Final rule · 2025-20352

Approval and Promulgation of Implementation Plans; State of Utah; Salt Lake City and Provo, Utah PM2.5 Redesignations to Attainment and Utah State Implementation Plan Revisions

The Environmental Protection Agency (EPA) is approving the redesignation of the Salt Lake City, Utah and Provo, Utah nonattainment areas (NAAs) to attainment for the 2006 24-hour fine particulate matter with an aerodynamic diameter less than or equal to a nominal 2.5 microns (PM<INF>2.5</INF>) National Ambient Air Quality Standard (NAAQS), and also approving multiple related State Implementation Plan (SIP) submissions. We are approving SIP revisions submitted by the State of Utah on January 19, 2017; February 4 and 15, 2019; January 13, 2020; December 17, 2020; and July 15, 2025. These SIP submissions include revisions to Utah Administrative Code (UAC) section R307-110; revisions to Utah state law SIP sections IX.H.11, 12, and 13; best available control measures/best available control technologies (BACM/ BACT) PM<INF>2.5</INF> determinations for Salt Lake City and Provo; maintenance plans for the Salt Lake City and Provo areas for PM<INF>2.5</INF> including motor vehicle emissions budgets used for transportation conformity purposes; and the request for redesignation under the 2006 24-hour PM<INF>2.5</INF> standard. The EPA is also finding the budgets adequate for transportation conformity purposes. The EPA is taking this action pursuant to the Clean Air Act (CAA or the Act).