What is radon?

Radon is a radioactive gas that comes from the breakdown of uranium in soil and rock. It is invisible, odourless and tasteless.

When radon is released from the ground into the outdoor air, it is diluted and is not a concern. However, in enclosed spaces, like homes, it can accumulate to high levels and become a risk to the health of you and your family.

How radon gets into your home

Radon can enter a home any place it finds an opening where the house contacts the ground: cracks in foundation floor and walls, construction joints, gaps around service pipes, support posts, window casements, floor drains, sumps or cavities inside walls.

Measuring levels of radon in a building

To know the concentration of radon in your house, you must use a measuring instrument called a dosimeter. You can measure radon concentration in your house by yourself or hire a professional.

Do not rely on test results from a neighbouring house as radon concentration may vary widely between houses, even if they are close to each other.

You can get a dosimeter the following ways:

To obtain a list of professionals certified to measure radon in Québec, use the search tool provided by the Canadian National Radon Proficiency Program. This certification program is recognized by Health Canada and the Ministère de la Santé et des Services sociaux du Québec.

Health Canada recommends that, if the result of a radon concentration test reveals a concentration above the guideline level of 200 Bq/m3, property owners take mitigation measures to reduce the concentration level of radon in their house.

It is also possible to know the percentage of homes in your area which exceed the national guideline as the Quebec Chapter of The Lung Association has been keeping records of the measuring results of radon tests done by thousands of Quebecers over the last fifteen years. To see the results for your area, simply enter your postal code on their web page (in French only).


Corrective measures for your home

If you must take action to reduce the radon concentration in your home, you will get better results by applying more than one corrective measure. For instance, you can do the following:

  • Seal cracks in the foundation
  • Seal openings in contact with soil
  • Ensure that drains are covered and ventilated to the outside
  • Improve ventilation in your home, especially in the basement

If the radon level in the house is too high, these measures will not be enough and you will need to hire a qualified contractor who will install a system that allows radon beneath the foundation to be evacuated before it reaches the building’s living spaces. It is very important to deal with a certified company. You can consult a list of these companies on Health Canada’s Canadian National Radon Proficiency Program website.

Sources and useful links:

Government of Canada – Radon

Government of Quebec – Residential Radon