or
    retaining a specific level of a standard. We do this so that no one can
    ever question our science as having been created solely for the purpose
    of supporting an advocacy position. We do, however, attempt to provide
    the best possible impartial interpretation of the science to help
    inform such decisions. In that spirit, I would like to re-iterate and
    strengthen several points I made on this question in the hearing:

        (a) First, the science on the relation between different levels of
    air pollution--and whether there are health effects at all levels or a
    "threshold" level below which there are no effects--has improved since
    1997.
        (b) Second, as I noted in my testimony, these so-called
    "concentration-response" relationships have shown for short-term
    studies (that inform the 24-hour standard) a fairly consistent
    relationship between levels of air pollution and increases in premature
    mortality at levels below the current standard.
        (c) Third, for longer-term studies such as the American Cancer
    Society Study (that inform decisions on the annual standard), there is
    also evidence of a relationship between air pollution and premature
    mortality that extends below 15, but the level of uncertainty on that
    relationship is somewhat greater than for the short term studies.
        (d) Finally, there is no widely accepted scientific method for
    setting the level of a standard. Rather, as the Clean Air Act
    envisions, decisions on levels of the standard are a public health
    policy judgment by the Administrator, in which he has to weigh evidence
    that suggests that there are effects below the current standard against
    the level of certainty or uncertainty surrounding that evidence (i.e.
    the degree to which he can be certain from the science that a lower
    standard would result in greater public health benefits than the
    current standard.)

        Question 2. Mr. Greenbaum, please explain what you mean by this
    statement in your testimony: ``there has been some evidence that the
    population health effects we had seen in those earlier studies may in
    some cases be smaller than previously thought." Since 1997 there have
    been extended reanalyses of a number of daily and long term studies of
    relationships between air pollution and health.
        In the case of short term (daily) studies, after HEI investigators
    at Johns Hopkins discovered an issue with the software to conduct these
    studies in 2002, those investigators and many others revised their
    analyses using better techniques, and HEI was asked to intensively peer
    review those results and draw conclusions on the new findings. In that
    report HEl's Review Committee found, among other things, that for the
    major multi-city daily time series studies done in the United States
    and Europe--some of the most systematic and rigorous of these studies--
    the estimates of risk went down between 30 percent and 50 percent
    (although they were still statistically significant). For example, for
    the National Morbidity, Mortality, and Air Pollution Study (NMMAPS)
    conducted by HEI investigators, the estimates of effects went from 0.4
    percent increase in premature mortality per 10 u/m3 of
    paniculate matter to 0.2 percent per 10 u/m3. (Health
    Effects Institute. 2003. Revised Analyses of Time-Series Studies of Air
    Pollution and Health. Special Report. Health Effects Institute, Boston
    MA.) In the case of long-term studies (of people living for many years
    in more-and less-polluted cities), the effects have been smaller in
    some analyses and larger in others. HEI's reanalysis of the American
    Cancer Society (ACS), which audited and in general validated the
    results of the original study, found lower estimates of health risk
    when one includes other pollutants in the analysis. However, some
    recent analyses of the ACS data by HEI investigators using improved
    estimates of personal exposure have actually found higher estimates of
    effect (see: Jerrett, M; Burnett, R. T.; Ma, R.; Pope, C. A., Ill;
    Krewski, D.; Newbold, K. B.; Thurston, G.; Shi, Y.; Finkelstein, N.;
    Calle, E. E.; Thun, M. J. (2005) Spatial analysis of air pollution and
    mortality in Los Angeles. Epidemiology 16: 727-736. )

        Question 3. Mr. Greenbaum, please comment on the peculiarity that
    no effect is found for people with higher education?
        Response. As I mentioned in response to a similar question in the
    hearing, a careful reading of the full results of recent studies does
    not necessarily suggest that the studies have found ``no effect'' for
    people with a higher education. The HEI Reanalysis of the Harvard Six
    Cities and American Cancer Society studies was the first analysis to
    attempt to look at whether there were differential effects in people
    with different levels of education (which is generally an indicator of
    different levels of socioeconomic status). That analysis, and a
    subsequent extended analysis in the ACS study, found a distinctly
    higher effect on mortality for those with lower education (and likely
    lower socioeconomic status). The HEI Reanalysis also found, for those
    with more than a high school education, a positive but not
    statistically significant association with all- cause mortality (a
    relatively crude measure of mortality since it includes causes of death
    which we expect could not be related to air pollution). When one looks
    at more specific causes of death, one finds that even for those with
    higher education, there is an association of mortality for
    cardiopulmonary deaths, and especially cardiovascular deaths. (See
    Table 52 in Health Effects Institute. 2000. Reanalysis of the Harvard
    Six Cities Study and the American Cancer Society Study of Paniculate
    Air Pollution and Mortality: A Special Report of the Institute's
    Particle Epidemiology Reanalysis Project.) There are several reasons
    why these differences in effects among people of different levels of
    socioeconomic status might be seen. First, it is plausible that people
    of lower socioeconomic status have higher exposures to air pollution
    due to: living in more heavily polluted areas; the likelihood that they
    have less access to air conditioning; and the jobs they have which may
    involve more outdoor exposure. Second, it is also well known that
    poorer people have worse levels of nutrition and poorer access to
    quality medical care, which could reduce their underlying health and
    make them more susceptible to the effects of air pollution. Third, it
    is also possible that, although these studies have made extensive
    efforts to separate the effects of ``being poor'' from the effects of
    ``being exposed to air pollution'', there are some results in these
    studies that continue to reflect the impacts of poverty on health.
                                   __________
    Statement of Roger McClellan, Advisor, Toxicology and Human Health Risk
                                    Analysis
                               executive summary
         The scientific basis for policy decisions on setting the
    PM2.5 National Ambient Air Quality Standard remain highly
    uncertain.
         The continued use of the PM2.5 indicator is a default
    decision driven by EPA's past emphasis on regulatory compliance
    monitoring--``monitor that which is regulated.'' As a result, there is
    no database for considering alternative PM indicators that might target
    specific PM constituents or exclude certain constituents.
         The scientific database provides a basis for the Administrator
    making policy choices for a PM2.5 NAAQS with 24-hour
    averaging time concentration in the range of 25 to 35 m3,
    with a 98th percentile form, and an annual standard in the range of 12
    to 15 m3.
         The scientific database for policy decisions on setting a
    PM10-2.5 NAAQS is very weak and highly uncertain. A science-
    based decision, as contrasted with a judicial decision, would be to
    continue with a PM10 NAAQS.
         There are major uncertainties in risks associated with exposure
    to ambient PM2.5 at current levels and the benefits of
    reducing PM2.5. These uncertainties need to be clearly
    documented and conveyed in numerical calculations used for policy
    decisions and in the Agency's final Regulatory Impact Analysis.
         Expert elicitations of opinions on PM2.5 risks are
    very likely flawed with a blurring of the distinction between
    scientific evaluation and policy choices. Scientists, as do all
    citizens, have values that influence choices of standard setting
    options. However, scientific evaluations should be as free as possible
    of concern for the ultimate policy decisions.

