Image source, Getty Images

Though Ottawa's air quality looks to be improving this evening, New York City's has reaching an alarming 413 on the Air Quality Index (AQI).

The AQI indicates how clean or polluted the air is around you. The index runs from 0-500 and the higher the number, the worse it is for your health. The city has never gone above 174 in recorded history.

Anything from 151-200 is designated as "unhealthy". When the number is between 201-300 it's "very unhealthy" and the the risk is increased for everyone. The highest level is "hazardous" and occurs when the AQI is above 301.

These are the AQI levels in a handful of US east coast cities as of 17:00 local time (22:00 BST).

• New York, NY - "hazardous" - 413
• Buffalo, NY - "unhealthy" - 179
• Washington, DC - "unhealthy" - 180
• Atlanta, GA - "unhealthy for sensitive groups" - 122

Image source, Shutterstock

The air quality in Canada's capital city appears to have improved from this morning.

According to Environment Canada, which measures air quality risk on a scale from one to 10, Ottawa has dropped to a six - classified as "moderate risk" - as of 16:00 local time (21:00 BST).

This is a big improvement from the air quality earlier in the day, which broke the scale at above 10 and was deemed "very high risk".

Air in Toronto is also deemed at a "moderate risk" as of Wednesday afternoon, though it is expected to worsen to "high risk" - a nine on Canada's Air Quality Index - by late tomorrow morning.

Image source, Getty Images

Tuesday's New York Yankees Major League Baseball game versus the Chicago White Sox at Yankee Stadium in New York City has been rescheduled, the team announced on Twitter., external

In their statement, the Yankees said the reason is due to "poor air quality due to smoke from the Canadian wildfires".

The team says the game will be made up on Thursday.

Another game between the Philadelphia Phillies and the Detroit Tigers has also been rescheduled to Thursday due to poor air quality in the Philadelphia area.

So far, a game between the Arizona Diamondbacks and the Washington Nationals will be played as scheduled a few hours south in Washington DC.

Image source, .

The easiest way to avoid the negative effects of inhaling smoke is to stay inside, preferably with windows and doors closed.

The smoke can be particularly harmful for children, the elderly and people with health problems that affect their heart or lungs.

By now we’re used to air quality updates as part of many weather forecasts, and the US government has a site where you can check the air quality, external in your local area. Canadians can check their local conditions here, external.

The US AirNow site also has some safety tips – it notes that cloth masks won’t protect you from wildfire smoke, but others such as N95 respirator masks can provide some protection.

Experts also suggest running a standalone air filter if you have one, or using your home’s HVAC/air conditioning system, if it has a filter.

Brandon Livesay
Live editor

Image source, Getty Images

I was in Sydney during Australia's deadly bushfires in 2020, and I now live in New York City as the Big Apple's sky turns that same shade of apocalpyptic orange.

It's a colour, and a smell, that I didn't think I'd experience again.

While the smoke grips millions in major population centres, it's important to remember those people in the literal line of fire who have been evacuated from their homes in Canada.

I'm finishing up my stint as editor of this live page for the day, and am going to be hiding indoors once I make it safely to my home.

Marianna Brady in Washington DC will be bringing you the next slew of updates, along with the rest of our evening team.

We're expecting plenty more striking images, and will keep an eye on new health warnings, flight cancellations or any other news you need to know.

Stay safe.

Robin Levinson-King
Reporting from Toronto, Canada

Image source, Whitney Tushingham

The wildfires mean it's going to be a “boring day inside” for Whitney Tushingham and her 10-month-old daughter Margot.

Whitney, a midwife, spoke to us by phone from the Canadian capital Ottawa.

“My husband has asthma and he finds that it’s exacerbated by the smoke,” she says. “And I obviously don’t want to risk it with Margot.”

Even the family dog is feeling the effects and has been lethargic while walking around the park.

“Yesterday in the morning it was spooky, it looked like Mars,” she says. “The shadows seemed very muted and weird and there was this kind of otherworldly orange cast.”

“It seems a bit clearer today but the smell has intensified.”

A storm system in eastern Canada and the US is dragging toxic wildfire smoke from Quebec down to New York City and out into the Atlantic.

Watch the video below to see BBC weather break down the path of the smoke, as well as what to anticipate in the next few days:

Richard Gray
Editor, BBC Future

Image source, NOAA

While wildfires can devastate the land, wildlife, homes and lives of people caught up in the flames, the smoke can travel around the world.

Ash, smoke and even burning material can be carried upwards by super-heated updrafts, creating a type of fire-induced thundercloud known as a pyrocumulonimbus.

These allow the thick plumes that belch from large wildfires to rise up to 14 miles (23km) into the air, reaching into the stratosphere. Air currents can then carry this smoke over vast distances, crossing entire continents and even oceans to affect air quality far away from the flames themselves.

In 2019, pollution billowing from forest fires in Alberta, Canada, spread down the east coast of the US, across the Atlantic Ocean and into Europe.

The devastating bushfires in Australia in January 2020 produced some of the largest pyrocumulonimbus clouds ever recorded, external, leading to smoke turning the skies in South America hazy.

These satellite images taken by NASA and the National Oceanic and Atmospheric Administration show the extent of the current Canada wildfire smoke.

Image source, NOAA

Image source, Getty Images

The National Zoo in Washington, DC is "closely monitoring all of their animals, especially those that are predominantly outside".

