Radon is a radioactive, colourless, odourless and tasteless gas. It comes from the decay of uranium found naturally in soil, rock or water. Radon is quickly diluted when it is released into the outside air. However, when radon seeps into closed spaces like a house it can quickly accumulate to levels that are dangerous for humans to breathe.
Radon exposure is the leading cause of lung cancer in non-smokers and is responsible for 3200 lung cancer deaths in Canada each year.
The Canadian guideline for radon is 200 becquerels per cubic metre (Bq/m3). The United States has set their guideline at 148 Bq/m3 and the World Health Organization has a guideline of 100 Bq/m3. Health Canada recommends that buildings and homes with high radon levels, above the 200 Bq/m3 guideline, be fixed and states:
Individual dwelling owners may wish to reduce radon levels as much as they reasonably can, using methods they find affordable and practical. However, the level in a dwelling should not be above the guideline … We take precautions against accidental deaths by putting on our seatbelts, wearing lifejackets or ensuring that our smoke detectors are working—we should also be testing our homes for radon.
The only way to know if a home or building has high radon levels is to test. Radon levels can fluctuate significantly hour to hour and day to day so Health Canada recommends that a long-term radon test of at least three months duration be conducted. The following graphic provides a summary of information about radon concentration levels in Canada and recommended action levels.
All areas and buildings in Canada have the potential for high radon and all buildings should be tested to determine radon levels. Geological conditions in some areas, (such as in much of Alberta), result in a much higher relative radon hazard. In Canada approximately 6.9% of homes have elevated radon levels. However, our testing in the Calgary area indicate approximately 50% of the homes have radon levels over the 200 Bq/m3 Health Canada Action Level.