        Good Morning, Mr. Chairman and members of the subcommittee. Thank
    you for the invitation to present my views on the U.S. Environmental
    Protection Agency's current review on the National Ambient Air Quality
    Standards (NAAQS) for Particulate Matter (PM).
                                 my background
        My biography is attached to this statement. Since 1999, I have
    served as an Advisor to public and private organizations on issues
    related to air quality in the ambient environment and workplace drawing
    on more than 45 years of experience in comparative medicine,
    toxicology, aerosol science, and risk analysis. I served as President
    of the Chemical Industry Institute of Toxicology in Research Triangle
    Park, NC from 1988 to 1999, providing leadership for a research program
    directed to understanding the mechanisms of action of chemicals in
    producing either beneficial or harmful effects on humans. I was with
    the Lovelace organization in Albuquerque, NM from 1966 to 1988,
    providing leadership for one of the World's major research programs
    directed toward understanding the potential human health effects of
    inhaled materials.
        The testimony I offer today draws on my experience serving on
    numerous scientific advisory committees. This has included service on
    many EPA advisory committees from the origin of the Agency to date,
    including the Clean Air Scientific Advisory Committee (CASAC), which I
    chaired from 1988 to 1992, all of the CASAC PM Panels as well as CASAC
    Panels that considered other criteria pollutants. My involvement in
    advising EPA on the setting of NAAQS for criteria pollutants began with
    my chairing in 1977 and 1978 an ad hoc committee to review the first
    lead criteria document, a committee that was required since the
    Congress had not yet authorized creation of CASAC. I also served on the
    National Academy of Sciences/National Research Council (NAS/NRC) on
    Research Priorities for Airborne Particulate Matter and the earlier
    NAS/NRC Committee that produced the report ``Science and Judgment in
    Risk Assessment.'' It is important to note that the testimony I offer
    today reflects my own views and is not being offered on behalf of any
    of the Committees I have served on for the EPA, the NAS/NRC nor for any
    other agencies or firms.
                   setting national ambient quality standards
        Each NAAQS consists of four elements: (a) an indicator (such as
    PM2.5), (b) an averaging time (such as 24 hours or annual),
    (c) a numerical level (such as 65 m3 for PM2.5
    averaged over 24 hours), and (d) a statistical form (such as a 98th
    percentile). The indicators for five of the criteria pollutants are for
    measurement of the mass concentration of specific chemicals such as
    O3, SO2, NO2, CO and Lead. Only in the
    case of particulate matter is the indicator based on the mass
    concentration of airborne particulate matter in a specific size range,
    irrespective of the chemical composition of the PM.
        Under the Clean Air Act, the EPA Administrator is required to
    review the NAAQS for the criteria pollutants at 5-year intervals to
    evaluate whether or not the four elements of the NAAQS are still deemed
    to be acceptable based on current scientific knowledge as it applies to
    the assessment of public health risks. In practice the interval between
    reviews has been longer. The process for review and promulgation of a
    NAAQS, either continuation of the existing standard or establishing a
    new NAAQS, consists of multiple phases. The initial phase, which is
    obviously on-going, consists of conduct of research on the various
    criteria pollutants. This includes a broad spectrum of activities;
    understanding emissions of pollutants, transport and transformation of
    pollutants in the atmosphere, ambient measurements of pollutants,
    estimation of personal exposures to pollutants, assessment of toxic
    effects and mechanisms of action in cells, tissues and animals, conduct
    of controlled exposure studies to pollutants in human volunteers and
    epidemiological investigations of human populations. Most of the
    research is funded by the EPA, some in the Agency's own laboratories
    and some in academic and other laboratories, the National Institutes of
    Health and, to a modest extent, private industry. The dominance of
    Federal Government support of research on criteria pollutants relates
    to their effects being of broad societal concerns with the pollutants,
    by and large, having no unique industrial emission source.
        The findings of this research are used by the EPA's Office of
    Research and Development to prepare a criteria document (CD). Each CD
    traditionally has been essentially an encyclopedia of everything known
    about a given criteria pollutant and is used as a basis of information
    for the preparation of a Staff Paper (SP) by the EPA's Office of Air
    Quality Planning and Standards. This is a Policy Assessment of
    Scientific and Technical Information; in short, an integration and
    synthesis of the information in the CD that is most relevant to setting
    the four elements of a NAAQS. In recent years, the Staff Papers have
    made substantial use of risk assessments for the criteria pollutant
    being considered. These risk assessments have been conducted by a
    single EPA Contractor organization. The various versions of the CD and
    SP are released to the public with an invitation to provide comments as
    a basis for improving the documents.
        Throughout this process, a Clean Air Scientific Advisory Committee
    Panel, operating as an element of the EPA's Science Advisory Board, is
    involved in reviewing and advising on the scientific content of both
    the CD and the SP, including the related risk assessment. This has
    typically involved several revisions. Prior to the current cycle of PM
    review, the CASAC Panel sent a closure letter to the EPA Administrator
    when the CASAC was of the opinion that the revised documents were
    suitable for use by the Administrator in promulgating a NAAQS. In the
    current review, the ``closure letter'' process was abandoned.
        At the next step, the Administrator proposes, via a Federal
    Register Notice, a NAAQS including specific proposals for each of the
    four elements of the NAAQS; the indicator, averaging times, numerical
    levels and statistical forms. Comments are solicited from the Public
    with the opportunity to submit written comments to a specific Docket.
    In the current PM review, the CASAC PM Panel offered written comments
    on the Administrator's proposal.
        The next step is for the Administrator to promulgate a NAAQS
    consisting of the four elements discussed previously. I purposefully do
    not use the phrase ``final step,'' because the Courts may have a role
    in deciding whether the Administrator's proposed NAAQS will stand. The
    NAAQS are to be based on the available scientific information reviewed
    in the CD and SP and summarized in the notice of proposed standards.
    The primary, health-based NAAQS are to be set at a level that will
    protect public health, including sensitive populations, with an
    adequate margin of safety. The Administrator is precluded from
    considering cost in the setting of the NAAQS.
        At this point, I would like to emphasize that there exists no
    absolute and unambiguous scientific methodology that can determine
    which specific indicator, the precise averaging time, numerical level
    or statistical form that will be adequate to protect public health. The
    available scientific information can inform the NAAQS decisions,
    however, the Administrator must ultimately use policy judgment in
    making decisions on each of the four elements from among an array of
    scientifically acceptable options including consideration of their
    attendant scientific uncertainties.
        Once the NAAQS are finalized, individual states have responsibility
    for planning and taking actions to meet the NAAQS. This includes the
    formal step of preparing ``State Implementation Plans (SIPs). In
    developing strategies for meeting the NAAQS, the States can give
    consideration to costs in setting the pace for achieving the NAAQS.
    However, attainment of the NAAQS cannot be postponed indefinitely.
       epa administrator made policy choices consistent with the science
        At this juncture, I note that I personally find acceptable the
    Administrator's policy choices for the PM NAAQS, as published in the
    Federal Register (January 17, 2006) from among an array of science-
    based options, to be acceptable. Specifically, I find scientifically
    acceptable his proposal to use (a) a PM2.5 indicator with a
    24-hour averaging time and a reduction in the concentration level from
    65 m3 to 35 m3 with a 98th percentile form, (b)
    retention of the PM2.5 annual standard at 15 m3
    with additional constraints on the use of spatial averaging, and (c)
    use of a PM10-2.5 indicator with a 24-hour averaging time
    concentration level set at 70 m3 with a 98th percentile
    form. I support the exclusion of any ambient mix of PM10-2.5
    where the majority of coarse particles are rural windblown dust and
    soils and PM generated by agricultural and mining sources.
        Of these several policy choices, I have the greatest reservation
    concerning the proposal for a PM10-2.5 indicator with a 24-
    hour averaging time concentration level set a 70 m3 with a
    98th percentile form. The scientific basis for the proposed
    PM10-2.5 standard is very weak and uncertain. I would have
    personally preferred to see the PM10 standard continued to
    provide public health protection from particulate matter mass in the
    PM10-2.5 range. However, EPA personnel have related that
    this option has been precluded by Court decisions.
       selection of a pm indicator--chained to the regulatory compliance
                              monitoring lamp post
        The primary scientific data used to select indicators for PM NAAQS
    has been derived from epidemiological investigations. Prior to 1970,
    there was limited regulation of particulate matter in air pollution.
    Limited monitoring, relative to that being carried out today, was
    conducted using relative crude metrics of Black Smoke and Total
    Suspended Particulates (TSP). TSP was the mass of particulate matter,
    not identified as to chemical form, collected on a filter in a high
    volume air sampler. This included material up to about 40 m in size.
    Scientists studied the relationship between the air concentration of
    these TSP measurements and increases in health effects. This
    epidemiological data provided the basis for setting the 1971 PM NAAQS
    with TSP as an indicator. The 24-hour averaging time standard set at
    260 m3, not to be exceeded more than once a year, and an
    annual standard set at 75 m3, annual geometric mean. The TSP
    indicator then became the ``law of the land'' and TSP began to be
    routinely monitored to determine regulatory compliance.
        During the 1970s and early 1980s, an increased awareness emerged on
    the role of particle size in determining the fraction of inhaled
    particles that would be deposited and where they would be deposited in
    the respiratory tract. This led to some groups making measurements of
    ambient air particulate matter mass in different size fractions; less
    than 15 m, less than 10 m, less than 2.5 m and less than 1 m. However,
    the primary epidemiological data in the 1980s that could be used for
    standard setting was TSP--remember TSP was required to be measured for
    regulatory compliance.
        In 1987, the PM NAAQS indicator was changed from TSP to
    PM10. The choice of PM10 was heavily influenced
    by a decision in the international community to use a PM10
    metric rather than a PM15 metric. The United States followed
    suit. Much of the epidemiological evidence for setting a
    PM10 NAAQS was based on extrapolations from epidemiological
    studies using the TSP monitoring data. The PM10 primary
    standards were set at 50 m3, expected annual arithmetic mean
    over 3 years, and 150 m3, 24-hour average, with no more than
    one expected exceedance per year. With the promulgation of the
    PM10 indicator the regulatory compliance monitoring shifted
    from TSP to PM10. Unfortunately, ambient air monitoring of
    PM15, PM2.5 and PM10 was essentially
    discontinued. Obviously, it would have been expensive to continue, and,
    after all, it was not required for regulatory compliance.
        In the early 1990s, epidemiological data began to be published on
    the association between elevated PM2.5 levels and their
    association with increased health effects. The data came principally
    from the Harvard Six Cities study that fortunately had included in its
    early years measurements of PM10 and PM2.5. Other
    analyses were published based on an American Cancer Society cohort
    taking advantage of fragmentary PM2.5 ambient monitoring
    data. Other investigations conducted using the PM10 ambient
    monitoring data were extrapolated to a PM2.5 indicator.
    These data provided the basis for promulgating a PM2.5 NAAQS
    in 1997. The PM2.5 NAAQS were set at 15 m3,
    annual arithmetic mean, and 65 m3, 24-hour averaging time
    with a 98th percentile of concentration at each population-oriented
    monitor. Associated with this was a change in the regulatory compliance
    monitoring network to emphasize PM2.5 mass measurements
    without regard to chemical composition. Because a PM10 mass
    NAAQS was still in place measurements of PM10 mass, not
    characterized as to chemical composition, continued. Using the
    difference between the PM10 mass measurements and
    PM2.5 mass measurements, it was possible to estimate
    PM10-2.5 mass concentrations.
        At various times there has been an interest in measuring PM sulfate
    mass concentration, a secondary pollutant arising in the atmosphere
    from conversion of SO2 gas. There have also been some short-
    term monitoring campaigns in which extensive chemical characterization
    of a number of particulate matter constituents have been measured.
    However, the extent of this monitoring data is limited in comparison
    with that developed for regulatory compliance purposes on
    PM10 mass and PM2.5 mass, not characterized as to
    chemical composition. Indeed, to date the database on specific PM
    constituents has been insufficient to set a NAAQS for a specific PM
    component. Obviously, Lead is an exception. Likewise, the data on
    specific PM constituents were not viewed as to exclude any constituent
    from regulation.
        The most recent CD and SP focuses on the PM2.5
    indicator. The focus on PM2.5 was not based on any careful
    scientific analysis that led to the conclusion that PM2.5
    mass, not identified as to chemical composition, as the most
    appropriate metric to relate to an increase in health effects. The
    simple fact is that because of the EPA's emphasis on regulatory
    compliance monitoring, the only PM air quality metrics that could be
    evaluated epidemiologically were PM10 mass, PM2.5
    mass and to a lesser extent PM sulfate and to an even lesser extent,
    PM10-2.5. I will be so bold as to say the focus on
    PM2.5 mass, irrespective of chemical composition, was a
    default decision, not a science-based decision.
        My discussion so far has focused on epidemiological evidence
    without considering the results of toxicological studies using cells,
    tissues or laboratory animals. As a toxicologist, I wish I could give
    more emphasis to the conduct and interpretation of toxicological
    studies. However, such studies have a very limited role in the PM NAAQS
    setting process. Although such studies can use new tools of modern
    molecular and cellular biology and genomics, the results are not
    necessarily relevant to setting the NAAQS. The challenges of
    extrapolating from laboratory animals to humans, from high to low
    levels of exposure, from studies of a few days or even a few months to
    human lifetimes and from studies of a few normal healthy young animals
    to large human populations including individuals with cardiopulmonary
    disease, principally from smoking, are substantial. At best, the
    toxicological investigations can help provide some guidance to the
    design and conduct of epidemiological investigations. The toxicological
    methods are simply to blunt and yield results that at best can be
    extrapolated qualitatively to human populations. I know of no
    scientific methods for using the results of toxicological studies with
    PM, not characterized as to chemical composition, or those conducted
    with specific PM constituents to develop quantitative numerical
    standards that are at the core of PM NAAQS.
         a shift in monitoring strategy to facilitate epidemiological
                                  evaluations
        What are the prospects for the next PM NAAQS review in 5 years
    including a rigorous evaluation of specific PM constituents? Without a
    major revolutionary change in the EPA's approach to ambient air
    monitoring, I think it will be more of the same. In short, because of
    the past focus on measuring PM2.5 and PM10-2.5,
    these metrics will continue to be evaluated in future epidemiological
    studies. Because of the substantial and continuing improvements in air
    quality, including PM2.5, PM10 and
    PM10-2.5, it will be even more difficult to detect
    associations between these PM mass metrics and health effects. Future
    epidemiological studies will also be challenged due to continuing
    reductions in cardiopulmonary disease related to reductions in the
    primary risk factor for these diseases--Cigarette Smoking.
        How can the prospects for improved epidemiological investigations
    be changed? If the EPA, in cooperation with States and Municipalities,
    radically modifies its ambient air monitoring network over the next 2
    years, it may be possible to have the results of improved
    epidemiological studies in 8 to 10 years. The development of an
    improved ambient air monitoring network will require some tough
    decisions. It is obvious that the expense of an altered monitoring
    network will require that only a modest number of PM constituents be
    measured in multiple cities in different regions across the United
    States. Some clear candidates would be sulfates, nitrates, organic
    carbon, elemental carbon, silica and some specific metals for which
    concern may exist as to their potential hazard. It is essential that
    all of the criteria pollutant gases, ozone, SO2,
    NO2 and CO, continue to be measured. With a richer array of
    monitoring data available it may be possible to test hypotheses as to
    the relative potency of the various PM constituents as well as the
    gaseous pollutants. In any long-term studies, it will be crucial to
    have accurate smoking history data if the very small potential effects
    of air pollution are to be separated from the large cardiopulmonary
    impacts of cigarette smoking. In addition, because of the relationship
    between PM-associated hydrocarbons and volatile and semi-volatile
    hydrocarbons these should be measured. In my opinion, it will be futile
    to measure dozens of individual chemical species with the view that
    these measurements could be useful in future epidemiological studies.
    The current highly uncertain signal of air pollution associated health
    effects is so small that ``teasing out'' effects related to any single
    PM chemical constituent will be extraordinarily challenging.
      selection of averaging times, numerical levels and statistical forms
        Having selected an indicator, it is necessary to proceed to
    decisions on the averaging times, numerical levels and statistical
    forms for the NAAQS. These three elements are inter-related and are set
    based on the epidemiological database. The averaging times are driven
    by the temporal characteristics of the monitoring data, 24-hour
    measurements that can be aggregated to yield annual values which, in
    turn, are used in the epidemiological investigations. Hence, it is
    reasonable to use 24-hour and annual averaging times.
        The selection of specific numerical levels for the 24-hour standard
    has been guided primarily by considering the results of epidemiological
    studies of the association between daily changes in the PM indicator
    and changes in mortality (all cause, cardiovascular and respiratory
    mortality). The power of these studies is directly related to the size
    of the population being studied and the number of days being monitored.
    Thus, results can only be developed for quite large cities. This
    approach would not be feasible for small communities and rural areas.
        The primary input for establishing the PM2.5 annual
    standard comes from long-term follow-up of cohort populations, the
    Harvard Six City Study of about 8,000 individuals initiated in 1979 and
    the American Cancer Society cohort assembled starting in 1979. In these
    studies, sophisticated statistical techniques have been used to attempt
    to tease out an association between differences in PM2.5
    ambient concentrations in different communities and the risk of death
    from various diseases. The analyses are very complicated because of the
    numerous factors that can influence the death rate including age,
    cigarette smoking, work history, education, socio-economic status,
    exposure to other pollutants as well as other factors.
        The results of the cohort epidemiological studies are typically
    reported as a linear coefficient of increase in relative risk per 10
    m3 of PM2.5 using whatever PM2.5
    monitoring data are available for the specific cohort. Thus, for the
    studies initiated in 1979, this may be PM2.5 measurements
    made in 1979-1983. Recall that in the 1980s, there was a move to
    regulate PM10 measurements of PM2.5 were
    discontinued and not re-instituted until after the PM2.5
    NAAQS was promulgated in 1997. The PM2.5 exposure of
    individuals in the cohort prior to 1979 is unknown although it is well
    recognized that in most areas air quality has substantially improved
    since 1970.
        A major challenge in analyzing and interpreting the results of the
    cohort studies relates to the uncertain role of pollution exposures for
    the individual populations prior to initiation of the studies and the
    uncertainty in the statistical models used to attribute relative risk
    to the various risk factors including PM2.5. The small size
    of the PM2.5 relative risk poses a special challenge. This
    includes the difficulty of determining the shape of the exposure-health
    response relationship extending from past high levels down to current
    levels. Especially vexing is the issue of whether a threshold does or
    does not exist in the exposure-health response relationship. In my
    view, the exposure-response relationships are highly uncertain in the
    range of typical ambient PM2.5 concentrations in the United
    States. The substantial uncertainty in the applicability of the
    PM2.5 exposure-health response coefficients at current
    ambient concentrations requires caution in calculating either
    PM2.5 associated risks or the benefits of any reductions in
    PM2.5 concentrations.
                           expert advice elicitation
        In an attempt to better characterize the uncertainties in
    PM2.5-associated health risks and, conversely, the benefits
    in reductions in PM2.5, some individuals have suggested the
    use of an ``expert advice elicitation'' approach. I am familiar with
    this approach having served as one of the five experts in EPA's pilot
    project to elicit opinions on the relationship between PM2.5
    exposure and death. I have also participated in such approaches in the
    initial stages of planning and interpreting safety assessment studies.
    I think the expert opinion elicitation process may have merit in
    obtaining a qualitative assessment of the impact of exposure to
    hazardous materials. However, I have serious reservations as to its use
    in eliciting quantitative characterizations of risk for various levels
    of PM2.5 exposure for different populations in different
    parts of the United States.
        The interviewers eliciting the expert opinions play a major role in
    determining the outcome of the process. In the session I participated
    in, I found the interviewer focusing on eliciting quantitative linear
    exposure-response coefficients. Since it is my professional opinion
    that it is very unlikely that a linear relationship exists between
    PM2.5 exposure and health responses down to and including
    current ambient levels, the interview and the follow-up discussions
    proved frustrating for both me and the interviewer. In short, the
    sponsor (in this case, the EPA) can influence the interviewer to frame
    a series of questions that will yield a pre-determined answer. In my
    case, I felt the desired answer was what linear risk coefficient
    (exposure health-response) would I prefer.
        I am also concerned about the process used to select experts for
    participation. In my opinion, the process should be very transparent
    with regard to the criteria used to include or exclude individual
    experts from a Panel. My concerns extend to the inclusion of
    individuals who may have conducted and reported on the key studies
    being used in the expert opinion elicitation process. It is human
    nature to want to have one's own data and analyses used in the same
    manner as originally reported.
        Any additional concern with the process is the approach of using
    secondary interviews in an attempt to gain consensus from the experts
    as to the outcome. I understand that was done with the full-scale
    expert elicitation panel whose input is to be used in the final
    regulatory impact analysis. A major challenge in any elicitation of
    expert advice is separating the individuals science-based input from
    their personal sources with regard to a policy outcome. In my opinion,
    the results of that expert elicitation are likely to be seriously
    flawed. I would urge the Administrator to not use the results of the
    expert opinion elicitation as input for quantitative estimates of
    risks/benefits associated with PM2.5 exposure. Such an
    approach is not a substitute for more rigorous uncertainty analysis
    that attempts to characterize all the factors that impact on estimating
    risks of PM2.5 exposure and the benefits of reductions in
    PM2.5 exposure.
        As an alternative to expert opinion elicitation, I urge CASAC to
    document the scientific views of each of the CASAC PM Panel members
    with regard to quantitative aspects of the PM NAAQS. This approach was
    used in the previous PM review that concluded with promulgation of the
    1997 PM2.5 NAAQS. A copy of the table included in the CASAC
    PM Panel's ``closure letter'' is attached. As may be noted, individual
    Panel members had a wide range of views with regard to setting the
    PM2.5 NAAQS. I would personally prefer to see each of my
    scientific colleagues express their individual science-based opinions
    rather than have CASAC Panel participants cajoled to reach a consensus.
                 scientific evaluations versus policy decisions
        A major challenge I see for all scientists, and especially for
    CASAC PM Panel members participating in the NAAQS review process, is to
    recognize the distinction between scientific evaluations and policy
    judgments. In my comments to Mr. Bill Wehrum and Dr. George Gray on
    improving the NAAQS review process, I noted--``It would be helpful if,
    at each step in the NAAQS process including each meeting of the
    scientists preparing the Criteria Documents and the Staff Paper and
    their review by CASAC, if each participant were reminded. ``Every
    individual should recognize the distinction between scientific
    evaluation and policy decisions and recognize that the matters being
    dealt with are at the interface of science and policy. Each individual
    participant is asked to leave their individual ideologies and thoughts
    on policy decision outcomes at the door before deliberating on the
    science.'' This is not a matter of an individual's employment, i.e.,
    academic, government, industry, etc. or political affiliation. It
    applies to all participants. This is an especially vexing issue for
    scientists involved in evaluating their own research results or that of
    close colleagues. In today's resource constrained world everyone wants
    to have their work used in the public arena, moreover, they would like
    to see the door left open or opened wider for them to do more work on
    the topic under consideration. Indeed, some individuals, including
    CASAC Panel Members, desire a ``sense of accomplishment''--some
    individuals interpret that as--did we participate in lowering the
    NAAQSs' Some have suggested that there would be a ``limited sense of
    accomplishment'' if only the 24-hour PM2.5 standard were
    lowered and the Annual PM2.5 standard was left unchanged.
    Yes, scientific evaluations and policy decisions do get intertwined by
    individual scientists in expressing their own personal preferences on
    life science issues.''
                                     ______

            Response by Roger McClellan to Additional Question from
                               Senator Voinovich
        Question 1. Dr. McClellan, as you heard Dr. Gray testify, he said
    characterization of uncertainties is extremely important. EPA is using
    a process called expert elicitation to respond to the NAS
    recommendation on this important issue. We will see the elicitation's
    results when the rule is finalized. Please elaborate on your concerns
    with this process.
        Response. I am very familiar with the ''expert elicitation'' being
    used by the EPA to obtain expert opinions on the quantitative
    relationship between changes in PM.5 concentrations in
    ambient air and changes in indices of adverse health effects. As I
    noted in my written testimony, I participated in a pilot expert
    elicitation study conducted by an EPA contractor as a prelude to the
    larger study recently conducted for the EPA.
        In my professional opinion, the expert opinion elicitation process
    being used by the EPA is not a scientifically adequate approach to
    characterizing either the central estimate nor associated range of
    potential values for changes in adverse health outcomes associated with
    changes in ambient PM2.5 concentrations for contemporary
    PM2.5 levels found across the United States. The process is
    at best an elicitation of the opinions of a selected group of experts.
    It is not a substitute for rigorous scientific characterization of
    uncertainty of the kind I understand was recommended by the National
    Academy of Science/National Research Council in its 2002 report,
    ``Estimating the Public Health Benefits of Proposed Air Regulations.''
         The outcome of the expert opinion elicitation process is
    influenced by five factors:

         (1) the nature of the request from the sponsor, in this case the
    EPA, to the
        organization or individual(s) eliciting the opinions;
         (2) the nature of the questions posed by the opinion elicitators;
         (3) the manner in which the experts are identified and selected;
         (4) the scientific background and personal biases of the experts;
    and
         (5) how the individual opinions are compiled and reported.

