Canadian wildfires are causing unhealthy air quality again in Chicago and other parts of the US

Earlier this month, massive fires burning stretches of Canadian forests blanketed the northeastern United States and the Great Lakes region, turning the air yellowish grey, and prompting warnings for people to stay inside and keep windows closed.

The small particles in wildfire smoke can irritate the eyes, nose and throat, and can affect the heart and lungs, making it harder to breathe. Health officials say it’s important to limit outdoor activities as much as possible to avoid breathing in these particles.

Fires in northern Quebec and low pressure over the eastern Great Lakes are sending smoke through northern Michigan, and across southern Wisconsin and Chicago, said Bryan Jackson, a meteorologist with the National Weather Service.

Jackson added that a north wind would push the smoke further south, moving into Illinois, Indiana and Kentucky later Tuesday and overnight.

The Minnesota Pollution Control Agency issued an air quality alert for southern, east central, and northeast Minnesota until Thursday night.

Jackson also noted that southwestern Michigan has high air quality index, over 200 on a 500-point index. That’s considered unhealthy for everyone because it denotes high levels of fine particle pollution, or PM2.5 particles.

“Until the fires are out, there’s a risk,” Jackson said. “If there’s any north component to the wind, there’s a chance it’ll be smoky.”

In early June, US President Joe Biden said in a statement that hundreds of American firefighters and support personnel have been in Canada since May, and called attention to the fires as a reminder of the impacts of climate change.