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Radon action month

Radon action month

What is radon?

Radon is a radioactive gas formed from uranium that occurs naturally in the earth’s crust. Radon is found everywhere on the Earth’s surface. Levels of radon in soil vary greatly from place to place and can also be found in underground water.

Radon can seep into buildings, especially through foundations. It can sometimes accumulate and reach levels that can be harmful to health. It has no taste, smell or colour, and therefore cannot be detected with the senses.

Health effects

Radon can be inhaled into the lungs. International organizations and agencies have recognized radon as a carcinogen. It emits radioactive particles that can cause lung cancer over the long term.

Radon is the second leading cause of lung cancer after smoking. It is also the leading cause of cancer in non-smokers. In Québec, 10% to 16% of lung cancer deaths are attributed to radon. This represents over 600 deaths a year. Of these deaths,

  • 60% occur in smokers;
  • 30% in ex-smokers;
  • 10% in non-smokers.

The risk of lung cancer linked with radon increases with

  • radon levels: the more a person is exposed to high levels of the gas, the greater the risk of cancer;
  • duration of exposure: the risk of developing cancer increases in people exposed to radon for several decades;
  • smoking: smokers exposed to radon are at higher risk of having lung cancer than non-smokers.

Radon doesn’t cause

  • breathing problems such as chronic bronchitis or emphysema;
  • allergies;
  • asthma;
  • birth defects.

Sources of radon in a building

Outdoor radon levels are usually very low. Radon disperses quickly in outdoor air and therefore doesn’t cause health problems. However, radon can enter into buildings through various openings, such as

  • dirt floors;
  • cracks in concrete slabs or foundation walls;
  • drains;
  • crawlspaces;
  • joints;
  • openings around vent pipes and service lines, such as pipe fittings;
  • faucets, especially ones in showers. Faucets can be a point of entry for radon coming from groundwater rich in the gas. Therefore, they can contribute to increasing radon levels in indoor air.

Measuring radon levels in a home

To know the concentration of radon in your home, you must use a measuring instrument called dosimeter. It is advised to measure for a period of at least three months, during winter.

Don’t rely on results of tests done in homes next door to you or in other dwellings around your neighbourhood. Radon concentrations can vary widely between homes, even if the buildings are close to each other.

You can measure radon concentrations in your home yourself or hire a professional.

Learn more


See also

Public, Prevention, News, MSSS

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Last Update : 01 July 2020