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Radon is a radioactive gas that naturally occurs from traces of uranium in soil and rock. It can be found at varying levels around the world.
In outdoor air, radon is present in low concentrations. However, in indoor air or enclosed spaces, radon levels can increase to produce levels that may be a long-term health risk. Action may be required to reduce levels.
Radon may be a problem in buildings such as homes, schools and small office buildings, as well as residential care and other facilities.
Special monitoring devices must be used to detect and measure radon because it is an odorless, colorless gas. A unit of measurement commonly used for radon in air is Becquerel per cubic meter (Bq/m3). Another unit still in use is picocuries per litre (pCi/L).
The only known risk is lung cancer. About 100 deaths a year is estimated to be related to radon induced lung cancer in British Columbia.
The risk of developing lung cancer depends on the concentration of radon in the air, as well as length of exposure. Short-term exposure to radon does not result in an immediate, significant risk.
Experts state that exposure to a radon level of 200 Bq/m3 (~ 5 pCi/L) at home, on a continuous basis over a lifetime, gives you a 2 in 100 (2 per cent) chance of developing lung cancer. If you are also a smoker, your lifetime chance of lung cancer is much higher, at around 30 in 100 (30 per cent).
National guidelines recommend that where radon levels in dwellings are found to be above 200 Bq/m3, action should be taken to reduce the level of radon in the dwelling.
Radon surveys have been conducted in more than 22 BC communities to monitor radon levels and to identify radon-prone areas.
The survey results show that in the interior and east of the Coast Mountain Range, the results from homes tested for radon and other data on natural radioactivity in the province, indicate that from 5 to 40 out of 100 homes (5-40 per cent) may have radon levels of more than 200 Bq/m3 (~5 pCi/L). Elevated levels of radon are less likely in BC’s coastal regions.
Radon levels vary widely not only from area to area, but even from house to house. Your home is more likely to have high radon levels if:
Newer buildings that are tightly sealed tend to have higher radon levels. In homes with more than one floor, radon levels are often about twice as high in the basement as on the main floor.
As the only one way to be absolutely sure of the level of radon gas in your home is to have your home tested, BC residents are encouraged to have their homes tested, especially those homes that are in the interior of the province.
You can easily do it yourself. You will need a radon detector. Place it in the lowest level of your home that is regularly occupied a period of three to six months, depending on the device you use.
Then return it to the supplier for analysis. The supplier will give you the results of the test reported either in Becquerels per cubic meter (Bq/m3) or picocuries per litre (pCi/L).
For more accurate results, a radon test should be done during cold and warm weather, preferably for a period of six months or longer. Radon levels can vary greatly over a period of 24 hours so short-term tests, lasting only a few days, may be less reliable. Generally, levels can be higher in the winter months when the home is closed up. The aim is to get a long-term, average reading.
A list of suppliers of radon testing devices is available from Radiation Protection Services at the British Columbia Centre for Disease Control (BCCDC), or under home inspection services in your local phone listings. The cost of a testing device and results is about $50.
There are several things you can do to greatly reduce the levels of radon in your home. Some of these are inexpensive, including:
If high radon levels continue, sub-slab ventilation is recommended. A small air pump is installed to draw the radon from below the concrete slab to vent it outside before it can enter the home.
If you decide to take any actions to reduce radon levels in your home, you should have a follow-up test afterwards to confirm that the levels have been lowered, below 200 Bq/m3 (~ 5 pCi/l). Before proceeding with any corrective action, get detailed information on how you can reduce indoor radon levels.
Both the federal and provincial governments continue to explore ways to prevent or reduce radon in buildings. Information is available from the Canada Mortgage and Housing Corporation (CMHC) about how a homeowner can reduce levels of radon gas in both new and existing buildings. Changes have been made to the National Building Code to include ways to reduce radon in new home construction.
For more information, contact your local environmental health officer, or contact:
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