New homes in Canada have 467% higher radon levels than in Sweden: researchers

A stock photo shows a suburb with single-family homes in Calgary, Alta. (Getty Images)

CALGARY — A team of researchers at the University of Calgary says new homes built in Canada have drastically higher radon gas levels than those built in Sweden.

The team, consisting of architects and cancer researchers, used artificial intelligence tools to analyze long-term radon tests and buildings from more than 25,000 Canadian and 38,000 Swedish residential properties constructed since the Second World War.

The researchers found that, on average, radon gas levels in new homes built in Canada were 467 per cent higher than those built in Sweden.

"We don't 100 per cent know exactly why," said Dr. Aaron Goodarzi, an associate professor in the Cumming School of Medicine at the University of Calgary.

The researchers chose to compare Canada to Sweden because of the similar climate and available data dating back decades, a news release explained.

"We looked at a whole variety of components about the way that our properties are built; they're both cold climate regions, they're relatively similar in terms of populations, and yet they have this enormously different radon levels,” Goodarzi said.

While Swedish properties in the 1950s had higher radon versus those built in Canada, the situation changed over the years.

From the 1970s to 1980s, Canadian and Swedish properties had essentially the same radon risks.

However, since 1980, radon levels have consistently risen in Canada while falling in Sweden, the team said.

"We do know that there are some foundational differences between the two regions – and the way we heat our properties is actually quite different. For example, in the prairies here, about 94 per cent of our houses are heated with forced-air ventilation and a natural gas furnace in the basement,” Goodarzi said.

"That's not what happens in Sweden. Less than 10 per cent of houses in Sweden use that tech. Is that one reason? We don't know.

"One of the important take-away messages is that we almost don't need to know, because we have identified a huge problem, and we also know that lung cancer rates here are higher than there – 163 per cent higher here than there. Yet smoking (rates are) essentially the same."

In a Tuesday news release, the U of C team noted that “radioactive radon gas inhalation is the leading cause of lung cancer in non-smokers and is responsible for about 88,000 cases of lung cancer in Canada since 2001.”

Goodarzi explains radon is dangerous because it emits a type of radiation that we have not evolved to cope with.

The long-term hope, Goodarzi said, is to change the 2025 building code to include proactive radon mitigation systems in all new residential properties built from then on.

"Being able to integrate radon mitigation solutions into the build code is going to be key to addressing population health," said Joshua Taron, associate dean (research and innovation) for the School of Architecture, Planning and Landscape at the University of Calgary.

In the meantime, there are steps Canadians can take to protect themselves.

"What you can do today is you can obtain a radon test," Goodarzi said. "You can get a kit, you can test your house this winter."

"What we find is one in five Canadian houses exceeds 200 Becquerels – that’s a measure of radon – that means 200 emissions of that radiation per second per cubic metre of air. If you're at or above that, you should fix your house.

"A radon retrofit for mitigation through the Canadian National Radon Proficiency Program (is) a couple of days work in the house – it's going to be a permanent fix. So you can do something today to save yourself from potentially (getting) that lung cancer diagnosis."

To purchase a radon test, or for more information on radon, you can visit  www.evictradon.org.