A multidisciplinary team of Canadian architects and cancer researchers has found that the average radon gas levels in new homes in Canada are 467 percent higher than in Sweden.

The researchers predict that without intervention in 2050, the average radon content in a new Canadian home will increase by another 25 percent above current levels, which is already the third highest in the world.

“It is important to recognize that widespread, uncertain radon exposure is a relatively new, man-made problem with roots in the design of our built environment,” said Joshua Taron, associate professor (research and innovation) and associate professor at the School of Architecture, Planning and Landscape at University of Calgary. “Canadian construction and design practices over the past 40 years have produced residential, commercial and industrial buildings that capture, contain and concentrate radon to unnatural and unsafe levels.”

Inhalation of radioactive radon gas is the leading cause of lung cancer in non-smokers and has been responsible for approximately 88,000 cases of lung cancer in Canada since 2001. The lung cancer rate in Canada is currently 163 percent higher than in Sweden, although the smoking rate is essentially the same .

The researchers, part of the national study Evict Radon 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 built since World War II.

The researchers chose to compare Canada with Sweden due to the similar climate and available data dating back decades. While Swedish properties in the 1950s had higher radon compared to those built in Canada, the situation has changed dramatically over the years. From the 1970s to the 1980s, Canadian and Swedish properties had largely the same radon risks. But since 1980, radon levels have risen steadily in Canada while falling in Sweden. The reasons for this change are complex, with no single decision or event being responsible for reducing or increasing radon in any of the countries.

According to Dr. Aaron Goodarzi, PhD, Canada Research Chair for Radiation Exposure Disease and an Associate Professor at the Cumming School of Medicine at the University of Calgary, “Given the 10 to 30-year latency period for lung cancer – time between exposure and detection of cancer – a plausible explanation to the difference between canadian and swedish lung cancer incidence are differences in exposure to radon in homes. ”

Given the scale of the problem, and with the same trends prevailing in all Canadian provinces and territories, the team demands that proactive radon reduction systems be included in all new residential properties built with 2025 building codes.

Dr. Goodarzi says: “We can not afford to wait. The lives of tens of thousands of Canadians are at stake here, not to mention huge amounts of healthcare dollars that we will never have to spend if we work towards prevention today.”