Philadelphia air quality index nears max possible reading after Canada wildfire smoke

Philadelphia has now become the epicenter for toxic smog from Canadian wildfires, after the air quality in the city reached 'hazardous' levels.

An air quality index reading recorded last night hit 431, with 500 being the highest and worst, due to ongoing wildfire smoke covering the city. 

The index is a measure of five common pollutants and runs on a scale from 0 to 500, with a rating over 150 considered 'unhealthy.' 

Advice given by Air Now, is urging people to stay indoors and reduce activity levels due to the toxic air outside. 

While New York City had recorded the worst air quality in the world on Wednesday afternoon, Philadelphia took the top spot last night. 

People who live in the city are now being urged to stay indoors and avoid any strenuous activities

The smoke cast a haze over the Philadelphia skyline, seen here from New Jersey

A view of the smoke covered Benjamin Franklin Parkway in Philadelphia, on Wednesday

Philadelphia Public Health announced that due to the smoke they had gone to Code Red due to the unhealthy air

On Wednesday morning, Philadelphia Public Health announced that due to the smoke they had gone to Code Red due to the unhealthy air.

Advice issued by the city is urging people to wear a high quality mask outdoors, avoid any form of strenuous activities and to keep air recirculating in homes using fans and AC units. 

The smog is now said to be heading southwest after a change in winds, but is expected to linger over the next few days. 

On Wednesday night, the baseball game between the Philadelphia Phillies and the Detroit Tigers was cancelled due to the air quality. 

Images taken of the city show a thick white smog descended down on it, with some of the notable sights covered in smoke. 

On Wednesday night, Joe Biden directed his administration to deploy ' all available federal firefighting assets' to help tackle the blazes.

The White House said Biden made the order after speaking with Canadian Prime Minister Justin Trudeau about the evolving wildfire situation.

A readout of the call said: 'The President has directed his team to deploy all available Federal firefighting assets that can rapidly assist in suppressing fires impacting Canadian and American communities.'

CBS Philadelphia meteorologist Andrew Kozak shared a video of himself on Wednesday night on Twitter urging residents to stay indoors. 

He said: 'As if today couldn't get any crazier, Philadelphia has officially entered the hazardous category for air quality.

'It means stay inside at all costs, avoid outdoors. Even the most healthy individuals will be effected by the smoke.

'Have the AC going or at least keep the fan circulating, and anytime you have to go outside make sure to wear the mask.'

The Benjamin Franklin Bridge in the city is barely visible in this picture due to the thick smog

The baseball game between the Philadelphia Phillies and the Detroit Tigers was cancelled due to the air quality.

Smoke from the blazes in various parts of Canada has been moving into the U.S. since last month but intensified with a recent spate of fires in Quebec, where hundreds were burning and considered out of control.

The Canadian Interagency Forest Fire Centre database shows that around 430 fires were burning in nine provinces and two territories. More than half were considered out of control.

As well as the state of Pennsylvania, air quality alerts have also been introduced in states including Massachusetts, New Hampshire, New York, Maryland, Illinois, Virginia and the Carolinas, according to the National Weather Service.

Health experts have warned breathing the fog can be as damaging as smoking 22 cigarettes a day. 

Nanoparticles from the smog are so small they can penetrate the lungs and bloodstream, with side effects also including irritation to the eyes and throat as well as breathing problems.