         It is apparent that a requested organization can influence the
    results by how they frame the question(s) presented for use in the
    elicitation process. In similar fashion the manner in which the
    questions are posed to the experts is critical. I understand that the
    central question asked, which was similar to that posed to me in the
    pilot study, was ``What is the percent reduction in excess health risks
    associated with a 1 m3 decrease in the ambient
    PM2.5 concentration'' This question assumes that there is a
    linear relationship between changes in PM2.5 concentrations
    and excess health risks. This is an assumption, not a scientific fact.
    Indeed, I would argue that the results of the recent papers by Enstrom
    (2005) and Laden et al. (2006) clearly indicate a lack of a
    statistically
        significant excess in mortality associated with contemporary
    ambient PM2.5 levels and, thus, an absence of a linear
    exposure-response relationship at low levels of PM2.5.
    Interestingly, this includes results from SouthernCalifornia and
    Stuebenville, OH, areas in which PM2.5 levels were quite
    high in the past and have been substantially reduced.
        The scientific background of the experts, their personal biases and
    how they are selected can influence the outcome of the elicitation
    process. Individuals whose research findings are under consideration in
    the expert opinion elicitation process are placed in an awkward
    position. Are they willing to set aside their own vested interest in
    seeing their results used in favor of giving a broader opinion? In
    giving an opinion, can they avoid being concerned with how the results
    will be used? Will a tighter standard result in a generally more
    favorable view of their research?
        The manner in which results are ultimately compiled and presented
    is of critical importance. In the most recent process, the experts were
    polled individually and then brought together as a group to re-affirm
    the outcome. I argue that this consensus building approach suppresses
    uncertainty rather than contributing to a full expression of
    uncertainty. I would urge the EPA Administrator to not give significant
    weight to the results of the expert opinion elicitation process in
    setting the annual standard for PM2.5. Moreover, I
    definitely feel it would be inappropriate to use the results of the
    expert elicitation process as input to the calculation of benefits in
    the Regulatory Impact Analysis.
        Let me again emphasize that it is my professional opinion that it
    is imperative that the uncertainties associated with estimation of the
    excess adverse health effects of exposure to PM2.5 at
    contemporary levels be rigorously characterized. In my opinion, the EPA
    at each step in the PM review process, failed to adequately
    characterize uncertainties. This was true of the Criteria Document, the
    Staff Paper and the Risk Assessment that under-girded the Staff Paper.
        A rigorous uncertainty analyses would have started with critically
    examining the base data from critical studies and the very
    sophisticated statistical methods used. When the original published
    reports did not contain sufficient detail, the EPA should have obtained
    more detailed data and, if necessary, conduct additional analyses. This
    was done in a laudatory manner for some studies under the auspices of
    the Health Effects Institute, however, even more critical analysis
    would have been useful in better characterizing uncertainty in
    estimating PM2.5 risks.
        For example, very little was done to examine the validity of the
    Cox proportional hazard model for characterizing the very small
    estimated excess risks for PM2.5 exposure and other
    confounders. Moolgavkar (2005 and 2006) has noted the limitations in
    this widely used model for estimating small excess risks. In none of
    the key studies being used to set the annual PM2.5 standard
    were results presented for cigarette smoking, the major risk factor for
    cardiorespiratory disease. These results would have given an indication
    of how well the Cox model was working for the major risk factor,
    cigarette smoking, and, thus, gave some greater confidence in the use
    of the model for characterizing much lower levels of risk for
    PM2.5. If historical information were not available on
    cigarette smoking this should have been identified as an uncertainty
    and, indeed, quantified.
        The impact of cigarette smoking is apparent from the analysis of
    Enstrom (2005) using data for Southern California. Beyond presenting
    the analysis of PM2.5 risks, the Enstrom paper also included
    the results of an analysis of the relative risk of death from all
    causes by cigarette smoking status. These results are of special value
    because they illustrate the substantial magnitude of the cigarette
    smoking effects relative to other risk factors such as air pollution.
    The baseline was never smokers (as of 1959 and 1972) for deaths 1973 to
    2002 set at 1.000. Former smokers (as of 1959 and 1972) were Relative
    Risk (RR)-1.054 and increased to 1.253 for former smokers (as of 1972
    only). Current smokers (as of 1972) had relative risks that increased
    with smoking intensity 1-9 cigarettes per day (cpd)RR-1.239; 10-19
    cpdRR-1.97 cpdRR-1.871, 21-39 cpdRR-2.068 and 40+ cpdRR-2.543. The
    large relative risks related to cigarette smoking level provide
    perspective for the small relative risks reported for long-term
    PM2.5 exposure. Indeed, in part because he had smoking
    histories available on the subjects in the Southern California cohort
    he was able to conclude These epidemiologic results do not support a
    current relationship between fine particulate pollution and total
    mortality in elderly Californians, but they do not rule out a small
    effect, particularly before 1988. For 1983-2002, the RR was 1.00. This
    included a substantial number of individuals exposed to
    PM2.5 at concentrations above the current Annual Standard of
    15 m3. Moreover, the substantial effects of cigarette
    smoking emphasize the importance of accurate inclusion of cigarette
    smoking history in any long-term cohort study of the effects of PM and
    dictate that consideration of smoking be included in any quantitative
    characterization of uncertainty in estimating PM2.5 risks.

        Question 2. Dr. McClellan, you have been on these panels for a long
    time. Does the science ever point specifically to a number or are these
    standards really set in the judgment of the Administrator?
        Response. I have served on each of EPA Clean Air Scientific
    Advisory Committees that have provided advice to the Administrator of
    the setting on revision of National Ambient Air Quality Standards for
    Particulate Matter. There has been a general acknowledgement by the
    Advisory Panel members that the science should inform the decisions on
    the four elements of the standard; (a) indicator, such as
    PM2.5, (b) averaging time, such as annual, (c) numerical
    level, such as 15 m3, and (d) the statistical form. There
    has also been general recognition that the Administrator has the
    ultimate responsibility for setting the standard using his/her
    judgment. The Advisory Panels have regularly reviewed and commented on
    the range of numerical levels presented in the Staff Paper, thereby
    acknowledging that the science can inform a broad range for setting the
    standard rather than the science yielding a specific numerical level.
    Each successive review of the Particulate Matter standard has become
    more contentious. In my opinion, some of the contentious nature has
    been driven by early concern by special interest groups and some
    members of the Panel as to the outcome of the process. In short, a
    premature view has developed that the PM2.5 standard should
    be tightened, a view advanced long before the scientific evaluation had
    been completed. One way for CASAC to enhance the potential for the
    standard being tightened is to endorse a range of numerical values
    below that of the current standard. If this is done the judgment of the
    Administrator is constrained. This is exactly what was done when the
    CASAC PM Panel truncated the proposed range for setting an Annual
    PM2.5 standard from 12 to 15 m3 to 13-14
    m3. The CASAC PM Panel advanced an argument for changing the
    lower limit of the range from 12 to 13 m3, i.e. uncertainty
    increased below 13 m3. In none of the letters from the CASAC
    Chair to the Administrator was a rigorous rationale provided for
    reducing the upper bound of the range from 15 to 14 m3. In
    my view, by endorsing an exceptionally narrow range of 13 to 14
    m3 the CASAC PM Panel ignored the uncertainty in the science
    and attempted, inappropriately in my view, to exercise some of the
    judgment that is reserved for the Administrator by the Clean Air Act.
    The CAA wisely calls for CASAC to advise the Administrator and for the
    Administrator to use judgment in setting the standard. The CASAC PM
    Panel, in narrowing the range to 13 to 14 m3, stopped one
    small step short of attempting to set the PM2.5 Annual
    standard.

        Question 3. As a member of the CASAC panel was there complete
    agreement on the recommendations.
        Response. There was not complete agreement among CASAC PM Panel
    Members on the narrowing of the range for the Annual PM2.5
    standard from 12 to 15 G53 to 13 to 14 m3. George Wolff and
    I, who had both previously served as Chair of the Clean Air Scientific
    Advisory Committee, disagreed with the proposal. It is of interest that
    the decision to narrow the range was reached during short conference
    calls of the Panel and by electronic exchanges among small groups of
    members. The decision was not one reached on the basis of a typical
    face-to-face public meeting of the Panel. There was also intense
    pressure to obtain and present a consensus view and to provide a letter
    from CASAC to the Administrator that was devoid of attached individual
    views as customary for CASAC letters to the Administrator, especially
    on important matters. I exercised my rights as a private citizen to
    prepare a letter to the docket expressing my views on the setting of
    the PM standard. In my professional opinion, the available scientific
    information is consistent with setting an Annual PM.5
    Standard in the range of 12 to 15 m3 as articulated in the
    EPA Staff Paper with the specific numerical level to be selected by the
    Administrator based on judgment as specified in the Clean Air Act.
                                   __________
      Prepared statement of Anne Smith, Vice President, CRA International
        Mr. Chairman and members of the committee, thank you for your
    invitation to participate in today's hearing. I am Anne Smith, and I am
    a Vice President of CRA International. I am a specialist in
    environmental risk assessment and integrated assessment to support
    environmental policy decisions, which was a core element of my Ph.D.
    thesis at Stanford University in economics and decision sciences. I
    have performed work in the area of risk assessment over the past 30
    years, including as an economist in the USEPA's Office of Policy,
    Planning, and Evaluation, as a consultant to the USEPA Air Office, and
    in many consulting engagements since then for Government and private
    sector clients globally while employed first at Decision Focus
    Incorporated and then CRA International. I have also served as a member
    of several committees of the National Academy of Sciences focusing on
    risk assessment and risk-based decision making.
        I have been deeply involved in assessment of the evidence on risks
    from ambient fine particulate matter (PM2.5) since EPA first
    turned to the task of identifying an appropriate National Ambient Air
    Quality Standard (NAAQS) for PM2.5 over 10 years ago. I
    testified to this same committee in 1997 on the nature of the
    scientific evidence underlying the PM2.5 NAAQS proposed at
    that time. I thank you for the opportunity to share my perspective
    today on the current scientific evidence and associated risk assessment
    for PM2.5 and how it has evolved since 1997. My written and
    oral testimony today provide a statement of my own research and
    opinions, and does not represent a position of my company, CRA
    International.
        I would like to start by summarizing what I think are the most
    important and overarching considerations that should be accounted for
    when considering whether to alter the current PM2.5 NAAQS,
    which include an annual average limit of 15 m3 and a 24-hour
    average limit where the 98th percentile of observations over all days
    must be below 65 m3. I will then summarize results of
    analyses I have done to synthesize the recent PM2.5 health
    studies into an assessment of risks. Complete details and documentation
    of my analyses are in my written comments on the current Proposed Rule
    for a revised PM2.5 NAAQS, which were submitted into the
    PM2.5 docket in April, 2006. I am attaching a copy of my
    written comments to EPA to further substantiate the points that I make
    in my testimony today.
        The key points that I wish to make about the scientific evidence on
    risks of PM2.5 that are relevant for making a decision on
    the standard are:

         EPA and the courts recognize that the PM2.5 NAAQS must
    be set at a level that still has some positive level of risk, because
    the science has yet to advance far enough to identify any threshold
    exposure level for effects, below which risk would be indistinguishable
    from zero. This was true in 1997 and it remains true today.
         EPA's own quantitative estimates of mortality risk at attainment
    of the current NAAQS are lower today than they were when EPA set that
    standard in 1997 ``with an adequate margin of safety,'' after
    accounting for the many uncertainties. This is true for both long-term
    (``chronic'') exposures to PM2.5 (which are addressed by the
    annual average limit) and short-term (``acute'') exposures (which are
    addressed by the 24-hour average limit).
         The reduction in the quantitative estimates of risk is apparent
    even in EPA's own risk analysis, but most of the reasonable alternative
    results reported in the same studies that EPA has relied on imply even
    lower quantitative risk estimates for PM2.5.
         Looking more broadly beyond quantitative risk estimates, the many
    additional studies of PM2.5 mortality risks since 1997 have
    demonstrated that many of the risk estimates become ``statistically
    insignificant'' when re-estimated in reasonable alternative ways. A
    ``statistically insignificant'' result directly implies a positive
    probability that there is no effect at all. Thus, when we look at all
    of the data in the new studies as a group, we find more statistical
    evidence now than was available in 1997 that PM2.5 may not
    be the culprit pollutant, and that there may be no causal relationship
    at all between PM2.5 and mortality.

        In thinking about whether to tighten either the annual or daily
    standard, one might ask, what has changed in our knowledge since 1997
    that would undermine the Administrator's 1997 judgment that the current
    PM2.5 NAAQS are neither more nor less stringent than
    necessary to protect the public health with an adequate margin of
    safety? A thorough review of the new evidence suggests that the margin
    of safety that the Administrator selected in 1997 is likely to be
    larger than was thought at the time.
     quantitative estimates of risk remaining at the current standard have
                                     fallen
        EPA has acknowledged that the PM2.5 NAAQS cannot be set
    at a level that corresponds to zero risk.\1\ However, EPA has also
    argued that its quantitative risk estimates cannot be used to identify
    a specific point where it should set a standard:
    ---------------------------------------------------------------------------
        \1\ See, for example, the Proposed Rule, p. 2622 (i.e., 71 FR
    2622).

        ``[I]n the Administrator's view, a risk assessment based on studies
    that do not resolve the issue of a threshold is inherently limited as a
    basis for standard setting, since it will necessarily predict that ever
    lower standards result in ever lower risks, which has the effect of
    masking the increasing uncertainty inherent as lower levels are
    considered. As a result, while the Administrator views the risk
    assessment as providing supporting evidence for the conclusion that
    there is a need to revise the current suite of PM2.5
    standards, he judges that it does not provide a reliable basis to
    determine what specific quantitative revisions are appropriate.'' \2\
    ---------------------------------------------------------------------------
        \2\ 71 FR 2648.

        I concur that a risk assessment that makes no attempt to
    incorporate the uncertainty on where a threshold may exist will indeed
    only serve to promote ever lower standards without a sound basis. Since
    EPA has not incorporated such uncertainty into its risk assessment,
    that risk assessment is indeed incapable of helping to identify where
    to set the standard. However, since EPA views the risk assessment as
    supporting a conclusion on whether there is a need to revise the
    standard, it is appropriate and relevant to compare EPA's current
    quantitative risk estimates and the associated statistical measures of
    a PM2.5 effect to those estimates that were available in
    1997. In the Proposed Rule, EPA partially acknowledges that risk
    estimates are lower today than in 1997 for the two cities that were
    included in both its 1997 and current risk analyses. With respect to
    short-term exposure risk estimates, EPA states that ``the magnitude of
    the estimates associated with just meeting the current annual standard.
    . .  is similar in one of the locations. . .  and the current estimate
    is lower in the other location.'' \3\ With respect to the long-term
    exposure risks, EPA states that the risk estimates ``are very similar
    for the two specific locations included in both the prior and current
    assessments.'' \4\
    ---------------------------------------------------------------------------
        \3\ 71 FR 2640.
        \4\ 71 FR 2640.
    ---------------------------------------------------------------------------
        EPA does not provide the actual numerical estimates for these two
    cities. They are:

         For acute risks in Los Angeles, in 1997 EPA estimated that 1.7
    percent of mortality would continue to be attributable to
    PM2.5 once Los Angeles would be in attainment with the
    current NAAQS. Today EPA's risk estimate has fallen to 0.5 percent and
    this current estimate is statistically insignificant (which means that
    there is a fairly large chance that this particular estimate suggests
    that there is really no PM2.5 effect at all).
         For acute risks in Philadelphia, in 1997 EPA estimated that 1.5
    percent of mortality would continue to be attributable to
    PM2.5 at attainment of the current NAAQS. The risk estimate
    that EPA now uses for Philadelphia is 2.2 percent. Although this is
    higher than in 1997, EPA has selected a single estimate out of a very
    large number of estimates reported in the epidemiological study it is
    relying on for Philadelphia. In fact, that study actually concluded
    that PM2.5 did not appear to explain the mortality risk as
    well as ozone, and the residual risk for PM2.5 after
    simultaneously accounting for the role of ozone would have produced a
    lower estimate--about 0.8 percent--which is lower than in 1997. This
    more thoroughly-controlled estimate also is not statistically
    significant.
         Chronic risk estimates do not vary from city to city, because the
    statistical method to estimate relative chronic risks produces a single
    value that applies to all cities. I will therefore only relate the
    results for Los Angeles here. For chronic risks, in 1997 EPA estimated
    that 2.0 percent of mortality would continue to be attributable to
    PM2.5 at attainment of the current NAAQS. Today, EPA's risk
    estimate for the same attainment status is 1.8 percent--in other words,
    the chronic risk estimate also is lower now, even though the quote from
    the Proposed Rule above suggests that the estimate has not changed.

        The Proposed Rule only referred to a comparison of risks for these
    two cities. However, it is actually possible to make the same
    comparison for the other six cities that EPA has included in its
    current risk analysis. This is because there was only one
    PM2.5 acute mortality study it could have used for each of
    those cities back in 1997 the same one that it used for Los Angeles and
    Philadelphia.\5\ For five of the other six cities in the current risk
    analysis, EPA's acute risk estimates today are lower than they would
    have been estimated to be in 1997, and all the cities have lower
    chronic risk estimates. Table 1 summarizes the cities and the results
    of my comparison of their risk estimates.
    ---------------------------------------------------------------------------
        \5\ This was the paper by Schwartz, Dockery, and Neas (1996) on
    acute risks in six U.S. cities.
    ---------------------------------------------------------------------------
        When I reviewed the original papers that EPA is relying on, I also
    found that EPA's risk analysis has selectively used the highest or
    near-highest risk estimates supported by each paper. This means that
    risks estimates that more fully reflect the body of evidence are likely
    lower still than EPA's risk analysis suggests. Additionally, as for
    Philadelphia, I found that San Jose would have had a much lower risk
    estimate than in 1997--literally zero now--if EPA had chosen to use the
    one reasonable alternative result for PM2.5 reported in the
    San Jose study.\6\ Thus, the full body of evidence can support risk
    estimates that would be lower now than in 1997 for every one of the
    eight cities in EPA's current risk analysis.
    ---------------------------------------------------------------------------
        \6\ That is, EPA's risk estimate for San Jose is based on a 1-
    pollutant regression that associated mortality with PM2.5 on
    the same day as death. The study also reported results of a comparable
    1-pollutant regression that was identical in all ways except that it
    associated mortality with PM2.5 from the day before death.
    The latter regression produced a negative risk estimate, which I
    interpret to be evidence of no effect at all (rather than evidence of a
    beneficial effect of PM2.5).

