Learn More about Ozone

Ozone Season May Through October Logo
Ozone Season
According to the Environmental Protection Agency (EPA), ozone season in the Dallas / Fort
Worth area begins in March and goes through October. Ozone is a gas that occurs in the Earth’s upper atmosphere and at ground level. It can be good or bad, depending on where it is found.
Good Ozone
Good ozone occurs naturally in the Earth’s upper atmosphere, 6 to 30 miles above the Earth’s surface. It forms a protective layer that shields the Earth from the sun’s harmful ultraviolet rays. Man-made chemicals are known to destroy this beneficial ozone. An area where the protective ozone layer has been significantly deplete for example, over the North or South Pole, is sometimes called the "ozone hole."

The United States, along with more than 180 other countries, recognized the threats posed by ozone depletion and in 1987 adopted a treaty called the Montreal Protocol to phase out the production and use of ozone-depleting substances. The EPA has established regulations to phase out ozone-depleting chemicals in the United States.

Bad Ozone

Bad ozone in the Earth’s lower atmosphere, near ground level, ozone is formed when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources react chemically in the presence of sunlight. Ozone at ground level is a harmful air pollutant. Reduce the bad ozone or ozone-forming emissions by:
  • Avoiding the use of small gas powered engines, such as garden equipment, between 10 a.m. to 6 p.m.
  • Bicycling or walking instead of driving
  • Combining trips and traveling less
  • Considering clean fuels and technology
  • Limiting or avoiding idling
  • Maintaining vehicles by getting them inspected, keeping tires properly inflated, and changing filters regularly
  • Observing the speed limit
  • Reporting smoking vehicles
  • Using mass transit or carpooling
For more information about Go Green Breathe Clean, a campaign for clean air, visit 
Air North Texas' website