An air quality alert was issued for parts of Southern California because of the effects of the Canyon Fire, fueled by dry brush and extremely high temperatures.

Millions are under air quality alerts as wildfire smoke blankets large swaths of U.S. Millions of people across the Upper Midwest and the Northeast are under air quality alerts Monday, as smoke from wildfires in Canada drift over the region.

Smoke from hundreds of wildfires in Canada is lingering over the northern U.S., spreading across to roughly a dozen states from Wisconsin to Maine.