Image copyright Courtesy Nasa Image caption A Nasa satellite image shows smoke from wildfires blanketing British Columbia

Western Canada has been blanketed by smoke for days as hundreds of wildfires burn in British Columbia (BC).

The smoke has also wafted south into the US state of Washington, where a group of friends in Spokane now want to try blowing it right back to Canada.

They calculate that if each resident places at least five fans on the roof of their home, the city of 550,000 people could blow the smoke back.

The organisers insist their maths is solid.

"Team work makes the dream work," they wrote in the Facebook event page they created to promote the idea. "Let's do this, Spokanites. Let's send this smoke right back to those Canucks!"

Spokane is about 200km (125 miles) south of the Canadian border.

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Spokane resident Nic Huber, one of the event organisers, conceded to local news channel KREM that the idea of blowing the smoke back to Canada is "mostly a joke".

But the event is not entirely tongue-in-cheek.

The friends who organised "Blow Spokane's Smoke Away to Canada" are also promoting links to the BC SPCA, which is running an emergency animal shelter, and Food Banks BC, whose operations have also been affected by the wildfires.

British Columbia is under a state of emergency as fire crews battle more than 550 wildfires throughout the province, and thousands of people have been evacuated from their homes or have been told to be ready to leave.

Air quality warnings have been in place for days in BC and in neighbouring Canadian provinces.

Image copyright Arnaud Lebon via Reuters Image caption A haze from the wildfires in British Columbia descends on Calgary, Alberta

Canadians and Americans have been weighing in on Facebook, some offering light-hearted tips and advice to improve the smoke-blowing event.

"Y'all are all missing an important step! Put a filter on your fan before you put it on your roof! Then it not only sends the smoke back, but also cleans our air!" one user wrote.

One suggested Canadians turn on their vacuums at the same agreed upon time - Friday 24 August, at noon - to make it a cross-border effort.

Another pointed out organisers had made an error in their equation.

"Use 10 fans each," he said. "That way you can make up for the percentage that say they will [participate] but actually don't."

By Tuesday afternoon, about 2,000 people had expressed interest in taking part.