Hazardous air quality alerts have been issued in cities, including Chicago and Grand Rapids in Michigan, Pittsburgh in Pennsylvania and Toledo in Ohio, according to the US Air Quality Index program.

Many outdoor activities were cancelled on Thursday, including events for children’s summer camps, and beaches were shuttered along popular lakes. An outdoor concert for the rock group The Black Keys was being rescheduled in Chicago due to the dangerous air quality.

There are currently 858 fires actively burning in Canada, including 30 new fires that sparked on Thursday, according to the Canadian Wildland Fire Information System. The vast majority are burning out of control.

The large cluster of fires affecting northwestern areas of Ontario are responsible for sending thick plumes of smoke and poor air quality across Thunder Bay and Toronto, with lower concentrations of smoke high in the atmosphere drifting over the Great Lakes and above New York with hazy skies.

“We’re in a very serious health situation right now,” New York Governor Kathy Hochul said in an announcement on Thursday. She noted thick smoke was “blanketing” much of the state, making it “very unhealthy to be outdoors” in many areas.

“This is bad news for every New Yorker,” she said. “There will be great impacts.”

In western regions of New York state, the air quality on Thursday is considered “very unhealthy”, while in the New York City metro area the air quality is “unhealthy”. Many across the city – the most populous across the US – were wearing masks over their mouths and nose hoping to protect themselves.

A thick haze of smoke blocked views across the city of sights including the Empire State Building and the Statue of Liberty.

New York has extended its heat emergency plans and activated its air quality emergency protocols – with hundreds of cooling centres and KN95 masks being made available citywide.