Colorado issues air quality, health warning over wildfire smoke

Thick smoke from wildfires gathers over Lake Catamount in Steamboat Springs, Colorado on Monday, July 22, 2024. (Photo by Zachary Spindler-Krage/The Denver Post)

A blanket of smog hung over Colorado on Monday as smoke from wildfires drifted up from Canada. The gray skies are expected to remain over the country for at least another 24 hours.

The smoke from the wildfires prompted the Colorado Department of Public Health and Environment and the Regional Air Quality Council to issue a public health advisory Monday, advising people to limit outdoor activities. The smoke is causing increased levels of ozone and particulate matter in the air.

Air monitors in northern Colorado and the Front Range showed high concentrations of fine particulate matter, which can be smoke, soot, ash or liquid particles that people can inhale.

The highest concentration at 3:45 p.m. Monday was in Louisville, where air monitors recorded an air quality index of 537 PM2.5, nearly 16 times higher than the level of fine particulate matter considered safe by the Environmental Protection Agency, according to the agency’s fire and smoke map. People were advised to stay indoors.

A boy crosses a rope bridge in Adventure Forest outside the Children’s Museum of Denver on a smoky afternoon in Denver on July 22, 2024. Smoke from wildfires in Canada has seeped into the metro area. (Photo by RJ Sangosti/The Denver Post)

The warning was issued for the Front Range, which stretches from Douglas County to Larimer and Weld County, and will remain in effect until at least 4 p.m. Tuesday.

The state health department also issued health advisories for Mesa, Moffat, Grand, Jackson and Routt counties. Poor air quality was also forecast for Colorado Springs and Pueblo.

People with heart or lung conditions, the elderly and children are particularly vulnerable to wildfire smoke. They should avoid prolonged or strenuous exercise, while everyone is advised to limit outdoor activities.

The Regional Air Quality Council advises people not to drive or use petrol-powered lawnmowers until after 5pm, when temperatures begin to cool.

The Colorado Smoke Blog, run by the state health department, said the highest concentrations of smoke are at higher elevations in north-central Colorado, including the Park Range and northern parts of the Front Range. Rocky Mountain National Park also is blanketed in smoke.

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