Air Quality Alert: Denver-Boulder Area Reaches Unhealthy for Sensitive Groups Level

Air Quality low EPA · · Denver-Boulder, CO

On March 20, 2026, air quality in the Denver-Boulder area reached an AQI of 128, categorized as Unhealthy for Sensitive Groups due to PM10 levels.

Current Air Quality

The Denver-Boulder area in Colorado reported an Air Quality Index (AQI) of 128 on March 20, 2026. The primary pollutant of concern is PM10, which has reached the “Unhealthy for Sensitive Groups” category. Other readings for the area include PM2.5 at an AQI of 70 (Moderate) and Ozone (O3) at an AQI of 47 (Good).

What This Means

An AQI level of 128 is classified by the EPA as “Unhealthy for Sensitive Groups.” This category indicates that air quality is reaching levels where members of sensitive groups may experience health effects, though the general public is less likely to be affected.

Who Should Take Precautions

Groups at increased risk from this level of particle pollution include people with heart or lung disease, older adults, children, and teenagers. These individuals should be mindful of their outdoor activities while these conditions persist.

What You Should Do

Members of sensitive groups should reduce prolonged or heavy exertion outdoors. It is recommended to take more breaks and engage in less intense outdoor activities. Watch for symptoms such as coughing or shortness of breath. The general public can continue normal outdoor activities.

Source

Data provided by EPA AirNow.

Source: EPA Official Notice

Frequently Asked Questions

What is this air quality alert about?
On March 20, 2026, air quality in the Denver-Boulder area reached an AQI of 128, categorized as Unhealthy for Sensitive Groups due to PM10 levels.
Which agency issued this alert?
This alert was issued by EPA. The original notice is available at the source link at the bottom of this article.
How severe is this alert?
This alert is classified as "low" severity. No immediate action required, but stay aware.
What area is affected?
This alert affects Denver-Boulder, CO. Check with EPA for the most current geographic scope.
Where can I find more air quality alerts?
Browse all air quality alerts on Areazine at areazine.com/air-quality/ for the latest updates from EPA and other agencies.