Colorado Ozone Action Day: Air Quality Alert in Effect for Denver, Boulder, and Front Range Until Thursday Afternoon
DENVER — The Colorado Department of Public Health and Environment has issued an Ozone Action Day Alert for Denver, Boulder, Fort Collins, and several surrounding counties as air quality levels deteriorate across the Front Range.
The alert began at 4 p.m. on Wednesday and will remain in effect until 4 p.m. Thursday, urging residents — particularly children, older adults, and those with asthma or other respiratory conditions — to take precautions due to rising ground-level ozone pollution.
Counties Under Alert
According to the Colorado Department of Public Health and Environment, the advisory affects a wide area, including:
- Denver
- Boulder
- Fort Collins
- Larimer County
- Weld County
- Broomfield
- Arapahoe
- Jefferson
- Adams
- Douglas County
These areas comprise much of the Front Range Urban Corridor, a densely populated region where ozone levels are projected to spike due to stagnant air and intense summer heat.
Why the Alert Was Issued
With light winds and rising temperatures, air pollutants from vehicles and industrial sources have little chance to disperse. This creates ideal conditions for the formation of ground-level ozone, a pollutant that can trigger asthma, respiratory distress, and other health complications — particularly for sensitive groups.
The alert forecasts conditions reaching the “Unhealthy for Sensitive Groups” threshold — the highest air pollution level recorded this summer so far in the area.
Health Recommendations for Residents
Officials recommend the following precautions:
- Avoid prolonged outdoor exertion, especially during the afternoon when ozone levels tend to peak.
- Postpone driving or use public transit, particularly avoiding gas and diesel-powered vehicles where possible.
- Stay indoors if you experience coughing, shortness of breath, or wheezing.
- Monitor your symptoms if you belong to a sensitive group (children, elderly, or anyone with chronic respiratory conditions).
Ongoing State Response
The alert comes as Colorado continues to tackle persistent summer ozone pollution, which remains a seasonal health concern. State leaders are developing new regulatory policies aimed at reducing long-term ozone emissions from transportation and industry.
While ozone advisories are common during the hotter months, the current conditions represent one of the more serious ozone episodes this season. Updates may be issued if pollutant levels worsen or extend beyond Thursday afternoon.
How to Stay Informed
Residents are encouraged to check real-time air quality data via colorado.gov/airquality or local news updates.
Have you changed your plans this week because of the ozone alert? Are you or a family member affected by poor air quality? Comment below and share your experience.
