Prevention of Significant Deterioration for Particulate Matter Less Than 2.5 Micrometers-Significant Impact Levels and Significant Monitoring Concentration: Removal of Vacated Elements

On January 22, 2013, the United States Court of Appeals for the District of Columbia Circuit (the Court) granted a request from the EPA to vacate and remand to the EPA portions of two Prevention of Significant Deterioration (PSD) regulations, promulgated in 2010 under the authority of the Clean Air Act (CAA), regarding the Significant Impact Levels (SILs) for particulate matter less than 2.5 micrometers (PM<INF>2.5</INF>). The Court further vacated the portions of the PSD regulations establishing a PM<INF>2.5</INF> Significant Monitoring Concentration (SMC). The EPA is amending its regulations to remove the vacated PM<INF>2.5</INF> SILs and SMC provisions from the PSD regulations in the Code of Federal Regulations (CFR). This action is exempt from notice-and-comment rulemaking because it is ministerial in nature. The EPA will initiate a separate rulemaking in the future regarding the PM<INF>2.5</INF> SILs that will address the Court's remand.