UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                                  WASHINGTON D.C. 20460
                                     June 8, 2005
EPA-SAB-CASAC-CON-05-001
                                                              OFFICE OF THE ADMINISTRATOR
                                                                SCIENCE ADVISORY BOARD
Honorable Stephen L. Johnson
Administrator
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue, NW
Washington, DC  20460

       Subject: Clean Air Scientific Advisory Committee (CASAC) Ozone Review Panel's
               Consultation on EPA's Draft Ozone Health Assessment Plan (April 2005)

Dear Administrator Johnson:

       EPA's Office of Air Quality Planning and Standards (OAQPS), within the Office of Air
and Radiation (OAR), is conducting technical analyses and assessments in consideration of
revising the National Ambient Air Quality Standards (NAAQS) for ozone and related photo-
chemical oxidants. As part of this process, the Agency's National Center for Environmental
Assessment, Research Triangle Park, NC (NCEA-RTP), within the EPA Office of Research and
Development (ORD), is revising the air quality criteria document for ozone; and OAQPS has
developed a draft Ozone Health Assessment Plan: Scope and Methods for Exposure Analysis
and Risk Assessment (April 2005).

       EPA's Clean Air Scientific Advisory Committee (CASAC) was asked to provide early
expert input on this draft Ozone Health Assessment Plan in the form of a consultation.
Accordingly, the CASAC, supplemented by subject-matter-expert Panelists  collectively
referred to as the CASAC Ozone Review Panel ("Panel")  met in a public meeting held in
Research Triangle Park (RTF), NC,  on May 5, 2005, to conduct a consultation with staff from
OAQPS on this draft Ozone Health Assessment Plan. The current Panel roster is found in
Appendix A of this report. The charge questions provided to the Panel by EPA are found in
Appendix B to this report.

       The SAB Staff Office has developed the consultation as a mechanism for an advisory
body such as the CASAC to advise EPA on technical issues that should be considered in the
development of regulations, guidelines, or technical guidance before the Agency has taken a
position. Consultations are conducted under the normal requirements of the Federal Advisory
Committee Act (FACA), as amended (5 U.S.C., App.), which include advance notice of the
public meeting in the Federal Register.

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       Since a consultation represents non-consensus advice  with experts providing their
individual input which was summarized in technical minutes for Agency consideration  there
will be no formal report from the CASAC or the SAB as a result of this consultation, nor do we
expect any formal response from the Agency. Nevertheless, we hope that the individual Panel
member comments expressed during the meeting were helpful to EPA, and we look forward to
reviewing the Agency's ozone health risk assessment in the near future.

                                             Sincerely,
                                                   /Signed/

                                             Dr. Rogene Henderson, Chair
                                             Clean Air Scientific Advisory Committee
Appendix A - Roster of the CASAC Ozone Review Panel
Appendix B - Charge to the CASAC Ozone Review Panel
cc:     Steve Page (MD-10)                     Harvey Richmond (MD-15)
       John Bachmann (MD-10)                 Anthony Maciorowski (1400F)
       Lydia Wegman (MD-15)                 Fred Butterfield (1400F)
       Karen Martin (MD-15)

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           Appendix A - Roster of the CASAC Ozone Review Panel
                     U.S. Environmental Protection Agency
                   Science Advisory Board (SAB) Staff Office
              Clean Air Scientific Advisory Committee (CASAC)
                         CASAC Ozone Review Panel*


CHAIR
Dr. Rogene Henderson*, Scientist Emeritus, Lovelace Respiratory Research Institute,
Albuquerque, NM

MEMBERS
Dr. John Balmes, Professor, Department of Medicine, University of California San Francisco,
University of California - San Francisco, San Francisco, California

Dr. Ellis Cowling*, University Distinguished Professor-at-Large, North Carolina State
University, Colleges of Natural Resources and Agriculture and Life Sciences, North Carolina
State University, Raleigh, NC

Dr. James D. Crapo*, Professor, Department of Medicine, Biomedical Research and Patient
Care, National Jewish Medical and Research Center, Denver, CO

Dr. William (Jim) Gauderman, Associate Professor, Preventive Medicine, Medicine,
University of Southern California, Los Angeles, CA

Dr. Henry Gong, Professor of Medicine and Preventive Medicine, Medicine and Preventive
Medicine, Keck School of Medicine, University of Southern California, Downey, CA

Dr. Paul J. Hanson, Senior Research and Development Scientist, Environmental Sciences
Division,  Oak Ridge National Laboratory (ORNL), Oak Ridge, TN

