Multiple U.S. states and Canadian provinces are experiencing poor air quality from wildfire smoke. Here's where.

Wildfire smoke degrades air quality in swaths of Ontario, with Toronto ranking among the worst in the world on Monday.

The air quality is expected to worsen slightly across parts of southern Ontario over the next few days. According to Environment Canada, areas in the GTA, including Mississauga, Brampton, Halton, ...

Smoke from wildfires in Manitoba, a Western province facing its worst fire season in 30 years, has created hazardous air ...

Air quality warnings are in effect for a large area of Western and Central Canada this weekend as wildfire smoke continues to choke parts of the country. Many communities in Manitoba, as well as ...

Intense wildfires in Canada’s western provinces continued blazing Wednesday, sending smoke southward and triggering air quality alerts throughout the United States. More than 400 wildfires are ...

Millions of Americans are under air quality alerts as wildfires burn in Canada. Experts say the weather pattern could change by early next week, and stress the need to take precautions until then.

Canadian wildfire smoke lingers in Michigan. Officials issued an air quality advisory in southeast Michigan for July 15.

As parts of the East Coast are expected to experience poor air quality through at least the weekend — and winds might move dense smoke farther south into the Mid-Atlantic — experts say pets ...

Air quality alerts are triggered by a number of factors, including the detection of fine-particle pollution — known as “PM 2.5″ — which can irritate the lungs.

There will be pleasant summer temperatures for the weekend, with a steamy and stormy heat wave expected next week.

Tips to stay protected from harmful air quality 01:57. Smoke from wildfires in Canada has drifted into the U.S., prompting air quality alerts for Americans as it continues to spread.. But when ...