The Federal Aviation Administration instituted a ground stop on all arrivals to Philadelphia International Airport on Thursday due to low visibility caused by the smoke from Canada’s wildfires.
The outright stop in Philadelphia, which banned all landings, lasted from 8:29 a.m. to 10:07 a.m.
Ground delays at LaGuardia Airport in New York and Newark Liberty International Airport were also implemented, and they will not be lifted until 10 p.m.
Unlike a ground stop, a ground delay means the airport can only accept a few landings at a time, and thus flights will be delayed.
Flights going to Newark should expect an average delay of 34 minutes, while flights to LaGuardia can anticipate an average delay of 54 minutes due to the visibility concerns.
As of 2:22 p.m. EDT, there had been 44 delayed flights in Philadelphia, 153 delayed and seven canceled at Newark, and 349 delays and five cancellations at LaGuardia, according to flight data tracking website FlightAware.
The air quality across the East Coast is waxing and waning as the smoke moves. On Wednesday, hazardous levels of air pollution with an air quality index score of 400 or “code maroon” were recorded in Syracuse, New York.
Overnight from Wednesday into Thursday, the world-worst air quality designation shifted from New York state (and the eponymous city) to the Philadelphia area, where the index hit a staggering 447 at one point.
Any index score over 300 is considered “hazardous” and public health officials advise even the fittest people to curtail outdoor physical activity.
Conditions improved in the area over the course of Thursday, with the smoke projected to abate in American skies by Sunday, according to KYW-TV.