A second straight Ozone Action Day hits Denton County on Tuesday, August 4, as dangerous heat continues to cook smog across North Texas.
The National Weather Service Fort Worth office issued the air quality alert at 3:35 p.m. Monday, August 3, covering 13 North Texas counties including Denton County, home to Flower Mound and Highland Village. The alert remains in effect until 6:45 p.m. Tuesday.
The Texas Commission on Environmental Quality issued the declaration after atmospheric conditions on Monday — sunny skies, highs near 101°F, and light southeast winds — created the same stagnant pattern expected to persist into Tuesday, driving ground-level ozone formation.
Who's most at risk
Children and teenagers, older adults, adults with respiratory or cardiovascular illness, and outdoor workers face the greatest health threat on Ozone Action Days, according to Air Central Texas. Smog levels exceeding 70 parts per billion are considered unhealthy for these groups.
The DFW region's ozone design value sits at 82 parts per billion, well above the EPA's 70 ppb standard, according to the Fort Worth Report. That metric averages the fourth-worst ozone day across a three-year period.
What residents can do
The NWS and TCEQ advise residents to reduce time spent outdoors, avoid strenuous activity during peak afternoon hours, and reschedule lawn care.
To help cut ozone-forming pollution, the agencies recommend sharing rides, walking or biking, taking lunch to work instead of using drive-through lanes, conserving energy, and keeping vehicles properly tuned.
A worsening pattern
North Texas had already recorded 14 days of unhealthy smog levels as of July 30, with 10 Ozone Action Day alerts issued before this week's back-to-back declarations. The running total is now higher.
Ozone season runs through Nov. 30.
Ground-level ozone forms when nitrogen oxides and volatile organic compounds react with sunlight and heat. TCEQ issues alerts a day in advance so industries, businesses, and residents can reduce pollutants that feed the reaction.
Residents can check real-time air quality at AirNow.gov.
