Smoke from Canadian wildfires is causing air quality concerns for millions of Americans in the Midwest and Northeast.

Wildfires burning in Canada were causing unhealthy air quality across parts of North America on Monday. Canadian wildfires burning across northern Manitoba and Saskatchewan are sending smoke through central Canada, the Great Lakes region and the northeastern United States, reducing air quality and visibility in major cities.

Canadian wildfire smoke has affected Wisconsin all week, prompting multiple air quality alert extensions from the DNR.