The Environmental Protection Agency (EPA) has approved Texas’ State Implementation Plan (SIP) to improve air quality in the San Antonio area. The approval is part of the new administration’s efforts to address the nation’s massive backlog of both state and tribal implementation plans. When announced, there were 685 SIPs, with 322 considered overdue.
Texas’ plan to enforce a clean-air environment in the San Antonio region prioritizes measures to address vehicle emissions and improve air quality. These include vehicle inspections and maintenance requirements in Bexar County.
Implementing these measures will be a critical step in ensuring the San Antonio region complies with the Clean Air Act, enabling better transparency and identification of vehicles with malfunctioning emission control systems. The area has been classified as a moderate nonattainment zone since the 2015 ozone standard.
The state was required to revise its SIP to reduce vehicle emissions after finding its ground-level ozone was 70 parts per billion. Ground-level ozone is the result of chemical reactions between oxides of nitrogen and volatile organic compounds. These pollutants—commonly emitted by cars, power plants, industrial boilers, refineries and chemical plants—chemically react in sunlight to contaminate the air.
The state must exercise and expand its revised inspection and maintenance program in Bexar County by Nov. 7, 2026. Under the program, all gasoline-powered vehicles between 2 and 24 years old must undergo annual onboard diagnostics testing.
Photo by Khunkorn Laowisit
