Ozone season is upon North Texas, meaning air quality will be top of mind for some residents.
The season — which marks the window when there’s a greater risk of harmful amounts of ground-level ozone — is actually majority of the year in Dallas-Fort Worth, lasting from March 1 to November 30.
What is ozone?
Ozone is a gas formed in the atmosphere when three atoms of oxygen combine, according to the Texas Commission on Environmental Quality. Sometimes it’s referred to as smog.
There are two categories of ozone: stratospheric and ground-level.
Stratospheric ozone is naturally found in the earth’s atmosphere anywhere from 6 to 30 miles above ground. It acts as a protective layer shielding us from the sun’s ultraviolet rays.
Ground-level ozone, also called tropospheric ozone, is a common air pollutant that can be harmful to human health. The pollutant forms when certain organic compounds interact with sunlight and intense heat.
While ozone precursors come from multiple sources, vehicles, construction equipment, locomotives and aircraft account for about 60% of emissions, according to the North Central Texas Council of Governments.
Why does ozone season last so long in D-FW?
Dallas-Fort Worth and Houston have the longest ozone seasons among Texas cities, while areas like Austin, San Antonio and Corpus Christi have seasons that last two months shorter.
Weather patterns play a major role in air quality, so there’s a higher risk of pollutants like ground-level ozone when there are higher temperatures and less wind.
Therefore, ozone levels typically rise during the day and peak in the late afternoon before decreasing after the sun sets, according to the National Weather Service.
North Texans tend to get a break from December to February, since temperatures usually cool off.
Do ozone exceedance days happen often in Dallas-Fort Worth?
Between May and September, there were 31 “exceedance days,” meaning the air quality became unhealthy for some people in North Texas, according to NCTCG data.
Ozone pollution has improved in Dallas-Fort Worth since the 1990s based on the number of high-ozone days, American Lung Association data show.
While overall air quality has improved over the last few decades, ozone levels continue to exceed federal standards.
How is air quality measured?
The Environmental Protection Agency developed the Air Quality Index to measure and categorize pollution levels. The index takes a range of pollutants into consideration but ozone is a key component.
There are six categories with corresponding colors, according to the EPA.
- Green: Ozone levels are low; air quality is good for everyone.
- Yellow: Moderate ozone levels; some sensitive groups may want to reduce time spent outside.
- Orange: Unhealthy ozone levels for sensitive groups; all sensitive groups should reduce the amount of time spent outside.
- Red: Unhealthy ozone levels for all; everyone should reduce time spent outside and sensitive groups should avoid it if possible.
- Purple: Very unhealthy ozone levels; the general public may feel serious effects.
- Maroon: Most serious rating, indicating hazardous ozone levels; the entire population is likely to be affected.
Who is considered part of a sensitive group?
Sensitive groups include children ― because their lungs are still developing ― adults older than 65, other adults with lung disease, such as asthma, or cardiovascular disease and people who are active outdoors including workers, according to Air Central Texas.
Air pollution has been linked to health problems such as coughing and wheezing. Sometimes the impacts are more severe, causing asthma, bronchitis or strokes.
The workers are currently putting in eleven-hour workdays and taking frequent water breaks in shaded areas to cope with the heat.(Irwin Thompson / Staff Photographer)
Can you check air quality online in real time?
You can check the air quality and see if there are any warnings at AirNow.gov or the Texas Commission on Environmental Quality website.
Is there a way to improve the air quality?
Ozone formation is a regional issue, but Air North Texas officials say individual actions can make a difference.
Some actions residents can take to help reduce the ozone pollution include:
- Driving less: Carpool or take public transit when possible and be fuel-efficient when you are driving.
- Limit idling: Turn off your car when parked to reduce emissions.
- Use eco-friendly products: Choose products like paints, cleaners and lawn care products that have low volatile organic compound.
- Reduce energy usage where possible: Turn off lights and appliances when they aren’t in use and set the air conditioning at a conservative range, especially when not home.
This reporting is part of the Future of North Texas, a community-funded journalism initiative supported by the Commit Partnership, Communities Foundation of Texas, The Dallas Foundation, the Dallas Mavericks, the Dallas Regional Chamber, Deedie Rose, the McCune-Losinger Family Fund, The Meadows Foundation, the Perot Foundation, the United Way of Metropolitan Dallas and the University of Texas at Dallas. The News retains full editorial control of this coverage.
