US EPA

The Clean Air Act (CAA) requires periodic review of existing criteria that form the basis for carbon monoxide (CO) air quality standards. These air quality criteria are to reflect the latest scientific information useful in indicating the kind and extent of all identifiable effects on pubic health that may be expected from the presence of CO in ambient air. n keeping with the requirements of the CAA, the U.S. Environmental Protection Agency has stated to review the criteria for CO. umber of critical issues germane to this review are presented. dditional session papers provide more detailed discussion of these Issues. his paper discusses specific health issues pertaining to: 1) mechanisms of action of CO, particularly an evaluation of intracellular mechanisms secondary to impaired oxygen delivery caused by the formation of carboxyhemoglobin (COHb); (2) exposure assessment, including an evaluation of the accuracy and reliability of different methods for determining COHb; and (3) specific health effects occurring in groups of individuals considered to ba at greatest risk to CO at ambient or near-ambient exposure levels including a reevaluation of previous dose-response functions for CO utilizing the information gained from recently completed studies. These critical issues will need to be resolved in order to determine the extent to which adverse effects are occurring in the population, particularly at the lower COHb levels of greatest interest to standard setting.

Raub, J. AND L. Grant. CRITICAL HEALTH ISSUES ASSOCIATED WITH REVIEW OF THE SCIENTIFIC CRITERIA FOR CARBON MONOXIDE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/D-91/090 (NTIS PB91191304).

Presented at 82nd Annual Meeting of APCA, Anaheim, CA, June 25-30, 1989