What you need to know about radon

Radon is a radioactive gas that occurs naturally when uranium in soil and rock breaks down. It is invisible, odourless and tasteless. When released from the ground into the outdoor air, radon is diluted and is not a concern. However, in enclosed spaces such as homes, it can sometimes accumulate to high levels, which can put people’s health at risk.
  • Exposure to high levels of radon in indoor air results in increased risk of developing lung cancer. Radon is the second leading cause of lung cancer after smoking. The risk exists for both smokers and non-smokers; however, malignancy from radon exposure is more likely to occur in cigarette smokers.

    Radon gas breaks down to form radioactive elements which, if inhaled, can become deeply lodged in the lungs. These elements emit ionizing radiation that penetrates the cells of the mucous membranes, bronchi, and other lung tissues, damaging the lung cells. When cells are damaged, they have the potential to result in cancer when they reproduce.

    One in 20 people exposed to high levels of radon over a long period of time are at risk of developing lung cancer. For smokers, the risk is even greater. Smokers exposed to high levels of radon have a 1 in 3 risk.  More than 10 per cent of lung cancer deaths in Canada are linked to radon exposure.

    Health Canada estimates 3,200 lung cancer deaths occur each year due to radon exposure in buildings. 

  • The air pressure inside your home is usually lower than in the soil surrounding the foundation. This difference in pressure draws air and other gases, including radon, from the soil into your home.

    Radon can enter a home through openings where the house contacts the soils, such as cracks in foundation walls and in floor slabs, construction joints, gaps around service pipes, support posts, window casements, floor drains, sumps or cavities inside walls.

  • Since radon occurs naturally in soil, it is found across Canada but concentrations differ greatly. Radon levels are usually higher in areas where there is a larger amount of uranium in underlying rock and soil. Radon levels will vary from one building to another, even if they are similar, and next to each other. 

    Radon levels vary drastically, but test result data has led to radon mapping; these maps highlight parts of the province that tend to have higher radon levels.

    According to available radon test data, we know areas exist in parts of the Okanagan, Fraser-Fort George, Peace River, Columbia-Shuswap, Kootenays, Thompson-Nicola and Gulf Islands. 

  • The current Canadian guideline for radon in indoor air is 200 Becquerels per cubic metre (200 Bq/m3). A Becquerel means one radioactive disintegration per second.

    Health Canada has lowered the Canadian guideline for indoor exposure to radon from 800 Bq/m3 to the current 200 Bq/m3 based on new information which indicates that the health risk of radon-induced lung cancer occurs at lower levels of exposure than previously thought.

  • Testing for radon in your home is easy and inexpensive. There are different types of devices that can be used to test for radon. Short term radon test devices are typically used for a 2 to 7 day period of time, while long term radon test devices are used for 3 to 12 months. Since the radon concentration inside a home varies over time, Health Canada recommends that homes be tested for a minimum of 3 months (ideally between October and April). Measurements gathered over a longer period of time will give a much better indication of the annual average radon concentration.

    When testing for radon, place the radon detector in the lowest lived-in level of your home that is used or occupied for more than 4 hours a day (e.g., basement with a rec room, the ground floor, etc.). The preferred location for the device is by an interior wall at least 0.8m (3 ft) off the floor, at least 50cm (20in) from the ceiling, and 20cm (8in) from other objects.

  • Get your radon test kit here. AccuStar will mail you the test kit with instructions on how to set up the device and send it back to a lab for analysis. The cost of the test kit is $29.99 plus shipping and handling.

    Alternatively, radon test devices are available at select Home Hardware and Walmart locations, as well as at all Home Depot stores throughout British Columbia. Prices and types vary.

  • The term used for removing radon in a home is ‘mitigation’. 

    Regardless of whether the result of your radon test result is above the guideline of 200 Bq/m3, you can take the following steps to help reduce the level of radon:

    • Increase mechanical ventilation to allow an exchange of air.
    • Seal all cracks and openings in foundation walls and floors, and around pipes and drains.
    • Paint basement floors and foundation walls with two coats of paint and a sealant.
    • Ventilate the basement sub-flooring by installing a small pump to draw the radon from below the concrete slab to the outside before it can enter your home.
    • Renovate existing basement floors, particularly earth floors.


    Ultimately, if your home tests high for radon, the best method for reducing levels will depend on how radon enters your home and the design of your home.

    We recommend hiring a certified radon mitigation specialist. A fix usually costs between $500 and $3,000, but costs vary depending on the size and design of your home.  

  • Radon is measured in a unit called Bq/m3.  The current Health Canada guidelines are: less than 200 Bq/m3 is below the Health Canada Guideline – but if you can reduce it, do. If you have between 200 and 600 Bq/m3   a fix is suggested within 2 years and if your results indicate more than 600 Bq/m3, a fix is suggested within 1 year.