The Environmental Protection Agency (EPA) finds that the Illinois portion of the Chicago-Naperville, IL-IN-WI area (Chicago area) is attaining the 2008 ozone National Ambient Air Quality Standard (NAAQS or standard) and is acting in accordance with a January 25, 2022, request from Illinois to redesignate the Illinois portion of the Chicago area to attainment for the 2008 ozone NAAQS because the request meets the statutory requirements for redesignation under the Clean Air Act (CAA).

This action corrects an omission of timely comment and response in the September 28, 2021, Environmental Protection Agency (EPA) partial approval/partial disapproval of elements of a State Implementation Plan (SIP) submission from Michigan to address the infrastructure requirements of section 110 of the Clean Air Act (CAA) for the 2015 ozone National Ambient Air Quality Standards (NAAQS). Accordingly, this action amends the effective date of the final approval to reflect EPA's current response to the previously omitted comment.

The Environmental Protection Agency (EPA) is approving a state implementation plan (SIP) revision submitted by the Commonwealth of Pennsylvania on behalf of the Allegheny County Health Department (ACHD). The revision updates Allegheny County's portion of the Pennsylvania SIP, which includes regulations concerning sulfur content in fuel oil. This revision pertains to the reduction of the maximum allowable sulfur content limit for Number 2 (No.

The Environmental Protection Agency (EPA) is approving a state implementation plan (SIP) revision submitted by the State of Colorado. The submittal certifies that the State of Colorado has fulfilled, through previous SIP revisions, Nonattainment New Source Review (NNSR) Permit Program requirements under the 2015 8-hour ozone National Ambient Air Quality Standards (NAAQS) for the Denver Metro/North Front Range (DMNFR) area. The State of Colorado submitted the certification to meet the nonattainment requirements for Marginal ozone nonattainment areas (NAAs) for the 2015 8-hour ozone NAAQS.