An air quality alert issued by the National Weather Service (NWS) for two of Texas’ most populous metro areas is advising residents against idling in drive-thru lanes due to elevated ozone levels.

Why It Matters

With a combined metropolitan population of over 10 million, the recommendation affects a significant portion of the state’s urban population.

The U.S. Environmental Protection Agency (EPA) notes that even short-term exposure to elevated ozone can lead to breathing difficulties, lung inflammation, and worsening of conditions such as asthma.

What To Know

The Texas Commission on Environmental Quality (TCEQ) issued Ozone Action Days for both the Dallas-Fort Worth and the San Antonio areas for Tuesday, an air quality alert published by the NWS said.

According to officials, atmospheric conditions were forecast to be favorable for producing high levels of ozone pollution.

“You can help prevent ozone pollution by sharing a ride, walking or riding a bicycle, taking your lunch to work, avoiding drive through lanes, conserving energy, and keeping your vehicle properly tuned,” the alert read.

Elsewhere, air quality alerts were also in effect for the western two-thirds of Minnesota, including the Twin Cities Metro, following previous alerts issued for the day prior.

“Mostly sunny skies, warm temperatures and low humidity will provide a favorable environment for two types of pollutants (volatile organic compounds and nitrogen oxides) to react with sunlight in the air to produce ground-level ozone,” the alerts for the state said.

“Ozone will remain elevated on Wednesday as sunny skies, warm temperatures and dry conditions persist.”

In the northeastern part of the state, an air quality alert had also been issued due to the ongoing Camp House, Jenkins Creek, and Munger Shaw fires, which had each burned over 1,000 acres as of Monday night. Smoke was expected to impact areas near and downwind of the blazes, with smoke being observed as far north as the Canadian border, the alert said.

What People Are Saying

AccuWeather meteorologist Brandon Buckingham previously told Newsweek: “Ozone is a secondary pollutant, meaning it’s not emitted directly from sources but is formed through chemical reactions. These reactions require sunlight and higher temperatures, making warmer months more prone to ozone formation. When air is stagnant, pollutants don’t get dispersed, allowing ozone to build up to unhealthy levels.

“Ozone pollution is often more severe in urban areas where there are higher concentrations of pollutants from sources like cars, power plants, and industrial activities.”

Professor of pediatric respiratory and environmental medicine Jonathan Grigg, with Queen Mary, University of London, previously told Newsweek There are “very clear links” between inhaling particles and earlier death from both respiratory and cardiovascular diseases.

Additionally, he added that conditions such as asthma are also exacerbated by exposure to air pollution.

What Happens Next

At the time of writing, Ozone Action Days for Texas were in effect through Tuesday. The next ozone action day, if required, would be issued by 3 p.m. Tuesday.