Preliminary data from a study being conducted at the University of Calgary’s Cumming School of Medicine show high levels of radon in the Calgary area. One out of eight homes have unacceptably high levels of the gas, posing a public health concern that every homeowner should take seriously.
What Is Radon?
Radon is a heavy radioactive gas that occurs naturally. It is part of the decay chains of both uranium and thorium, elements that exist in large quantities within granite bedrock. As uranium and thorium slowly transform into lead, radon is one of the byproducts. It has a short half-life (just 3.8 days) but is a concern because there’s so much of it around; just how much depends upon local geology. Lifelong chronic exposure to radon is a leading cause of lung cancer, second only to smoking.
Why Would Radon Be In Your House?
Underground spaces can accumulate radon in much the same way they can accumulate water. Given the right conditions, the foundation of a house can act as a radon well, literally pulling traces of the gas from the ground. Invisible and odorless, it can pool in the basement and be drawn into air circulation through your cold air return vents.
Larger, newer homes have a greater tendency to draw the gas, due partly to sheer surface area, and partly to their tendency to be more airtight. As the interior of the house is heated, warm air rises to create slight negative pressure in the basement that pulls in the radon. The taller the house, the more pronounced this effect will be.
Acceptable Radon Levels
Radon is measured in units called becquerels per cubic metre (Bq/m3). Health Canada’s maximum average radon level is 200 Bq/m3, and the U of C data indicates that one home in eight exceeds this in the Calgary region.
For perspective, although levels vary seasonally and from place to place, radon concentration in outdoor air is usually well below 10 Bq/m3. Meanwhile, an unventilated mine shaft can reach 700,000 Bq/m3.
It’s worth noting that Canada’s safety standard for radon is not stringent; the World Health Organization recommends a maximum average half that of Health Canada, at 100 Bq/m3. About half the homes in the Calgary region could potentially exceed the WHO safety average!
Testing For Radon
Just about any home supply store can sell you a radon test kit; they range in price from $35 to $75. Simply expose the detector to the air inside your house as directed, then send it to a lab for testing. Make sure the one you buy is a long term test device– ideally at least 3 months– and that it includes the lab analysis fee.
This DIY option is a good one because day-to-day radon concentration will vary, while long-term average exposure is what really matters to your health. A low measurement on a particular day could give you a false sense of security. If you do hire someone to do a single-day measurement, it’s best to do so in the winter when your house is closed up and readings are more likely to coincide with the average.
If the radon level in your home is a concern, it can be dealt with very effectively. Probably the best solution is a method called sub-slab depressurization: holes are made in the foundation, and a small fan creates negative pressure in the ground beneath the house, venting the gas outside before it can seep into the basement. This method is the standard for new construction and can reduce radon levels by more than 90%. If your home is a recent build, it may already have the necessary infrastructure in place.
Retrofitting an older house for sub-slab depressurization is prohibitively expensive. In that case, the solution is to install a Heat Recovery Ventilation system (HRV) that brings in additional fresh air, gently creating a constant positive pressure inside the house to cancel out the radon drawing effect, leaving the gas in the ground. Many houses may have passive HRV already installed; we recommend installing a powered HRV system that can be tuned and balanced to your requirements.
We Can Help
Cost for radon mitigation will vary, depending on the type & size of the house, existing infrastructure, and specifics of the installation. Contact us for a free consultation, and we can help ensure your indoor air quality is safe.