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**Ex Parte Meeting Summary: Ozone NAAQS**

**Date:** December 20, 2007, 9:00 -- 10:00 am

**Attendees:**

**Visitors:**

Dr. Anne E. Smith

Vice President

CRA International

1201 F Street, N.W., Suite 700

Washington, DC 20004-1204

202-662-3800

<asmith@crai.com>

Dr. Roger McClellan

Advisor, Toxicology and Human Health Risk Analysis

13701 Quaking Aspen Pl NE

Albuquerque, NM 87111

Dr. Richard Smith

Mark L Reed III Distinguished Professor of Statistics

Department of Statistics and Operations Research

University of North Carolina,

Chapel Hill NC 27599-3260

Dr. Mark Utell

Professor of Medicine and Environmental Medicine

University of Rochester Medical Center

601 Elmwood Avenue,

Rochester, NY 14642

**EPA attendees:**

George Gray, ORD

Pamela Williams, ORD

Bob Fegley, ORD

John Vandenberg, ORD

Bill Briggs, Office of Public Outreach, EPA

Ila Cote, ORD

Lydia Wegman, OAR

Harvey Richmond, OAR

Dave McKee, OAR

Mary Ross, ORD

Debra Walsh, ORD

Jim Brown, ORD

Tom Bateson, ORD

John Langstaff, OAR

**Summary of discussion:**

Dr. McClellan introduced the visitors as contributors to a workshop
report submitted to the Ozone Docket ("the Rochester Report) and that
individual comments also had been submitted to the Docket by Dr.
McClellan including input from Dr. Richard Smith, and also individual
comments had been submitted to the Docket by Dr. Anne Smith.

Dr. Utell summarized background on the Rochester workshop and related
Report and noted that the goal was to review and evaluate ozone evidence
germane to setting ozone policy. He stated their concentration was on
areas of uncertainty, that they did not focus on developing
recommendations regarding the NAAQS, and that Dr. McClellan had taken
the lead on writing up the workshop report. There was no EPA nor API
(the organization that funded the workshop) input on the Rochester
Report.

Dr. McClellan stated that there was controversy regarding national
background levels of ozone (i.e., policy relevant background, PRB)
related to the 'bluntness' of the geochemical model used by EPA to
estimate PRB, and that air quality related to ozone had been improving.
Dr. Gray asked the visitors if they were aware of better alternatives to
the current model and Dr. McClellan indicated there was "no right way"
but that alternative approaches (not specified) added comfort to the
interpretation of model results. Dr. Anne Smith noted that the
comparison of model outputs and monitoring data indicated variability in
time and space (e.g., the monitors at Trinity Head were double the
modeled PRB). Dr. McClellan stated there was no simple algorithm with
respect to estimation of policy relevant background.

Dr. Utell then described the human clinical evidence reviewed at the
Rochester workshop. He stated that whereas there was substantial new
evidence at the time of the \[1997\] ozone NAAQS review, there was but
one "interesting and important" new study for the current review, the
Adams study. Further, he stated there was a debate over the
interpretation of the findings from the Adams study and, as there is
uncertainty related to there just being this one study, the clinical
evidence was inconclusive. Dr Richard Smith then summarized the use of
the Scheffe correction for multiple comparisons and stated the Adams
study did not provide definitive conclusions and needed replication.

Dr. Gray asked the visitors to comment on how human exposure chamber
ozone concentrations related to ambient ozone exposures. Dr. Utell
stated that chamber exposures "pretty nicely" represent ambient ozone
exposures.

Dr. McClellan then noted comments on the other line of evidence, related
to epidemiological evidence, had been submitted in his docket comments
and was summarized also in the Rochester Report. Dr. Richard Smith then
summarized the Rochester approach to literature review and that he had
some additional unpublished data analysis, including analysis of NMAPPS
data that had not been fully elaborated in the Dominici paper (JAMA,
2004). Dr. Richard Smith stated that his unpublished analyses were based
on 24-hour ozone metric, and there was substantial intercity variability
in effects due to copollutants, for example particulate matter. Dr.
Richard Smith did not provide to the participants any copies of his
unpublished analyses.

Dr. Anne Smith then discussed her docket comments on the evaluation of
time series data. She stated that there is a risk distribution across
days e.g., most of the risk is from days with less than 60 ppb ozone.
Her analyses of days with ozone above 70 ppb, and of days above the
current standard, indicate small relative risks at current exposure
levels. Further, she stated that in the ozone NAAQS proposal that EPA
had collapsed risk estimates down to simple aggregate estimates of risk,
and that in her opinion this was inappropriate. She stated that
city-specific risk estimates show risks above 70 ppb were small with a
broad range of uncertainty.

Dr. Anne Smith then commented on policy relevant background (PRB). She
stated that much of the risk that was estimated was due to exposures
near PRB and therefore the risks estimates near PRB were speculative.
For example, she stated that risks can decrease by 50% or more with
small PRB changes, and she stated that this "squishiness" needed to be
communicated (she pointed to Figure 2 in the Rochester Report as
relevant to this point).

Dr. McClellan then made some concluding statements, that the Rochester
workshop participants had not stated a preference with respect to the
NAAQS, that the limitations in evidence made for a tough decision, and
that science doesn't drive the policy but judgment was needed. Further,
Dr. McClellan felt that CASAC combined both science and policy in their
development of NAAQS recommendations and in his opinion the level of
discourse was not as high as had been the case in prior reviews. Lydia
Wegman noted to Dr. McClellan that CASAC had many lengthy discussions of
the ozone evidence over a several year period that such discussions had
served as the basis for their recommendations to the Administrator.

Dr. Gray thanked the visitors for their time, noted that the
Administrator had not decided about the NAAQS, and that their comments
had been heard and the comments played and important role in the
decision process.