Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Determination of Attainment of the 2006 24-Hour Fine Particulate Standard for the Liberty-Clairton Nonattainment Area

The Environmental Protection Agency (EPA) is proposing to make a determination of attainment regarding the Liberty-Clairton, Pennsylvania 2006 24-hour fine particulate matter (PM2.5) nonattainment area (hereafter ``Liberty-Clairton Area'' or ``the Area''). EPA is proposing to determine that the Liberty-Clairton Area has attained the 2006 24-hour PM2.5 National Ambient Air Quality Standard (NAAQS), based upon quality-assured, quality- controlled and certified ambient air monitoring data for the calendar years 2012-2014. If EPA finalizes this ``clean data determination,'' the requirement for the Liberty-Clairton Area to submit an attainment demonstration, reasonably available control measures (RACM), reasonable further progress (RFP), and contingency measures related to attainment of the 2006 24-hour PM2.5 NAAQS would be suspended for so long as the Area continues to attain the 2006 24-hour PM2.5 NAAQS. If finalized, this determination will not constitute a redesignation to attainment. This proposed action is being taken under the Clean Air Act (CAA).