The Environmental Protection Agency (EPA) is approving a state implementation plan (SIP) revision submitted by the State of Maryland. The revision certifies that Maryland's existing nonattainment new source review (NNSR) program, covering the Baltimore nonattainment area, the Philadelphia-Wilmington-Atlantic City nonattainment area, and the Washington, DC nonattainment area for the 2015 8-hour ozone national ambient air quality standards (NAAQS), is at least as stringent as applicable Federal requirements. EPA is approving these revisions to the Maryland SIP in accordance with the requirements of the Clean Air Act (CAA).