Thursday Pollution Forecast For Metro Denver, Boulder

Air quality worsened in metro Denver and Boulder on Wednesday as smoke continues to flow in from Colorado, Wyoming and California wildfires.

Fine particulate matter concentrations from the smoke are expected to be in the 'unhealthy for sensitive groups' category on Thursday in metro Denver, Boulder, Longmont, Greeley and Colorado Springs, according to the Colorado Department of Public Health and Environment.

"Throughout these areas, people with heart or lung disease, older adults, and children should reduce prolonged or heavy exertion," the agency said in an air quality advisory.

Visibility along the Front Range is expected to be 'poor' Thursday, public health officials said.

"Daytime mixing of the atmosphere will generally allow smoke to lift, and surface concentrations to decrease, however periods of moderate to heavy smoke are expected to return during overnight and early morning hours," the advisory read.

Ozone concentrations are expected to be in the 'good' category.

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Carbon monoxide and nitrogen dioxide levels are also expected to remain in the 'good' category on Thursday, health officials said.

>> Read the full air quality advisory here.