The people most at risk from radon are children and inactive people over 55 years of age.
Radon gas concentrations above Health Canada‘s acceptable limit can be found in both new and older buildings. The Quebec building code does not impose any mitigation measures, unless a house is located in an area identified by Health Canada as being at risk. Although Health Canada has identified areas at risk of exposure, radon gas can be found almost anywhere in Quebec.
If your house is well insulated or if your house has a direct opening to the ground (in the case of a house with a crawl space or an earthen cellar, for example), it is at greater risk of being exposed to harmful concentrations.