Radon

Radon is a colourless, odourless, tasteless radioactive gas found naturally in the environment. It is released into the air during the natural breakdown of uranium in rocks and soil. Once released, radon breaks down into radioactive elements that can attach to dust and other substances in the air we breathe. It’s also a common type of radiation exposure.

How you’re exposed to radon

We are exposed to radon when we breathe in contaminated air. You may be exposed to radon-contaminated air for a variety of reasons:

Indoor air can have high levels of radon when radon from the soil and rocks around the home seeps in and builds up in enclosed spaces that are poorly ventilated. Health Canada recommends that if the indoor radon level is more than 200 Bq/m3, something should be done to reduce it.
Workplace exposure can occur from air in uranium and other underground mines that naturally have high levels of radon if proper ventilation systems are not in place. The Canadian Nuclear Safety Commission and provincial mining authorities regulate the levels of radon in these mines.
Outdoor air also contains some radon. Radon levels outdoors or in the open air are usually very low (between 5 and 15 Bq/m3) since the radon gas is continuously diluted by fresh air. Because of this, radon gas is unable to build up to levels high enough to pose a health risk.
It’s rare, but radon can also be found in water. Radon in water can be a problem when the water is from the ground, such as from private or community wells. Radon is released from the water into the air during normal use such as showering or cooking. However, most communities get water from reservoirs or other open bodies of water where radon concentrations are very low.

Radon and cancer

The International Agency for Research on Cancer (IARC) classifies radon as a known cause of cancer. Find out more about how cancer-causing substances are classified.

Exposure to radon gas increases your risk of lung cancer. This risk depends on the level and length of exposure, as well as if you are a smoker. Lung cancer can develop after years of radon exposure. Experts agree that about 16% of lung cancer deaths are related to being exposed to radon in the home. Radon exposure is the leading cause of lung cancer in non-smokers and it’s estimated that in Canada there are about 3000 lung cancer deaths related to radon each year. If you smoke, you are at an even higher risk of developing lung cancer if you are exposed to radon.

The Canadian Cancer Society believes that you shouldn’t be exposed to substances that cause cancer. If exposure can’t be eliminated, it should at least be reduced wherever possible. We support Health Canada’s indoor air quality guidelines for radon.

The Society will continue to monitor this issue and advocate on behalf of Canadians where appropriate.

Tips to reduce your exposure

At present, it isn’t possible to reduce indoor radon levels to the same level as outdoors. Radon levels in most homes can be reduced to around 75 Bq/m3 or less. The age of your home is not a good indicator of how high indoor radon levels could be – you need to test to know for sure. Find out how to test for radon in your home.

To reduce radon levels, you can:

Seal cracks and holes in basement floors and walls (including joints between the wall and the floor), and openings in the basement for utility connections (for example, openings for water, sewer, electrical, natural gas and fuel oil).
Cover sump pumps and drains. (But don’t do anything that interferes with how they work.)
Increase air circulation by regularly opening windows or by installing a mechanical ventilation system that helps make sure there is a balanced flow of indoor or outdoor air.
Install an active soil depressurization system. This reduces the concentration of radon in the soil, especially next to your home’s foundation.

Radon

How you’re exposed to radon

Radon and cancer

Tips to reduce your exposure

Suggested links for more information