    [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

        Table 1 also reports that the PM2.5 findings are not
    statistically significant across all of the alternative reasonable risk
    estimates in each underlying study. This was not the case in 1997. At
    that time, there was a much more limited set of studies and estimates
    within each study--but for some cities, all the estimates available at
    the time were statistically significant. Today, the opposite it true.
    Every single study that EPA has relied on for its current risk analysis
    contains alternative estimates that indicate that PM2.5 does
    not have a statistically significant association with mortality, yet
    EPA chose not to use this part of the new information.
        In conclusion, EPA has stated that the risk assessment's role is to
    provide ``supporting evidence'' on whether there is a need to revise
    the PM2.5 standard. In this role, EPA's own risk analysis
    provides no evidence supporting a decision to tighten the standard now.
    The risks are lower now than they were when the standard was set in
    1997. The higher estimates of risks were determined to be ``requisite
    to protect the public health with an adequate margin of safety'' in
    1997, and the quantitative risk analysis suggests that that margin of
    safety has grown, not narrowed, as a result of the many more recent
    PM2.5 health effects studies.
        The question then remains whether other aspects of the new evidence
    provide an overriding reason for tightening the standard. The other
    part of EPA's reasoning for how to set the standard relies on what EPA
    calls an ``evidence-based approach.'' Simply put, EPA looks at all of
    the studies that estimate the statistical relationship of
    PM2.5 with health effects, and seeks to identify a level of
    PM2.5 above which statistically significant effects are
    found, and below which statistically significant effects are not found.
        In applying the evidence-based approach, EPA states that the large
    quantity of new studies of acute effects justifies the use of acute
    studies to set the 24-hour standard, and that chronic studies should be
    used to determine where to set the annual standard:

        ``Given the extensive body of new evidence based specifically on
    PM2.5 that is now available, and the resulting broader
    approach presented in the Staff Paper, the Administrator considers it
    appropriate to use a different approach from that used in the last
    review to select appropriate standard levels. More specifically, the
    Administrator's proposal relies on an evidence-based approach that
    considers the much expanded body of evidence from short-term exposure
    PM2.5 studies as the principal basis for selecting the level
    of the 24-hour standard and the stronger and more robust body of
    evidence from the long-term exposure PM2.5 studies as the
    principal basis for selecting the level of the annual standard.'' \7\
    ---------------------------------------------------------------------------
        \7\ 71 FR 2648.

        I will next discuss how the evidence in the long-term exposure
    studies of PM2.5 has weakened since 1997, thus removing any
    necessity to tighten the annual standard under EPA's evidence-based
    approach. I will then discuss how the evidence in the short-term
    exposure studies of PM2.5 that are the basis for the 24-hour
    standard also has weakened.
       the evidence in long-term exposure studies has weakened since 1997
        In 1997, the two prominent long-term exposure studies (one based on
    a sample population, or ``cohort'' in 154 U.S. cities that was tracked
    by the American Cancer Society, and one based on a sample population in
    just six US cities that was tracked by Harvard School of Public Health)
    both had published findings of a statistically significant relationship
    between long-term exposure to PM2.5 and life expectancy.
    These studies were subjected to an extensive process of reanalysis
    under the auspices of the Health Effects Institute (HEI) that was
    released in 2000.\8\ This reanalysis is widely reputed to have
    confirmed the original studies' results; however, a complete reading of
    the actual report shows that some major statistical concerns underlying
    those results were unearthed. Although a positive PM2.5
    effect was still found in those data sets, the ability to interpret
    those results as clearly causal in nature was weakened.
    ---------------------------------------------------------------------------
        \8\ The report on findings of these reanalyses is Krewski et al.
    (2000).
    ---------------------------------------------------------------------------
        EPA acknowledges that the concerns identified in the HEI reanalyses
    of the long-term exposure studies for PM2.5 remain
    unresolved to the present time:
        The Administrator also recognizes a contrasting view as to the
    interpretation of and weight to be accorded to the results from the
    ACS-based studies (Pope et al., 1995; Krewski et al., 2000; Pope et
    al., 2002). In this view, the ACS-based studies are not sufficiently
    robust to support a policy response that would tighten the annual
    PM2.5 standard based on the evidence. This view emphasizes
    the sensitivity of the results of these studies to plausible changes in
    model specification with regard to accounting for the geographical
    proximity of cities and the correlation of air pollutant concentrations
    within a region, effect modification by education level, and inclusion
    of SO2 in the model. In this view, these sensitivities
    suggest potential confounding or effect modification that has not been
    taken into account. For example, concern has been raised about the
    sensitivity of results in the reanalysis of data from the ACS cohort
    study (Krewski et al., 2000) to inclusion of SO2 in the
    models. [T]he reanalysis found that PM2.5, sulfates, and
    SO2 were each associated with mortality in single-pollutant
    models. However, in two-pollutant models with SO2 and
    PM2.5, the relative risk for PM2.5 was
    substantially smaller and no longer statistically significant, whereas
    the effect estimates for SO2 were not sensitive to inclusion
    of PM2.5 or sulfates in two-pollutant models. In this view,
    the ACS-based risk estimates are more robust for SO2 than
    for PM2.5 or sulfates. In further extended analyses, Pope et
    al. (2002) reported that effect estimates were not highly sensitive to
    spatial smoothing approaches intended to address spatial
    autocorrelation, while findings of effect modification by education
    level were reaffirmed. Results of multi-pollutant models were not
    reported by Pope et al. (2002). Because the correlation coefficient
    between PM2.5 and SO2 was 0.50 in the ACS data,
    in this view it is plausible to believe that the independent effects of
    the two pollutants could be disentangled with additional study.'' \9\
    ---------------------------------------------------------------------------
        \9\ 71 FR 2652.
    ---------------------------------------------------------------------------
        The quote above is lengthy, which highlights that the concerns
    identified in the long-term exposure studies are many. The quote above
    also indicates that the new set of results using the American
        Cancer Society cohort that was published after the HEI reanalyses
    (i.e., Pope et al., 2002) did not help resolve these issues.
    Specifically, the 2002 paper ignores concerns that the purported
    PM2.5 effect instead might be attributable to the gaseous
    pollutant SO2, and re-affirms a troubling finding that
    PM2.5 only seems to create mortality risk only for
    individuals who have not continued their education beyond the high
    school level. (The latter finding is discussed further below.)
    Additionally, the 2002 paper still finds that the PM2.5
    effect is diminished and rendered insignificant when applying
    statistical methods to correct a clear statistical error that the HEI
    report found in the original results. Nevertheless, the Pope et al.
    (2002) paper continues to use the estimation method that is subject to
    error except in a sensitivity analysis; and EPA continues to rely on
    the uncorrected estimates in its risk analysis. Even with these dubious
    selections from the full body of literature, EPA's estimates of long-
    term exposure risk are lower than in 1997.
        Figure 1 illustrates the degree to which the evidence on long-term
    exposure risk has fallen, both in the overall magnitude of the risk
    estimate, and also in terms of a greater degree of uncertainty in the
    estimate. Figure 1 uses the case of Los Angeles at attainment of the
    current standard, yet the relative patterns evident in this figure are
    the same for all cities in the U.S. All of the risk estimates in Figure
    1 labeled ``1'' through ``7'' are based on the American Cancer Society
    cohort, which has received the majority of attention. The estimate on
    the far left of the figure, labeled ``1'' is the estimate from 1997
    (note that the estimate is 1.5 percent, as reported for Los Angeles in
    the preceding section), and the estimates to the right are other key
    results from the HEI reanalyses and from the more recent Pope et al.
    (2002) paper. The estimate labeled ``2'' is the single result from the
    many new estimates that is used for the current EPA estimates of long-
    term risk (which is 1.3 percent, as I stated in the previous section).
        It is quite apparent from the figure that the current risk estimate
    is among the highest that could be found among the more recent results.
    If any of the others (labeled ``3'' through ``7'') had been used for
    EPA's risk analysis, the current risk estimate of 1.3 percent for Los
    Angeles would instead be in the range of 0.3 percent to 1.0 percent--
    much lower than the original 1997 risk estimate that was available when
    the current standard was first set.
        The set of results on the far right of the figure (labeled ``8''
    through ``12'') reflect the findings based on a new study of a third
    sample population that had not been identified or studied as of 1997.
    It is known as the ``Veterans' Cohort.'' I believe this study to be of
    some policy relevance regarding whether or not the annual standard
    needs to be tightened, given that this study finds no effect at all of
    PM2.5 on life expectancy in this particular cohort. EPA has
    chosen to give ``greatest weight'' to results from the American Cancer
    Society and the Six Cities cohorts because they have been reanalyzed
    and scrutinized so thoroughly. While this may be a reasonable judgment,
    EPA has actually gone further than that, and accorded the Veterans'
    Cohort results zero weight. Its findings should be acknowledged with
    somewhat more than zero weight. When one does so, the overall evidence
    regarding long-term PM2.5 risks is further weakened.

    [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

        EPA also refers to the perplexing finding that level of education
    determines whether or not there is a PM2.5 association.
    Figure 2 illustrates this finding, which was first identified in the
    HEI reanalyses, and which remains in the more recent Pope et al. (2002)
    study. Clearly education per se is not believed to be the cause of
    sensitivity to exposure to PM2.5, yet the important (and
    still unanswered) question is: what is educational level indicating
    about risks that these sample populations face? What could possibly
    explain the complete lack of a PM2.5 effect among those with
    higher educations? When such a pattern appears in epidemiological study
    results, it indicates that there is still an important explanatory
    factor that is missing from the statistical estimation method something
    correlated with education. Until that factor is identified and included
    in the estimation of PM2.5 risks, estimates of the effect of
    PM2.5 are biased. The PM2.5 estimate could be
    higher, or it could vanish altogether. Thus, the unexplained pattern
    related to education in all of these studies remains a very important
    warning about the pitfalls of making a causal interpretation regarding
    long-term exposure risks of PM2.5.
        In summary, the evidence against a need to tighten the annual
    standard is not just founded on the fact that the numerical long-term
    risk estimates are now lower than when the current standard was set.
    The more important point is that the basis for interpreting the long-
    term studies as unbiased evidence of a causal relationship between
    PM2.5 and chronic mortality risk has weakened. This was a
    concern in 1997, and the reanalyses and new studies since then have
    done more to amplify these concerns than to allay them. In the face of
    this evidence of greater uncertainty, combined with the reduced
    quantitative risk estimates, there is no justification for tightening
    the annual standard on the basis of the long-term exposure studies.

    [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

        A Summary CASAC's Case for Tightening the Annual Standard
        EPA's Clean Air Scientific Advisory Committee (CASAC) has made the
    case to tighten the annual standard with two lines of reasoning,
    neither of which is founded on the long-term risk studies.\10\
    ---------------------------------------------------------------------------
        \10\ CASAC's reasoning is stated in a letter to the Administrator
    on March, 21 2006, pp. 3-4.
    ---------------------------------------------------------------------------
        CASAC's first line of reasoning is that EPA reports substantial
    risk would remain at the current standard. As EPA and the courts have
    long established, the PM2.5 NAAQS cannot be a zero-risk
    standard. CASAC was concerned by the estimates of remaining risk, but
    never deliberated the question of whether this risk estimate had risen
    or fallen since the standard was deemed ``requisite to protect the
    public health with an adequate margin of safety.'' As I have shown
    above, the risk estimates fell, both for chronic and acute risks, but
    EPA never reported this fact to CASAC during CASAC's review of the
    Staff Paper and associated risk assessment. In the face of this fact,
    the only other argument to tighten the annual standard might be if
    there were stronger reason to believe that the effects found in these
    studies are causal in nature. However, EPA set the current standards
    with a presumption (precautionary in nature) that the estimated
    PM2.5 risks were causal. This cannot therefore be the
    rationale to tighten the standards.
        Hence, to argue that the standard should be tightened because there
    is evidence that risk remains at the current standard is a logic that
    would force a tightening of the standard in every future review cycle,
    even if no new evidence were to have become available at all since the
    previous review. There is nothing in the law or in precedent that
    dictates that the standard has to be tightened as the result of a NAAQS
    review.
        CASAC's second line of reasoning comes closer to the heart of how
    EPA first set the standard. CASAC notes that there are three new acute
    studies that find PM2.5 associations with mortality at
    annual averages below the current annual standard (all with reported
    annual averages in the range of 13 to 14 m3). These studies
    are: Burnett and Goldberg (2003) for 8 Canadian cities combined; Mar et
    al. (2003) for Phoenix, and Fairley (2003) for Santa Clara County, CA
    (referred to in the risk analysis as San Jose).\11\
    ---------------------------------------------------------------------------
        \11\ CASAC actually cites a paper by Lipsett et al. (1997) in its
    letter, but that paper has nothing to do with PM2.5
    mortality. I interpret CASAC to have wanted to cite Fairley (2003).
    ---------------------------------------------------------------------------
        The first thing to realize about this part of CASAC's case for a
    tightened annual standard is that it is using studies that consider
    only how day-to-day changes in PM2.5 levels affect day-to-
    day numbers of deaths relative to the number of deaths that might
    otherwise be expected on each day (e.g., relative to numbers of deaths
    that are expected to occur on each day based on established patterns
    related to the time of year, time of week, weather, etc.). Such acute
    effects of a pollutant are generally believed to be associated with
    spikes in PM2.5, although studies to date rarely report
    evidence of any threshold level below which the association disappears.
    Nevertheless, there is no clear linkage between the annual average in a
    city, and the extent to which day-to-day spikes in PM2.5
    might be occurring. If an acute effect is found in a city that happens
    to have a low annual average, there is no reason to believe that the
    estimated association is not still due to sudden upward changes in
    PM2.5 from one day to the next. The city may simply have a
    large number of very clean days that pull the annual average
    PM2.5 down, while not eliminating the presence of many days
    of sudden increases in pollution that are logically likely to be the
    cause of any acute risk that the study is finding.
        Thus, it is not necessarily correct to assume that if acute risks
    are found in a city with a low annual average pollution, then such
    risks exist in all cities with low annual average pollution. In fact,
    if one believes that there must be a threshold where the acute risk
    from exposure to pollution drops off somewhere above zero, then the
    linkage between the annual average of pollution and existence of acute
    risk is not only unclear, but illogical. For reasons such as these, EPA
    has decided to use the plethora of acute risk studies now available to
    set the 24-hour standard that that type of study more meaningfully
    informs. EPA has decided not to use acute studies to set an annual
    standard.\12\
    ---------------------------------------------------------------------------
        \12\ See the quote on p. 5 above, taken from 71 FR 2648.
    ---------------------------------------------------------------------------
        Nevertheless, even if one were to use acute effects studies to
    determine an ``adequate margin of safety'' for lower levels of long-
    term exposure to pollution, there are good reasons to believe that the
    annual average PM2.5 reported for each of the three studies
    cited by CASAC may not be a good indicator of the long-term exposure
    levels that account for the risk findings in these studies. I explain
    why for each of the three:

