Role of Science Advisory Groups in Eastablishing Standards for Ambient Air Pollutants

Abstract

The scientific data bases on the sources, transport, transformations, sampling and analytical technology, exposures and effects of ubiquitous air pollutants have been essential resources in the development of the National Ambient Air Quality Standards (NAAQSs), and the Clean Air Scientific Advisory Committee (CASAC) has provided critical review and oversight of the Environmental Protection Agency (EPA) staffs use of the data in developing proposed standards for the Administrator. It has also provided guidance to EPA in planning research needed to address critical knowledge gaps. This paper provides a review of the development of the current process used in developing ambient air standards, a chronology of some landmark events, a critique of the current process, and a summary of CASAC's recent recommendations for improving the process. Standards for point source pollutants are developed by a process that differs in many respects from those used for the more ubiquitous “criteria” pollutants. The health assessment documents for the “hazardous” pollutants from point sources receive critical review from the Environmental Health Committee of the EPA's Science Advisory Board (SAB). They contain quantitative probability estimates of cancer risk based on animal toxicology and human epidemiology studies. While exposure assessments developed for NAAQSs are subject to CASAC review, those for hazardous air pollutants have not been subjected to SAB review. The National Emissions Standards For Hazardous Air Pollutants (NESHAPs) are based primarily on the application of specific source control technologies. There is currently no established procedure for SAB review of the scientific basis for EPA's proposals for NESHAPs. A chronology of some landmark events in the development of regulatory controls for point source pollutants is presented and discussed.