Engine exhaust is one of the leading causes of ozone pollution in Bexar County.
Engine exhaust is one of the major sources of air pollution in Bexar County. Credit: Scott Ball / San Antonio Report

The U.S. Environmental Protection Agency announced Wednesday a proposed action to move Bexar County into an air quality classification that would require stricter pollution reduction efforts.

Should that move be finalized, Bexar County would move from “marginal” to “moderate” ozone nonattainment. This new designation will mean the region will be required to comply with federal air quality regulations and meet the ozone standard of 70 parts per billion by September 2024. 

EPA and TCEQ officials said this move was coming in August of 2021 after the region had failed to improve its air quality over the previous three years.

But the action wasn’t fast enough for San Antonio environmentalists, who threatened to sue the EPA last month for not more quickly bumping the region up into the more strict moderate ozone nonattainment classification, which would force city and county leaders to take additional steps to enforce cleaner air policies.

“It’s time to do what is necessary to improve the air quality in San Antonio,” stated the Sierra Club’s Chrissy Mann in a press release announcing the intent to sue. “CPS Energy can do its part, as the owner of the biggest single source of ozone-forming pollution in Bexar County, by following through with their commitments to quickly retire Spruce Unit 1, a coal plant that does not have modern pollution control for nitrogen oxides, a key ingredient to ozone pollution.”

CPS Energy “is committed to doing our part to improve our community’s air quality,” the utility said in a statement to the San Antonio Report Wednesday. “We will continue to work collaboratively with the City of San Antonio, Bexar County and partner organizations, including the Alamo Area Council of Governments, to take action locally to reduce ozone-forming emissions.” 

Recent actions CPS Energy has taken in this pursuit include closing the Deely coal plant in 2018 and developing a plan for reducing emissions that includes adding more solar and battery storage to its generation mix.

San Antonio was one of 24 areas across the country did not meet the EPA’s ozone standard by the fall 2021 deadline. Other places in Texas that didn’t meet federal ozone standards include the Dallas-Fort Worth and the Houston-Galveston-Brazoria areas.

With the reclassification to moderate nonattainment, the Texas Commission on Environmental Quality will have the regulatory role of enforcing the EPA’s Clean Air Act regulations in San Antonio. TCEQ officials would be required to submit a model to the EPA showing a long-term plan for improving Bexar County’s conditions within a year from the reclassification date. Officials would need to begin implementing that plan the following year.

It will also require Bexar County residents to get vehicle emissions inspections annually under a basic vehicle inspection and maintenance program. Other Texas counties already have programs like this to reduce emissions.

The San Antonio region’s air quality dropped out of compliance with the federal Clean Air Act in July 2018, when Bexar County was first declared to be under marginal nonattainment, meaning it was too polluted to meet the federal standard for ozone. Ozone — three oxygen atoms bound together — is a key ingredient of smog that irritates and damages the lungs and has been tied to chronic conditions such as asthma. 

High levels of ozone can impact respiratory health, especially on hot sunny days when ozone can reach unhealthy levels, the city said in a press statement issued Wednesday; even relatively low levels of ozone can cause adverse health effects.

“Ozone can cause coughing and sore or scratchy throat, inflame and damage the airways, make the lungs more susceptible to infection, aggravate lung diseases such as asthma, emphysema, and chronic bronchitis, and can also increase the frequency of asthma attacks,” the city said in the release.

The comment period for the EPA’s proposed action closes on June 13, 2022 and a virtual hearing will be held on May 9, 2022. Additional information about San Antonio’s air quality can be found here.

Lindsey Carnett

Lindsey Carnett is the Science & Utilities reporter for the San Antonio Report.