The Environmental Protection Agency (EPA) is approving a revision to the Jefferson County portion of the Kentucky State Implementation Plan (SIP) submitted by the Commonwealth of Kentucky through the Kentucky Energy and Environment Cabinet (Cabinet) on June 13, 2022. The changes were submitted by the Cabinet on behalf of the Louisville Metro Air Pollution Control District (District, also referred to herein as Jefferson County). EPA is approving changes to the District's rules on the construction or modification of major stationary sources that are located within nonattainment areas or that have emissions impacting nonattainment areas. EPA also is approving the certification submitted by Kentucky on behalf of the District that the new version of the Nonattainment New Source Review (NNSR) permitting regulations for incorporation into the Jefferson County portion of the Kentucky SIP meets the NNSR nonattainment planning requirements for the 2015 8-hour ozone National Ambient Air Quality Standards (NAAQS). The certification covers the Jefferson County portion of the Louisville, Kentucky-Indiana multi-state nonattainment area for the 2015 8-hour ozone NAAQS. This action is pursuant to the Clean Air Act (CAA or Act) and its implementing regulations.