The Environmental Protection Agency (EPA) is finalizing an approval and a limited approval and limited disapproval of revisions to the Mojave Desert Air Quality Management District (MDAQMD or ``District'') portion of the California State Implementation Plan (SIP). These revisions concern the District's New Source Review (NSR) permitting program for new and modified sources of air pollution under part D of title I of the Clean Air Act (CAA or ``Act''). This action updates the District's portion of the California SIP with ten revised rules.

The Environmental Protection Agency (EPA) is approving portions of a State Implementation Plan (SIP) revision submitted by the State of Tennessee, through the Tennessee Department of Environment and Conservation (TDEC), on November 19, 2016, as supplemented on January 20, 2023, in response to a finding of substantial inadequacy and SIP call published on June 12, 2015, regarding provisions in the Tennessee SIP related to excess emissions during startup, shutdown, and malfunction (SSM) events.

On March 30, 2023, the Environmental Protection Agency (EPA) proposed to approve revisions to the Idaho State Implementation Plan (SIP) submitted by the State of Idaho (Idaho or the State) on December 29, 2022. The SIP revision, applicable in the Boise-Northern Ada County Carbon Monoxide area (Northern Ada County CO area) in Idaho, removes the Inspection and Maintenance (I/M) program, which was previously approved into the SIP for use as a control measure in the State's plan to address motor vehicle emissions in the nonattainment area.

The Environmental Protection Agency (EPA) is approving, under the Clean Air Act (CAA), revised sulfur dioxide (SO<INF>2</INF>) regulations submitted by Ohio on May 23, 2022. Ohio updated its regulations to make changes to facility information, remove requirements for shutdown facilities and units, consolidate county-wide requirements, and revise requirements for the Veolia Fort Hill plant in Miami, Ohio and the DTE St. Bernard facility in Cincinnati, Ohio.