The Environmental Protection Agency (EPA) published the original Cross-State Air Pollution Rule (original CSAPR) on August 8, 2011, to address interstate transport of ozone pollution under the 1997 ozone National Ambient Air Quality Standards (NAAQS) and interstate transport of fine particulate matter (PM<INF>2.5</INF>) pollution under the 1997 and 2006 PM<INF>2.5</INF> NAAQS. The EPA is finalizing this Cross-State Air Pollution Rule Update (CSAPR Update) to address interstate transport of ozone pollution with respect to the 2008 ozone NAAQS. This final rule will benefit human health and welfare by reducing ground-level ozone pollution. In particular, it will reduce ozone season emissions of oxides of nitrogen (NO<INF>X</INF>) in 22 eastern states that can be transported downwind as NO<INF>X</INF> or, after transformation in the atmosphere, as ozone, and can negatively affect air quality and public health in downwind areas. For these 22 eastern states, the EPA is issuing Federal Implementation Plans (FIPs) that generally provide updated CSAPR NO<INF>X</INF> ozone season emission budgets for the electric generating units (EGUs) within these states, and that implement these budgets via modifications to the CSAPR NO<INF>X</INF> ozone season allowance trading program that was established under the original CSAPR. The EPA is finalizing these new or revised FIP requirements only for certain states that have failed to submit an approvable State Implementation Plan (SIP) addressing interstate emission transport for the 2008 ozone NAAQS. The FIPs require affected EGUs in each covered state to reduce emissions to comply with program requirements beginning with the 2017 ozone season (May 1 through September 30). This final rule partially addresses the EPA's obligation under the Clean Air Act to promulgate FIPs to address interstate emission transport for the 2008 ozone NAAQS. In conjunction with other federal and state actions to reduce ozone pollution, these requirements will