Photos: Terrifying images of Canadian wildfire smoke blanketing the U.S.

Smoke from Canadian wildfires poured into the U.S. East Coast and Midwest on Thursday, covering Washington D.C., New York, and Pennsylvania in an unhealthy haze — forcing school recesses indoors and prompting some people to wear pandemic-era face masks.

For the third day in a row, Toronto was under a special weather statement for high levels of pollution in the air — and Thursday's air quality is now about the same as the day before. Similarly, New York City has had the worst air quality of any major city in the world for much of this week, according to IQAir.

"Year after year, with climate change, we're seeing more and more intense wildfires and in places where they don't normally happen," Canadian Prime Minister Justin Trudeau said in a news conference.