The signs displayed across Fort Worth’s highways can be intimidating. With summer heat rippling through the state, drivers zoom by screens blaring “OZONE WATCH” and warnings to stay inside.
If you’re not familiar with the science behind air quality alerts — and why North Texas has struggled to reduce ground-level ozone, also known as smog — you’re not alone. Smog is created when pollutants from transportation, commercial operations and natural sources combine with sunlight and heat.
Through July 10, the region tallied 16 days where smog exceeded healthy levels. Those numbers are roughly similar to most previous summers at this point, said Jenny Narvaez, an air quality program manager for the North Central Texas Council of Governments. Last year was an outlier with 48 ozone warnings, becoming the worst air quality year since 2012.
More unhealthy ozone days are on the horizon as the region enters its hottest season in July and August, she said.
“We’re just, like, the perfect nesting ground for ozone formation,” Narvaez said. “With low wind, ozone tends to form and then it’ll stay instead of being blow off by the wind. A lot of our summers are not very windy days, and humidity tends to drive it as well.”
As poor air quality continues to affect North Texans, here’s what residents can do to prepare and understand the challenges facing the region.
What do air quality alerts mean?
Daily air quality is measured using the Air Quality Index scale designed by the Environmental Protection Agency. The scale, which uses a color code, gives a rough estimate of how polluted the air is each day and any potential health effects. Breathing in ground-level ozone can inflame and damage airways, aggravate lung diseases and increase the frequency of asthma attacks.
Here’s how to interpret the index, according to the North Central Texas Council of Governments:
- Green: Air quality is good and no action is necessary to protect health. Ozone levels are between zero and 54 parts per billion.
- Yellow: Air quality is moderate. People unusually sensitive to pollution, including those with respiratory issues, should consider limiting prolonged or intense outdoor activity. Ozone levels are between 55 and 70 parts per billion.
- Orange: Air quality is unhealthy for sensitive groups, including children and adults with respiratory diseases like asthma. These groups should reduce outdoor activity. Orange warnings are the most common in North Texas. Ozone levels are between 71 and 85 parts per billion.
- Red: Air quality is unhealthy for everyone. Children and adults with respiratory issues should avoid prolonged outdoor activity. People who don’t fit into those categories should reduce prolonged or heavy outdoor activity. For the past decade, red warnings have been uncommon in North Texas, with a high of seven alerts issued in 2018. This designation means ozone levels are between 86 and 105 parts per billion.
- Purple: Air quality is very unhealthy. Children and adults with respiratory issues should avoid all outdoor activity. Others should avoid prolonged or heavy outdoor activity. Ozone levels are between 106 and 200 parts per billion.
- Maroon: Air quality is hazardous, and the entire population is more likely to face health risks from spending time outdoors. The designation counts as a health emergency, and all people in the area should avoid spending time outside. Anything above 200 parts per billion falls into this category. This is extremely rare, but no longer unheard of — Canadian wildfires caused a “Code Maroon” in Ohio last month.
What time is best to be outdoors?
The worst time periods for ozone conditions are about 10 a.m., after drivers have been on the road for their morning commutes, and after 5 p.m., when commuters head home from work, Narvaez said.
“We’ve had high ozone days that have been high up until 11 p.m. at night,” she said.
That means the best time for strenuous outdoor activity is in the early morning, before smog has had the chance to form. Narvaez noted that the hottest days of the summer are typically not the worst air quality days — the heat helps break the bonds that create ozone, she said.
Residents can plan ahead for poor air quality days by using an email alert service run by Air North Texas, a campaign led by the council of governments.
The campaign sends alerts when air quality is predicted to be in the unhealthy range and offers weekend forecasts so residents can plan to be outside on healthier air quality days. Air North Texas features tips for individuals, businesses and governments on how to reduce ozone pollution.
Those suggestions include reducing vehicle idling, postponing mowing until air quality improves and delaying business opening until 9 a.m. or later to reduce the number of cars on the road during rush hour.
North Texas faces fines if air quality doesn’t improve
Beyond the daily air quality alerts, North Texas is facing a key deadline to improve its air quality and meet standards set by the Environmental Protection Agency. Last fall, the region became a “severe” violator of the EPA’s 2008 ozone standards because its average smog levels lingered above the federal limit of 75 parts per billion.
If government officials fail to reduce smog levels by the end of 2026, the industries most responsible for air pollution in the region could pay $45 million in annual fines to the EPA starting in 2028.
This hasn’t been a good summer so far in terms of helping North Texas meet the requirements of the Clean Air Act, Narvaez said. Because the EPA standards are based on a three-year average of ozone levels, 2023 would need to have a lower number of ozone action days to bring air quality into compliance with the law. That doesn’t seem likely, she said.
The council of governments is consulting with the Texas Commission on Environmental Quality on a plan to reduce ozone levels. Revisions of that plan are due to the EPA by May 2024.
“We follow this so closely because we have the federal requirements … but we also have a focus on helping human health and plant and animal health,” Narvaez said. “That’s why it’s so important to us as well.”
Haley Samsel is the environmental reporter for the Fort Worth Report. You can reach them at haley.samsel@fortworthreport.org.
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