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.

H visibility_1534786381879.png.jpg
KUSA

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.

RELATED | How to keep your pets safe in unhealthy air quality

RELATED | This DIY air filter for wildfire smoke is less than $20

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.

H Poor air quality_1534786380296.png.jpg
KUSA

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.

H live on Boulder_1534786380291.png.jpg
KUSA