July 12, 1999 EPA-SAB-CASAC-CON-99-006 Honorable Carol M. Browner Administrator U.S. Environmental Pro tection Agency 401 M Str eet, SW Washington, DC 20460 Subject: Notification of a Consultation on the Estimation of Carbon Monoxide Exposures and Associated Carboxyhemoglobin L evels in Denver Residents using pNEM/CO (Ver. 2.0) Dear Ms. Browner: The Clean Air Scientific Advisory Co mmittee (CASAC) of the Science Advis ory Board (SAB), met on June 9-10, 1999 to review and/or consult on several issues. During the meeting, the Committee c ondu cted a Consultation with staff from the Office of Air and Radiation (OAR) on OAR’s draft Estimation of Carbon Monoxide Exposures and Associated Carboxyhemoglobin Levels in Denver Residents using pNEM/CO(Ver. 2.0). This document was discussed as part of the continuing peer review by CASAC of the National Ambient Air Quality Standards (NAAQS) for Carbon Monoxide. The SAB has developed the Consultation as a mechanism to advise the Agency on technical issues that should be considered in the development of regulations, guidelines, or technical guidance before the Agency has taken a position. A Consul tation is c ondu cted under the normal requirements of the Federal Advisory Co mmittee Act, which include advance notice of the public meeting in the Federal Register

. As is our customary pr actice, there w ill be no formal report from the SAB as a result of this consultati on, nor do we exp ect any formal response from the Agency. However, the Committee l ooks forward to continuing its peer review of the scientific basis of the Carbon Monoxide NAAQS.
Sincerely,

Dr. Joe Mauderly, Chair Clean Air Scientific Advisory Co mmittee Science Advisory Boardi 

### U.S. Environmental Protection Agency Science Advisory Board Clean Air Scientific Advisory Committee (CASAC)

Chair Dr. Joe Mauderly , Director of External Affairs, Senior Scientist, Director of National Environmental Respiratory Center, Lovelace Respiratory Research Ins titute, Albuquerque, NM
Members Mr. John Elston , Administrator, Office of Air Quality Management, State of New Jersey, Department of Environmental Protection and Energy, Trenton, NJ Dr. Philip K. Hopke , Dean of the Graduate School, and R.A. Plane Professor of Chemistry, Clarkson University, Potsdam, NY Dr. Eva J. Pell, , Steimer Professor of Agricultural Sciences, Pennsylvania State University, University Park, PA Dr. Arthur C. Upton, M.D. , Director, Independent Peer Review, CRESP, Environmental and Occupational Health Sciences Institute, Piscataway, NJ Dr. Sverre Vedal , M.D. , Professor of Medicine, University of British Columbia, Vancouver, BC, Canada
Dr. Warren White , Senior Research Associate, Washington University, Chemistry Department, St. Louis, MO
Consultants Dr. Stephen M. Ayres, M.D. , Director, International Health Programs, Virginia Commonwealth University/Medical College of Virginia, Richmond, VA
Dr. Thomas E. Dahms , Professor and Director, Anesthesiology Research, Department of Anesthesiology, St. Louis University School of Medicine,St. Louis, MO
Dr. Victor G. Laties , Professor Emeritus, Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY
Dr. Brian Leaderer, Professor, Division of Environmental Health Sciences, Yale University School of Medicine, New Haven, CT Dr. Lawrence D. Longo, M.D. , Professor, School of Medicine, Department of Physiology, Center for Perinatal Biology, Departments of Physiology and Gynecology and Obstetrics, School of Medicine, Loma Linda University, Loma Linda, CA (did not attend meeting) Science Advisory Board Staff Mr. Robert Flaak , Designated Federal Official (DFO) and Team Leader, Committee Operations Staff, US Environmental Protection Agency, Science Advisory Board, Washington, DC Ms. Diana Pozun , Management Assistant, US Environmental Protection Agency, Science Advisoryii Board, Washington, DC 

### NOTICE
This report has been wri tten as a part of the activities of the Science Advis ory Board, a public advisory group providing extramural scientific information and advice to the Administrator and other officials of the Environmental Pro tection Agency. The Board is structured to provide balanced expert assessment of scientific m atters related to problems f aced by the Agency. This report has not been reviewed for approval by the Agency; and hence, the contents of this report do not n ecessarily represent the views and policies of the Environmental Protection Agency or other agencies in the Federal government. Mention of trade names or commercial products does not constitute a recommendation for use.

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