The Environmental Protection Agency (EPA) is approving a revision to the Idaho State Implementation Plan (SIP) submitted on May 4, 2022. The submission updates the incorporation by reference of the national ambient air quality standards and related planning and monitoring requirements into the Idaho air quality rules as of July 1, 2021. Idaho undertakes such updates regularly to ensure the state air quality rules and the federally enforceable Idaho SIP remain consistent with EPA air quality regulations over time.

The Environmental Protection Agency (EPA) is taking final action to approve revisions to the Missouri State Implementation Plan (SIP) received on November 29, 2016, and March 7, 2019. The revisions were submitted by Missouri in response to a finding of substantial inadequacy and SIP call published on June 12, 2015, for a provision in the Missouri SIP related to excess emissions during startup, shutdown, and malfunction (SSM) events. In the submissions, Missouri requests to revise a regulation related to restriction of emissions of visible air contaminants.

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 15, 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).

The Environmental Protection Agency (EPA) is finalizing a program to further reduce air pollution, including ozone and particulate matter (PM), from heavy-duty engines and vehicles across the United States. The final program includes new emission standards that are significantly more stringent and that cover a wider range of heavy-duty engine operating conditions compared to today's standards; further, the final program requires these more stringent emissions standards to be met for a longer period of when these engines operate on the road.