Thick wildfire smoke drifting in from the west on Tuesday has Colorado health officials sounding the alarm about a potential ozone spike along the northern Front Range. A hazy lid settled over the Denver area as plumes from out-of-state fires slid across the Rockies, and forecasters say the mix of smoke, heat, and sluggish winds could drive up ground-level ozone through the afternoon and early evening. People with asthma or COPD, along with seniors and kids, are being urged to take it easy outside during peak afternoon hours when ozone tends to build the fastest.
According to the Colorado Department of Public Health and Environment, the agency and the Regional Air Quality Council have declared an Ozone Action Day for much of the Front Range through at least Wednesday, warning that "elevated levels of ozone are possible" in Denver, Fort Collins, and Greeley. State forecasters also flagged heavy smoke over western Colorado in an update on the Colorado Smoke Blog and urged residents to keep an eye on local conditions as the haze shifts.
Ozone Action Day in Effect
The latest Front Range forecast calls for ozone levels to climb into the Moderate to Unhealthy for Sensitive Groups range on Tuesday and Wednesday, with the worst readings expected in the southern and western parts of the Denver metro. Officials are advising active children, older adults, and people with lung disease to cut back on strenuous outdoor activity from about noon to 8 p.m., according to CDPHE. Earlier this spring, Hoodline covered an early-season ozone alert in an article on the ozone alert from Denver to Pueblo.
Where the Smoke Is Coming From
State forecasters have traced the incoming haze to several fast-growing fires in Utah and Nevada that are pushing smoke east into Colorado. One of the biggest contributors: the Iron Fire near Eureka, which has surged in recent days and forced evacuations as crews work to get a handle on the flames, according to KSL. No homes have burned, but residents remain on edge as the fire grows.
Health Guidance and Where to Check Conditions
To keep tabs on the haze, Coloradans can turn to the EPA’s Fire and Smoke map for live readings and plume forecasts: AirNow Fire & Smoke. On days with high ozone or thick smoke, health officials recommend skipping long or intense outdoor workouts, keeping windows shut, running HVAC systems with good filtration if you have them, and following your healthcare provider’s instructions if you have asthma, heart disease, or other chronic conditions.
State agencies say they will keep tracking the situation and updating advisories as conditions change. Before planning that afternoon hike or park workout this week, officials suggest checking the latest alerts and forecasts.
