# HEADLINE
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OZONE ACTION DAY ALERT FROM 400 PM SATURDAY UNTIL 400 PM SUNDAY
# SUMMARY
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The Colorado Department of Public Health and Environment has issued the following...
WHAT...Ozone Action Day Alert.
# DETAILS
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WHERE
Douglas, Jefferson, Denver, western Arapahoe, western Adams, Broomfield, Boulder, Larimer, and Weld Counties
WHEN
400 PM Saturday July 04 to 400 PM Sunday July 05
IMPACTS
Ozone Action Day Alert is now in effect for the Front Range Urban Corridor. Ozone concentrations in the Unhealthy for Sensitive Groups category are possible both Saturday and Sunday 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. Sunday, July 5, 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.
ISSUED AT
Saturday, July 4, 2026 at 5:10 PM MDT
ISSUED BY
Relayed by National Weather Service Boulder CO
HEADER
Air Quality Alert Message | Colorado Department of Public Health and Environment
# AREAS AFFECTED
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Broomfield, Adams, Arapahoe, Boulder, Denver, Douglas, Jefferson, Larimer, Weld