In the Fort Worth-Dallas area, the largest component of air pollution is ozone that forms in the lower atmosphere near ground level. In simple terms, this is bad ozone. This lower level ozone should not be confused with the ozone layer that forms in the upper atmosphere. While they are the same gas, ozone in the upper atmosphere is essential to life because it filters ultraviolet radiation from the sun. This is called good ozone.
Ozone is created when the weather is extremely hot and sunny, with low or non-existent winds.
Evaporative chemicals such as gasoline and paint thinners, auto exhaust and industrial emissions mix in the lower atmosphere, and when they interact with sunlight a photochemical reaction occurs resulting in ozone. These conditions tend to become most severe during the months of May through October, which is the area s ozone season. On days when ozone levels are high, people with respiratory problems may be affected the most while doing daily outdoor activities. They may have shortness of breath more frequently. Young children with asthma problems may need more oxygen on days with high concentrations of ozone.