Air Quality Forecast For Metro Denver, Boulder County: July 13

An action day alert for pollution was issued Tuesday for parts of the Front Range and Eastern Plains.

Ozone concentrations are expected to range between the 'unhealthy for sensitive groups' to 'moderate' categories in metro Denver, Boulder, Greeley and Fort Collins, the Colorado Department of Public Health and Environment said.

"Active children and adults, and people with lung disease, such as asthma, should reduce prolonged or heavy outdoor exertion on Tuesday," the agency said in its alert.

Fine particulate matter concentrations along the Front Range and Eastern Plains are expected to be in the 'good' category Tuesday, and visibility will be in the 'poor' category in Denver due to smoke from the Morgan Creek wildfire.

"Smoke from out-of-state wildfires will continue to impact Colorado on Tuesday," the advisory read. "However, increasing showers and thunderstorms along with a shift in the upper level winds should bring some improvement, particularly across the western half of the state."

Carbon monoxide and nitrogen dioxide levels are expected to be in the 'good' category, health officials said.

Don’t miss the latest news updates in Denver, Boulder, Arvada, Lakewood and Littleton. Sign up for free Patch news alerts and newsletters for what you need to know daily.

Metro Denver is the 8th worst metro area in the nation for high ozone days, according to the American Lung Association's 2021 "State of the Air" report released in April.

Ozone pollution, often called smog, forms when gases that come out of tailpipes and smokestacks, among other sources, come into contact with sunlight. Ozone is "one of the most dangerous and widespread pollutants in the U.S.," the lung association said.

Ozone can damage people's airways, make their lungs more susceptible to infection and aggravate lung diseases, according to the U.S. Environmental Protection Agency.

>> Read the full air quality advisory here.