The winter season brings increased levels of radon in the workplace, and is a prime time to test for and address any issues. During these colder months, buildings tend to be regularly sealed, creating lower ventilation.
According to Health Canada, radon is an odourless and tasteless gas that occurs naturally when uranium in soil and rocks begins to decay. The gas omits radioactive particles, which can be inhaled and lead to cancer. About 188,000 Canadians are expected to be exposed to radon at work every year. Health Canada says radon results in an estimated 3200 deaths per year and is responsible for 16 per cent of all lunch cancer deaths in the country.
Dr. Cheryl Peters, postdoctoral fellow at Carelton University and occupational exposures lead scientist at CAREX Canada recently offered some radon reduction insight via The Canadian Centre of Occupational Health and Safety.
She says radon can be found in anywhere, such as hospitals, schools and long-term care facilities, and levels are higher in indoor air compared to outdoor air. Workers in underground mines are at the most risk, janitors, caretakers and teachers can all be exposed because they spend a considerable amount of time indoors.
Where radon is found
Peters notes that radon gas enters buildings when air pressure indoors is lowers than the soil foundation surrounding the building. The pressure difference draws air and other gas indoors through openings and cracks in the foundation, gaps around pipes and windows and cavities inside walls.
While radon levels vary from province to province, most buildings contain some levels of concentration. So, no area is really free of radon, she notes.
“Radon levels in buildings also vary across the seasons and can change significantly even in 24 hours, by a factor of two or three,” she said. “The highest levels usually occur in winter because windows and doors are kept closed; this seals buildings and, therefore, decreases ventilation. Sealing buildings to conserve energy can result in higher levels of radon as well.”
Rooms closer to the ground and in confined spaces, such as offices in basements, could be a concern.
Reduce radon exposure risk
Measuring through radon detectors is the only ways to determine if radon is present. These are small devices placed in a workplace for a period of time and sent to a lab for analysis.
Peters suggests following Health Canada’s radon reduction guidelines. Use a long-term detector and test for a minimum three months, especially during winter. The more popular long-term device is to filter air through the device and measure particles released when radon decays
Testing is available through certified service professionals, who can be found through the Canadian Association of Radon Scientists and Technologists or the Canadian National Radon Proficiency Program.
For workplaces, Peters suggests using raw materials that are low in naturally occurring radioactive materials. Construct and modify buildings to prevent radon entry through the soil gas or facilitate its removal. Increase air circulation by regularly opening windows or installing mechanical ventilation and reduce the amount of time workers spend in areas where radon may be found.
Specific methods for removing radon from existing buildings include several factors, including the concentration and soil type. The most effective measure is called active sub-slab depressurization. According to Peters, this means a remediator installs a pipe through the floor slab of a foundation. This pipe is attached to a fan that runs continuously, drawing radon gas out from beneath the workplace to the outdoors where it is then diluted.