Air Plan Approval; Delaware; State Implementation Plan for Interstate Transport for the 2008 Ozone Standard

The Environmental Protection Agency (EPA) is approving a state implementation plan (SIP) revision submitted by the State of Delaware. The Clean Air Act's (CAA) Good Neighbor Provision requires EPA and states to address the interstate transport of air pollution that affects the ability of downwind states to attain and maintain the national ambient air quality standards (NAAQS). Specifically, the Good Neighbor Provision requires each state in its SIP to prohibit emissions that will significantly contribute to nonattainment, or interfere with maintenance, of a NAAQS in a downwind state. Delaware submitted a SIP revision on March 23, 2013 that addresses the interstate transport requirements for the 2008 ozone NAAQS. On September 27, 2017, EPA published a proposed rule and a direct final rule approving Delaware's SIP in regard to the Good Neighbor Provision. However, EPA received adverse comments on its September 27, 2017 proposed rule, and subsequently withdrew the accompanying direct final rule. After considering the comments, EPA is approving Delaware's SIP revision submittal in regard to the Good Neighbor Provision for the 2008 ozone NAAQS in accordance with the requirements of the CAA.