HealthLinkBC File #42, May 2010

Radon in Homes and Other Dwellings

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What is radon?

Radon is a colourless, odorless radioactive gas that is released naturally from traces of uranium in soil and rock. It can be found in varying levels around the world.

In outdoor air, radon is present in low concentrations. However, in indoor air or enclosed spaces, radon may build up to the point where it can create a long-term health risk. Action may be required to reduce levels indoors.

Radon may be a problem in buildings such as homes, schools and small office buildings, as well as residential care and other facilities.

How is radon measured?

The unit of measurement commonly used for radon in air is Becquerel per cubic meter (Bq/m3). Small wall-mounted air monitoring devices are used to detect and measure radon. The small monitoring device should remain on the wall for several months to one year.

Can radon affect my health?

The only known risk from breathing radon is lung cancer. About 100 deaths a year are 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 the duration of exposure. Short-term exposure to radon does not result in a significant risk.

Radon exposure does not produce immediate symptoms. You may not realize exposure to dangerous levels of radon has occurred until you or someone in your family is diagnosed with lung cancer.

Experts state that exposure to a radon concentration of 200 Bq/m3 at home, on a continuous basis over a lifetime, gives a 2 in 100 (2%) chance of developing lung cancer. For a smoker, the lifetime chance of developing lung cancer is much higher, at around 30 in 100 (30%).

National guidelines recommend that where radon levels in dwellings are above 200 Bq/m3, action should be taken to reduce the level of radon in the dwelling.

What is the situation in B.C.?

Radon sampling has been conducted in more than 22 B.C. communities to monitor radon levels and to identify radon-prone areas.

Sampling results show that in the Interior and east of the Coast Mountain Range, anywhere from 5 to 40 per cent of dwellings may have radon levels of more than 200 Bq/m3, depending on the community. Elevated levels of radon are less likely in B.C.'s Coastal Regions.

Should I get my home tested?

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 dwellings 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.

The only one way to be absolutely sure of the concentration of radon gas in your home is to have your home tested. B.C. residents are encouraged to have their homes tested, especially those homes that are in the interior of the province.

How do I get my home tested?

You can easily do it yourself. You will need to obtain a small radon detector. Place it in the lowest level of your home that is regularly occupied. Place it away from drafts caused by heating, ventilating vents, air conditioning vents, fans, etc. It should be at least three feet from doors and windows to ensure that drafts do not interfere with the measurement. Keep it away from direct sunlight, or from sources of humidity such as sinks, aquariums, or showers. It should be at least 20 inches from the floor and at least 12 inches from an outside/exterior wall. Keep it in place for a period of 3 to 6 months (depending on the instructions that come with the device you use) and 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). To convert from one to the other use 4 pCi/L = 148 Bq/m3 or 200 Bq/m3 = 5.4 pCi/L.

For more meaningful results, a radon test should be done over an entire year, or at a minimum over six months during the cold season. Indoor radon levels are higher in the winter months when windows and doors are closed. The aim is to get a long-term, average reading. Radon levels can vary greatly over a period of 24 hours so short-term tests that may last only a few days are less reliable.

A list of suppliers of radon testing devices is available from the BC Centre for Disease Control (BCCDC) at www.bccdc.ca/healthenv/Contaminants/Radon/default.htm, or under 'home inspection services' in your local phone listings. The cost of a testing device and results is about $50.

What can I do if tests show my home has elevated radon levels?

There are several things you can do to greatly reduce the levels of radon in your home. Some of these are inexpensive, including:

If elevated 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.

What changes are being made to address radon?

Both the federal and provincial governments continue to explore ways to prevent or reduce radon levels in buildings.

Additional information on current building codes may be found at the National Building Codes website at www.nationalcodes.nrc.gc.ca/eng/nbc/index.html.

For More Information

For more information, please contact your local health authority environmental health officer by visiting www.health.gov.bc.ca/socsec/contacts.html.

Or by phone at:

Additional information can be obtained by contacting:


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