Canadian wildfire smoke updates: New York City tops list of world's worst air quality rankings

New Yorkers are urged to stay inside.

Millions of Americans experience dangerous air quality from Canada wildfires

Hazy and dangerous fumes from ongoing wildfires in Canada have engulfed the skies over much of the Northeast, prompting serious air quality alerts in at least 16 states.

Canadian officials said firefighters are scrambling to put out the blazes. So far this wildfire season, Canada has seen more than 8.7 million acres burned -- an area larger than the state of Vermont.

President Joe Biden and Canadian Prime Minister Justin Trudeau spoke Wednesday about the wildfires in Canada, the White House said.

Biden offered additional assistance and also discussed the health impact of the fires, according to the White House.

"To date, the United States has deployed more than 600 U.S. firefighters and support personnel, and other firefighting assets to respond to the fires," the White House said in a statement.

Trudeau also tweeted that "hundreds" of American firefighters have arrived in Canada, "and more are on the way."

-ABC News' Ben Gittleson

A number of shows on Broadway were canceled over health concerns of the actors, in the wake of the wildfire smoke blanketing NYC.

"Shakespeare in the Park," which is performed outside, was canceled, as well as "Hamilton" and "Camelot."

-ABC News' Darren Reynolds

As New York City was bombarded with dangerous air and smoke that turned the skyline orange, some residents and environmental experts questioned if the city's leader acted quickly enough to warn people about the dangers of the "smoke wave."

The city's Office of Emergency Management issued warnings on its social media pages and city alert system starting Tuesday afternoon and Mayor Eric Adams put out a news release about the dangerous air quality around 11:30 p.m.

Some environmentalists said the late notice was unacceptable given that the city's environment was already showing poor visibility and unhealthy air earlier in the morning.

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-ABC News' Ivan Pereira

Photos show the stark differences of the New York City skyline due to the wildfire smoke.