Radon is an invisible, odorless gas that comes from the natural breakdown of uranium in soil, rock and water. Radon gas escapes from the ground into the air. In open spaces, the concentration of radon gas is small and does not pose a health risk.
In confined spaces, such as basements and underground mines, radon can accumulate to high levels and become a health hazard. Prolonged exposure to high levels of radon can increase the risk of developing lung cancer.
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 their home, homeowners can:
- 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).
Radon levels can vary from home to home depending on the soil, construction and ventilation. Testing is the only way to check the radon level in your home. You can purchase a test kit online or hire a radon testing company.
The Canadian guideline for radon in indoor air dwellings is 200 Bq/m3. If testing shows levels of radon above this threshold, remedial measures should be taken.
For more information
For more information on radon, visit:
- Health Canada for information about measuring and reducing levels of radon in your home.
- The 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.
- The Canadian National Radon Proficiency Program for a list of companies that are certified to do radon monitoring and mitigation.