Introduction to Radon

The Issue and Background

Exposure to high levels of radon increases the risk of developing lung cancer. This relationship has prompted concern that radon levels in some Canadian homes may pose a health risk.

Radon is a colourless, odorless, radioactive gas that occurs naturally in the environment. It comes from the natural breakdown of uranium in soils and rocks.

The Health Effects of Radon

In the open air, the amount of radon gas is very small and does not pose a health risk. However, in some confined spaces like basements and underground mines, radon can accumulate to relatively high levels and become a health hazard. Exposure to high levels of radon has been associated with an increased risk of lung cancer, depending on the time length of exposure.

Because it is radioactive, radon decays. As it decays, it produces decay products, sometimes called "radon daughters" or "radon progeny." Two of these progeny, polonium-218 and polonium-214 decay rapidly themselves, and emit alpha particles. When alpha particles hit an object, the energy in them is absorbed by the surface of the object. Human skin is thick enough to not be affected, but if you breathe in alpha particles, they can damage bronchial and lung tissue, and can lead to lung cancer.

Studies of the incidence of lung cancer among uranium miners showed a correlation between radon exposure and deaths from lung cancer. Until recently, there had been no evidence of a direct link between radon levels in the home and lung cancer. However, two recent independent scientific studies in Europe and North America show that lung cancer risks extend to levels of radon found in some homes.

-- From the Health Canada website (hc-sc.gc.ca).