Denver's brown cloud


Today’s Ozone Action Alert Status

Unlike the good, protective ozone layer in the upper stratosphere, ground-level ozone is a harmful air pollutant that affects all of us. It’s formed when emissions from everyday activities like:

  • Fueling
  • Painting
  • Solvent use
  • Driving
  • Lawn mowing
  • Industrial emissions

When combined, these pollutants “cook” in the heat from sunlight to form ozone.

Ozone continues to be a serious health issue and air pollution concern in Boulder County, and the nine-county Denver region. Currently five monitors along the Denver Metro Area/North Front Range indicate ozone levels that significantly exceed the new ozone standard, including the monitor in south Boulder.

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Air Quality Program

Main: 303-441-1564
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