Hundreds of wildfires still burning in Canada are expected to undermine air quality across the Upper Midwest and Northeast into Tuesday.

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.

Smoke from wildfires burning in Canada is filling the skies high above New Hampshire, triggering concerns about the air quality. An air quality alert will go into effect for all of New Hampshire once again on Tuesday.