Policy Assessment for the Review of the Ozone National Ambient Air Quality Standards Second External Review Draft (English Edition)

This second draft Policy Assessment (PA) has been prepared by staff in the Environmental Protection Agency’s (EPA) Office of Air Quality Planning and Standards (OAQPS) as part of the Agency’s ongoing review of the primary (health-based) and secondary (welfare-based) national ambient air quality standards (NAAQS) for ozone (O3). It presents analyses and preliminary staff conclusions regarding the policy implications of the key scientific and technical information that informs this review. Preliminary staff conclusions are presented regarding the adequacy of the current standards and, as appropriate, potential alternative standards appropriate for consideration in this review. Staff analyses in this second draft PA are based on the scientific and technical information, as well as uncertainties and limitations related to this information, assessed in other EPA documents, including the scientific assessment presented in the Integrated Science Assessment for Ozone, the second draft Health Risk and Exposure Assessment for Ozone and the second draft Welfare Risk and Exposure Assessment for Ozone. The final 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 16 whether to retain or revise the current standards.