[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.''

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    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\
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    \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.
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    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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