        Goldberg and Burnett (2003). This study reports a PM2.5
    association for eight Canadian cities combined. The annual average of
    13.3 m3 is an average over all of the eight cities, while
    the annual averages in the individual cities vary from 9.5
    m3 to 17.7 m3. There are no city-specific results
    reported to help indicate whether the estimate of an acute effect is
    due to effects in each of the eight cities, or only in a few.\13\
    Evidence in the paper suggests that there may in fact be different
    effects in each city.
    ---------------------------------------------------------------------------
        \13\ The other multi-city PM2.5 mortality studies (based
    on the Six Cities data set) report effects by individual city as well
    as for the combined set. This was the data on which EPA set the current
    standards, and in doing so, EPA used annual averages for only the
    individual cities that did have significant effects within the set of
    six. The lowest such city was Boston, with an annual average of 15.6
    m3, which was the basis for the current annual average
    standard of 15 m3.
    ---------------------------------------------------------------------------
        Another concern with this study is that it is a reanalysis of a
    more comprehensive study that included consideration of the role of
    gaseous pollutants as well.\14\ The original study concluded that the
    gaseous pollutants had a much greater ability to explain mortality
    risks
    ---------------------------------------------------------------------------
        \14\ The original paper was Burnett et al. (2000)
    ---------------------------------------------------------------------------
        than both PM2.5 and PM10-2.5 combined.
    However, when the paper had to be reanalyzed, the authors did not
    reanalyze the portions that considered gaseous pollutants in
    conjunction with particulate pollution, and so this finding is no
    longer discussed.
        Fairley (2003). This study used data from Santa Clara County, CA,
    over a seven year period, and during that time pollution levels were
    falling dramatically. Although the annual average PM2.5 that
    is attributed to this study is 13.6 m3, the annual average
    was as high as 18.4 m3 at the start, and fell progressively
    to 9.5 m3 by the end of the 7 years studied.\15\ Peak levels
    of PM2.5 were also falling, starting at a 98th percentile of
    88 m3 for the first year and ending at 25 m3.
    Such a wide range within this one city's data set begs the question:
    are the reported acute effects relationship driven largely by the high
    levels in the early years, or are they also evident in the later years?
    This highly relevant question is never mentioned, let alone analyzed,
    by the authors. Lacking any exploration of such an obviously relevant
    issue, it would seem a dubious proposition to use the annual average
    over the entire time period in this one study as the basis for a
    national ambient standard.
    ---------------------------------------------------------------------------
        \15\ To know this, one must go back and read the original study
    that this is a reanalysis of, Fairley (1999).
    ---------------------------------------------------------------------------
        Another concern with this study is that it reports PM2.5
    risk estimates for two alternative methods of estimation, both of which
    are reasonable. One method considers whether deaths tend to fluctuate
    with the same day's PM2.5 levels and the other method
    considers whether deaths tend to fluctuate with the previous day's
    PM2.5 levels. The same-day estimate finds the positive
    association that this study is known for, but the estimate based on
    PM2.5 on just the previous day is actually in the negative
    direction. Complete reversal of evidence of a PM2.5
    mortality effect by considering PM2.5 levels only 24 hours
    apart in time presents a concern for interpreting the study's same-day
    estimate as a causal one. However, there is no discussion of what these
    conflicting results might mean.
        Mar et al. (2003). This study considered acute risks in Phoenix,
    AZ, with annual average PM2.5 levels of 13.5 m3.
    There are 10 estimates of PM2.5 risk in the paper, and only
    3 of them are significant. More importantly, this is not the only paper
    that studied the ability of this same set of PM2.5 data to
    explain acute mortality risks in Phoenix. One of the other studies
    found that PM2.5 did not have any explanatory power, and
    found instead that the coarse fraction of PM had explanatory power.\16\
    The third study found evidence that there is a threshold below which
    PM2.5's apparent ability to explain changes in daily
    mortality disappeared.\17\ That threshold appeared to be above 20
    m3. If there is a threshold, then the rationale for a
    linkage between annual average PM2.5 and acute risks simply
    falls apart.
    ---------------------------------------------------------------------------
        \16\ Clyde et al. (2000).
        \17\ Smith et al., (2000)
    ---------------------------------------------------------------------------
        A final concern with all three of the Phoenix studies is that none
    of them considered whether the PM2.5 effect would remain if
    pollutants such as CO, SO2, ozone, or NO2 were
    also included in the analysis. This is a critical gap in many of the
    current studies because the new body of papers on PM2.5
    health effects reveals that PM2.5 effects usually disappear
    when one of the gaseous pollutants is explored. This is addressed in
    the next part of my testimony.
        In summary, CASAC makes its case to tighten the annual standard on
    the basis of acute, not chronic effects studies. There are logical
    problems with this approach to setting an annual standard; these
    logical problems become apparent when looking at each of the three
    acute studies that CASAC cites as its basis for recommending an annual
    standard that is tighter than the current one.
    the statistical evidence on acute effects of pm2.5 has also
                              weakened since 1997.
        In 1997, there existed only one study that had used actual
    measurements of PM2.5 and estimated whether daily numbers of
    deaths might be associated with day-to-day variations in the
    PM2.5. This was a study using the data from the Harvard
    study of six U.S. cities reported in Schwartz et al. (1996), and it was
    used as the basis for the current standards. In that study,
    statistically significant associations of PM2.5 and acute
    mortality were found in three of the four cities with the highest 98th
    percentile PM2.5 levels, which ranged from 42 m3
    to 44 m3. The city with the highest PM2.5 98th
    percentile (which was 82 mG53) did not produce a statistically
    significant association, nor did the two cities with the lowest 98th
    percentile levels of 32 and 34 m3. This was the best
    available information at the time,. Other than the anomaly for the city
    with the highest PM2.5 exposures, it did at least suggest
    that there might be a range above which effects were more likely and
    below which they were more unlikely.
        While this study was used as the primary basis for the current
    standards (including the annual standard), there were many concerns
    expressed with uncertainties in the estimation methods. In particular,
    there was concern that this study had not considered the explanatory
    role of any of the other common pollutants like CO, SO2,
    ozone, and NO2. (These are often called the ``gaseous
    pollutants'' because that distinguishes them from various forms of
    particulate pollutants that are regulated under the PM NAAQS.) It was
    argued that PM2.5 might be simply playing a proxy role for a
    gaseous pollutant also present in the air in these cities.
        As new acute PM2.5 studies were performed after 1997, a
    number of these studies did strive to explore the respective roles of
    PM2.5 and gaseous pollutants in the observed statistical
    associations. This was done by using ``2-pollutant'' or ``multi-
    pollutant'' methods, as contrasted to the ``1-pollutant'' method that
    only allows a single pollutant (e.g., PM2.5 in this case) to
    have any opportunity to explain mortality risk. One of the little
    recognized but important insights of this body of studies is that when
    gaseous pollutants also have been considered in a study, the gaseous
    pollutant has taken over the explanatory role from PM2.5 in
    a majority of the cases.
        I determined this in my review of the studies since 1997.
    Specifically, I attempted to identify all of the PM2.5
    health effects studies cited in the Criteria Document (including both
    mortality and morbidity effects studies) that had reported results of
    any estimates for PM2.5 using a 2-pollutant method of
    estimation for at least one gaseous pollutant. I found 10 such papers
    among all the new studies that did report a statistically significant
    association for PM2.5. Of these 10, 8 saw PM2.5
    lose its ability to explain mortality risk when studied using a 2-
    pollutant method. (In the other two studies, both the PM2.5
    and gaseous pollutant retained statistical explanatory power.)
        Often it is suggested that 2-pollutant methods are not useful
    because it is impossible to unravel the effects of two pollutants that
    both move up and down together in near synchrony (i.e., they are highly
    ``correlated''). However, my review of these papers did not find
    evidence that this was a problem. If it were a problem, then both the
    PM2.5 and gaseous pollutant would lose their explanatory
    power. What I found instead was that in seven of the eight studies
    where PM2.5 lost its erstwhile explanatory power when it was
    the only pollutant considered, the gaseous pollutant retained its
    explanatory power. Otherwise stated, of the ten studies that I started
    with, only one seemed to be affected by intractable statistical
    problems making it impossible to unravel the separate effects of the
    two pollutants.
        These papers are summarized in Table 2, which is more fully
    explained in my written comments to EPA of April 2006, which I am
    submitting with this testimony.

    [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

        The above findings represent just one of many ways that the new
    body of acute effects evidence has been found to vary depending on the
    particular method of estimation. Other sources of variation in the
    evidence include the methods for accounting for time and weather
    considerations. The new studies have demonstrated that concerns with
    variability of epidemiological estimates of risk, which were expressed
    but not well explored in 1997, are real. Table 1 at the beginning of my
    testimony shows that even the ``best'' PM2.5 health effects
    studies that EPA could select for its risk analysis present a highly
    uncertain picture of whether PM2.5 is playing a causal role
    for acute effects. Even if there is a causal relationship, which is
    what the current standard assumed when EPA set it in 1997, there
    appears to be great difficulty in determining what the size of the
    effect is. The one trend that is clear is that the size of the
    PM2.5 acute mortality estimates found in the many new
    studies since 1997 are generally lower than the estimates that were
    available when the current standards were set.
        As I have already noted, EPA has chosen to use an evidence-based
    approach to set the 24-hour standard. EPA has proposed to tighten the
    24-hour standard from the current level of 65 m3 to 35
    m3. This decision was made even though the quantitative risk
    estimates based on these studies are lower and statistically weaker
    than they were when the standard was set. Nevertheless, it is true that
    there are many more studies available now than at the time of the
    standard, and it is relevant to ask if this new body of evidence might
    provide a better indication of a 98th percentile PM2.5 level
    where observed effects start to drop off. EPA has attempted to make
    such a case for a cut-off point of 35 m3 in the Proposed
    Rule.\18\ I have gone through that case very carefully, and I have
    found it incomplete. I will state what I found in general terms
    here.\19\
    ---------------------------------------------------------------------------
        \18\ See 71 FR 2649.
        \19\ My written comments to EPA that are being submitted into the
    record with this testimony provide complete documentation of my review
    of the literature and application of an evidence-based approach for the
    24-hour standard. Although the full discussion includes both mortality
    and morbidity studies, I only summarize the mortality findings here.
    However, the patterns I describe are similar in studies of
    hospitalizations, emergency room visits, and frequency of ``symptoms''
    that are not severe enough to entail a hospital visit.20 Further,
    although a majority of estimates are statistically significant because
    the paper focused on the lag period that was found to be significant in
    the simplest, 1-pollutant starting point of the analysis, the single
    other alternative 1-pollutant result found a negative risk estimate,
    implying no risk at all.
    ---------------------------------------------------------------------------
        EPA's verbal summary of its evidence-based approach used a selected
    subset of ten PM2.5 mortality studies. I found another eight
    such acute studies of United States or Canadian mortality cited in the
    Criteria Document, that used actual measurements of PM2.5,
    and that did not appear to have any unreanalyzed statistical problems
    associated with the GAM software. (If a single paper reports results
    for more than one city, I treat each city as a separate ``study''.) Six
    of the eighteen studies that I considered are the original ``Six
    Cities'' used to set the current standard. All of the others are
    studies published between 1997 and the cut-off time for consideration
    in this review cycle.
        I read each study, and determined whether all the PM2.5
    estimates reported in a study were ``more often insignificant than
    significant'', ``a near 50-50 mix'', or ``more often significant than
    insignificant.'' After categorizing them in this way, I found that
    there is no clear pattern where statistically significant results tend
    to be found for studies with higher PM2.5 levels, and that
    increasingly mixed evidence is found in studies with progressively
    lower PM2.5 levels. Figure 3 graphically summarizes my
    findings for the mortality studies. It shows that many of the data sets
    with the highest 24-hour average PM2.5 levels demonstrate
    the least likelihood of a statistically-significant association with
    mortality. This is contrary to what EPA states in its discussion of the
    evidence-based approach in the Proposed Rule. I attribute the
    difference to the fact EPA considered only a selected set of the new
    studies, and not the more complete set that I identified. (The ten
    studies EPA considered are shown as blue diamonds in Figure 3, while
    the additional eight studies that I also considered are shown as red
    diamonds in Figure 3.)
        Figure 3 also shows that I determined that only 3 of the 18 studies
    found statistically significant PM2.5 effects for a majority
    of the methods of estimation that they reported. Of these:

         One is for eight Canadian cities combined by Goldberg and Burnett
    (2003), which I described earlier in this testimony. Its 98th
    percentile value is about 39 m3, but this value has the same
    flaw that I described for its annual average--the actual peak exposures
    faced by people in the eight separate cities ranged from 27 to 48
    m3, and there is no information to indicate which of the
    various city-specific 98th percentiles might be accounting for the
    effects estimated when all cities are combined.
         Another of these was Fairley (2003) for Santa Clara County, CA,
    with a 98th percentile value of 59 m3, which I also
    discussed above. This study had very high exposures at first, and we
    have no idea whether the statistical significance is related to the
    earlier high levels, or equally attributable to later, lower
    PM2.5 peaks.\20\
    ---------------------------------------------------------------------------
        \20\ Furthery, although a majority of estimates are statistically
    significant because the paper focused on the lag period that was found
    to be significant in the simplest, 1-pollutant starting point of the
    analysis, the single other alternative 1-pollutant result found a
    negative risk estimate, implying no risk at all.
    ---------------------------------------------------------------------------
         The third is the Boston data from the Harvard Six Cities study
    that served as the basis for the current PM2.5 NAAQS in
    1997. The magnitude and statistical significance of the association
    observed in this data set has been reduced in reanalyses since 1997,
    and none of these estimates include consideration of the potential role
    of any gaseous pollutants in explaining these associations.

    [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

        In conclusion, the evidence regarding a causal relationship between
    short-term exposures to PM2.5 and health has not
    strengthened since 1997. To draw this conclusion, one must consider
    more than just the number of new studies that have reported at least
    one statistically significant association; one must also explore the
    extent to which the effects reported in these studies remain
    statistically significant under a range of different plausible methods
    for making such estimates. In particular, the new evidence strongly
    suggests that many or most of these associations may actually be
    attributable to a gaseous pollutant, not PM2.5.
        But even setting aside the weaknesses in the statistical evidence,
    EPA's evidence-based approach for where to set a 24-hour standard for
    PM2.5 leads us right back to the very data set on which the
    current PM2.5 NAAQS were based in the Boston ``Six Cities''
    data set. Thus, the evidence-based approach that EPA is trying to apply
    provides little additional insight beyond the simple point that I
    started my testimony with: the quantitative estimates of risks
    remaining at the current standards are lower now than when they were
    determined to offer an ``adequate margin of safety.'' They therefore do
    not support a tightening of the current NAAQS.
          integrated analyses of alternative results may help inform
                             naaqs decisions better
        It is easy to feel lost regarding how to effectively interpret a
    plethora of alternative studies, and of alternative risk estimates
    within each study. EPA's method in performing risk analyses has been to
    rely on a single estimate that it selects from the large pool of
    alternatives, and to base its summaries of quantitative risk estimates
    on that single estimate. In many of these summaries, even the
    statistical errors associated with that one estimate are often not
    reported. Some, but not all, of the remaining alternative estimates are
    studied through ``sensitivity analyses.'' However, these are usually
    relegated to the back pages of a technical support document. The result
    of this approach is that the degree of certainty about the risk
    estimates becomes greatly overstated by the time summary results reach
    the eyes of decision makers, advisors, and the public. Further, the
    method of selecting the single risk estimate to rely on for the primary
    analysis can lead to a substantial bias in the quantitative risk
    estimates reported.
        There are alternative methods for performing risk assessments that
    integrate multiple alternative risk estimates, and even key
    uncertainties that remain purely judgmental. These methods are
    sometimes called probabilistic analysis, or integrated uncertainty
    analysis. EPA has not used such methods in the documents supporting the
    Administrator's decision on the PM2.5 NAAQS, such as the
    Staff Paper. I believe that such methods could be very useful, and
    would reveal better the true extent of uncertainty that I have tried to
    characterize qualitatively in my testimony above.
        In 2003, at an early stage of the drafting of the current risk
    assessment, I prepared some illustrative examples of an integrated
    uncertainty analysis to show how the reams and reams of sensitivity
    results in the risk assessment document could be condensed to more
    decision-relevant information. The results of that illustrative
    analysis remain of some interest:

         Using just the alternative long-term exposure studies in the
    Criteria Document, I found that there could be about a 40 percent
    probability that there would be no long-term mortality benefit from
    tightening the current NAAQS. I also estimated that the probability
    that actual longterm mortality would be less than the primary risk
    estimate that EPA reports in its risk analysis is about 75 percent.
         I did a less thorough example for the short-term mortality risk,
    based only on Los Angeles. (Short-term risk estimates and their
    uncertainty vary by city). For Los Angeles, I estimated a 42 percent
    probability there would be no benefits from tightening the standard
    from the current level when using only the risk estimates that EPA had
    itself cited in its risk analysis, and a 64 percent probability that
    acute risk reductions would be lower than EPA's primary risk
    estimate.\21\
    ---------------------------------------------------------------------------
        \21\ For documentation of these calculations, see Smith (2003).

        These probability estimates were based solely on actual estimates
    in the new body of literature on PM2.5 mortality, and do not
    include any external judgments such as whether any of these estimates
    can be interpreted as causal, whether some particles are more toxic
    than others, or the hypothetical presence of a threshold.
    (Consideration of these issues would raise the probabilities that I
    calculated.) They are strictly based in the published evidence reviewed
    in the Criteria Document. They are thus indicative of the degree of
    uncertainty that the published studies themselves reveal.
        I believe that the process of decision making leading up to the
    point where a new rule is proposed would benefit greatly if such a
    synthesis of statistical and modeling uncertainties were to be
    developed as a part of that process. Controversies would remain
    regarding the judgments that are necessary for such estimates, but if
    they are conducted in an open manner, with ample opportunity for public
    review and comment, more insight about the overall implications of the
    body of scientific evidence would be created before a decision must be
    made than we have at the present moment. I emphasize that this should
    be done during the NAAQS review cycle, with opportunities for public
    review and comment, before a rule is proposed.
                                     ______

             Responses by Anne Smith to Additional Questions from
                               Senator Voinovich
        Question 1. As you stated in your statement, EPA, Dr. Thurston, and
    others seem to be ignoring your argument that the acceptable level of
    risk identified in 1997 has gone down. This is a very intuitive and
    convincing argument. If risk has gone down, then the standard should
    not be revised. I would like to give you more time to explain this
    argument and respond to the other side.
        Response. The current standards for PM2.5 were set by
    EPA in 1997 with full knowledge that these standards would not reduce
    health risks to zero. The risk analysis produced by EPA at that time
    reported positive estimates of risk remaining at the current standard.
    EPA's risk analysis also explicitly estimated lower levels of risk for
    alternative, tighter standards than the standard that EPA ultimately
    selected. EPA had to defend the risk level that it adopted in court.
    The DC Circuit Court of Appeals ruled that the risks associated with
    the current PM2.5 standards were ``requisite'' to protect
    the public health with an adequate margin of safety, as required by the
    Clean Air Act.\1\ ( ``Requisite" means that the standards are ``not
    lower or higher than is necessary'' to protect public health with an
    adequate margin of safety.\2\) Thus, the level of risk estimated in
    1997 for the current standards was associated with an adequate margin
    of safety.
    ---------------------------------------------------------------------------
        \1\ United States Court of Appeals for the District Of Columbia
    Circuit in American Trucking Associations, Inc., et al., v.
    Environmental Protection Agency, No. 97-1440, March 26, 2001.
        \2\ Ibid, p. 10.
    ---------------------------------------------------------------------------
        As I wrote in my statement: ``In thinking about whether to tighten
    either the annual or daily standard, one might ask, what has changed in
    our knowledge since 1997 that would undermine the Administrator's 1997
    judgment that the current PM2.5 NAAQS are neither more nor
    less stringent than necessary to protect the public health with an
    adequate margin of safety? A thorough review of the new evidence
    suggests that the margin of safety that the Administrator selected in
    1997 is likely to be larger than was thought at the time."
        As I documented in my written testimony to the Committee, EPA's own
    estimates of health risks remaining at the current standards are lower
    now than the earlier 1997 estimates. They are lower in all cities for
    long-term exposure risks, and they are lower for short-term exposure
    risks in 6 of the 8 cities that are in the current risk analysis.
        I presented my comparison of risk estimates from 1997 to those
    estimated today in person to EPA air office staff on several occasions,
    and never heard any disagreement regarding its factual accuracy. I have
    never heard secondhand of EPA staff disagreeing with these facts in any
    subsequent meetings or conversations where I was not present. I also
    submitted detailed documentation of the risk comparisons in my written
    comments to EPA on the draft risk analysis documents and staff paper
    for PM2.5. However, EPA did not provide any such comparative
    analysis to its Clean Air Scientific Advisory Committee (CASAC) during
    the course of CASAC's deliberations leading up to CASAC's
    recommendation to EPA for tightening the PM2.5 standards.
    Thus, CASAC members were probably unaware of these facts when they made
    their recommendation.\3\
    ---------------------------------------------------------------------------
        \3\ Although my risk comparisons are based on material that EPA
    placed into the record during both the 1997 and current rulemakings,
    CASAC could not be expected to have easily made such comparisons on
    their own. For one, the relevant measures of risk are not readily
    observed given the formats in which EPA has presented its risk
    findings. Further, they require one to consult risk analysis documents
    from 10 years ago.
    ---------------------------------------------------------------------------
        EPA is clearly aware of these facts, however, and even partially
    acknowledged them at the time that it published the Federal Register
    notice for the proposed new PM2.5 standards:

