What is Radon?

Radon is a colourless, odourless gas that is widely present in the earth's surface. It comes from the radioactive breakdown of uranium. Uranium occurs naturally and can be found in small amounts in the soil, water and air.

Radon seeps into a home from surrounding soil. It comes up through pores in the soil under homes and buildings through gaps and cracks in the foundation, concrete walls and floors, sumps, joints, basement drains and other openings. Unsafe levels of radon could accumulate in poorly ventilated homes and buildings.

What are the health affects of radon exposure

Radon is a radioactive gas and naturally breaks down to form decay products, called "radon daughters." These can be inhaled deep into the lungs and damage lung tissue.

Exposure to high levels of radon increases the risk of developing lung cancer. Your risk depends on the amount of time you are exposed to radon. Radon also increases the risk of lung cancer from smoking.

How do I know if I have radon in my home?

Since radon concentration varies from house to house even in the same area, the only way to find out if you have radon in your home is to test for it. Radon levels may vary daily, weekly, or even seasonally, depending on the climate, indoor ventilation and heating systems used. The best time to measure radon levels in your home is during cold weather (e.g., October to April) when indoor radon levels are generally highest. Health Canada recommends testing for a minimum of three months. Radon levels are usually higher in basements and other areas of the home that are in contact with soil.

The map below shows where in Canada high levels of radon can be found:

What levels of radon are considered safe?

Radon concentration in air is measured in units of Becquerels (Bq). The new guideline from Health Canada recommends that the level of radon in the air in a home in a normal living area be no more than 200 Becquerels per cubic metre (Bq/m3) per year.

 Health Canada's recommendations on radon mitigation:

Radon Concentration Recommended Action Time
1. > 600 Bq/m³ In less than 1 year
2. 200 - 600 Bq/m³ In less than 2 years

3. < 200 Bq/m³

No action required

What are the solutions to reduce radon levels in my home?

Sealing the Basement

Reduce radon emission from the ground into your home by caulking and sealing cracks and holes in basement floors and walls. Painting the basement floor and wall surfaces may also help.

Sub Slab Depressurization

Most homes will be fixed with a “Sub slab depressurization” system, which uses a fan and PVC pipe to draw air from below the basement floor and exhausts it above the roof.  The radon fan creates a vacuum under the basement floor.  With the fan running, if you puff smoke by a crack or opening in the basement floor, you will see the smoke slowly pulled down through the crack or opening.  Turn the fan off, and the smoke will blow back in your face.  As long as the fan is running, there is literally no underground air entering the home.  Typically, the pipe will run through the garage, and the fan will be in the garage attic.  Other methods consist of the pipe in a closet and the fan in the attic, or both the pipe and fan outside.



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