Proposed rule · 2026-21288

Approval and Promulgation of Implementation Plans-Pinal County (Part); West Pinal, AZ PM10 Nonattainment Area; Moderate Area, Serious Area, and Section 189(d) Plan for Attainment of the 24-Hour PM10 Standard

The U.S. Environmental Protection Agency (EPA) is proposing to approve a state implementation plan (SIP) revision submitted by the State of Arizona to meet Clean Air Act (CAA or "Act") requirements applicable to the Pinal County (Part); West Pinal PM<INF>10</INF> nonattainment area ("West Pinal County PM<INF>10</INF> Nonattainment Area"). The EPA is proposing to find that the submitted SIP revision meets all applicable "Moderate" area, "Serious" area, and CAA section 189(d) requirements for the PM<INF>10</INF> national ambient air quality standards (NAAQS). Additionally, the EPA is proposing to approve the PM<INF>10</INF> motor vehicle emissions budgets included with the SIP revision for transportation conformity purposes. The EPA is also starting the adequacy process for these budgets. Our proposed approval of the SIP revision would establish an attainment date of December 31, 2026, for the area.