        With respect to short-term exposure mortality and morbidity . . .
    [c]omparing the risk estimates for the only two specific locations that
    were included in both the prior and current assessments, the magnitude
    of the estimates associated with just meeting the current annual
    standard, in terms of percentage of total incidence, is similar in one
    of the locations (Philadelphia) and the current estimate is lower in
    the other location (Los Angeles).  . . . With respect to long-term
    exposure mortality risk estimates, the estimates in terms of percentage
    of total incidence are very similar for the two specific locations
    included in both the prior and current assessments.\4\
    ---------------------------------------------------------------------------
        \4\ PR, p. 2640.
    ---------------------------------------------------------------------------
        This quote is only a partial acknowledgment of the risk comparison,
    however, because it only mentions two cities' risk estimates, and for
    those two cities, one risk estimate rose and the other fell. However,
    there were actually 8 cities in the current risk analysis, and the risk
    estimate has fallen in 6 of those 8. Further, the statement that risk
    estimates are ``similar'' for long-term exposure does not reveal that
    the current risk estimate is actually lower. Notably, this statement
    was made only after EPA had finalized the Staff Paper, and after CASAC
    had made its recommendations.
        Dr. Thurston, in his testimony before the committee, attempted to
    rebut my argument in the following way:

        You know, I think that unfortunately what Dr. Smith has done here
    is exactly what she accuses EPA of having done. She has cherry- picked
    certain results that support her position and unfortunately hasn't
    looked in a balanced unbiased way at this question.\5\
    ---------------------------------------------------------------------------
        \5\ EPW Committee Hearing transcript, July 19, 2006.
    ---------------------------------------------------------------------------
        This is a completely false statement, as anyone should be able to
    tell from the record of the hearing: my comparison is based only on
    EPA's own numbers. All that I have done is assemble the information
    from EPA documents and repeat it in a format that allows a direct
    comparison. I made this clear in my own oral statement:

        Risks due to long-term mortality have fallen in every location. The
    risks due to daily exposure, which vary by city, have fallen in six of
    the eight cities that are in EPA's risk analysis. This new information
    suggests that the margin of safety provided by the current standards is
    actually greater than we originally thought. What I have told you so
    far is based entirely on EPA's own point estimates of risk.\6\
    ---------------------------------------------------------------------------
        \6\ Ibid, emphasis added.
    ---------------------------------------------------------------------------
        Dr. Thurston's comment is an attempt to sidestep the inconvenient
    truth that even EPA's analyses support the conclusion that the
    estimates of mortality risk associated with the current ambient
    PM2.5 standard have fallen since the time that they were
    deemed acceptable by EPA and the Court. His sidestepping tactic may be
    useful in a purely oral exchange, but the transcript makes it clear
    that his comment has no substance or merit in refuting my argument.
        I did go on to describe how the evidence on lower risk estimates is
    even stronger when one looks at the full body of evidence in the
    studies that have been released since 1997, rather than just using
    EPA's own numbers. However, it is illogical to claim that I have
    ``cherry-picked'' the evidence when I show that the downward risk
    trends would be more pronounced if I use almost any other risk estimate
    than those used by EPA. This is the opposite of cherry-picking.
        I would also like to directly address Dr. Thurston's own argument
    that there is new evidence to support tightening the annual standard.
    The essence of his argument is that further analyses of the American
    Cancer Society study find that there is no evidence of a threshold in
    the long-term exposure risk data below the level of the current annual
    standard. He presents a figure (Figure 3 in his written testimony),
    that indicates that the risks from PM2.5 exposure extend
    below 15 m3, supporting a reduction in the annual
    PM2.5 standard at this time.\7\ While it is true that this
    specific figure had not been produced at the time that the current
    annual standard was established, it does not provide a case for
    tightening the standard to a level below 15 m3. Dr.
    Thurston's implicit premise is that the PM2.5 standard
    should be a zero-risk standard, which was not and still is not the
    premise of EPA (and upheld by the Court). Moreover, EPA assumed that a
    causal relationship between PM2.5 and long-term mortality
    risk did exist down to 9 m3
    ---------------------------------------------------------------------------
        \7\ Statement of Dr. George D. Thurston, Sc. D. to the Committee on
    Environment and Public Works of the United States Senate RE: the
    Science and Risk Assessment of Particulate Matter (PM) Air Pollution
    Health Effects, July 19, 2006.
    ---------------------------------------------------------------------------
        in its risk analyses when it chose to set the annual standard at 15
    m3. Thus, the ``new'' information that Dr. Thurston says
    supports reducing the standard to a lower level was already assumed to
    exist in the 1997 risk analyses.

        Question 2. Your testimony indicates that EPA has selectively used
    study results in developing the proposal. EPA emphasized studies that
    show associations between particulates and negative health effects and
    ignored those that do not. You also point out that in many of the
    studies relied upon, the associations become statistically
    insignificant when another pollutant is included in the analysis.
    Please elaborate.
        Response. Each of the epidemiological studies of PM2.5
    risk contains many different alternative estimates of risk. Different
    estimates of risk are possible because the researchers have to specify
    what set of risk factors in addition to PM2.5 will be
    simultaneously accounted for when estimating the quantitative amount of
    risk that is associated with PM2.5. For example, one can
    estimate a PM2.5 risk level with or without also including
    the humidity level. PM2.5 concentrations may tend to be
    higher on days of higher humidity, yet humidity is known to be a
    physiological stressor and there is an established increased risk of a
    sick individual dying on the relatively more humid days of a year. If
    humidity is left out of the analysis, then PM2.5 could serve
    as a ``proxy'' for the missing humidity information, and this could
    bias the level of risk estimated for PM2.5 upwards. All of
    the current studies take care to address humidity, because its role as
    a stressor is so well established. However, there is no objective
    method for determining exactly how to specify humidity. Further, there
    are many alternative ways to specify a wide range of other factors that
    also need to be accounted for to avoid bias in the PM2.5
    effect, and not all of the relevant health stressors are known. Thus,
    researchers tend to try different methods for incorporating non-
    PM2.5 determinants of health, and each different method
    results in a different PM2.5 risk estimate.
        Sometimes two seemingly comparable methods produce dramatically
    different results. For example, the study of PM2.5 risk in
    Santa Clara County, CA by Fairley (2003) reports results of two
    estimates that differ in one single way: in one case, mortality risk
    one a particular day was compared to PM2.5 levels on the
    same day, and in the second, mortality risk on each day was compared to
    PM2.5 levels that occurred the day before.\8\ The first of
    these finds a positive and statistically significant association
    between rises in PM2.5 and mortality risk. The second finds
    the opposite: a negative association (i.e., mortality risk tended to be
    lower if PM2.5 on the day before had been relatively high).
    There is no objective statistical means for determining whether one of
    these statistical findings is closer to the truth than the other, but
    they produce extremely different estimates of health risk from ambient
    PM2.5. In this case, EPA has selected the positive and
    statistically significant result for use in its risk analysis, and EPA
    makes no mention of the opposite alternative result that it could have
    selected from the same paper.
    ---------------------------------------------------------------------------
        \8\ Fairley, D. (2003) Mortality and Air Pollution for Santa Clara
    County, CA, 1989-1996 Revised Analyses of Time-series Studies of Air
    Pollution and Health, Special Report. Boston, MA: Health Effects
    Institute; pp. 97-106.
    ---------------------------------------------------------------------------
        One important class of researcher judgments where very different
    risk estimates can result is that related to ``single-pollutant''
    versus ``multi-pollutant'' estimation methods. Most commonly, the only
    pollutant that is included in the statistical estimation procedure is
    PM2.5 (at least, in studies that report PM2.5
    risk estimates). If any other pollutant has an association with
    mortality risks, then PM2.5 will be the only pollutant that
    could adopt its explanatory power and it will do so if PM2.5
    is statistically correlated with the missing pollutant. As a result,
    the PM2.5 risk estimate will be biased, and may appear
    falsely to be statistically significant. In a multi-pollutant
    statistical estimation procedure, PM2.5 and one or more
    other pollutants are all included in the analysis at the same time.
    Then, each can account for its own role as a health stressor, and the
    resulting estimates for each pollutant, including PM2.5, are
    less likely to be biased.
        I attempted to identify all of the PM2.5 health effects
    studies cited in the Criteria Document (including both mortality and
    morbidity effects studies) that had reported results of any estimates
    for PM2.5 using a multi-pollutant method of estimation for
    at least one gaseous pollutant. I found ten such papers among all the
    new studies that did report a statistically significant association for
    PM2.5. Of these 10, 8 found that PM2.5 lost its
    ability to explain mortality risk when studied using a 2-pollutant
    method. (In the other two studies, both the PM2.5 and
    gaseous pollutant retained statistical explanatory power.) This
    suggests a reasonable concern that PM2.5 may not be the
    pollutant that is actually causing the reported health risks. However,
    EPA's risk analysis is relying solely on the one-pollutant results from
    each of these papers, and thus is overstating the degree of confidence
    in these results. Notably, 2 of the 8 cities in EPA's risk analysis are
    being estimated using single-pollutant estimates from papers that also
    reported that PM2.5 risk estimates are not statistically
    significant if estimated in a two-pollutant model: Los Angeles and
    Philadelphia.\9\, \10\ In both cases, the authors concluded that a
    different pollutant had more explanatory power than PM2.5,
    yet EPA has used only the obviously biased estimate of PM2.5
    risk that came from the single-pollutant methods that the original
    researchers have repudiated. (Even with use of the one-pollutant
    estimate, EPA's mortality risk estimate for Los Angeles is not
    statistically significant.)
    ---------------------------------------------------------------------------
        \9\ Moolgavkar, S. H. (2003) "Air Pollution and Daily Deaths and
    Hospital Admissions in Los Angeles and Cook Counties" Revised Analyses
    of Time-series Studies of Air Pollution and Health, Special Report
    Boston, MA: Health Effects Institute; pp. 183-198.
        \10\ Lipfert, F. W.; Morris, S. C.; Wyzga, R. E. (2000a) Daily
    Mortality in the Philadelphia Metropolitan Area and Size-classified
    Particulate Matter Journal of the Air & Waste Management Association
    15011513.
    ---------------------------------------------------------------------------
        In my response so far, I have explained how EPA has been selective
    in the way it has made risk estimates for 3 of the 8 cities in its
    mortality risk assessment (i.e., for Santa Clara County/San Jose,
    Philadelphia, and Los Angeles). Problems with the remaining 5 cities
    risk estimates also deserve mention:

         For both Pittsburgh and Detroit, the risk estimate that EPA uses
    is not statistically significant.\11\, \12\
    ---------------------------------------------------------------------------
        \11\ Chock, D. P.; Winkler, S.; Chen, C. (2000) A Study of the
    Association Between Daily Mortality and Ambient Air Pollutant
    Concentrations in Pittsburgh, Pennsylvania Journal of the Air & Waste
    Management Association 50: 1481-1500.
        \12\ Ito, K. (2003) Associations of Particulate Matter Components
    with Daily Mortality and Morbidity in Detroit, Michigan. Revised
    Analyses of Time-series Studies of Air Pollution and Health. Special
    report. Boston, MA: Health Effects Institute; pp. 143-156.
    ---------------------------------------------------------------------------
         For Phoenix, there are 2 other papers by other authors that use
    the same PM2.5 data set.\13\ One of the other papers finds
    no PM2.5 association at all (but does find a coarse fraction
    association).\14\ The third paper reports a PM2.5
    association only above a threshold. EPA's risk assessment does not
    include such a threshold.\15\
    ---------------------------------------------------------------------------
        \13\ The paper EPA relies on is: Mar, T. F.; Norris, G. A.; Larson,
    T. V.; Wilson, W. E.; Koenig, J. Q. (2003) ''Air Pollution and
    Cardiovascular Mortality in Phoenix, 1995-1997'' Revised Analyses of
    Time-series Studies of Air Pollution and Health, Special Report Boston,
    MA: Health Effects Institute; pp. 177-182.
        \14\ Clyde, M. A.; Guttorp, P.; Sullivan, E. (2000) ''Effects of
    Ambient Fine and Coarse Particles on Mortality in Phoenix, Arizona''
    Seattle, WA: University of Washington, National Research Center for
    Statistics and the Environment; NRCSE technical report series, NRCSE-
    TRS no. 040.
        \15\ Smith, R. L.; Spitzner, D.; Kim, Y.; Fuentes, M. (2000)
    ''Threshold Dependence of Mortality Effects for Fine and Coarse
    Particles in Phoenix, Arizona'' Journal of the Air & Waste Management
    Association 50: 1367-1379.
    ---------------------------------------------------------------------------
         Risk estimates for both St. Louis and Boston are based on single-
    pollutant methods because the researchers do not report any multi-
    pollutant methods at all.\16\, \17\ However, for both cities, the
    authors do report a number of different PM2.5 risk estimates
    using different ways of accounting for non-pollutant variables that
    also account for changes in mortality risk and EPA has adopted the
    estimate for each city that produces the highest level of
    PM2.5 risk. Several of the alternative estimates are also
    not statistically significant (particularly for St. Louis). There is no
    reason to expect those higher risk estimates to be more valid than the
    alternative estimates reported by the researchers. In summary, there is
    a substantial amount of uncertainty associated with risk estimates for
    all eight of the cities in EPA's current risk assessment. The way EPA
    has selected a single risk estimate out of the many estimates provided
    in the original epidemiological studies for each city has a clear
    tendency to overstate the level of PM2.5 mortality risk and
    to understate the uncertainties.
    ---------------------------------------------------------------------------
        \16\ Klemm, R. J.; Mason, R. (2003) ``Replication of Reanalysis of
    Harvard Six-City Mortality Study.'' Revised Analyses of Time-series
    Studies of Air Pollution and Health. Special report. Boston, MA: Health
    Effects Institute; pp. 165-172.
        \17\ Schwartz, J. (2003) ``Daily Deaths Associated with Air
    Pollution in Six US Cities and Short-term Mortality Displacement in
    Boston'' Revised Analyses of Time-series Studies of Air Pollution and
    Health. Special report. Boston, MA: Health Effects Institute; pp. 219-
    226.

