Ozone is a gas composed of three oxygen atoms. It is not usually emitted directly into the air, but at ground-level is created by a chemical reaction between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) in the presence of sunlight. Motor vehicle exhaust and industrial emissions, gasoline vapors, and chemical solvents as well as natural sources emit NOx and VOCs.

Ozone can be "good" or "bad" depending on its location in the atmosphere. In the earth's lower atmosphere, ground-level ozone is considered "bad". Many urban areas tend to have high levels of "bad" ozone, but even rural areas are subject to increased ozone levels because wind carries ozone and pollutants that form it hundreds of miles away from their original sources. There is one federal standard for ozone. Several Oklahoma sites exceed the current standard.

Ozone Formation

Sunlight and hot weather cause ground-level ozone to form in harmful concentrations in the air. Ground-level ozone is the primary constituent of smog.

The "Good" vs. the "Bad"

In the upper atmosphere the ozone layer protects us from the harmful rays of the sun. At the ground level, ozone is a pollutant that is detrimental to human health.

Ozone Monitoring Equipment

Ozone Monitoring Sites

The division monitors ozone at 17 sites across the state. These locations report data hourly and are the basis of the Air Quality Health Advisory program. Near real-time ozone data may be accessed here.

Ozone and Your Health

Ozone presents a serious air quality problem in many parts of the United States. Even at low levels, ozone can cause health effects. People with lung disease, children, older adults, and people who are active outdoors may be particularly senstive to ozone. Numerous scientific studies have linked ozone pollution exposure to a variety of problems, including:

  • irritation of the respiratory system
  • aggravated asthma
  • decreased lung function
  • increased susceptibility to infection
  • coughing or difficulty breathing
  • permanent lung damage

2013 Ozone Data

Primary Ozone Standard = 0.075 ppm (8-hour)

**To attain this standard, the 3-year average of the annual fourth-highest daily maximum 8-hour average ozone concentrations measured at each monitor within an area over each year must not exceed 0.075 ppm (effective May 27, 2008).

2013 Ozone Values