State air quality officials have issued an Ozone Action Day Alert for the northern Front Range, warning that hot temperatures and stagnant weather are expected to push ozone pollution into unhealthy levels for sensitive groups Monday afternoon and evening across Boulder, Weld, and Larimer counties.
The advisory remains in effect until at least 4 p.m. Monday, although officials could extend it if weather conditions continue to favor ozone formation. Forecasts call for ozone concentrations ranging from Moderate to Unhealthy for Sensitive Groups between noon and 8 p.m., the period when pollution levels are expected to peak.
As of Monday morning, the state’s highest reported ozone Air Quality Index reading was 77, within the Moderate category. The highest PM2.5 reading was 72, also Moderate, indicating elevated fine particle pollution that can aggravate heart and lung conditions, particularly among older adults and people with underlying health issues. Visibility across the Front Range was also expected to remain poor because of haze and smoke…