Air Plan Approval, Conditional Approval, Limited Approval and Limited Disapproval; Colorado; Serious Attainment Plan Elements and Related Revisions for the 2008 8-Hour Ozone Standard for the Denver Metro/North Front Range Nonattainment Area

In this final action the Environmental Protection Agency (EPA) is addressing all or part of several State Implementation Plan (SIP) revisions submitted by the State of Colorado (as explained further in this document, we are taking no action on some specific portions of the State's submittals). We are approving specified parts of SIP revisions submitted by Colorado on March 22, 2021, related to Clean Air Act (CAA) requirements for the 2008 8-hour ozone National Ambient Air Quality Standards (NAAQS) for the Denver Metro/North Front Range (DMNFR) Serious nonattainment area. We are also finalizing a limited approval and limited disapproval of reasonably available control technology (RACT) SIP revisions from submissions made on May 14, 2018, May 8, 2019, May 13, 2020, March 22, 2021, May 18, 2021, and May 20, 2022. Further, we are finalizing a limited conditional approval and limited disapproval of additional RACT related SIP submissions made on May 31, 2017, and May 10, 2019. Finally, in this document, the EPA is notifying the public of findings as to certain motor vehicle emissions budgets in the DMNFR nonattainment area. This action is being taken under the authority of the CAA.