This Staff Paper, prepared by staff in the U.S. Environmental Protection Agency's (EPA) Office of Air Quality Planning and Standards (OAQPS), evaluates the policy implications of the key studies and scientific information contained in the document, Air Quality Criteria for Particulate Matter (EPA, 2004; henceforth referred to as the Criteria Document (CD) and cited as CD), prepared by EPA's National Center for Environmental Assessment (NCEA). This Staff Paper also presents and interprets results from staff analyses (e.g., air quality analyses, human health risk assessments, and visibility analyses) that staff believes should be considered in EPA's current review of the national ambient air quality standards (NAAQS) for particulate matter (PM). Finally, this Staff Paper presents staff conclusions and recommendations as to potential revisions of the primary (health-based) and secondary (welfare-based) PM NAAQS, based on consideration of the available scientific information and analyses and related limitations and uncertainties.

Project officer: Mary Ross. "December 2005." "EPA-452/R-05-005a." PB2006-102406. Includes bibliographical references.