# 2026-07405: EPA Proposes Approving Arizona's Vehicle Upgrade Credits for Cleaner Air 2026-07405, Air Plan Revisions; Arizona; Maricopa County Air Quality Department; New Source Review; Emission Reduction Credits, is a Federal Register proposed rule from Environmental Protection Agency published 2026-04-16, effective Comments must be received on or before May 18, 2026.; PRIA reads it as touching household money (as of 2026-06-11). - Canonical: https://policyrisk.com/federal-register/2026-07405 - As of: 2026-06-11 - Plain-text twin of the page above; the HTML and this file carry the same facts. ## Facts - Document number: 2026-07405 - Title: Air Plan Revisions; Arizona; Maricopa County Air Quality Department; New Source Review; Emission Reduction Credits - Type: Proposed Rule - Agencies: Environmental Protection Agency - Citation: 91 FR 20394 - Published: 2026-04-16 - Effective: Comments must be received on or before May 18, 2026. - Comments close: not stated - Significant: no - Touches household money: yes - Regulation identifier numbers: none - Last updated: 2026-06-11 ## In one line EPA Proposes Approving Arizona's Vehicle Upgrade Credits for Cleaner Air ## Summary The EPA wants to approve a new rule in Maricopa County, Arizona, that lets fleet owners earn credits by upgrading their vehicles to cleaner ones. These credits can help big polluters meet air quality rules, encouraging cleaner air without extra costs. People have until May 18, 2026, to share their thoughts before the rule becomes final. ## Abstract The Environmental Protection Agency (EPA) is proposing 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 fleet owners/operators to generate emission reduction credits (ERCs) by either retrofitting or replacing existing fleet vehicles with lower emitting vehicles while meeting other Clean Air Act (CAA or "Act") requirements. These ERCs are intended for use as offsets for major stationary sources under the Department's Nonattainment New Source Review (NNSR) program. We are proposing to approve a local rule to allow for the generation of ERCs through voluntary on-road mobile source emission reductions under the CAA. We are taking comments on this proposal and plan to follow with a final action. ## Effects PRIA read - Fleet Owners Can Earn Mobile Emission Credits: benefit, medium. If you run a vehicle fleet in Maricopa County, you can generate emission reduction credits (MERCs) by permanently retrofitting or replacing fleet vehicles with lower-emitting models under Maricopa County Rule 205 (revised May 21, 2025). Those MERCs apply only to ozone precursors (NOX and VOC) and c… - Generators Face Monitoring and Reporting Rules: cost, medium. Fleet owners who generate MERCs must submit applications, follow specified methodologies to calculate reductions, and comply with ongoing monitoring, recordkeeping, and reporting before the Department will issue MERC certificates under Rule 205. These procedures are required for generators to have… - Stationary Sources Can Use Mobile Credits for NNSR Offsets: benefit, medium. Major stationary sources in the relevant Maricopa County nonattainment areas may use MERCs from on-road mobile sources to offset projected NOX or VOC emissions increases for NNSR permitting, subject to NNSR rules and the requirement that offsets be real, surplus, quantifiable, permanent, and federa… - Federal SIP Approval Would Make MERCs Federally Enforceable: benefit, low. The EPA is proposing to approve Maricopa County Rule 205 into the Arizona SIP; if finalized, MERCs generated under Rule 205 would become part of the federally enforceable SIP and must meet federal offset integrity criteria before an NNSR permit may be issued. The public comment period for this prop… ## Related documents - [2026-19071](https://policyrisk.com/federal-register/2026-19071): Partial Repeal of the Carbon Pollution Standards for Fossil Fuel-Fired Electric Generating Units, 2026-09-17 - [2026-19072](https://policyrisk.com/federal-register/2026-19072): Rescission of the Greenhouse Gas Findings for Fossil Fuel-Fired Power Plants and Repeal of Regulations for Power Plant Greenhouse Gas Emiss…, 2026-09-17 - [2026-18317](https://policyrisk.com/federal-register/2026-18317): Updated Definition of “Waters of the United States”, 2026-09-09 - [2026-14112](https://policyrisk.com/federal-register/2026-14112): Amendments and Nonconformance Penalties for Model Year 2027 and Later Heavy-Duty Highway Engines and Amendments to Inducement Provisions fo…, 2026-07-14 - [2026-13667](https://policyrisk.com/federal-register/2026-13667): Minor New Source Review Program Air Permitting Public Participation Requirements for State Implementation Plans, 2026-07-07 - [2026-13263](https://policyrisk.com/federal-register/2026-13263): Revisions To Establish the Sixth Unregulated Contaminant Monitoring Rule (UCMR 6) for Public Water Systems, 2026-07-01 ## Sources - [2026-07405 on federalregister.gov](https://www.federalregister.gov/documents/2026/04/16/2026-07405/air-plan-revisions-arizona-maricopa-county-air-quality-department-new-source-review-emission) - [2026-07405 as published (PDF)](https://www.govinfo.gov/content/pkg/FR-2026-04-16/pdf/2026-07405.pdf) ## Related - [Previous: 2026-07334, Airworthiness Directives; Airbus Helicopters](https://policyrisk.com/federal-register/2026-07334) - [Next: 2026-07417, Establishment of Class E Airspace; Freer, TX](https://policyrisk.com/federal-register/2026-07417) - [All Federal Register documents](https://policyrisk.com/federal-register) Source: PRIA, https://policyrisk.com/federal-register/2026-07405 (as of 2026-06-11).