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News Release

Summer Ozone Season Begins

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Department: Health & Environment
Release Date: Jun 9, 2017

Contact Information:

Lea Schneider
Larimer County Environmental Health
(970) 498-6777

Cassie Archuleta
Fort Collins Environmental Planner
(970) 416-2648

June 1 marked the beginning the summer ozone season along Colorado’s Front Range.  Ozone Action Alerts are issued on days when meteorologists from the Colorado Department of Public Health and Environment (CDPHE) expect weather conditions to lead to increased ground-level ozone concentrations in the metropolitan-Denver and Front Range region. The cities of Loveland, Fort Collins, and Greeley are included in the alert area.  

Ozone that occurs at ground level is an important air pollutant.  Elevated levels can cause symptoms in people that include stinging eyes and throat, chest pains, coughing and respiratory distress. Those at highest risk of symptoms due to elevated ozone levels include the elderly, young active children, and anyone with a pre-existing respiratory condition such as emphysema or asthma.  Even healthy adults who spend a lot of time working or exercising outdoors may be affected by elevated ozone levels.  During ozone alert days, people can lower their risk of developing symptoms by limiting prolonged outdoor exercise.  Particularly sensitive individuals may even be advised to stay indoors.  
Ozone is different from most other air pollution in that it is not emitted directly into the atmosphere.  Instead, ozone forms in the lower atmosphere when other primary emissions react in the presence of heat and sunlight.  Those emissions are volatile organic compounds and nitrogen oxides.
The sources of these ozone forming emissions include cars and trucks, industrial operations, oil and gas wells, residential activities such as mowing lawns and using paints and stains, as well as from naturally-occurring sources such as volatile organics from evergreen trees.
Ozone alerts serve two important purposes:  They provide specific health advice for people who may be affected by elevated ozone levels, and they inform the community about steps that can be taken to help reduce ozone during those times.  Because ozone formation occurs when air emissions bake in the hot summer sun, citizens can help by taking voluntary steps to reduce these pollutants.  Some suggestions for individual action include:
  • Keep your car tuned and tires well inflated to increase mileage and reduce fuel use
  • Stop at the click when refueling your car or truck to limit vapors at the gas pump
  • Refuel after dusk in the summer to avoid the period of intense sunlight
  • Combine trips, take the bus, or postpone a trip during an alert if possible
  • If you use a gas-powered mower, delay lawn mowing until evening to avoid the period of intense ozone formation
Ozone also occurs in the upper atmosphere at an altitude of 10 to 30 miles above the Earth’s surface.  This upper-level ozone is not a form of air pollution, and in fact blocks ultraviolet rays thereby protecting us from skin cancer, cataracts, and possibly immune system damage.  
More information about ozone in our area is available at  A link on that website allows individuals to sign up to receive a daily email ozone level advisory.  Ozone air quality alerts are also published in most daily newspapers, on Fort Collins Comcast Channels 14 and 881, and on most metro-area news channels.
In Colorado, the Regional Air Quality Council is leading the planning efforts to reduce ozone levels and attain compliance with the ozone air quality standard.  Technical information about this planning process is available at
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