Air Quality State Implementation Plans; Approvals and Promulgations: New Hampshire; Repeal of Motor Vehicle Inspection and Maintenance Program

What it does

• •Proposes conditional approval of New Hampshire's State Implementation Plan (SIP) revision to remove the statewide motor vehicle inspection and maintenance (I/M) program as an active air quality control measure, effective January 31, 2026.
• •Requires New Hampshire to submit an additional SIP revision within one year of final approval to place the I/M program on the list of potential contingency measures for the 1997 ozone National Ambient Air Quality Standard (NAAQS) maintenance area in southern New Hampshire.
• •Converts the conditional approval to automatic disapproval if New Hampshire fails to submit the required follow-up SIP revision within one year of final approval.

Why it matters

• •The proposed removal is predicated on EPA analysis finding that eliminating the I/M program will not interfere with New Hampshire's compliance with the NAAQS or other Clean Air Act requirements, based on the state's demonstration that projected 2026 emissions will remain substantially below established budgets.
• •The conditional approval links to a separate EPA action on New Hampshire's petition to be removed from the Ozone Transport Region (OTR), which mandates vehicle I/M programs under Clean Air Act section 184(b)(1)(A).
• •By placing the I/M program on a contingency list rather than eliminating it entirely, the EPA preserves the measure as a potential tool if future air quality monitoring shows non-compliance with NAAQS.

Who is affected

• •New Hampshire residents and vehicle owners, as the state's motor vehicle I/M program will cease to be an active requirement.
• •The New Hampshire Department of Environmental Services (NHDES), which must submit a follow-up SIP revision within one year to avoid automatic disapproval.
• •Air quality in the City of Manchester and City of Nashua, which are currently in maintenance status for carbon monoxide and ozone NAAQS.

What happens next

The EPA is accepting public comments until September 25, 2026, after which it will issue a final rule; if the rule is finalized as a conditional approval, New Hampshire must submit the required SIP revision by one year from the approval date or the conditional approval automatically converts to disapproval.