Final rule · 2026-22647

Air Plan Revisions; Arizona; Maricopa County Air Quality Department; New Source Review; Emission Reduction Credits

The U.S. Environmental Protection Agency (EPA) is taking final action to approve a revision to the Maricopa County Air Quality Department (MCAQD or "Department") portion of the Arizona State Implementation Plan (SIP). This revision establishes a federally enforceable program allowing for the generation of emission reduction credits (ERCs) by retrofitting or replacing existing on-road vehicles with lower emitting vehicles while meeting other Clean Air Act (CAA or "Act") requirements. These ERCs are intended to be used as offsets for major stationary sources under the Department's Nonattainment New Source Review (NNSR) program. The EPA is approving this SIP revision because we find that it meets the applicable CAA requirements.