The Environmental Protection Agency (EPA) is approving revisions to the Illinois State Implementation Plan (SIP) that were submitted by the Illinois Environmental Protection Agency (IEPA) on September 22, 2020, and amended on November 5, 2020, and March 3, 2021. These revisions implement new preconstruction permitting regulations for certain new or modified sources of air pollution in attainment and unclassifiable areas under the Prevention of Significant Deterioration (PSD) program of the Clean Air Act (CAA).

The Environmental Protection Agency (EPA) is approving changes to the North Carolina State Implementation Plan (SIP) submitted through the North Carolina Division of Air Quality (NCDAQ) on October 9, 2020. The SIP revision seeks to modify the State's monitoring, recordkeeping, and reporting regulations by adding one definition, adding references to approved testing methods, updating the reference format, and making minor changes to general formatting and language use for clarity purposes. EPA is approving these changes pursuant to the Clean Air Act (CAA or Act).

The Environmental Protection Agency (EPA) is approving state implementation plan (SIP) revisions submitted by the State of Tennessee, through the Tennessee Department of Environment and Conservation (TDEC), through letters dated February 26, 2020. Specifically, EPA is approving the removal of Tennessee's motor vehicle inspection and maintenance (I/M) program requirements for Davidson, Sumner, Rutherford, Williamson and Wilson Counties in Tennessee (also known as the Middle Tennessee Area) and Hamilton County (also known as the Chattanooga Area), from the federally-approved SIP.

The Environmental Protection Agency (EPA) is approving a revision to the Oregon State Implementation Plan (SIP) submitted on January 29, 2021. The revision updates the date by which Federal provisions are adopted by reference into the Oregon SIP, making air quality requirements more current.