Environment Canada's air quality index has reported moderate to high risk since Saturday morning in Calgary, as many parts of the country struggle with the effects of wildfire smoke.

Parts of Canada are seeing some of their most unhealthy air yet, and the smoke is likely to move over the United States again this weekend.

We believe quality journalism should be available to everyone, paid for by those who can afford it. Smoke from wildfires still raging in Canada is degrading air quality across the northern U.S ...

Wildfire smoke has sparked the national weather agency to issue air quality warnings around the county of Grande Prairie and the northwestern corner of Alberta, and air quality statements for much of northern Alberta.

Many fires burning across Canada, forcing evacuations and threatening air quality in the United States, cannot simply be put out, authorities and experts say.

RALEIGH, N.C. -- Over the weekend, a haze lingered in the North Carolina air, caused by wildfires in Canada that have forced thousands to evacuate across three provinces. The smoke has worsened air quality and reduced visibility in Canada and parts of the U.S,.