This Policy Assessment (PA) has been prepared by staff in the Environmental Protection Agencys (EPA) Office of Air Quality Planning and Standards (OAQPS) as part of the Agencys review of the primary (health-based) and secondary (welfare-based) national ambient air quality standards (NAAQS) for ozone (O3). The current O3 standards were established in 2008 at the end of the previous review cycle. These standards include a primary O3 standard of 75 ppb,1 and a secondary O3 standard set identical to the primary standard. These 2008 standards are now under review, as required by sections 108 and 109 of the Clean Air Act (Act). The PA presents analyses and staff conclusions regarding the policy implications of the key scientific and technical information that informs this review. Staff conclusions are presented regarding the adequacy of the current standards and potential alternative standards appropriate for consideration. Staff analyses in this PA are based on the scientific and technical information, including the uncertainties and limitations related to this information, assessed and presented in the Integrated Science Assessment for Ozone (ISA), the Health Risk and Exposure Assessment for Ozone (HREA), and the Welfare Risk and Exposure Assessment for Ozone (WREA). The PA is intended to bridge the gap between the relevant scientific evidence and technical information and the judgments required of the EPA Administrator in determining whether to retain or revise the current standards. Development of the PA is also intended to facilitate advice and recommendations on the standards to the Administrator from an independent scientific review committee, the Clean Air Scientific Advisory Committee (CASAC), as provided for in the Act. Staff considerations and conclusions in this final PA have been informed by comments and recommendations from CASAC, and by public comments.

Project Officer: Susan Lyon Stone. Revision of EPA document EPA-452/P-14-002. "EPA-452/R-14-006." "August 2014." Includes bibliographical references.