The Environmental Protection Agency (EPA) is making a final determination that the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD- DE marginal ozone nonattainment area (the Philadelphia Area) has attained the 2008 ozone national ambient air quality standard (NAAQS) by the July 20, 2016 attainment date. This final determination is based on complete, certified, and quality assured ambient air quality monitoring data for the Philadelphia Area for the 2013-2015 monitoring period. The effect of this determination of attainment (DOA) is that the Philadelphia Area will not be bumped up or reclassified as a moderate nonattainment area. The determination of attainment is not equivalent to a redesignation, and the States in the Philadelphia Area must still meet the statutory requirements for redesignation in order to be redesignated to attainment. This determination is also not a clean data determination. This action is being taken under the Clean Air Act (CAA).