Air Quality Alert: Denver-Boulder Air Quality Reaches Unhealthy for Sensitive Groups Level
Areazine synthesizes this EPA air-quality advisory directly from EPA's official public data feed. See our methodology for full source attribution and refresh cadence.
On February 23, 2026, the Denver-Boulder area recorded an AQI of 104, categorized as Unhealthy for Sensitive Groups, with PM10 identified as the primary pollutant.
What this EPA air-quality advisory tells you, and what most readers miss
This notice was issued by EPA on April 6, 2026 and geographically references Denver-Boulder, CO. Its severity classification of "low" signals how the issuing agency weighs the risk of harm if no action is taken - "critical" and "high" tier alerts typically carry direct consumer actions, while "medium" and "low" tend toward informational guidance or monitoring advisories. The category it belongs to - Air Quality - determines the informational context it sits in, and which agency or body is the authoritative source for updates.
Most readers skim a notice like this, check whether they are personally affected, and move on. The more useful lens is to verify its scope, source, and timestamp, then compare related notices without assuming that one record proves a broader trend.
Areazine pairs this record with the original agency URL so you can check the primary source before acting. Its related labels are air-quality, epa, aqi, Denver-Boulder.
Current Air Quality
In the Denver-Boulder, CO reporting area, the air quality index (AQI) reached a peak of 104 on February 23, 2026. The primary pollutant of concern is PM10, which is currently in the "Unhealthy for Sensitive Groups" category. Other measured pollutants include PM2.5 at an AQI of 78 (Moderate) and Ozone (O3) at an AQI of 45 (Good).
What This Means
An AQI of 104 falls into the "Unhealthy for Sensitive Groups" category. According to standard EPA guidance, this level indicates that air quality is unhealthy for certain groups of people, while the general public is unlikely to be affected.
Who Should Take Precautions
Groups at risk include people with heart or lung disease, older adults, and children. These individuals are more likely to be affected by the presence of PM10 in the air.
What You Should Do
Members of sensitive groups should consider reducing prolonged or heavy exertion outdoors. The general public does not need to take special precautions and can continue with normal outdoor activities.
Source
EPA AirNow
Original source: EPA Official Notice ↗
Related Air Quality
All Air Quality →Frequently Asked Questions
Common questions about this EPA air-quality advisory.