Government of Nova Scotia Government of Nova Scotia Nova Scotia, Canada


Inspection, Compliance and Enforcement


Radon and Human Health

homesRadon is a radioactive gas that is formed naturally by the breakdown of uranium. Recent scientific studies have linked an increased risk of developing lung cancer to exposure to radon at levels found inside some homes. Radon cannot be detected by the senses. It has no colour, odour or taste. However, it can be detected with special instruments. The only way to know if you have a radon problem is to test your home.


Radon gas is slowly released from soil, rock and water, and also some building materials that contain small amounts of uranium, such as concrete, bricks, tiles, and gyproc. You cannot see, smell or taste radon. When radon gas escapes from the ground outdoors it mixes with fresh air and gets diluted to low concentrations that do 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 concentrations in the home fluctuate seasonally, but are usually higher in winter than in summer, and are usually higher at night than during the day. This is because the sealing of buildings (to conserve energy) and the closing of windows and doors.

Radon in Nova Scotia

Testing is the only way to find out how much radon is in your home, so it is important to test no matter where you live. Some areas of Nova Scotia have a higher risk of radon because of the local geology.

The radon risk map for Nova Scotia from Department of Natural Resources website shows areas with high, medium and low risk.

Test results have shown that 40% of buildings in the high risk areas exceed the radon guideline. In the medium risk areas, 14% of buildings exceed the guideline and in the low risk areas 5% exceed the guideline. These results tell us that even homes in low risk areas should be tested.

The Health Risk of Radon

Radon gas in the air can be breathed into the lungs where they breakdown further and emit "alpha particles". Alpha particles release small bursts of energy which are absorbed by nearby lung tissue. This results in lung cell death or damage. When lung cells are damaged, they have the potential to result in cancer when they reproduce.

Long-term exposure to high levels of radon in the home may increase the risk of developing lung cancer. For smokers, the combination of smoking and exposure to radon can significantly increase the risk of lung cancer. If you are a lifelong smoker but are not exposed to radon, your risk of getting lung cancer is one in ten. If you add exposure to a high level of radon, your risk becomes one in three. On the other hand, if you are a non-smoker, your lifetime lung cancer risk at the same high radon level is only one in twenty. Radon exposure is linked to roughly 16% of lung cancer deaths in Canada, and is the second leading cause of lung cancer after smoking.

Radiation from inhaled radon gas can damage cells in the lungs. The effects depend on the levels of radon and how long a person is exposed to these levels. The Canadian guideline is based on an exposure period of about 70 years spent in a dwelling that contains elevated levels of radon 75% of that time. Other than lung cancer, there is no evidence that radon exposure causes other harmful health effects such as any other form of cancer, respiratory diseases such as asthma, or symptoms such as persistent coughing or headaches.

Research has shown that drinking water that contains radon is far less harmful than breathing radon, and as a result there is no Canadian guideline for radon in drinking water. When the ground produces radon, it can dissolve and accumulate in water from underground sources, such as wells. When water that contains radon is agitated when used for daily household requirements radon gas escapes from the water and goes into the air. The health risk is not from ingestion but from radon inhalation.

Measuring Radon Levels in the Home

Testing a home for radon is easy. There are two options: Buy do-it-yourself radon test kits from a home improvement store, over the phone or on the internet (to get an accurate measure, a few kits should be placed in your home at various spots – in the basement and where you spend most of your time), or hire a professional radon measurement service provider (make sure they are certified and will conduct a long-term test). Do-it-yourself radon testing kits can be ordered on-line from the Lung Association of Nova Scotia or borrowed from your local library.

If you would like to hire a professional to test your home for radon, a list of certified radon measurement professionals in Canada can be found here:

The current Canadian guideline for radon in indoor air for dwellings is 200 Becquerels per cubic metre (200 Bq/m3). The Becquerel is a unit that describes one radioactive disintegration per second. 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 Canadian guideline of 200 Bq/m3.

Reduce Your Risk

In 2010, new National Building Codes were introduced to protect against radon. These new codes require new homes to have a vapour barrier to reduce the entry of radon. They also require a ‘rough-in’ for a radon reduction system. The rough-in will significantly lower costs if action has to be taken later to reduce radon levels in the home.

Steps you can take to reduce radon in your home include; increasing the ventilation to allow an exchange of air, seal all cracks and openings in foundation walls and floors, and around pipes and drains; and renovate existing basement floors – particularly earth floors. The standard method for reducing radon in a home is called active soil depressurization. It’s usually done by a contractor. A pipe is installed through the foundation floor and is connected to the outside. A fan attached to the pipe draws radon from under the home, before it gets inside, and releases it outside, where it gets diluted.

Radon professionals can help you determine the best way to reduce the radon level in your home. To find a certified radon professional in Canada visit the following website:

The average cost to reduce radon levels in the home is $1,500 to $3,000.

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