Approval of One-Year Extension for Attaining the 1997 8-Hour Ozone Standard for the Delaware, Maryland, and Pennsylvania Portions of the Philadelphia-Wilmington-Atlantic City Moderate Nonattainment Area

EPA is proposing to extend the attainment date from June 15, 2010 to June 15, 2011 for the Delaware, Maryland, and Pennsylvania portions of the Philadelphia-Wilmington-Atlantic City nonattainment area (Philadelphia Area), which is classified as moderate for the 1997 8-hour ozone national ambient air quality standard (NAAQS). This extension is based in part on air quality data recorded during the 2009 ozone season. Specifically, the Philadelphia Area's 4th highest daily 8-hour monitored ozone value during the 2009 ozone season is 0.084 parts per million (ppm) or less. Accordingly, EPA is revising the tables concerning the 8-hour ozone attainment dates for the Philadelphia Area in the States of Delaware and Maryland, and the Commonwealth of Pennsylvania. EPA is proposing to approve the extension of the attainment date for the Delaware, Maryland, and Pennsylvania portions of the Philadelphia Area in accordance with the requirements of the Clean Air Act (CAA). EPA is proposing to approve the extension of the attainment date for the New Jersey portion of the Philadelphia Area in a separate rulemaking in this Federal Register.