Local bedrock and surficial geology influences the potential for high radon levels. The glaciers that flowed from northern Canada ground up, distributed and deposited granitic uranium-rich soils across our province. These porous glacial tills are highly permeable, so radon gas can flow through them into our homes undetected. The result is, your home does not have to be sitting on granite bedrock to have high radon. High radon levels can be found anywhere.
Radon is a naturally occurring radioactive gas that is invisible, odourless and tasteless. It is formed by the breakdown of uranium and can enter a home via entry points in a basement floor, such as cracks, floor drains and sump pits.
Radon becomes a problem when it collects in high concentrations and creates a significant health risk for building occupants. Radon does not differentiate between an old or new home or a large or small one. In our well-sealed homes, it can enter faster than it escapes, resulting in elevated levels and an increased health risk.
Radon is measured in units called Becquerels per meter cubed (Bq/m3). Health Canada’s current action level for mitigation/radon reduction is 200 Bq/m3.
Radon levels are highest during home heating months, predominantly due to Stack Effect. During the winter, the warm air within the house rises and escapes to the colder air outside.
As air escapes to outdoors, fresh air enters the house through drafty windows and doors to equalize pressure. Houses also get new air from the soil beneath the basement floor, which can be drawn in through cracks in the concrete, plumbing pipe penetrations, sump pump pits, floor drains, crawlspaces and any other areas that have contact with the soil. This new air entering the home may contain radon gas.