CHICAGO (AP) — The U.S. Environmental Protection Agency posted air quality alerts for several states stretching from Montana to Ohio because of smoke blowing in from Canadian wildfires.

“Air Quality alerts are in place for much of the Great Lakes, Midwest, and northern High Plains,” the National Weather Service said. “This is due to the lingering thick concentration of Canadian wildfire smoke over these regions. While the concentration of smoke in the atmosphere should begin to wain by Monday, there is still enough smoke to support unhealthy air quality that is unhealthy for sensitive groups in parts of these regions into the start of the upcoming week.”

The U.S. EPA’s AirNow air quality page rated the air in Chicago as “unhealthy” as of 9 a.m. CDT Sunday. And in Michigan, state environmental officials said the air “is unhealthy for sensitive groups.”

The Michigan Department of Health and Human Services advised people in the state to check the Air Quality Index regularly to decide if they should be participating in outdoor activities.

The Indianapolis Office of Sustainability issued a Knozone Action Day for Sunday, saying people throughout central Indiana should avoid time spent outdoors as much as possible, especially active children, the elderly, anyone who is pregnant, and those with asthma, COPD (chronic obstructive pulmonary diseas), emphysema, heart disease or COVID-19. Sensitive groups should remain indoors Sunday and refrain from activities that degrade indoor air quality, including burning candles and vacuuming.

New York Gov. Kathy Hochul said Sunday that unhealthy air from the wildfires in Canada was expected to hit parts of New York state again Monday, mostly in northern and western parts of the state. She said the air quality index was forecasted to be 100 to 150 in those areas, when 0 to 50 is the norm. Her comments came at a news conference about heavy rain and flooding.

“As if the rain coming out of the sky isn’t enough, if you start looking up tomorrow you’re going to see a similar situation to what we had a couple of weeks ago because of the air quality degradation resulting from the wildfires in Canada,” she said. “We’re likely to be issuing a air quality alert for portions of our state. It seems to be projected to be mostly around western New York and the North Country at this time. But as we saw, it can shift very quickly and start developing in more populated areas.”

Health officials have recommended people can stay safe by taking steps such as wearing a mask, staying indoors and keeping indoor air clean.