Thick smoke from wildfires across the west and northwest are plaguing multiple states, with thick smoke and dangerous air quality, including Colorado.
Visibility across the I-25 corridor was reduced to 3 miles to 5 miles Monday morning.
An Air Quality Health Advisory for Wildfire Smoke is in effect for northeastern Colorado -- including Denver, Boulder, Fort Collins and Greeley -- until 4 pm Monday.
Air quality has fluctuated Monday from moderate to unhealthy. People with heart or lung disease, respiratory issues, older adults and children should take it easy outdoors.
Expect slow improvement as we head into the overnight and Tuesday, as a more west/southwest flow develops. It will be gradual, with smoke near the ground along the I-25 corridor especially slow to move out.