The Utah Division of Air Quality reported to the Transportation Coordinating Committee on June 15 that the state’s current moderate ozone State Implementation Plan (SIP) does not meet the required reasonable further progress (RFP) reductions. Ryan Bars, an environmental scientist with the Utah Division of Air Quality, said the Northern Wasatch Front nonattainment area (Salt Lake, Davis, Weber and Tooele counties) has a 2024 design value of about 79 parts per billion — above the 2015 NAAQS ozone standard of 70 ppb — and explained the SIP’s shortfall and likely transportation implications.

Bars said the RFP test requires a 15% reduction in volatile organic compound (VOC) emissions relative to a 2017 baseline — roughly equal to about 14 tons per day in the nonattainment area. He said the current SIP accounts for approximately 3.7 tons per day of VOC reductions, leaving roughly 10 tons per day of additional reductions to identify and implement. Bars told the committee that the SIP was out for public comment and that state staff plan to submit a final package to the Air Quality Board in September for transmittal to EPA; EPA generally has up to 12 months to act on SIP submittals.

The transportation consequence is direct: motor vehicle emission budgets (MVEBs) included in the SIP are used to determine whether regional transportation plans and TIPs conform to air quality goals. Wayne Bennion of the Wasatch Front Regional Council told the committee that if EPA disapproves the SIP and the MVEBs — a likely outcome unless additional reductions are added — WFRC will not be able to conduct new conformity analyses for regional emissions. That condition leads to a practical “conformity freeze” in which only projects that are: (a) in the first four years of the TIP and phase 1 of the RTP, or (b) exempt from conformity requirements (certain safety, operations, maintenance and some transit projects), could proceed until a new, approvable SIP is in place. Bennion said the conformity freeze period under EPA rules could last two years; after that, sanctions or funding restrictions could apply unless the state submits and EPA approves a subsequent serious SIP.

Bars said the state is continuing to identify and roll out additional emissions‑reduction measures, and noted the SIP’s public comment period was open from June 1 to July 17 with planned board consideration in September. He cautioned that much of the lowest‑cost, readily achievable precursor reductions were already captured in prior winter particulate work, and identifying the remaining 10 tons per day will be technically difficult.

Committee discussion emphasized the gravity of the situation. Kevin Cromer (Utah Air Quality Board) called the potential consequences “very serious,” noting the prospect of constrained project delivery. WFRC and FHWA representatives said they would coordinate with the state to track SIP progress and with local agencies to prioritize any regionally significant capacity projects that members want to see advanced before a potential conformity freeze.

Why this matters: a SIP disapproval that removes approvable MVEBs directly pauses the ability to add regionally significant highway and transit capacity projects to the RTP and TIP unless they are already within the first four years of the TIP and phase 1 of the RTP; that restriction can delay construction and the use of federal funds for major projects. The committee was advised to review major project schedules and TIP amendments now if they want to avoid delay should EPA disapprove the SIP.

Ending: Division of Air Quality staff and WFRC staff will continue to coordinate; WFRC recommended jurisdictions ensure high‑priority regional projects are programmed into the RTP and TIP before the expected EPA action. The Air Quality Division will accept public comments through July 17 and planned final submittal to EPA in September.