The National Weather Service has issued air quality alerts in Texas, advising residents in the Dallas-Fort Worth area, as well as Houston, Galveston, and Brazoria, to limit vehicle use on Monday. High ozone levels are expected in these areas.
To help reduce ozone pollution, residents are encouraged to take steps such as carpooling, walking or biking, bringing lunch from home, avoiding drive-through lanes, conserving energy, and ensuring vehicles are well-maintained.
Ozone Action Days
Ozone Action Days have been declared, indicating a likelihood of elevated ozone levels. These alerts are based on the Seasonal Ozone Action Day Forecast, designed for the times when high ozone levels are most likely. Forecasts determine if ozone reaches or exceeds the EPA’s AQI Level Orange threshold, which means an eight-hour average of 71 parts per billion or a one-hour average of 125 ppb.
Texas Commission on Environmental Quality (TCEQ) meteorologists predict these levels using historical weather patterns, ozone monitoring data, and models. Notifications align with the National Weather Service.
Understanding Ozone
“Ozone is a secondary pollutant, meaning it is not emitted directly but formed through chemical reactions,” explained AccuWeather meteorologist Brandon Buckingham.
Ozone forms due to sunlight and higher temperatures, making it more prevalent in warmer months. Lack of air movement can lead to ozone accumulation, resulting in unhealthy levels.
Two types of ozone exist: stratospheric and ground-level. Stratospheric ozone provides a protective shield against ultraviolet rays in the Earth’s upper atmosphere. Ground-level ozone, considered air pollution, results from chemical reactions involving nitrogen oxides and volatile organic compounds in sunlight.
Health Implications
The Environmental Protection Agency (EPA) identifies groups at higher risk from ground-level ozone, including individuals with asthma, children, older adults, and outdoor workers. Ozone exposure can cause coughing, sore throat, difficulty in breathing, inflamed airways, and exacerbate lung conditions like asthma, emphysema, and bronchitis, potentially increasing asthma attacks.
EPA’s Air Quality Index
The EPA uses the Air Quality Index (AQI) to assess air quality in the U.S. The index, ranging from 0 to over 301, categorizes air quality from good to hazardous based on health risks.
- Green—Good (0 to 50): Satisfactory air quality with little or no risk.
- Yellow—Moderate (51 to 100): Acceptable air quality, though some may be at risk, particularly sensitive individuals.
- Orange—Unhealthy for Sensitive Groups (101 to 150): Health effects possible for sensitive groups. The general public less likely to be affected.
- Red—Unhealthy (151 to 200): General public may experience health effects, with more serious effects for sensitive groups.
- Purple—Very Unhealthy (201 to 300): Increased health risk for all.
- Maroon—Hazardous (301+): Emergency conditions with widespread risk.
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