The National Weather Service extended Friday's Air Quality Alert for North Texas into Saturday after the Texas Commission on Environmental Quality (TCEQ) declared the day an Ozone Action Day.
The TCEQ said Friday afternoon that atmospheric conditions are expected to again be favorable for producing high levels of ozone air pollution in Dallas-Fort Worth.
The ozone forecast for Friday and Saturday is considered unhealthy for sensitive groups. Sunday and going forward into the new week, the air quality forecast improves to moderate.
"Light to moderate winds, hot temperatures, abundant afternoon sunshine, and/or elevated incoming background levels could be enough for ozone to reach 'Unhealthy for Sensitive Groups' on the northwest sides of the Dallas-Fort Worth area."
The alert affects the following counties: Collin, Dallas, Denton, Ellis, Henderson, Hood, Hunt, Johnson, Kaufman, Parker, Rockwall, Tarrant and Wise.
Ground-level ozone is a respiratory toxic agent that can cause acute respiratory health effects when people breathe high concentrations of it over several hours. The TECQ said these effects include decreased lung function and pain with deep breaths, and aggravated asthma symptoms.
You can help prevent ozone pollution by sharing a ride, walking, riding a bicycle, taking your lunch to work, avoiding drive-through lanes, conserving energy, and keeping your vehicle properly tuned.