Wondering why it smells like smoke outside? Canadian wildfires are impacting millions in Ontario, Minnesota, Toronto, New York, Michigan, Wisconsin and Boston.

Over 800 wildfires are burning through forests in Canada, prompting heavy smoke warnings for millions of Americans.

Wildfires in Canada are pouring thick clouds of smoke into the US and will usher in unhealthy air quality for millions of people in Northeast and Midwest.

Wildfires in Canada are pouring thick clouds of smoke into the US and will usher in unhealthy air quality for millions of people in Northeast and Midwest.

Wildfire smoke has settled thickly in parts of New York, Connecticut, Wisconsin, Michigan and Minnesota—and it’s heading further south.

Wildfires in Canada and Minnesota are sending heavy smoke to the Midwest and Northeast U.S., causing poor air quality alerts.

A massive plume of smoke from wildfires burning across Canada has swept into the United States, degrading air quality across the Midwest, Northeast and Mid-Atlantic.

Around 100 million Americans could be affected by the wildfire smoke, though impacts will vary by location

The smoke from the Canadian wildfires is causing air quality issues in the U.S. See where.

Environment Canada has issued health warnings after sky over city turns yellow

Over 100 wildfires are burning in Canada, with winds carrying the smoke southeast. Warnings about unhealthy air extend from Minnesota through Toronto and into New York.

Warnings about dangerous, unhealthy air extended Wednesday from Minnesota through Toronto and into New York.

The smoke from the wildfires in northern Ontario is expected to linger around until Friday. Check where and how it's moving here.

TORONTO/NEW YORK: Toronto’s air quality ranked the worst among major cities globally on Wednesday as wildfire smoke from northwestern Ontario blackened skies and spread into the…

Roughly 100 wildfires are raging out of control in Ontario, sending smoke streaming more than 1,000 miles from their origin.

Fires in parts of Canada are blanketing several cities with smoke. Experts recommend limiting time outside, purifying indoor air and wearing a respirator if outside.

Wildfire smoke is dense enough in a handful of states that experts recommend masks for those who can’t stay indoors.

Massive plumes of Canadian wildfire smoke have started to pour over the border into the United States, bringing dangerous air quality to more than 100 million people in the…

Monitor ranks Toronto as having the worst air quality on earth, surpassing Kinshasa, DR Congo, and New Delhi, India.

Over 830 wildfires burn across Canada, with many classified as out of control. Thick smoke blankets parts of Canada and the United States, affecting air quality. Officials warn of…

Toronto recorded among the worst air quality of all major cities worldwide on Wednesday as thick smoke from wildfires in Ontario blanketed its skyline and drifted into the US,…