        Question 3. Please summarize the concerns that you have with the
    three studies that CASAC relied on in recommending a tightened annual
    standard.
        Response. CASAC notes that there are three new acute studies that
    find PM2.5 associations with mortality at annual averages
    below the current annual standard (all with reported annual averages in
    the range of 13 to 14 g/m3). Most importantly, there are
    logical flaws in setting an annual standard based on studies of daily
    mortality risk. Acute risks are associated with increases in
    PM2.5 on certain days and there is no logical link between
    the the annual average conditions at a given location and the riskiness
    of spikes in PM2.5 at that location.
        However, even if one were to want to set an annual standard based
    on short-term exposure risk studies, each of these papers presents
    reasons to be concerned about the prospect of using them as the basis
    for a national standard:

        Goldberg and Burnett (2003).\18\ This study reports a
    PM2.5 association for eight Canadian cities combined. The
    annual average of 13.3 m3 is an average over all of the
    eight cities, while the annual averages in the individual cities vary
    from 9.5 m3 to 17.7 m3. There are no city-
    specific results reported to help indicate whether the estimate of an
    acute effect is due to effects in each of the eight cities, or only in
    a few.\19\ Evidence in the paper suggests that there may in fact be
    different effects in each city.
    ---------------------------------------------------------------------------
        \18\ Burnett, R. T.; Goldberg, M. S. (2003) ``Size-fractionated
    Particulate Mass and Daily Mortality in Eight Canadian Cities.''
    Revised Analyses of Time-series Studies of Air Pollution and Health.
    Special report. Boston, MA: Health Effects Institute; pp. 85-90.
        \19\ The other multi-city PM.5 mortality studies (based
    on the Six Cities data set) report effects by individual city as well
    as for the combined set. This was the data on which EPA set the current
    standards, and in doing so, EPA used annual averages for only the
    individual cities that did have significant effects within the set of
    six. The lowest such city was Boston, with an annual average of 15.6
    um3, which was the basis for the current annual average
    standard of 15 m3.
    ---------------------------------------------------------------------------
        Another concern with this study is that it is a reanalysis of a
    more comprehensive study that included consideration of the role of
    gaseous pollutants as well.\20\ The original study concluded that the
    gaseous pollutants had a much greater ability to explain mortality
    risks than both PM2.5 and PM10-2.5 combined.
    However, when the paper had to be reanalyzed, the authors did not
    reanalyze the portions that considered gaseous pollutants in
    conjunction with particulate pollution, and so this finding is no
    longer discussed.
    ---------------------------------------------------------------------------
        \20\ Burnett, R. T.; Brook, J.; Dann, T.; Delocla, C.; Philips, O.;
    Cakmak, S.; Vincent, R.; Goldberg, M. S.; Krewski, D. (2000)
    ''Association Between Particulate- and Gas-phase Components of Urban
    Air Pollution and Daily Mortality in Eight Canadian Cities'' In: Grant,
    L. D., ed. PM2000: Particulate Matter and Health. Inhalation Toxicology
    12(suppl. 4): 15-39.
    ---------------------------------------------------------------------------
         Fairley (2003).\21\This study used data from Santa Clara County,
    CA, over a seven year period, and during that time pollution levels
    were falling dramatically. Although the annual average PM2.5
    that is attributed to this study is 13.6 m3, the annual
    average was as high as 18.4 m3 at the start, and fell
    progressively to 9.5 m3 by the end of the 7 years
    studied.\22\ Peak levels of PM2.5 were also falling,
    starting at a 98th percentile of 88 m3 for the first year
    and ending at 25 m3. Such a wide range of PM2.5
    levels within this one city's data set begs the question: Are the
    reported acute effects relationship driven largely by the high levels
    in the early years, or are they also evident in the later years? This
    highly relevant question is never mentioned, let alone analyzed, by the
    authors. Lacking any exploration of such an obviously relevant issue,
    it would seem a dubious proposition to use the annual average over the
    entire time period in this one study as the basis for a national
    ambient standard.
    ---------------------------------------------------------------------------
        \21\ Fairley, op. cit.
        \22\ To know this, one must go back and read the original study
    that Fairley (2003) reanalyzes: Fairley, D. (1999) Daily Mortality and
    Air Pollution in Santa Clara County, CA: 1989-1996? Environmental
    Health Perspectives 107: 637-641.
    ---------------------------------------------------------------------------
        Another concern with this study is that it reports PM2.5
    risk estimates for two alternative methods of estimation, both of which
    are reasonable. One method considers whether deaths tend to fluctuate
    with the same day's PM2.5 levels and the other method
    considers whether deaths tend to fluctuate with the previous day's
    PM2.5 levels. The same-day estimate finds the positive
    association that this study is known for, but the estimate based on
    PM2.5 on just the previous day is actually in the negative
    direction. Complete reversal of evidence of a PM2.5
    mortality effect by considering PM2.5 levels only 24 hours
    apart in time presents a concern for interpreting the study's same-day
    estimate as a causal one. However, there is no discussion of what these
    conflicting results might mean.
         Mar et al. (2003).\23\ This study considered acute risks in
    Phoenix, AZ, with annual average PM2.5 levels of 13.5
    m3. There are ten estimates of PM2.5 risk in the
    paper, and only three of them are significant. More importantly, this
    is not the only paper that studied the ability of this same set of
    PM.5 data to explain acute mortality risks in Phoenix. One
    of the other studies found that PM2.5 did not have any
    explanatory power, and found instead that the coarse fraction of PM had
    explanatory power.\24\ The third study found evidence that there is a
    threshold below which PM2.5's apparent ability to explain
    changes in daily mortality disappeared.\25\ That threshold appeared to
    be above 20 m3. If there is a threshold, then the rationale
    for a linkage between annual average PM2.5 and acute risks
    simply falls apart.
    ---------------------------------------------------------------------------
        \23\ Mar et al., op. cit.
        \24\ Clyde et al., op. cit.
        \25\ Smith et al., op. cit.
    ---------------------------------------------------------------------------
        A final concern with all three of the Phoenix studies is that none
    of them considered whether the PM2.5 effect would remain if
    pollutants such as CO, SO2, ozone, or NO2 were
    also included in the analysis. This is a critical gap in many of the
    current studies because the new body of papers on PM2.5
    health effects reveals that PM2.5 effects usually disappear
    when one of the gaseous pollutants is explored. (My response to
    Question 2 above addresses this point in more detail.)
                                   __________
         Statement of John Stephenson, Director, Natural Resources and
                Environment, U.S. General Accountability Office
        Mr. Chairman and members of the committee, I am pleased to be here
    today as the committee considers the science and risk assessment
    supporting the Environmental Protection Agency's (EPA) proposed
    revisions to the national air quality standards for particulate matter.
    A large body of scientific evidence links exposure to particulate
    matter a ubiquitous form of air pollution commonly referred to as soot
    to serious health problems, including asthma, chronic bronchitis, heart
    attack, and premature death. Under the Clean Air Act, EPA periodically
    reviews the appropriate air quality level at which to set national
    standards to protect the public against the health effects of
    particulate matter. As you are aware, EPA proposed revisions to the
    particulate matter standards in January 2006 and issued a draft
    regulatory impact analysis of the revisions expected costs and
    benefits.
        EPA's estimates of the expected benefits from its air pollution
    regulations have often been controversial, and the methods the agency
    has used to prepare these estimates have been questioned. In 2000, at
    the direction of the Senate Appropriations Committee, EPA asked the
    National Academies (Academies) to evaluate EPA's overall methodology
    for estimating the health benefits of proposed air regulations. In
    2002, the Academies issued a report that made recommendations focusing
    on con ducting more rigorous assessments of uncertainty, increasing the
    transparency of how EPA estimates benefits, conducting more detailed
    analyses of exposure, and estimating the benefits of each regulatory
    option under consideration. My testimony summarizes the highlights of
    our report being released today on the extent to which EPA applied the
    recommendations made by the Academies to its January 2006 proposed
    revisions to the particulate matter standards.\1\ Our report provides a
    more detailed discussion of each recommendation, including whether and
    how EPA applied it to the regulatory impact analysis on particulate
    matter.
    ---------------------------------------------------------------------------
        \1\ See GAO, Particulate Matter: EPA Has Started to Address the
    National Academies Recommendations on EstimatingHealth Benefits, but
    MoreProgress Is Needed, GAO-06-780 (Washington, DC: July 14, 2006).
    ---------------------------------------------------------------------------
                                    summary
        While the National Academies report generally supported EPA's
    overall approach to estimating benefits, it included 34 recommendations
    for improvements. EPA has begun to change the way it conducts and
    presents its analyses of health benefits in response to the National
    Academies? recommendations. In the case of the January 2006 proposed
    rule on particulate matter standards, EPA applied, at least in part,
    about two-thirds of the recommendations to its particulate matter
    health benefit analysis; it applied 8 and partially applied 14 more.
    For example, in applying the recommendations, EPA evaluated how
    benefits might change given alternative assumptions and discussed
    sources of uncertainty not included in the benefit estimates. In
    addition, EPA applied an alternative technique for evaluating one
    important source of uncertainty in its analysis the uncertainty
    underlying the causal link between exposure to particulate matter and
    premature death. Consistent with the National Academies recommendation
    to assess uncertainty by developing ranges of estimates of benefits and
    specifying the likelihood of attaining those levels of benefits, EPA
    systematically gathered expert opinions about this link and developed
    ranges reflecting the experts confidence in attaining reductions in
    premature death expected from the proposed revisions. However, the
    health benefit analysis did not assess how the benefit estimates would
    vary in light of other key uncertainties as the Academies recommended.
    Consequently, EPA's response represents a partial application of the
    recommendation. Agency officials told us that ongoing research and
    development efforts will allow EPA to gradually make more progress in
    applying this and other recommendations to future analyses.
        EPA did not apply the remaining 12 recommendations to the analysis,
    such as the recommendation to evaluate the impact of using the
    assumption that the components of particulate matter are equally toxic.
    EPA officials viewed most of these 12 recommendations as relevant to
    its health benefit analyses but noted that the agency was not ready to
    apply specific recommendations because of, among other things, the need
    to overcome technical challenges stemming from limitations in the state
    of available science. For example, EPA did not believe that the state
    of scientific knowledge on the relative toxicity of particulate matter
    components was sufficiently developed to include it in the January 2006
    regulatory impact analysis, but the agency is sponsoring research on
    this issue.
                                   background
        EPA is required by the Clean Air Act to conduct reviews of the
    National Ambient Air Quality Standards (NAAQS) for the six criteria
    pollutants, including particulate matter, every 5 years to determine
    whether the current standards are sufficient to protect public health,
    with an adequate margin of safety. If EPA decides to revise the NAAQS,
    the agency proposes changes to the standards and estimates the costs
    and benefits expected from the revisions in an assessment called a
    regulatory impact analysis. In January 2006, EPA prepared a regulatory
    impact analysis for one such rule?particulate matter that presented
    limited estimates of the costs and benefits expected to result from the
    proposed particulate matter rule. EPA developed the estimates by, for
    example, quantifying the changes in the number of deaths and illnesses
    in five urban areas that are likely to result from the proposed rule.
        The National Academies' 2002 report examined how EPA estimates the
    health benefits of its proposed air regulations and emphasized the need
    for EPA to account for uncertainties and maintain transparency in the
    course of conducting benefit analyses. Identifying and accounting for
    uncertainties in these analyses can help decision makers evaluate the
    likelihood that certain regulatory decisions will achieve the estimated
    benefits. Transparency is important because it enables the public and
    relevant decision makers to see clearly how EPA arrived at its
    estimates and conclusions. Many of the recommendations include
    qualifying language indicating that it is reasonable to expect that
    they can be applied in stages, over time; moreover, a number of the
    recommendations are interrelated and, in some cases, overlapping. Soon
    after the National Academies issued its report, EPA roughly
    approximated the time and resource requirements to respond to the
    recommendations, identifying those the agency could address within 2 or
    3 years and those that would take longer. According to EPA officials,
    the agency focused primarily on the numerous recommendations related to
    analyzing uncertainty. As is discussed below, EPA applied some of these
    recommendations to the particulate matter analysis.
        EPA Applied Some, but Not All, of the National Academies
    Recommendations to the Particulate Matter Regulatory Impact Analysis
        EPA applied either wholly or in part approximately two-thirds of
    the Academies recommendations in preparing its January 2006 particulate
    matter regulatory impact analysis and continues to address the
    recommendations through ongoing research and development. According to
    EPA, the agency intends to address some of the remaining
    recommendations in the final rule and has undertaken research and
    development to address others.
    Recommendations EPA Applied or Partially Applied to Its Particulate
            Matter Health Benefit Analysis
        The January 2006 regulatory impact analysis on particulate matter
    represents a snapshot of an ongoing EPA effort to respond to the
    National Academies recommendations on developing estimates of health
    benefits for air pollution regulations. Specifically, the agency
    applied, at least in part, approximately two-thirds of the
    recommendations 8 were applied and 14 were partially applied by taking
    steps toward conducting a more rigorous assessment of uncertainty by,
    for example, evaluating the different assumptions about the link
    between human exposure to particulate matter and health effects and
    discussing sources of uncertainty not included in the benefit
    estimates. According to EPA officials, the agency focused much of its
    time and resources on the recommendations related to uncertainty. In
    particular, one overarching recommendation suggests that EPA take steps
    toward conducting a formal, comprehensive uncertainty analysis the
    systematic application of mathematical techniques, such as Monte Carlo
    simulation and include the uncertainty analysis in the regulatory
    impact analysis to provide a more realistic depiction of the overall
    uncertainty in EPA's estimates of the benefits.\2\
    ---------------------------------------------------------------------------
        \2\ Monte Carlo simulation refers to a computer-based analysis that
    uses probability distributions for key variables, selects random values
    from each of the distributions simultaneously, and repeats the random
    selection over and over. Rather than presenting a single outcome such
    as the mostly likely or average scenario Monte Carlo simulations
    produce a distribution of outcomes that reflect the probability
    distributions of modeled uncertain variables.
    ---------------------------------------------------------------------------
        Overall, the uncertainty recommendations call for EPA to determine
    (1) which sources of uncertainties have the greatest effect on benefit
    estimates and (2) the degree to which the uncertainties affect the
    estimates by specifying a range of estimates and the likelihood of
    attaining them. In response, EPA examined a key source of uncertainty
    its assumption about the causal link between exposure to particulate
    matter and premature death and presented a range of expected reductions
    in death rates. EPA based these ranges on expert opinion systematically
    gathered in a multiphased pilot project. The agency did not, however,
    incorporate these ranges into its benefit estimates as the National
    Academies had recommended.
        Moreover, the Academies recommended that EPA's benefit analysis
    reflect how the benefit estimates would vary in light of multiple
    uncertainties. In addition to the uncertainty underlying the causal
    link between exposure and premature death, other key uncertainties can
    influence the estimates. For example, there is uncertainty about the
    effects of the age and health status of people exposed to particulate
    matter, the varying composition of particulate matter, and the
    measurements of actual exposure to particulate matter. EPA's health
    benefit analysis, however, does not account for these key uncertainties
    by specifying a range of estimates and the likelihood of attaining
    them. For these reasons, EPA's responses reflect a partial application
    of the Academies recommendation.
        In addition, the Academies recommended that EPA both continue to
    conduct sensitivity analyses on sources of uncertainty and expand these
    analyses. In the particulate matter regulatory impact analysis, EPA
    included a new sensitivity analysis regarding assumptions about
    thresholds, or levels below which those exposed to particulate matter
    are not at risk of experiencing harmful effects. EPA has assumed no
    threshold level exists that is, any exposure poses potential health
    risks.\3\ Some experts have suggested that different thresholds may
    exist, and the National Academies recommended that EPA determine how
    changing its assumption that no threshold exists would influence the
    estimates. The sensitivity analysis EPA provided in the regulatory
    impact analysis examined how its estimates of expected health benefits
    would change assuming varying thresholds.
    ---------------------------------------------------------------------------
        \3\ Recent EPA analyses used the natural background concentrations
    of particulate matter, rather than zero, for its assumption of no
    threshold level. The National Academies supported the assumption of no
    threshold level, but it recommended that EPA conduct a consistent and
    transparent sensitivity analysis to consider various threshold levels.
    ---------------------------------------------------------------------------
        In response to another recommendation by the National Academies,
    EPA identified some of the sources of uncertainty that are not
    reflected in its benefit estimates. For example, EPA's regulatory
    impact analysis disclosed that its benefit estimates do not reflect the
    uncertainty associated with future year projections of particulate
    matter emissions. EPA presented a qualitative description about
    emissions uncertainty, elaborating on technical reasons such as the
    limited information about the effectiveness of particulate matter
    control programs why the analysis likely underestimates future
    emissions levels.
    Recommendations EPA Did Not Apply to the Particulate Matter Analysis
        EPA did not apply the remaining 12 recommendations to the analysis
    for various reasons. Agency officials viewed most of these
    recommendations as relevant to its health benefit analyses and, citing
    the need for additional research and development, emphasized the
    Agency's commitment to continue to respond to the recommendations. EPA
    has undertaken research and development to respond to some of these
    recommendations but, according to agency officials, did not apply them
    to the analysis because the agency had not made sufficient progress.
         For example, EPA is in the process of responding to a
    recommendation involving the relative toxicity\4\ of components of
    particulate matter, an emerging area of research that has the potential
    to influence EPA's regulatory decisions in the future.\5\
    Hypothetically, the agency could refine national air quality standards
    to address the potentially varying health consequences associated with
    different components of particulate matter. The National Academies
    recommended that EPA strengthen its benefit analyses by evaluating a
    range of alternative assumptions regarding relative toxicity and
    incorporate these assumptions into sensitivity or uncertainty analyses
    as more data become available.\6\ EPA did not believe the state of
    scientific knowledge on relative toxicity was sufficiently developed at
    the time it prepared the draft regulatory impact analysis to include
    this kind of analysis. In a separate report issued in 2004, the
    National Academies noted that technical challenges have impeded
    research progress on relative toxicity but nonetheless identified this
    issue as a priority research topic. The Clean Air Scientific Advisory
    Committee also noted the need for more research and concluded in 2005
    that not enough data are available to base the particulate matter
    standards on composition. The Office of Management and Budget, however,
    encouraged EPA in 2006 to conduct a sensitivity analysis on relative
    toxicity and referred the agency to a sensitivity analysis on relative
    toxicity funded by the European Commission.
    ---------------------------------------------------------------------------
        \4\ Particulate matter is a highly complex mixture comprising
    particles emitted directly from sources and particles formed through
    atmospheric chemical reactions. Particles span many sizes and shapes
    and consist of hundreds of different chemicals. EPA identifies the
    major components of fine particulate matter as carbon, sulfate and
    nitrate compounds, and crustal/metallic materials such as soil and ash.
        \5\ Relative toxicity refers to the premise that different
    components of particulate matter have different levels of potency
    affecting premature mortality and illness. In the draft particulate
    matter regulatory impact analysis, EPA assumed equivalent toxicity,
    stating that while it is reasonable to expect that the potency of
    components may vary across the numerous effect categories associated
    with particulate matter, EPA's interpretation of scientific information
    considered to date is that such information does not yet provide a
    basis for quantification beyond using fine particle mass. EPA, Draft
    Regulatory Impact Analysis for the PMPM-2.5 National Ambient
    Air Quality Standards (Washington, DC, 2006), 3-21.
        \6\ In the context of the National Academies recommendations, a
    sensitivity analysis would assess how changes in one or more variables
    affect the outcome, whereas a comprehensive or formal uncertainty
    analysis evaluates the probability distributions of multiple variables.
    ---------------------------------------------------------------------------
         We found that EPA is sponsoring research on the relative toxicity
    of particulate matter components. For example, EPA is supporting long-
    term research on this issue through its intramural research program and
    is also funding research through its five Particulate Matter Research
    Centers and the Health Effects Institute. In addition, an EPA
    contractor has begun to investigate methods for conducting a formal
    analysis that would consider sources of uncertainty, including relative
    toxicity. To date, the contractor has created a model to assess whether
    and how much these sources of uncertainty may affect benefit estimates
    in one urban area. Agency officials told us, however, that this work
    was not sufficiently developed to include in the final particulate
    matter analysis, which it says will present benefits on a national
    scale.
        Another recommendation that EPA did not apply to the particulate
    matter analysis focused on assessing the uncertainty of particulate
    matter emissions. The National Academies recommended that EPA conduct a
    formal analysis to characterize the uncertainty of its emissions
    estimates, which serve as the basis for its benefit estimates.\7\ While
    the agency is investigating ways to assess or characterize this
    uncertainty, EPA did not conduct a formal uncertainty analysis for
    particulate matter emissions for the draft regulatory impact analysis
    because of data limitations. These limitations stem largely from the
    source of emissions data, the National Emissions Inventory,\8\ an
    amalgamation of data from a variety of entities, including state and
    local air agencies, tribes, and industry. According to EPA, these
    entities use different methods to collect data, which have different
    implications for how to characterize the uncertainty. EPA officials
    stated that the agency needs much more time to address this data
    limitation and to resolve other technical challenges of such an
    analysis. While the final particulate matter analysis will not include
    a formal assessment of uncertainty about emissions levels, EPA
    officials noted that the final analysis will demonstrate steps toward
    this recommendation by presenting emissions data according to the level
    emitted by the different kinds of sources, such as utilities, cars, and
    trucks.
    ---------------------------------------------------------------------------
        \7\ Because the precise levels of total emissions are not knowable
    but rather are approximations based on a sample of measurements, there
    is uncertainty about the true quantity of emissions.
        \8\ EPA compiles the National Emissions Inventory, a national
    database of air emissions data that includes estimates of annual
    emissions, by source, of air pollutants in each area of the country on
    an annual basis.
    ---------------------------------------------------------------------------
        Finally, EPA did not apply a recommendation concerning the
    transparency of its benefit estimation process to the particulate
    matter analysis. Specifically, the National Academies recommended that
    EPA clearly summarize the key elements of the benefit analysis in an
    executive summary that includes a table that lists and briefly
    describes the regulatory options for which EPA estimated the benefits,
    the assumptions that had a substantial impact on the benefit estimates,
    and the health benefits evaluated. EPA did not, however, present a
    summary table as called for by the recommendation or summarize the
    benefits in the executive summary. EPA stated in the regulatory impact
    analysis that the agency decided not to present the benefit estimates
    in the executive summary because they were too uncertain. Agency
    officials told us that the agency could not resolve some significant
    data limitations before issuing the draft regulatory impact analysis in
    January 2006 but that EPA has resolved some of these data challenges.
    For example, EPA officials said they have obtained more robust data on
    anticipated strategies for reducing emissions, which will affect the
    estimates of benefits. The officials also said that EPA intends to
    include in the executive summary of the regulatory impact analysis
    supporting the final rule a summary table that describes key analytical
    information.
                            concluding observations
        While EPA officials said that the final regulatory impact analysis
    on particulate matter will reflect further responsiveness to the
    Academies recommendations, continued commitment and dedication of
    resources will be needed if EPA is to fully implement the improvements
    recommended by the National Academies. In particular, the agency will
    need to ensure that it allocates resources to needed research on
    emerging issues, such as the relative toxicity of particulate matter
    components, and to assessing which sources of uncertainty have the
    greatest influence on benefit estimates. The uncertainty of the
    agency's estimates of health benefits in the draft regulatory impact
    analysis for particulate matter underscores the importance of
    uncertainty analysis that can enable decision makers and the public to
    better evaluate the basis for EPA's air regulations. While EPA
    officials said they expect to reduce the uncertainties associated with
    the health benefit estimates in the final particulate matter analysis,
    a robust uncertainty analysis of the remaining uncertainties will
    nonetheless be important for decision makers and the public to
    understand the likelihood of attaining the estimated health benefits.
        Mr. Chairman, this concludes my prepared statement. I would be
    happy to respond to any questions that you or members of the committee
    may have.
                                     ______

