It is very difficult to predict before construction whether a new home will have high radon levels. Fortunately, preventive measures can be taken during the design and construction process.
The soil can be tested. However, a strong radon source from the soil could be easily missed and many studies showed that the soil testing is not a good predictor of indoor radon concentration.
RADON: A Guide for Canadian Homeowners
— Epidemiological studies confirm that radon in homes increases the risk of lung cancer in the general population. Other health effects of radon have not consistently been demonstrated.
— The proportion of all lung cancers linked to radon is estimated to lie between 3% and 14%, depending on the average radon concentration in the country and on the method of calculation.
— Radon is the second most important cause of lung cancer after smoking in many countries. Radon is much more likely to cause lung cancer in people who smoke, or who have smoked in the past, than in lifelong non-smokers. However, it is the primary cause of lung cancer among people who have never smoked.
— There is no known threshold concentration below which radon exposure presents no risk. Even low concentrations of radon can result in a small increase in the risk of lung cancer.
— The majority of radon-induced lung cancers are caused by low and moderate radon concentrations rather than by high radon concentrations, because in general less people are exposed to high indoor radon concentrations.
The radon control methods listed above may not always be sufficient to achieve low annual average radon levels – 200 Bq/m3 or less. As a result, consider making provisions for an active soil depressurization system. It is more practical and less expensive to install the following components of an active soil depressurization system during, rather than after, construction of your new home.