The FCDO is warning travellers of poor air quality on the US east coast, and of potential flight disruption.
Earlier this week, there were delays at several New York airports due to poor visibility, which had a knock-on impact for flights to and from other airports – including Philadelphia.
Some 150 separate fires are understood to be burning in Canada’s Quebec region alone, accelerated by an early-June thunderstorm.
North America had the worst air quality in the world on Thursday morning (8 June), the BBC reports, citing data from the US Environmental Protection Agency. President Joe Biden said it was a "stark reminder of the impacts of climate change".
The Foreign Office updated its US travel advice late on Thursday. "Smoke from wildfires in Canada is currently causing poor air quality across parts of the east coast of the US," it said.
"You should check AirNow.gov for updates on the current air quality in your location and follow the advice given by the US authorities, including wearing a face mask to protect yourself.
"Air travel may also be disrupted. You should check the status of your flight with your airline before travelling."
