The Environmental Protection Agency (EPA) is finalizing the approval of a revision to the Kentucky State Implementation Plan (SIP), submitted by the Commonwealth of Kentucky, through the Kentucky Division for Air Quality (KDAQ), on March 29, 2021. The revision was submitted by KDAQ on behalf of the Louisville Metro Air Pollution Control District (District or Jefferson County), which has jurisdiction over Jefferson County, Kentucky.

The Environmental Protection Agency (EPA) is taking final action to disapprove revisions to the Antelope Valley Air Quality Management District (AVAQMD) and the Mojave Desert Air Quality Management District (MDAQMD) portions of the California State Implementation Plan (SIP) concerning rules submitted to address section 185 of the Clean Air Act (CAA or the Act) with respect to the 1-hour ozone standard.

The Environmental Protection Agency (EPA) is taking final action to find that the State of California has failed to submit State Implementation Plan (SIP) revisions to satisfy the contingency measures requirements of the Clean Air Act (CAA) for the 2008 8-hour ozone National Ambient Air Quality Standards (NAAQS or ``standards'') for both the Riverside County (Coachella Valley), California (``Coachella Valley'') and Los Angeles-San Bernardino Counties (West Mojave Desert), California (``West Mojave Desert'') nonattainment areas.

The Environmental Protection Agency (EPA) is approving revisions to Michigan Air Pollution Control Rules Part 1 Definitions, and Part 2 Air Use Approval for inclusion in the Michigan State Implementation Plan (SIP). Additionally, EPA is removing rules from the SIP that are part of Michigan's title V Renewable Operating Permit program, and rules that have been moved to other sections of the Michigan Administrative Code and approved into the Michigan SIP.