Smoke and grit from hundreds of forest fires have spread across large parts of Canada and the northern US, sending air quality across the Midwest and northeast US and Toronto to unhealthy levels.

Chicago air quality remains in the top five worst in the world Friday with an Air Quality Alert in place from Canadian ...

Hazy skies from wildfire smoke from Canada, which may become more concentrated with visibility potentially dropping to 3-5 ...

The hazy skies in the Chicago area are the visible sign of the poor air quality Thursday as smoke from Canadian wildfires ...

Most of the Chicago area remains under an Air Quality Alert this weekend due to smoke from Canadian wildfires.

Wildfire smoke from Canada is blanketing the skies in the Midwest, leaving millions with dangerous breathing conditions.

The National Weather Service has opted to extend an air quality alert in the Chicago area for another day.

Smoke from wildfires blazing across Canada is once again wafting over huge portions of the U.S. Midwest and worsening air ...

The smoke is expected to remain over the northern and central Plains of the United States for the next couple of days, ...

Smoke from raging wildfires in Canada is causing air quality alerts to blanket the Midwest. Lissette Nuñez is live from Chicago's Lollapalooza music festival.

Smoke from Canadian wildfires have continued to drift over the Midwest, blanketing the region with haze and poor air quality, prompting the National Weather Service (NWS) and local departments to ...

CHICAGO (WLS) -- Air Quality Alerts remain in effect for the Chicago area Friday due to smoke from Canadian wildfires.