The U.S. Environmental Protection Agency (EPA) is presently conducting a review of the national ambient air quality standards (NAAQS) for ozone (O3) and related photochemical oxidants. An overview of the approach to reviewing the O3 NAAQS is presented in the Integrated Review Plan for the Ozone National Ambient Air Quality Standards (IRP, US EPA, 2011a). The IRP discusses the schedule for the review; the approaches to be taken in developing key scientific, technical, and policy documents; and the key policy-relevant issues that will frame our consideration of whether the current NAAQS for O3 should be retained or revised. Sections 108 and 109 of the Clean Air Act (CAA) govern the establishment and periodic review of the NAAQS. These standards are established for pollutants that may reasonably be anticipated to endanger public health and welfare, and whose presence in the ambient air results from numerous or diverse mobile or stationary sources. The NAAQS are to be based on air quality criteria, which are to accurately reflect the latest scientific knowledge useful in indicating the kind and extent of identifiable effects on public health or welfare that may be expected from the presence of the pollutant in ambient air.

"July 2012". EPA Project Officer: Travis Smith. Includes bibliographical references. "EPA 452/P-12-004".