We know that smoking is the greatest risk factor for lung cancer but did you know there is a silent risk factor that many Canadians are unaware of.

It is radon gas. As the Canadian Cancer Society points out- many people think that smoking is the only cause of lung cancer, but in fact about 16 per cent of lung cancer deaths are caused by radon exposure, making it the second-leading cause of lung cancer after tobacco.

Exposure to radon gas increases your risk of lung cancer. It is estimated that 3,000 Canadians die every year from lung cancer caused by radon

The Canadian Cancer Society urges that testing your house for radon is the only way to know if you are at risk.

Why? Because radon is a colourless, odourless, tasteless radioactive gas found naturally in the environment that can seep in through cracks and crevices in houses and other enclosed spaces.

To test for radon, you can purchase a relatively inexpensive test kit at your local hardware store or hire a professional to perform a test for you. The age of your home or radon levels in other houses and buildings in your neighborhood are not good indicators of how high radon levels will be in your home.

Health Canada safety levels for radon guideline is  200 Bq/m3 (bequerels per cubic metre, a measure of radioactivity). If high then the home can be successfully mitigated for radon.

If the levels of radon in your home are higher than 200 Bq/m3, you should hire a certified radon professional to determine the best and most cost-effective way to reduce these levels.

Radon is released into the air as soil and rocks containing uranium naturally break down. Outdoors, the released radon is quickly dispersed and levels remain very low. However, when radon enters buildings through foundations, joints and vents, it can accumulate to higher concentrations. This is particularly true in basements, which are often poorly ventilated.

So how does radon cause lung cancer?

Radon is a radioactive gas, meaning that it naturally decays into smaller particles over time. We breathe these particles into our lungs, where they can break down even further. This process releases small bursts of energy that can damage the cells in our lungs, which can sometimes lead to lung cancer.  

The risk of developing lung cancer depends on how much radon a person is exposed to, how long they are exposed as well as whether or not they smoke. The risk from radon is much higher in people who smoke than in those who don't.

High concentrations of radon may increase lung cancer risk, and Health Canada recommends that homes with radon concentrations of 200 Bq/m3 or higher should be remediated to lower the levels of radon.

A radon testing kit can be purchased from your local hardware store and also online through some organizations. The kit should be placed in the home for 3 to 6 months during the time of year when most windows and doors are closed (fall and winter). The kit must be sent to a lab to receive the test results. The Society offers a list of resources to help you find out where to buy a radon test kit or contact a certified radon professional.

Yet 96 per cent of Canadians have not tested their homes for cancer-causing radon gas, a new Canadian Cancer Society survey shows.

Yet more than half of Canadians say they would move if the deadly gas was seeping into their home

The survey was conducted online by Angus Reid, from October 22-29, 2014, among a randomly selected sample of 1,238 Canadians aged 18+. The margin of error for a sample this size is +/-2.8 per cent, 19 times out of 20.