Dr. Jack  Harkema, Professor, Department of Pathobiology, College of Veterinary Medicine,
Michigan State University, East Lansing, MI

Dr. Philip Hopke**, Bayard D. Clarkson Distinguished Professor, Department of Chemical
Engineering, Clarkson University, Potsdam, NY

Dr. Michael T. Kleinman, Professor, Department of Community & Environmental Medicine,
University of California - Irvine, Irvine, CA

Dr. Allan Legge, President, Biosphere Solutions, Calgary, Alberta,  Canada
                                        A-l

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Dr. Morton Lippmann, Professor, Nelson Institute of Environmental Medicine, New York
University School of Medicine, Tuxedo, NY

Dr. Frederick J. Miller*, Consultant, Cary, NC

Dr. Maria Morandi, Assistant Professor of Environmental Science & Occupational Health,
Department of Environmental Sciences, School of Public Health, University of Texas - Houston
Health Science Center, Houston, TX

Dr. Charles Plopper, Professor, Department of Anatomy, Physiology and Cell Biology, School
of Veterinary Medicine, University of California - Davis, Davis, California

Mr. Richard L. Poirot*, Environmental Analyst, Air Pollution Control Division, Department of
Environmental Conservation, Vermont Agency of Natural Resources, Waterbury, VT

Dr. Armistead (Ted) Russell, Georgia Power Distinguished Professor of Environmental
Engineering, Environmental Engineering Group,  School of Civil and Environmental
Engineering, Georgia Institute of Technology, Atlanta, GA

Dr. Elizabeth A. (Lianne) Sheppard, Research Associate Professor, Biostatistics and
Environmental & Occupational Health Sciences, Public Health and Community Medicine,
University of Washington, Seattle, WA

Dr. Frank Speizer*, Edward Kass Professor of Medicine, Channing Laboratory, Harvard
Medical School, Boston, MA

Dr. James Ultman, Professor, Chemical Engineering, Bioengineering Program, Pennsylvania
State University, University Park, PA

Dr. Sverre Vedal, Professor of Medicine, Department of Environmental and Occupational
Health Sciences, School of Public Health and Community Medicine, University of Washington,
Seattle, WA

Dr. James (Jim) Zidek, Professor, Statistics,  Science, University of British Columbia,
Vancouver, BC, Canada

Dr. Barbara Zielinska*, Research Professor, Division of Atmospheric  Science, Desert Research
Institute, Reno, NV
SCIENCE ADVISORY BOARD STAFF
Mr. Fred Butterfield, CASAC Designated Federal Officer, 1200 Pennsylvania Avenue, N.W.,
Washington, DC, 20460, Phone: 202-343-9994, Fax: 202-233-0643 (butterfield.fred@epa.gov)
(Physical/Courier/FedEx Address: Fred A. Butterfield, III, EPA Science Advisory Board Staff
Office (Mail Code 1400F), Woodies Building, 1025 F Street, N.W., Room 3604, Washington,
DC 20004, Telephone: 202-343-9994)
                                         A-2

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* Members of the statutory Clean Air Scientific Advisory Committee (CASAC) appointed by the EPA
  Administrator

** Immediate past CASAC Chair
                                           A-3

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            Appendix B - Charge to the CASAC Ozone Review Panel
Air Quality Considerations:

1.    The importance of characterizing policy-relevant background Ch levels for both the
     exposure analysis and risk assessment is described in the draft plan.
     a.   What are the Panel members' views on the general approach described for
          characterizing policy-relevant background levels, considering both regional and
          seasonal differences?
     b.   In particular, what are the Panel members' views on using the global tropospheric Ch
          model GEOS-CHEM to estimate monthly average policy-relevant background Ch
          levels for different geographic regions across the U.S.?

2.    The draft plan notes that staff is currently considering various approaches to adjusting air
     quality to simulate just meeting the current and alternative Ch standards. The results of this
     evaluation will be described in the first draft Exposure Analysis Report; Panel members
     will have an opportunity to comment on this issue in conjunction with their review of that
     draft report and the first draft Ch Staff Paper later this Fall.

Exposure Analysis:

1.    Do Panel members have any comments on the overall approach to be used for the exposure
     analysis, including the use of the APEX model (as depicted in Figure 1 in the draft plan)?

2.    The draft plan notes that staff is currently developing a methodology for constructing
     longitudinal human activity patterns based on cross-sectional human activity diary data
     contained in the Consolidated Human Activity Data Base (CHAD). Are Panel members
     aware of sources of information or approaches developed by others that could help inform
     our development of this methodology?

