Rural communities face greater risks of radon exposure compared to urban areas

Henk de Haan built his home southwest of Okotoks, Alta. He was attracted to the wide-open spaces, mountain views, and fresh air. What he didn’t count on was radon. 

“When we built the home, I didn’t know radon was a potential problem. I had googled information on radon, but there weren’t any red flags,” says De Hann. “A few years later, I learned radon can be a problem here and tested for it. The levels were higher than those considered safe. Our kids slept in the basement. We mitigated right away and now the problem is gone.”

Homes in rural communities often have a much higher concentration of radon compared with homes in urban areas. A transdisciplinary team of University of Calgary researchers wanted to know why. 

Researchers from the disciplines of medicine, science and architecture looked at the geophysical makeup of areas, the style of home as well as unique features on or near the property. The team found a link between radon exposure in rural homes based on how close they are to drilled groundwater wells. 

Water wells themselves act as straws for radon gas

“For years now, in Canada and all across the world, people have documented higher radon levels in homes in more rural communities compared to homes in urban communities,” says Dr. Aaron Goodarzi, PhD, principal investigator and associate professor at the Cumming School of Medicine. 

“It's the water wells — not the water, but the wells themselves appear to be acting as unintended straws for radon gas deep in the ground. Thankfully, lowering radon levels in a home is fixable.” 

Many rural properties and communities rely on well water. The researchers  tested the water for radon and found there is not enough of the gas in the  water to significantly contribute to the high radon being observed in indoor air. Instead, the problem appears to result from the drill hole space existing around water well pipes. 

“We know that methane gas bubbles up around the outside of some oil and gas wells,” says Dr. Cathy Ryan, PhD, study co-lead and professor in the Faculty of Science. “This caused us to wonder if unintended, or 'fugitive,' radon gas migration might also be occurring along water wells.” 

Study uncovers important insights 

Radon is an invisible, odourless, tasteless and radioactive gas. Naturally rising from under the ground and diluting to virtually nothing in outdoor air, radon gas is often drawn up and concentrated inside modern buildings to unnaturally high and cancer-causing levels. Prolonged radon gas exposure is the leading cause of lung cancer among non-tobacco users in Canada.

“In order to design safe and healthy buildings, it’s imperative to understand the environment in which they exist,” says Josh Taron, MArch, study co-lead and the associate dean of research and innovation at the School of Architecture, Planning and Landscape at UCalgary. 

“While soil gas has often been overlooked in North American homes, this work gives us important insights into the geological issues that building designs must be able to safely address.”    

The study, published in Scientific Reports, found, on average, individuals living in rural communities were exposed to 30 per cent higher residential radon levels than people living in urban communities. The higher rural radon effect was consistent for households across Canada. The researchers say these findings underscore the importance of regular radon testing, particularly in rural areas where drilled groundwater wells are prevalent. 

'Mitigation was easy'

De Haan says the study helps him understand why his home had such high levels of radon. He’s glad the mitigation got rid of the danger and hopes other rural property owners will take the time to test for radon.

“Once I knew it posed a danger, I didn’t want my family exposed to it,” says De Haan. “Mitigation was easy. It’s given us incredible peace of mind. If I had known at the time of the build, I would have built a mitigation system in from the start.”

This study was supported by the Alberta Real Estate Foundation under the umbrella of the Evict Radon National Study. A Canada-wide transdisciplinary research project involving university-based scientists whose mission is to evict radon from homes. By integrating technology, skills and knowledge, the Evict Radon team aims to understand and prevent radon exposure while ensuring inclusivity in lung cancer screening programs. Learn more