Smoke from Canadian wildfires poured into the US East Coast and Midwest on Wednesday, covering the capitals of both nations in an unhealthy haze, holding up flights at major airports and prompting people to fish out pandemic-era face masks.
Canadian officials asked other countries for additional help fighting more than 400 fires nationwide that already have displaced 20,000 people.
Air with hazardous levels of pollution extended into the New York metropolitan area, central New York state and parts of Pennsylvania and New Jersey.
Smoke from Canada's wildfires has been crossing into the US since last month but intensified with recent fires in Quebec, where about 100 were considered out of control on Wednesday.
The air quality index, a US Environmental Protection Agency metric for air pollution, exceeded a staggering 400 at times in Syracuse, New York City and Pennsylvania’s Lehigh Valley.
A level of 50 or under is considered good; anything over 300 is considered “hazardous,” when even healthy people are advised to curtail outdoor physical activity.