Much of eastern Colorado is under an air quality health advisory because of smoke pouring into the area from fires in the northwestern U.S. and Canada.
The warning issued Monday by the Colorado Department of Public Health and Environment is for areas below 7,000 feet and includes Denver, Fort Collins, Colorado Springs, Pueblo, Greeley and Boulder.
Health officials say the young, the old and people with heart and respiratory problems should remain indoors if the smoke becomes too thick.
The smoke is expected to start decreasing Monday afternoon, but health officials say people should follow the recommendations through at least Tuesday morning.
