Air Quality Forecast For Metro Denver, Boulder County: June 10

An action day alert for pollution has been issued for the Front Range and Eastern Plains.

Ozone concentrations are expected to be in the 'moderate' to 'unhealthy for sensitive groups' range until 10 p.m. Thursday, the Colorado Department of Public Health and Environment said.

The ozone concentrations will be highest in Denver's west metro area and western Boulder County.

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

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.

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Fine particulate matter concentrations along the Front Range and Eastern Plains are expected to be in the 'good' category Thursday, and visibility will be in the 'poor' category in the morning and 'good' category in the afternoon.

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

>> Read the full air quality advisory here.