Salt Spring radon risk determined to be low

Roughly one in 25 homes tested on Salt Spring Island show unhealthy levels of radon, according to just released data, but those owners may need to take steps to ensure a healthy living space. 

Take Action on Radon’s Pam Warkentin presented results from recently completed testing Thursday, June 22, at Salt Spring’s Local Trust Committee (LTC) meeting. Radon is a naturally occurring radioactive gas released when uranium breaks down in soils and rocks; free test kits were distributed across the island in November through the 100 Radon Test Kit Challenge program. 

Of 66 test kits successfully deployed, returned and interpreted, three of them tested above Health Canada’s safe guidelines, according to Warkentin, with another 11 showing elevated levels. 

Radon concentrations in air are typically measured in becquerels per cubic meter (Bq/m3) — where a becquerel (Bq) is equal to one radioactive decay per second. When released from the ground into outdoor air, it becomes highly diluted and not harmful — outdoor air typically has a radon concentration of less than 10 Bq/m3 — but radon is a health risk in indoor settings where it can build up. 

“We’re finding that as more buildings are becoming airtight, that soil gas is coming into the building but not escaping,” said Warkentin, “and we’re seeing higher levels across the country in homes affecting people’s health.” 

On Salt Spring, homes testing between 200 and 600 Bq/m3 represent 4.5 per cent of the total; 16.7 per cent showed levels between 100 and 200 Bq/m3. According to the B.C. Centre for Disease Control (BCCDC), long-term exposure to radon — at any level, but especially at high concentrations — can cause lung cancer. 

“Radon is the leading cause of lung cancer in non-smokers,” said Warkentin, “and it greatly increases a smoker’s risk of lung cancer. Health Canada estimates that 3,000 Canadians per year are dying of radon-related lung cancer.” 

BCCDC hosts data from the BC Radon Data Repository, containing anonymized indoor radon observations integrated from multiple datasets. Previous measurements taken in 2021 — 52 homes across the Southern Gulf Islands, in that case — found a median radon concentration of 30 Bq/m3, placing the region’s risk category as “low” — although even then some concentrations were as high as 151 Bq/m3. 

In response to questions, Warkentin said there was no geographic “clustering” among the higher results on Salt Spring, and — at least with the small sample size, about one per cent of residences — no clear trend resulting from the age of homes.  

“From the data we’ve seen across the province, Salt Spring is certainly on the lower prevalence side,” said Warkentin, “and also below the provincial average.” 

Warkentin said there were resources, including grants, available for those who tested at high levels and wanted to hire professionals to mitigate radon in their homes. For information visit lung.ca/lungs-matter-radon-mitigation-support.