             Responses by John Stephenson to Additional Questions
                            from Senator Voinovich.
        Question 1. Mr. Stephenson, your testimony states ``The National
    Academies'' 2002 report examined how EPA estimates the health benefits
    of its proposed air regulations and emphasized the need for EPA to
    account for uncertainties and maintain transparency in the course of
    conducting benefit analyses. I agree that transparency is very
    important. However, right now, EPA is simply telling us that we need to
    wait until the final rule to see a more complete RIA, how they
    addressed more of these recommendations, and the inclusion of new
    science. In your opinion, has EPA ``maintained transparency'' through
    this process with the PM standards?
        Response. EPA has maintained transparency to the extent feasible
    under federal rulemaking procedures, which include collecting and
    reviewing public comments on the proposed rule and submitting the final
    rule package to the White House Office of Management and Budget for
    review at least 45 days before the EPA Administrator signs the rule.
    Proposed and final rules can differ substantially for a number of
    reasons, including changes made in response to public comments on the
    proposed rule and the availability of new or more complete data.
    Therefore, in developing and supporting both proposed and final rules,
    it is important for agencies to be transparent that is, to provide
    decision makers and the public with clear and relevant information
    about the data, assumptions, methodologies, uncertainties, etc.,
    underlying its regulatory impact analyses. As you are aware, the
    Congressional Review Act of 1996 established an expedited process under
    which Congress may disapprove a broad range of regulatory rules issued
    by Federal agencies by enacting a joint resolution of disapproval
    within 60 days after receiving the rule. The rule would not go into
    effect without subsequent statutory authorization.
        To date we have not identified major shortcomings concerning the
    transparency of EPA's current rulemaking process for particulate matter
    standards. For example, in the January 2006 regulatory impact analysis
    for proposed rule, EPA highlighted the fact that the benefits estimates
    were based only on five cities and were highly uncertain. According to
    EPA officials, the agency could not resolve data limitations in time to
    meet the court-issued deadline for the proposed changes. As you know,
    EPA plans to provide national estimates of the health benefits in the
    final rule using more robust data that it has subsequently been able to
    obtain. Thus, the regulatory impact analyses supporting the proposed
    and final rules are expected to be significantly different. EPA can
    maintain transparency in this rulemaking process by clearly discussing
    in the final regulatory impact analysis due in September 2006 the
    changes in its approach to estimating the benefits and the Agency's
    rationale for doing so and by clearly identifying key data,
    assumptions, methodologies, and uncertainties.
        In terms of transparency and the science supporting the rulemaking
    efforts, EPA made a commitment in the proposed rule to conduct a review
    and assessment of studies published after the completion of the
    scientific review of health effects linked to particulate matter
    emissions. EPA has recently made information about its review of new
    science available to the public; see EPA, Provisional Assessment of
    Recent Studies on Health Effects of Particulate Matter Exposure
    (Research Triangle Park, N.C., 2006). The July 2006 provisional
    assessment presents EPA's approach to reviewing new studies and
    summarizes the findings of these studies, including those that
    evaluated the links between particulate matter components and adverse
    health effects.

        Question 2. Mr. Stephenson, please elaborate on this very important
    statement that you make at the end of your testimony (quote): "While
    EPA officials said they expect to reduce the uncertainties associated
    with the health benefit estimates in the final particulate matter
    analysis, a robust uncertainty analysis of the remaining uncertainties
    will nonetheless be important for decision makers and the public to
    understand the likelihood of attaining the estimated health benefits.''
        Response. In estimating potential health benefits stemming from
    regulatory actions, some level of uncertainty is unavoidable, in part
    because the scientific information used to develop estimates, such as
    the inventory of particulate matter emissions, will never be perfect or
    complete. According to the Academies, high uncertainty does not imply
    that action to promote or protect public health should be delayed, but
    rather that a comprehensive and rigorous assessment of uncertainty
    would improve policy decisions. Many of the recommendations of the
    National Academies to EPA are aimed at the agency developing a more
    robust uncertainty analysis by providing comprehensive, quantitative
    information about the uncertainties underlying the estimates of health
    benefits. A quantitative uncertainty analysis can, among other things,
    identify which sources of uncertainties have the greatest effect on the
    benefit estimates and assess the degree to which the uncertainties
    affect the estimates by specifying a range of estimates and the
    likelihood of attaining them. While EPA has taken steps toward a more
    robust uncertainty analysis, the agency has not assessed uncertainty in
    the quantitative manner
        recommended by the National Academies. GAO believes it is important
    for EPA to continue to strengthen its uncertainty analysis. In
    evaluating estimates of health benefits, decision makers and the public
    can better assess the likelihood of achieving such benefits if they are
    provided with qualitative and quantitative information about the
    underlying uncertainties.

        Question 3. Mr. Stephenson, in your testimony (quote): ``We note
    that continued commitment and dedication of resources will be needed if
    EPA is to fully implement the improvements recommended by the National
    Academies.'' However, EPA's 2006 budget proposes to reduce funding for
    the State and Local Air Quality Management Program which is used by
    states and localities to conduct monitoring among other things. How
    would this budget cut impact EPA's ability to address more of these
    recommendations?
        Response. The proposed budget cuts could adversely impact EPA's
    ability to address more of the Academies recommendations, such as those
    concerning particulate matter emissions data. Emissions estimates are a
    key element in the analysis of potential health benefits, and EPA
    relies largely on state and local entities emissions monitoring data to
    develop estimates of emissions on a national scale. Thus, any
    reductions in emissions monitoring could affect EPA's ability to
    develop meaningful nationwide emissions estimates, increasing, for
    example, the uncertainty of such estimates. Moreover, as noted in our
    report, EPA has initiated long-term research and development to
    understand the relative toxicity of particulate matter components and
    to better evaluate the uncertainty of estimates of emissions. A
    reduction in monitoring data would likely limit EPA's progress to
    address these areas of research.
                                   __________
    Statement of George Thurston, Associate Professor, New York University,
            School of Medicine, Department of Environmental Medicine
        I am George D. Thurston, a tenured Associate Professor of
    environmental Medicine at the New York University (NYU) School of
    medicine. In addition, I served as the Deputy Director of the NYU-EPA
    Particulate Matter (PM) Health Research Center for the past 4 years. My
    scientific research involves the investigation of the human health
    effects of air pollution. In this testimony, I will primarily address
    three factors that need to be considered in the EPA's proposed
    revisions to the particulate matter air quality standards. First, I
    will address the fact that we are now far more certain of the adverse
    impacts and biological mechanisms of PM health effects: most of the
    uncertainties raised at the time of the initial setting of the
    PM2.5 standard are far better understood. Second, I will
    document that reducing ambient PM levels can and do result in
    significant reductions in the mortality risk associated with this
    pollutant. Finally, I will show that the adverse health impacts of PM
    air pollution extend below the current PM2.5 standard, and
    that there is, therefore, a public health imperative to reduce the fine
    particle (PM2.5) annual standard below 15 wg/m3,
    consistent with the advice of the U.S. EPA's Clean Air Science Advisory
    Committee (CASAC).
        Despite progress over the last few decades, Americans are still
    suffering from the adverse health effects of air pollution. The adverse
    health consequences of breathing air pollution are severe and well
    documented in the published medical and scientific literature. Over the
    past few decades, medical researchers examining air pollution and
    public health, including myself, have shown that air pollution is
    associated with a host of serious adverse human health effects,
    including: asthma attacks, heart attacks, hospital admissions, adverse
    birth outcomes, and premature death.
        PM is one of the air pollutants most carefully studied in the last
    decade. Small particles can bypass the defensive mechanisms of the
    lung, and become lodged deep in the lung where they can cause a variety
    of health problems. Indeed, the latest evidence indicates that
    exposures cannot only cause respiratory damage, but also cardiac
    effects, including heart attacks. Moreover, long-term exposure to fine
    particles increases the risk of death, and has been estimated to take
    years from the life expectancy of people living in the most polluted
    cities, relative to those living in cleaner cities (Brunekreef, 1997).
        The State of the science on particulate matter and health was
    thoroughly reviewed in the recently released U.S. EPA Criteria Document
    for Particulate Matter (U.S. EPA, 2004). Since the PM2.5
    standard was last set in 1997, more than 100 new published studies,
    taken together, collectively confirm the relationship between
    PM2.5 pollution and severe adverse human health effects. In
    the process, this new research has eliminated many of the doubts that
    were raised in the past regarding the causality and size of the PM-
    health effects relationships, and has now provided plausible biological
    mechanisms for the serious impacts associated with PM exposure. As
    outlined in Figure 1, the PM research funded since the setting of the
    last PM2.5 standard has collectively shown the existence of
    numerous biological pathways capable of causing damage in the human
    heart, lung, nervous system, and circulatory system consistent with the
    health impacts found by the PM epidemiology studies upon which the
    PM2.5 standard was set.

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        At the time of the last PM standard revisions, the largest landmark
    studies on particulate matter and death were the Harvard Six Cities
    Study (Dockery et al, 1993) and the American Cancer Society Study (Pope
    et al, 1995). The American Cancer Society study examined half a million
    people in over 150 metropolitan areas throughout the United States,
    finding a 17 percent greater risk of mortality between the city with
    the least PM and the city wit the highest levels of this particulate
    pollution. The results of these studies were challenged by industry,
    resulting in an independent reanalysis by the Health Effects Institute
    (HEI)--an organization funded by both industry and Government. The
    results of the HEI re-analyses have now confirmed the associations
    found by the original investigators, increasing our confidence in the
    results of these two already highly regarded studies of PM mortality.
        Since the setting of the original PM2.5 standard, more
    recent follow-up analyses of the Harvard and ACS studies have now
    considered longer records of time, and have confirmed and extended the
    conclusions from these two major studies. An extended analysis of the
    Harvard Six Cities Study (to include follow-up through 1990) has now
    shown that reductions in long-term ambient PM pollution results in
    concomitant reductions in the health risks associated with PM. As shown
    in Figure 2, large reductions in PM at four of the Harvard cities have
    resulted in likewise large reductions in the relative risk (RR) of
    mortality in those cities: Steubenville, OH(S), Harriman, TN(H), St.
    Louis, MO(L), and Watertown, MA(W). Other published studies have
    similarly found indications that reductions in ambient PM are
    associated with reduced mortality risk (e.g., Clancy et al., 2002).
    Thus, although we still carry very large health risks in the United
    States from our present levels of PM air pollution, amounting to tens
    of thousands of premature deaths per year, and although we still have a
    long way to go to have what can be called ``clean air'', recent
    research shows that the lowering of PM levels in the air is an
    effective way to improve public health.

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        In addition, a recent National Institute of environmental Health
    Sciences (NIEHS)-funded extension of the ACS study, of which I was
    Principal Investigator, strengthens the original conclusions of the ACM
    study and, importantly, now links increased risk of lung cancer to
    long-term exposure to particulate matter (Pope et al, 2002). As seen in
    Figure 3, this recent JAMA study also clearly indicates that the risks
    from PM2.5 exposure extend below 15 ug/m3, supporting a
    reduction in the annual PM2.5 standard at this time,
    consistent with the advice of the EPA's Clean Air Scientific Advisory
    Committee (Henderson, 2006).

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        In conclusion, since it was the level of uncertainty about PM
    biological mechanisms and effects at lower concentrations than 15 wg/m3
    that limited the standard to that level in 1997 (and not some specific
    acceptable level of health risk from PM), and since new sound
    scientific studies have greatly reduced or resolved those
    uncertainties, then concern about the health of the public clearly
    indicates that the long-term PMPM2.5 standard should now be
    reduced below 15 ug/m3, consistent with the advice of CASAC.
        Thank you for the opportunity to testify on this important issue.
                                     ______

          Response by George Thurston to an Additional Question from
                               Senator Voinovich
        Question. Dr. Thurston, at the end of your testimony, you state the
    annual standard was limited to 15 not because of (quote): ``some
    specific acceptable level of health risk from PM.''
        Am I correct that you are saying that you agree with Dr. Smith that
    the risk level identified in 1997 has gone down? I know that you do not
    think this should be the basis of setting the standard, but I am just
    looking for a yes or no answer on the level of risk.
        Response. No, I do not agree with Dr. Smith. As I noted in my
    verbal testimony, the consensus ``best-estimates'' for the mortality
    effects of long-term exposure to PM have actually increased in recent
    years, relative to what the U.S. EPA has been assuming in their risk
    analyses. Indeed, the Pope et al. (2002) overall mortality effect
    estimate, as derived from the American Cancer Society Cancer Prevention
    II study cohort, is now thought to be an underestimate of the actual
    risk for the general U.S. population. In fact, preliminary results from
    the EPA's recent PM Expert Elicitation evaluation of PM risk indicate
    that the central effect estimate, as derived from a distillation of all
    available studies by experts, yield a PM2.5 mortality effect
    (some 1 percent per ug/m3 PM2.5) that is roughly
    two thirds higher than given by the Pope et al. (2002) study. This
    further indicates that
        lowering the long-term PM2.5 standard below 15 ug/
    m3 would yield significant public health benefits when
    implemented across the United States.

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