Radon is an odourless, tasteless, colourless, radioactive gas that occurs naturally in the environment. No geographic area in Canada is radon free and levels vary by area and over time.
When radon is released from the ground into the outdoor air, it is diluted and not a concern. Exposure to high levels of radon indoors increases the risk of developing lung cancer. While the health risk from radon exposure below the Health Canada Guideline of 200 Bq/m3 is low, there is no safe level of radon.
Radon levels can vary from home to home depending on soil deposits, type of construction and ventilation. Testing is the only way to check the radon level. Radon test kits are available online as well as through several radon testing companies who offer professional services to building and home owners.
In confined spaces, such as basements, radon can accumulate to high levels and become a health hazard. Radon mitigation by a certified professional is recommended when test results exceed Health Canada's 200 Bq/m3 threshold.
Radon can enter a home through any opening where the house contacts soil, such as:
- Cracks in foundation walls and floor slabs;
- Construction joints;
- Gaps around service pipes and support posts;
- Floor drains and sumps;
- Cavities inside walls; and
- The water supply.
To reduce radon levels within your home:
- Renovate existing basement floors, particularly earth floors;
- Seal cracks and openings in walls and floor including openings around pipes and drains; and
- Ventilate the soil around the basement floor (i.e., sub-slab depressurization).
For more information on radon, visit:
- Health Canada for information on measuring and reducing levels of radon in your home.
- Government of Canada Radon: Action Guides
- Canada Mortgage and Housing Corporation (CMHC) for a free guide that helps identify routes of entry, explain how to measure indoor radon levels and provide solutions for radon reduction.
- Canadian National Radon Proficiency Program for a list of companies that are certified to do radon monitoring and mitigation.