Nov. 23, 2021

New Canadian houses found to have much higher radon gas levels than those in Sweden

UCalgary research correlates radon levels to increased lung cancer rates

A multi-disciplinary team of Canadian architects and cancer researchers has found average radon gas levels in new homes in Canada are 467 per cent higher than in Sweden.

In the study, published in the journal Scientific Reports at, researchers predict that without intervention, by 2050 the average radon level of a new Canadian home will increase another 25 per cent over current levels, which are already third highest in the world.

Machine learning prediction for future

"It is important to acknowledge that prevalent, unsafe radon exposure is a relatively recent, human-made problem rooted in the design of our built environment," says Joshua Taron, the associate dean (research and innovation) and associate professor with the School of Architecture, Planning and Landscape at the University of Calgary. "Canadian construction and design practices in the last 40 years have produced residential, commercial and industrial buildings that capture, contain and concentrate radon to unnatural and unsafe levels."

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. Lung cancer rates in Canada are currently 163 per cent higher than in Sweden, despite smoking rates being essentially the same.

The researchers, part of the Evict Radon national study involving teams from across Canada, 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 World War II.

The researchers chose to compare Canada to Sweden because of the similar climate and available data dating back decades. While Swedish properties in the 1950s had higher radon versus those built in Canada, the situation has changed dramatically 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 causes for this change are complex, with no single, decision or event responsible for reducing or increasing radon in either country.

According to Dr. Aaron Goodarzi, PhD, the Canada Research Chair for Radiation Exposure Disease and an associate professor in the Cumming School of Medicine at the University of Calgary, "Considering the 10- to 30-year latency period for lung cancer — the time between exposure and the detection of cancer — one plausible explanation for the disparity between Canadian and Swedish lung cancer incidence is differences in exposure to residential radon."

Given the scale of the problem, and with the same trends found across every Canadian province and territory, the team calls for proactive radon mitigation systems to be included in all new residential properties constructed using the 2025 Building Code.

Goodarzi says, "We can't afford to wait. The lives of tens of thousands of Canadians are on the line here, not to mention tremendous amounts of health-care dollars that we will never need to spend if we work toward prevention today."

Joshua Taron is the associate dean (research and innovation) and associate professor with the School of Architecture, Planning and Landscape at UCalgary.

Aaron Goodarzi is the Canada Research Chair for Radiation Exposure Disease and an associate professor in Biochemistry and Molecular Biology at the Cumming School of Medicine. He is a member of the Arnie Charbonneau Cancer Institute.

About the Evict Radon national study

Evict Radon is working toward educating Canadians about the harmful effects of radon gas. By testing your home with one of our research-grade radon test kits and enrolling in our UCalgary-based research study, you are helping Evict Radon-aligned researchers from across Canada to understand radon exposure and develop new ways to protect ourselves and loved ones.

Learn more. Follow @evictradon on Twitter, Facebook, LinkedIn, and Instagram.

The Evict Radon study is supported by grants from Health Canada and the Alberta Real Estate Foundation and represents a confederation of Canadian scholars with expertise in radon biology, architecture, population health, geology and communications.

About the School of Architecture, Planning and Landscape  

The School of Architecture, Planning and Landscape at the University of Calgary is one of the top design schools in Canada. Founded in 1971, SAPL celebrates its 50th anniversary this year. Since its inception, the school has demonstrated a commitment to challenging the status quo with holistic design thinking. Learn more. Follow @ucalgarysapl on Twitter, Facebook, LinkedIn and Instagram.

The Calgary Cancer Centre Campaign is on a mission to OWN.CANCER by raising $250 million in support of improved research, treatment and care at Calgary’s new world-class cancer centre. This game-changing initiative is backed by three trusted community institutions: Alberta Health Services, Canada’s first and largest fully integrated provincial health system; the University of Calgary, a globally recognized leader in medical research and home to tomorrow’s health-care professionals; and the Alberta Cancer Foundation, the official fundraising partner for all 17 cancer care centres across the province. Currently under construction, the Calgary Cancer Centre will open its doors in 2023 as the largest, most comprehensive cancer centre in Canada. To donate or learn more, please visit

About the Alberta Real Estate Foundation

Created through the Alberta Real Estate Act, the Alberta Real Estate Foundation is a nonprofit organization that makes purposeful impact-oriented grants and investments that make a difference to the real estate industry and for all Albertans.

We contribute to thriving Alberta communities and a stronger economy through our grant programs, benefiting homeowners, landowners, tenants, and real estate industry professionals. We do this by funding real estate-related education initiatives, law reform, research, and industry and community innovation activities. We connect people and share knowledge in collaboration with real estate industry and public stakeholders.

Since 1991, the foundation has invested $26.5 million in grants to over 665 initiatives across Alberta.

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