New York City and the Northeast are braced for several more days of hazardous smog as large swaths of the nation continues to be blanketed by smoke from over 400 Canadian wildfires. 

A thick, nicotine-yellow haze shrouded the famous Big Apple skyline, while the city briefly became the most polluted in the world as its Air Quality Index score soared past 200, which is deemed ‘very unhealthy’. 

The crisis led Mayor Eric Adams to advise the entire city to stay inside and avoid the pollution, as more than a dozen US states and over 100 million people are under air quality alerts. 

Health experts warn breathing the fog can be as damaging as smoking six cigarettes, with side effects from the smog including irritation to the eyes and throat alongside breathing problems. 

A sheet of smoke from the wildfires first descended on New York on Tuesday before thickening throughout the afternoon, leaving those in Manhattan unable to see the New Jersey skyline across the Hudson River. 

As well as sending New Yorkers inside, air quality alerts were also introduced in states including Massachusetts, New Hampshire, Pennsylvania, Maryland, Illinois, Virginia and the Carolinas, according to the National Weather Service. 

In the most recent developments; 

While some areas including Indiana and Ohio saw the smoke partially disperse Wednesday morning, other regions such as Pennsylvania and Virginia will see the fog remain for several days. 

At around 10pm Tuesday, New York briefly set the mark for the worst air pollution in the world, overtaking the Indian capital of Delhi. 

According to the IQAir rankings, New York had the second worst air pollution in the world as of Wednesday afternoon, with its air particle (PM2.5) concentration 14.6 times stronger than the WHO’s guidelines.

The city of Detroit, Michigan was also in the top five metros for the worst air quality on Wednesday morning, with numerous US cities continuing to be plagued by the smog. 

New York City Mayor Eric Adams urged vulnerable residents to be cautious amid the crisis, as he also blamed climate change for the yellow skies. 

‘This may be the first time we’ve experienced something like this on this magnitude,’ he said. ‘Let me be clear, it’s not the last.’

The city’s health advisory warning has since been extended until 8pm Thursday, as officials urge residents to avoid outdoor exposure and to stay indoors when possible. 

Much of the smoke has been from Quebec, where over 400 wildfires are burning as Canadian officials warn they are in the midst of their worst fire season on record. 

Throughout the nation, Canadian officials have deemed more than 240 of the blazes to be ‘out of control’. 

Many of the fires that sparked the smoke crisis have been burning for weeks, but were forced south in recent days due to a storm system blowing in over Nova Scotia. 

The weather pushed much of the smoke across the East Coast, and is expected to continue for the next several days. 

Meteorologist Metthew Cappuci tweeted Wednesday that New York’s air quality would be worse than the day before, bringing visibility in the city to below three miles. He warned that residents may even be able to taste the smoke and may experience stinging eyes.

Unseasonably dry and warm weather has been blamed for the crisis, with the coming months expected to bring more of the same conditions that turned Canadian forestry into a tinderbox. 

Last month alone saw around 6.6 million acres burn in wildfires, the equivalent of five million football fields. 

The US Environmental Protection Agency introduced sweeping air quality alerts throughout Tuesday as the smoke continued to blow in from across the northern border. 

Over 100 million people are under some form of warning, with residents in the northeast seeing their air quality reclassified as ‘unhealthy’. 

In New York City, officials also warned vulnerable individuals such as the elderly or those with breathing problems to avoid exercising outside and to ensure they have a high-grade mask. 

The effects are understandably worse at the source of the wildfires, as Environment Canada issued its strongest possible air quality warning by placing Ottawa under a ‘very high risk’ alert. 

Residents of Toronto and the surrounding areas also saw their air quality deemed ‘high risk’. 

Thousands of people have also been evacuated across the country, with fires also reported in British Columbia, Alberta, Ontario, Nova Scotia and the Northwest Territories. 

Air quality warnings are yet to be lifted throughout the US, with pollution levels at unhealthy levels in states including North Dakota, Missouri and Virginia. 

For those in cities with hazardous levels, residents are advised to exercise indoors and wear a good quality mask when stepping outside. 

The effects of breathing wildfire smoke and air pollution can be extremely damaging, causing symptoms including chest pains and irritation of the eyes, nose and throat. 

‘On these elevated air pollution days, we’ll see an increased number of visits to hospital,’ said Matthew Adams, professor at the University of Toronto and the director of its Centre of Urban Environments, to the BBC. 

‘And the people that are visiting the hospital typically have a pre-existing respiratory disease.’