The U.S. Environmental Protection Agency (EPA) is presently conducting a review of the national ambient air quality standards (NAAQS) for particulate matter (PM). The plan and schedule for this review were presented in the Integrated Review Plan for the National Ambient Air Quality Standards for Particulate Matter (IRP; US EPA, 2008a). The IRP identified key policy-relevant issues to be addressed in this review as a series of questions that frame our consideration of whether the current NAAQS for PM should be retained or revised. This Policy Assessment (PA), prepared by staff in the EPAs Office of Air Quality Planning and Standards (OAQPS), is intended to help bridge the gap between the relevant scientific information and assessments and the judgments required of the EPA Administrator in determining whether, and if so how, it is appropriate to revise the NAAQS for PM.1 This PA presents factors relevant to EPAs review of the primary (health-based) and secondary (welfare-based) PM NAAQS. It focuses on both evidence- and risk-based information in evaluating the adequacy of the current PM NAAQS and in identifying potential alternative standards for consideration. In so doing, we are seeking to provide as broad an array of options as is supportable by the available information, recognizing that the selection of a specific approach to reaching final decisions on the primary and secondary PM standards will reflect the judgments of the Administrator.

Project Officer: Beth Hassett-Sipple. "EPA 452/R-11-003." Policy assessment prepared by the staff of the EPA's Office of Air Quality Planning and Standards in conjunction with the Agency's ongoing review of the national ambient air quality standards for particulate matter, which include primary (health-based) and secondary (welfare-based) standards. It presents staff conclusions regarding the current adequacy of the current suite of particulate matter standards as well as potential alternative standards for consideration in this review. Revision: number of original document EPA-452/P-10-007. PB2011-109751.