Zoo officials said the great apes are inside due to a sensitive baby gorilla. At only two weeks old, it would be at higher risk from unhealthy air.

The Toronto Zoo is also bringing some animals indoors to escape the air pollution. Animals with respiratory illnesses were brought inside first.

There have also been multiple zoo closures in New York state and carriage horse rides in New York City have been suspended as of Wednesday.

Samira Hussain
New York business correspondent

Image source, CBS

It is eerily quiet in Lower Manhattan. There would normally be people sitting outside, eating their lunches or just taking a break from their desks.

Today, no one was sitting on the public tables. Of the few people I saw, a good smattering were wearing masks.

There is a thick orange haze that has drifted onto the city. It smells like a campfire.

New York City schools have cancelled all outdoor activities for today, to the ire of my children who heard the dreaded words of “indoor recess”.

Image source, Getty Images

Face masks have returned on the streets of New York and Toronto, but what kind of mask works best to protect from the harms of smoke inhalation?

First and foremost, Environment Canada recommends that people stay indoors at this time as much as possible.

If you must spend time outdoors, the agency recommends wearing a well-fitted respirator type mask, like an N95 or equivalent, as those masks don't allow air to pass through small openings between the mask and the face.

Looser masks can otherwise let some of the smoke in, which contains harmful, fine particles that cause health issues related to wildfire smoke.

A surgical mask will provide some protection if an N95 isn't available, but it is not recommended to wear them for long periods of time outside.

The Federal Aviation Administration (FAA) issued a brief ground stop advisory for LaGuardia Airport in New York City on Wednesday afternoon due to visibility issues from the wildfire smoke.

It was lifted as of 14:00 local time, but the FAA said further delays could follow.

Flights bound for Newark Liberty International Airport in New Jersey are also being delayed from taking off until midnight, the FAA said.

The FAA cautioned earlier today that the smoke may have an impact on flights in north-eastern US.

In a video posted on Twitter, external, FAA spokesperson Sam Ausby said Boston, the New York metro area, Philadelphia and the DC metro area are all experiencing poor visibility due to the smoke.

There are currently 1,475 flights delayed in the US, according to flightaware.com, many of which are out of LaGuardia and Newark.

Here's what the skyline looked like yesterday at this time (above), versus today (below), as the region suffers from hazardous air quality.

Image source, EarthCam

Image source, Getty Images

The White House said they are sending support to Canada as they battle the wildfires.

Press Secretary Karine Jean-Pierre said they are in contact with the Canadian government and "have already deployed over 600 US firefighters and personnel, as well as equipment like water bombers".

The White House is also working with state and local leaders in Michigan, Illinois and New York.

The White House is speaking to multiple agencies, like the Environmental Protection Agency, Centers for Disease Control and Prevention and Federal Emergency Management Agency about coordinating with local governments to get timely and accurate information out to US communities impacted by smoke in the air.

She said people can go to airnow.gov, external to "get real time information about air quality and precautions you can take".

"It is yet another alarming example of the ways in which the climate crisis is disturbing our lives and our communities," she said.

Image source, Getty Images

Canadian officials have just finished giving an update on the fires.

Prime Minister Justin Trudeau recounted a conversation he had with Kevin Corkum and Conor Scott, two firefighters in Nova Scotia who rescued an elderly man from his home.

“Firefighters are stepping up. First responders are stepping up in harrowing situations to save their fellow citizens,” Trudeau said.

“When we get an opportunity to see the direct impact it is all the more important that we say thank you.”

Officials said military firefighters have been deployed and more are on their way to fight the fires on the ground and with water bombers flying overhead.

Canada is also getting assistance from abroad to fight the blazes, including hundreds of firefighters from other countries.

The eastern part of Canada and the US are taking the brunt of the smoke from the wildfires.

Wildfires are typical for this time of year in Canada. But the frequency and size of fires seen this year are unusual, fuelled in part by drier and warmer temperatures.

If the fires continue to burn at this rate, federal officials have predicted that 2023 may be Canada's worst fire year on record in terms of size of area burned.

Image source, Reuters

We're hearing from Canada's Prime Minister Justin Trudeau and Canada's Minister of Public Safety, Bill Blair.

Blair has just given an update on the scope of the fires.

• He says there have been 2293 wildfires in Canada so far this season and approximately 3.8m hectares of land was burned
• There are 414 wildfires currently burning and 239 of them are out of control
• There are 20,183 people who remain evacuated from their homes

In an update to reporters just now, Quebec's premier Francois Legault says his province is struggling to contain all the 150 wildfires currently burning.

He says Quebec can only fight 40 fires at a time with the resources it has on the ground.

At the moment, there are more than 500 firefighters battling the flames, in addition to 150 Canadian soldiers that have been sent by the federal government to help.

Legault says the province hopes to have an additional few hundred firefighters in the coming days.

Some are arriving from other parts of Canada, but the majority will be coming from France, the US, Portugal, Spain and Mexico, he said.

Thousands have been evacuated this week as a result of the fires, and the province issued additional evacuation orders on Tuesday due to approaching forest fires.

"Don't put your life in danger," Legault pleads. “When we ask you evacuate it’s because there’s a real risk.”

Samira Hussain, BBC's New York business correspondent, just took this photo of what would usually be an incredible view of the Statue of Liberty.

If you stare closely, you can barely make out Lady Liberty's outline on the left side of the image.