Air Plan Approval; Mississippi; PSD and Air Quality Modeling Infrastructure Requirements for the 2015 8-Hour Ozone National Ambient Air Quality Standards

The Environmental Protection Agency (EPA) is approving a State Implementation Plan (SIP) submission provided by the State of Mississippi, through the Mississippi Department of Environmental Quality (MDEQ), via a letter dated February 28, 2024. Specifically, EPA is finalizing approval of updates to the incorporation by reference of Federal prevention of significant deterioration (PSD) rules in the Mississippi SIP. EPA is also converting the previous conditional approval of Mississippi's infrastructure SIP PSD and air quality modeling provisions for the 2015 Ozone National Ambient Air Quality Standards (NAAQS) to a full approval. EPA is also approving changes to public notice provisions for PSD permitting to provide for electronic notice (e-notice) and to remove the mandatory requirement to provide public notice in a newspaper, and other minor changes to the PSD rules. EPA is finalizing approval of these changes pursuant to the Clean Air Act (CAA or Act).