3.    The draft plan describes the basis for and selection of population groups of interest (i.e., all
     school-age children, active children, asthmatic children, and the general population) for
     which ozone exposure estimates are to be developed.
     a.   Do Panel members generally agree with the groups of interest identified in the draft
          plan?
     b.   In particular, what are the Panel members' views on the approach of using the
          median of daily PAI values for characterizing "active" children?

4.    An overall strategy and general approach for addressing uncertainty and variability in the
     exposure analysis is described in the draft plan, including the use of 2-dimensional Monte
     Carlo analysis to separately characterize uncertainty and variability for the most important
     input parameters.
                                          B-l

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     a.    What are the Panel members' views on this overall strategy and approach for
           addressing uncertainty and variability in the exposure analysis?
     b.    Staff plans to describe in more detail the approach for quantitatively addressing
           uncertainties in the first draft Exposure Analysis Report; Panel members will have an
           opportunity to comment on these more detailed plans in conjunction with their
           review of that draft report and the first draft Ch Staff Paper later this Fall.

Health Risk Assessment:

1.    Do Panel members have any comments on the general structure and overall approach that
     staff plans to use for the risk assessment, considering the different parts of the assessment
     based on controlled human exposure studies (as depicted in Figure 2 in the draft plan) and
     on epidemiologic and/or field studies (as depicted in Figure 3 in the draft plan)?

2.    In considering the part of the risk assessment to be based on controlled human exposure
     studies:
     a.    In general, are the criteria that staff plans to use for the selection of health endpoints
           and exposure-response functions clear and appropriate?
     b.    Do Panel members generally agree with focusing on lung function decrements in the
           quantitative risk assessment?
     c.    What are the Panel members' views on the methodology and specific studies that
           staff plans to use to estimate  probabilistic  exposure-response relationships for lung
           function decrements?
     d.    Do Panel members generally agree with the various risk measures that staff plans to
           generate in this part of the risk assessment?

3.    In considering the part of the risk assessment to be based on epidemiologic and/or field
     studies:
     a.    In general, are the criteria that staff plans to use for the selection of health endpoints,
           urban areas, studies, and concentration-response functions clear and appropriate?
     b.    In particular, based on these  criteria and the information in the first draft Ch AQCD,
           what are the Panel members' views on the specific choices considered for inclusion
           in the risk assessment as discussed in the draft plan (e.g., the locations and health
           endpoints listed in Table 1  and the specific studies listed in Table 2 of the draft
           plan)?

4.    Do Panel members have any comments or advice with respect to the general approach to
     addressing uncertainty and variability  in each part of the risk assessment as described in the
     draft plan?
     a.    What are the Panel members' views on the scope of the various sensitivity analyses
           that staff has planned to evaluate the influence of various uncertainties in both parts
           of the risk assessment?
                                           B-2

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b.    With respect to mortality associated with short-term exposures to Ch in epidemiologic
     studies, the plan describes the use of an Empirical Bayes technique to more
     efficiently make use of the city-specific and overall estimates for the concentration-
     response relationships to be incorporated in the risk assessment. What are the Panel
     members' views of this approach?
c.    Staff notes that several meta-analyses addressing the impact of various factors on
     estimates of mortality associated with short-term exposures to Ch will be published in
     June 2005. Staff plans to review these analyses and explore whether they provide
     additional information that can be used to assist in characterizing the uncertainties for
     this health outcome.  The first draft Risk Assessment Report will describe any
     additional plans to expand the uncertainty analyses based on these new publications;
     Panel members will have an opportunity to comment on any such additional plans in
     conjunction with their review of that draft report and the first draft Ch Staff Paper
     later this Fall.

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                                   NOTICE

       This report has been written as part of the activities of the U.S. Environmental
Protection Agency's (EPA) Clean Air Scientific Advisory Committee (CASAC), a
Federal advisory committee administratively located under the EPA Science Advisory
Board (SAB) Staff Office that is chartered to provide extramural scientific information
and advice to the Administrator and other officials of the EPA.  The CAS AC is
structured to provide balanced, expert assessment of scientific matters related to issue
and problems facing the Agency.  This report has not been reviewed for approval by the
Agency and, hence, the contents of this report do not necessarily represent the views and
policies of the EPA, nor of other agencies in the Executive Branch of the Federal
government, nor does mention of trade names or commercial products constitute a
recommendation for use. CASAC reports are  posted on the SAB Web site at:
http ://www. epa. gov/sab.

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