The Environmental Protection Agency (EPA) is redesignating the Oakridge, Oregon nonattainment area to attainment for the 1987 National Ambient Air Quality Standard for particulate matter of 10 microns or less (PM<INF>10</INF> NAAQS). The EPA is also approving a maintenance plan for the area that demonstrates continued compliance with the PM<INF>10</INF> NAAQS through the year 2035, which Oregon submitted, along with the redesignation request, for inclusion into the Oregon State Implementation Plan (SIP).

The Environmental Protection Agency (EPA) finds that the Indiana portion of the Louisville, Indiana-Kentucky area (Area) is attaining the 2015 primary and secondary ozone National Ambient Air Quality Standards (NAAQS), and acts in accordance with a request from the Indiana Department of Environmental Management (IDEM) to redesignate the Indiana portion of the area to attainment for the 2015 ozone NAAQS because the request meets the statutory requirements for redesignation under the Clean Air Act (CAA).

The Environmental Protection Agency (EPA) is approving the Limited Maintenance Plan (LMP) submitted by the State of Montana to EPA on November 4, 2021, for the Thompson Falls Moderate nonattainment area (NAA) for particulate matter with an aerodynamic diameter less than or equal to a nominal 10 micrometers (PM<INF>10</INF>) and concurrently redesignating the NAA to attainment for the 24-hour PM<INF>10</INF> National Ambient Air Quality Standard (NAAQS).

The Environmental Protection Agency (EPA) finds that the Indiana portion of the Chicago-Naperville, IL-IN-WI area (Chicago area) is attaining the 2008 ozone National Ambient Air Quality Standard (NAAQS or standard). In addition, in response to a December 6, 2021, request from the Indiana Department of Environmental Management (Indiana or the State), EPA is redesignating the Indiana portion of the Chicago area to attainment for the 2008 ozone NAAQS, because the State has met the statutory requirements for redesignation under the Clean Air Act (CAA).