Wildfire smoke and air quality updates: Northeast flights disrupted

Air quality alerts have been issued for states across the Northeast.

Hazy and dangerous fumes from ongoing wildfires in Canada have engulfed the skies over much of the East Coast, prompting serious air quality alerts in over a dozen 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.

Latest forecast

The large plume of hazardous wildfire smoke that moved through New York City on Wednesday drifted into the Mid-Atlantic Thursday, bringing dangerous air conditions to Philadelphia, Baltimore, and Washington, D.C.

By Thursday night, the thickest smoke will continue to spread over the Mid-Atlantic. AQI values may reach 400 in some areas. (Levels under 100 are generally considered safe.)

By Friday morning, the hazardous haze will be covering Pittsburgh and the Chesapeake Bay.

The smoke may thin out during the day on Friday with cities like New York City seeing clearer conditions by Friday evening.

Major relief will move in by Monday when a cold front sweeps across the East, washing away much of the smoke in the air.

-ABC News' Daniel Amarante

NYC extends Air Quality Health Advisory until Friday night

New York City's Air Quality Health Advisory has been extended to Friday night.

While the AQI in New York City has been dropping significantly throughout the day, as of Thursday afternoon it registered at 178, which is still considered unhealthy.

Totals were over 400 in New York City on Wednesday. Levels under 100 are generally considered safe.

NYC schools will be remote on Friday

Learning will be remote on Friday for New York City public schools.

What you need to know about the dangers of inhaling wildfire smoke

Air quality is measured by the Environmental Protection Agency’s air quality index (AQI), which ranges from 0 to 500. A higher level indicates a greater level of pollution and health concern.

Levels under 100 are generally considered safe.

Totals were over 400 in New York City on Wednesday.

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NYC mayor says air quality expected to 'deteriorate further' Wednesday

The air quality in New York City worsened Tuesday evening and is expected to "deteriorate further" Wednesday afternoon and evening, New York City Mayor Eric Adams said in a statement.

"At this point, the New York State Department of Environmental Conservation has issued an Air Quality Health Advisory for all five boroughs. While conditions are anticipated to temporarily improve later tonight through tomorrow morning, they are expected to deteriorate further tomorrow afternoon and evening," Adams said.

“Currently, we are taking precautions out of an abundance of caution to protect New Yorkers’ health until we are able to get a better sense of future air quality reports," he said.

Adams said students should still go to school on Wednesday, but New York City public schools won't have outdoor activities.

"These recommendations may change based on updated air quality conditions that come in, but, in the meantime, we recommend all New Yorkers to take the precautions they see fit to protect their health," he added.