Smog alerts have been issued across Quebec and parts of the north-eastern United States due to more than 50 forest fires in Canada.
At least eight blazes north of Montreal are reported to be out of control.
Smoke has moved over Massachusetts and New Hampshire in the US, with the city of Boston covered in a haze on Monday.
Officials in both countries have warned people with breathing problems to remain indoors until the smoke clears.
The BBC reports the fires - sparked by lightning strikes - have been burning for a week. More than 1260 sq km of forest have been burned.
