Smoke and haze filled the air in Fort Collins and northern Colorado during the Labor Day holiday.

The Colorado Department of Public Health and Environment issued an Action Day Alert on Monday afternoon. Action Day Alerts indicate that the current air quality is unhealthy or that air quality conditions are likely to worsen later in the day or the following day. The alert is anticipated to conclude on Tuesday at 4 p.m.

CDPHE stated the areas in eastern Colorado below 7,000 feet, including Denver, Boulder, Fort Collins, Greeley and Colorado Springs, are most affected by the air quality.

CDPHE recommends residents of the affected areas spend less time doing prolonged or heavy labor outside. Residents that are young children or older adults and residents who have heart or lung disease are recommended to avoid outdoor activities. 

According to CDPHE, the smoke lingering in the air was transported from wildfires in the northwestern area of the United States and the western part of Canada.

CDPHE also issued an air quality health advisory due to wildfire smoke moving into Colorado from Montana on Monday morning, according to Wellington Fire’s official Twitter account. The advisory is expected to conclude at 9 a.m. on Tuesday, according to CDPHE.

CDPHE advises residents to follow the health recommendations on their website through Tuesday even as the smoke subsides on Monday afternoon and evening.