Approval and Promulgation of Air Quality Implementation Plans; District of Columbia; Amendments to the Size Thresholds for Defining Major Sources and to the NSR Offset Ratios for Sources of VOC and NOX

EPA is taking direct final action to approve revisions to the District of Columbia (the District) State Implementation Plan (SIP). The revisions reduce the size thresholds for defining major sources and increase the new source review (NSR) offset ratio requirements for sources of ozone precursors to meet the Clean Air Act (CAA) requirements for 1-hour ozone nonattainment areas classified as severe. These amendments to the District's SIP are required pursuant to the reclassification of the Metropolitan Washington, DC 1-hour ozone nonattainment area from serious to severe. This action is being taken under the CAA.