The Canadian Grand Prix is “not at risk” despite wildfires causing air-quality issues across much of North America, Formula 1 has said.
Quebec, the province in which the Montreal race will be held next weekend, is the origin of much of the smoke.
F1 said it had been “assured the situation in Montreal is different to other parts of the country and US”.
It added: “The risk remains low and the air quality is good in Montreal.”
Millions of people have been advised to wear N95 masks outdoors as a result of poor air-quality levels due to the fires.
New York will begin distributing free masks on Thursday, while Canada has said people should wear a mask if they have to go outdoors.
The smog is expected to spread beyond New York to other east coast areas.
Environment Canada said conditions were worsening in Toronto on Thursday, as more smoke blows in.
There are 150 fires burning in Quebec, which is already facing its worst fire season on record.
F1 has been discussing the issue with the race promoter and Canadian authorities, and its own security and health and safety are in Canada preparing for the event, with the arrival of personnel from early next week.
The sport’s bosses have no concerns about going to Canada or for the event itself at this stage, but F1 will keep the situation under review in the coming days.
The Canadian Grand Prix is held on the Ile Notre-Dame, an island in the St Lawrence Seaway next to downtown Montreal.
The situation comes less than a month since F1 abandoned the Emilia-Romagna Grand Prix as a result of widespread flooding across northern Italy.