Bexar County’s ozone levels exceed the Environmental Protection Agency’s most recent standard, according to a study released by the City’s Office of Sustainability last week. This is the first local analysis that directly addresses how ground-level ozone pollution impacts San Antonio’s public health and economy.

According to the report, the county’s ozone levels hover around 73 parts per billion, slightly above the EPA’s standard of 70 parts per billion, set in 2015.

San Antonio Metropolitan Health District Director Colleen Bridger told the Rivard Report Monday that the ozone standard was initially created to improve public health. It is based on scientific evidence that ground-level ozone pollution can cause health problems and be particularly dangerous for people with respiratory diseases such as asthma.

“People need to better understand that ozone up high is a protective layer,” Bridger said. “But when you breathe in ground-level ozone, three components come together and become dangerous for the lungs.”

Bridger is referring to the chemical reaction that happens when certain man-made and natural chemical pollutants directly interact with the sun. She explained that the sun’s ultraviolet rays convert these emissions into ground-level ozone – generally referred to as smog – which is unhealthy to breathe.

“As climate changes, there will be corresponding health impacts,” Bridger said, adding that those could include an increase in vector-borne illnesses and weather events that put medically fragile people at risk. As the climate warms – an ever-present threat in South Texas – those consequences could worsen, she added.

Published in September, but released by the City on Nov. 21, the study revealed that San Antonio would see an additional 19 respiratory deaths per year if its ozone levels rise to 80 parts per billion, and would avoid 24 deaths annually if ozone levels drop below 68 parts per billion. The deaths of 19 people due to ozone-related respiratory issues would cost $170 million, the study found, while the 24 avoided deaths would save a total of $220 million.

Bridger explained that the numbers are not reflective of healthcare costs over time; rather they attempt to quantify the value of a life.

“If this many people die at these various ages you have lost this value in dollars,” Bridger said. “These are people who can no longer work, raise a family, contribute to the economy.”

According to a recent EPA report, out of 3,142 counties in the United States, 2,646 have met the air quality standard. This number includes non-county administrative or statistical areas that are comparable to counties, according to the report. However, the federal agency has yet to hand down any sanctions for counties that have not maintained the standard as of its Oct. 1 attainment deadline.

Douglas Melnick, chief sustainability officer with the city, explained that Bexar County is taking extra steps to address both air quality and climate change, regardless of what’s happening on the national stage. And while there is “only so much that a city can do,” he said, San Antonio is addressing the issue.

In June, Mayor Ron Nirenberg joined more than 300 U.S. mayors in support of the Paris Climate Agreement by signing a pledge to uphold the accord’s environmental policies aimed at countering global climate change.

The City has partnered with the University of Texas at San Antonio to research and evaluate best-practices for climate change, made possible by funding through CPS Energy. Researchers will work on updating the City’s greenhouse gas inventory and collaborate with organizations and community members to reduce emissions.

“It’s about quality of life,” Melnick said. “It’s about the future for people’s grandchildren and great-grandchildren.”

Roseanna Garza

Roseanna Garza reports on health and bioscience for the San Antonio Report.