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What is radon – and how are we exposed to it?

Radon is a radioactive gas found naturally in the environment. It has no colour, no odour and no taste. 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.

How we’re exposed to radon

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

Indoor air can have high levels of radon (more than 200 Bcq/m3) when radon from the soil and rocks around any building seeps in and builds up in enclosed spaces that are poorly ventilated.

If you work underground, such as in a subway or tunnel, you may be at high risk of radon exposure.

If you work in a mine (uranium or any other type that is underground), you may breathe air that has naturally high levels of radon if proper ventilation systems are not in place.

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 constantly diluted by fresh air. Because of this, radon gas doesn’t 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 levels are very low.