Ozone and your health

What is ground-level ozone and why is it harmful?

Ozone that is found high in the Earth’s atmosphere is helpful for humans because it protects us from harmful radiation from the sun. Lower in the atmosphere, ozone is formed from the mixing of pollutants at ground-level. High levels of ozone can cause health concerns for sensitive people, particularly the elderly, young children and those with asthma or other respiratory problems.

Symptoms include:

  • Stinging eyes and throat.
  • Chest pains.
  • Coughing.
  • Breathing difficulty.

If you are concerned about how ozone may be affecting you, we encourage you to see your doctor and talk to your local public health agency.

More information:

Ozone action day alerts

Sign up for the email list about ozone action days by emailing aq_subscribe@state.co.us and note that you would like to be added to the ozone.frontrange email list.

This list receives daily emails from June 1 -  August 31 with health advisories and air quality forecasts for the entire Front Range region. All primary pollutants are forecast on a daily basis, but during the summer we emphasize ozone.

Why are there more ozone action days now?

If you have been following Colorado’s ozone action days, you may have noticed that we had more action days last summer than in previous years. This is because, in 2015, EPA lowered the standard for ozone concentration from 75 parts per billion to 70 ppb. Since then, we issue an action day alert any time the expect the ozone level in Colorado to be over the 70 ppb standard. These action days do not mean that the air quality in Colorado is getting worse. In fact, the opposite is true. Since the 1990 Clean Air Act Amendments, EPA has slowly lowered the ozone standard from 85 ppb to 70 ppb, and Colorado has worked to lower the amount of ozone pollutants that are produced in our state. Despite the air pollution challenges associated with increasing population, our ozone levels have improved over time. Air quality in Colorado is getting better, but not quickly enough to meet EPA’s lowering standards. This is why there may be more ozone action days this ozone season.