Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania: Attainment Demonstration and Contingency Measures for the Liberty Borough PM-10 Nonattainment Area

EPA is approving State Implementation Plan (SIP) revisions submitted by the Pennsylvania Department of Environmental Protection (PADEP) consisting of an attainment demonstration and contingency measures for Allegheny County, Pennsylvania's Liberty Borough particulate matter moderate nonattainment area. EPA is approving the attainment demonstration because the Allegheny County Healthy Department's (ACHD) modeling analysis (submitted as a SIP revision by PADEP) adequately demonstrates that the regulatory portion of the attainment plan is sufficient to attain and maintain the National Ambient Air Quality Standards (NAAQS) for particulate matter that were in effect at the time of the submittal, and because its analyses have been corroborated by monitored air quality data. EPA is approving the contingency measures for the area because they satisfy the requirements of the Clean Air Act (the Act). EPA approved the regulatory portion of the attainment plan for the Liberty Borough area as a SIP revision in an earlier rulemaking action. Elsewhere in today's Federal Register, EPA has published its determination that the Liberty Borough area has attained the NAAQS for particulate matter. In an earlier action, EPA approved source-specific control requirements for the USX Clairton Coke Works which further strengthen the SIP for the Liberty Borough area.