What is radon?

  • Radon is a radioactive gas found naturally in the environment.
  • Radon is produced by the decay of uranium found in soil, rock and groundwater.
  • Radon gas is invisible, odourless and tasteless and emits ionizing radiation.

As a gas, radon can move freely through the soil and escape to the atmosphere or seep into buildings. When radon escapes from the bedrock into the outdoor air, it is diluted to such low concentrations that it poses a negligible threat to health.

However, if a building is built over bedrock or soil that contains uranium, radon gas can be released into the building through cracks in foundation walls and floors, or gaps around pipes and cables.

When radon is confined to enclosed or poorly ventilated spaces, it can accumulate to high levels. Radon levels are generally highest in basements and crawl spaces because these areas are nearest to the source and are usually poorly ventilated.

In the open air, the amount of radon gas is very small and does not pose a health risk.

How radon enters a house

Some amount of radon gas can be found in almost all homes that are in contact with the ground.

Radon can seep into a home through:

  • dirt floors
  • cracks in foundation walls and floors
  • sumps
  • gaps around pipes
  • basement drains

Radon moves easily through concrete-block walls because they are so porous. Also, radon trapped in water from wells can be released into the air when the water is used.

radon house

Diagram source: Health Canada and Natural Resources Canada 2008, courtesy of the Geological Survey of Canada

Factors that affect radon levels in the home include:

  • The amount of uranium in the ground around the home.
  • The entry points available into your home such as cracks in the foundation, and crawl spaces.
  • The way your home is ventilated.

What are the health effects of radon?

When radon gas escapes from the ground outdoors it gets diluted and does not pose a health risk. However, in some confined spaces, like homes, radon can accumulate to relatively high levels and become a health hazard.

Radon and lung cancer
Radon exposure increases your risk of developing lung cancer. It is the second leading cause of lung cancer after smoking.

Your risk of cancer depends on several factors:

  • the level of radon in your house
  • how long you are exposed
  • whether you smoke – exposure to radon and tobacco use together can significantly increase your risk of lung cancer.

Long-term exposure to high levels of radon in the home may increase the risk of developing lung cancer.

Radon, smoking and lung cancer
People who are exposed to elevated levels of radon and who smoke or are exposed to second-hand smoke, have a higher risk of developing lung cancer than people who are exposed to radon alone.

For smokers, and people exposed to second-hand smoke, the risk of lung cancer is increased due to the combined effects of radon and smoking. For example, if you are a lifelong smoker but are not exposed to radon, your risk of getting lung cancer is one in ten. If you are also exposed to a high level of radon, your risk becomes one in three.

Risk of Lung Cancer in Smokers versus Non-Smokers

radon smokers

Infographic source: Health Canada

Is radon a concern in Perth County?

A two year study from 2009 to 2011, conducted by Health Canada’s National Radon Program, found that 88% of homes that were tested in Perth County were in the acceptable range below 200 becquerels, cubic metre.

The Cross-Canada Survey of Radon Concentrations in Homes – Final Report provides further details of the study.

Do you have radon in your home?

Almost every home in Canada has some radon. But the levels vary from one house to another, even if they are next door to each other. The only way to know if you have a radon problem is to test your home. You have two options for testing:

  • Hire a certified radon measurement professional. If you hire a testing company, you should make sure it is certified and will conduct a long-term test. For a list of certified radon testing companies visit National Radon Proficiency Program.
  • Do it yourself. Home radon test kits cost between $30 and $60 and can be purchased from some hardware stores or ordered by phone or online. Kits include a radon detector that is meant to be exposed to the air inside your home for a period of time and then sent to a lab for analysis.

Reducing radon in your home

If the radon level is high, take action to reduce it. The higher the level, the sooner it needs to be fixed. If the radon level in your home is above the Canadian guideline of 200 becquerels, cubic metre, you are recommended to reduce it.

The Health Canada Radon page provides information about reducing radon in your home.

Adapted from Health Canada