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Ended official alertUpdated

Air Quality Alert for Larimer, CO; Denver, CO; Jefferson, CO +6 more

This alert has ended.Kept for recent context. Do not use it as a current warning.

Official alert fields

What you need to know

Effective
Ended
Official severity
Unknown
Official urgency
Unknown
Official certainty
Unknown

What is happening

The Colorado Department of Public Health and Environment has issued the following... WHAT...Ozone Action Day Alert. WHERE...Douglas, Jefferson, Denver, western Arapahoe, western Adams, Broomfield, Boulder, Larimer, and Weld Counties WHEN...400 PM Monday July 20 to 400 PM Tuesday July 21 IMPACTS...Ozone Action Day...

What the bulletin says to do

No separate action instruction was included in this NWS record. Read the complete official bulletin and follow local authorities.

Full official description

Bulletin details

The Colorado Department of Public Health and Environment has issued the following... WHAT...Ozone Action Day Alert. WHERE...Douglas, Jefferson, Denver, western Arapahoe, western Adams, Broomfield, Boulder, Larimer, and Weld Counties WHEN...400 PM Monday July 20 to 400 PM Tuesday July 21 IMPACTS...Ozone Action Day Alert is now in effect for the Front Range Urban Corridor. Hot and stagnant weather conditions will result in ozone concentrations reaching the Unhealthy for Sensitive Groups category both Monday and Tuesday during the afternoon and evening hours. For Colorado air quality conditions, forecasts, and advisories, visit: https://www.colorado.gov/airquality/colorado_summary.aspx If possible, please help us reduce ozone pollution by limiting driving gas and diesel-powered vehicles until at least 4 p.m. Tuesday, July 21, 2026. Colorado is also addressing ozone pollution through state policies. For more information about health impacts and how ozone pollution forms in Colorado, visit: https://cdphe.colorado.gov/ozone- pollution-and-your-health HEALTH INFORMATION...Increasing likelihood of respiratory symptoms and breathing discomfort in active children and adults and people with lung disease, such as asthma. Active children and adults, and people with lung disease, such as asthma, should reduce prolonged or heavy outdoor exertion.

Lifecycle record

Official revisions

1 captured
  1. Alert

    Air Quality Alert issued July 21 at 9:10AM MDT by NWS Denver CO

    Official revision

Source and limitations

Publisher: Weather Alert Watch. Primary source: NWS Denver CO. This page reorganizes official fields and does not add a forecast or expand the affected area.

CAP status
Actual
Message type
Alert
Last collected
Methodology and corrections