The Environmental Protection Agency (EPA) is approving a State Implementation Plan (SIP) revision submitted by the State of Tennessee on April 9, 2021. Specifically, EPA is approving updates to the incorporation by reference of Federal guidelines on air quality modeling in the Tennessee SIP. EPA is also converting the previous conditional approval regarding infrastructure SIP prevention of significant deterioration (PSD) elements for the 2015 ozone national ambient air quality standards (NAAQS) for Tennessee to a full approval.

The Environmental Protection Agency (EPA) is finalizing a determination that the Nevada County (Western part) and Ventura County areas in California, both classified as Serious for the 2008 ozone National Ambient Air Quality Standards (NAAQS), attained the 2008 ozone NAAQS by the July 20, 2021 attainment date. The EPA is also finalizing a determination that six areas in California classified as Marginal for the 2015 ozone NAAQS, attained the 2015 ozone NAAQS by the August 3, 2021 attainment date.

On February 28, 2022, the State of Georgia, through the Georgia Environmental Protection Division (GA EPD) of the Department of Natural Resources, submitted a request for the Environmental Protection Agency (EPA) to redesignate the Atlanta, Georgia 2015 8-hour ozone nonattainment area (hereinafter referred to as the ``Atlanta Area'' or ``Area'') to attainment for the 2015 8-hour ozone National Ambient Air Quality Standards (NAAQS or standards) and to approve a State Implementation Plan (SIP) revision containing a maintenance plan for the Area.

On January 5, 2021, the United States Court of Appeals for the Tenth Circuit granted the Environmental Protection Agency's (EPA) motion for a voluntary remand without vacatur of two parts of an EPA 2020 final rule approving Colorado's infrastructure state implementation plan (SIP) submission for the 2015 8-hour ozone national ambient air quality standards (NAAQS) (2020 final rule). In this document, EPA is taking final action to approve those two remanded parts of the 2020 final rule.