What is radon and why is it dangerous?
At the most basic level, radon is a chemical element, with an atomic number of 86 and the symbol Rn. It’s a colourless, odourless and tasteless gas. It is released from the ground and exists everywhere around the world.
The problem arises when this radioactive gas builds up indoors. When inhaled, it enters your lungs, which can damage them and cause cancer. In fact, radon is the leading cause of lung cancer for non-smokers. And if you do smoke, your chances of developing lung cancer are even higher if you’re exposed to elevated levels of radon.
How does radon get inside a home?
Radon can enter your home through many paths. Because it exists in the soil your home sits on, it may enter through any opening, crack or gap. Often, basements or the lowest level of a home will contain the highest levels of radon.
Outdoors, radon can be diluted by fresh air continually. But this isn’t possible indoors. As a result, radon levels can increase to dangerously high levels. Even if you open all the windows and doors, it can still accumulate in basements, crawl spaces and lower levels of a home and seep into the rest of it.
How much radon is too much radon?
Technically, there is no “safe” level of radon. But as mentioned, because it exists naturally everywhere, low levels of radon are present no matter where you go. Usually, outdoor levels of radon hover around 5 – 15 Bq/m³. “Bq” stands for becquerel, a unit used to measure radioactive decay, or disintegration, of a radioactive element. It represents one disintegration per second. The “m³” stands for metres cubed. So, 1 Bq/m³ is one disintegration per second per cubic metre.
Also as mentioned, levels indoors can be much higher than outdoor levels. The Government of Canada sets an “action level” at 200 Bq/m³. That is, if your home has radon levels above this point, you should take action to lower them. But even if you have lower levels of radon than this indoors, if they’re consistently above outdoor levels, it may still be a good idea to do something.
According to Health Canada, the following recommendations apply to radon:
- At levels between 200 – 600 Bq/m³: Take steps to reduce radon levels within two years.
- At levels greater than 600 Bq/m³: Take steps to reduce radon levels within one year.
What areas of BC have high levels of radon?
The BC Centre for Disease Control created a map of BC showing areas of the province and the percentage of homes in those areas with levels of radon exceeding 200 Bq/m³. Areas like Vancouver and Richmond have around 1% of homes that exceed this level, while areas near inner BC cities such as Kelowna and Penticton have over 30% of homes exceeding this level.
Note that radon levels can vary widely from home to home. High levels may be present in a home in an area otherwise known for low radon levels, too. The only true way to know the level of radon in your home is by testing. Even if your neighbours don’t have high levels of radon, that’s no guarantee you won’t either. The age of your home doesn’t matter, either. New and old homes alike can have high levels of radon.
How do I measure the levels of radon in my home?
Even though you can’t see or smell radon, there are ways to measure it. Radon levels can fluctuate due to many factors, including opening and closing windows and doors, how much is seeping up from the ground and other reasons, so it’s important to calculate an average over time.
The Government of Canada recommends measuring radon levels over a three- to 12-month period. And because doors and windows are usually closed during winter, levels are often higher during these months.
You can either take measurements yourself or hire a professional.
To measure radon levels yourself:
- Start by purchasing a radon test kit.
- Make sure it’s a long-term test kit for 90 or more days.
- After you receive the kit, follow the manufacturer’s instructions on how to use it and get test results.
To have a professional test your home for radon:
- Find a radon measurement professional in your area.
- Ask the professional to set up a test in your home. Ensure it’s a long-term test for more than 90 days.
- Follow the professional’s instructions on how to prepare your home for the test.
Testing is not a one-and-done scenario, either. Health Canada recommends testing once every two years. This will ensure that radon levels are still within acceptable limits throughout the time you’re living in your home.
How do I mitigate radon in my home?
If you determine that you have levels of radon above 200 Bq/m³ in your home, there are steps you can take to mitigate it. The most common method is known as active soil depressurization (ASD).
ASD works by sucking up air from underneath the foundation of a home and venting it outdoors. This usually means drilling a hole in the foundation, then installing a pipe and fan. The pipe is routed up to the roof or side of the home to safely blow the radon into the outdoor air, diluting it to low levels. This process also involves sealing cracks and holes in the foundation so that the air moves through the area under the foundation and does not leak into the home.
If you live in a newly built home a radon mitigation rough-in may be present; in BC, they’re required starting in 2024. This involves installing a vent pipe into the foundation and leaving it sticking up at least 1 ft. (300 mm), capped off and labelled “radon.” If testing determines you need an ASD system, you can attach the fan to the already roughed-in pipe.
If you have crawl space instead of a basement, a common method of radon mitigation involves spreading a plastic sheet (a vapour barrier) across the crawl space, called crawl space encapsulation, and venting the area below the sheet using a fan and vent system similar to ASD.
While these methods work well for detached homes, duplexes and some townhomes, if you live in a strata complex, you will have to work with your strata corporation or board to determine what to do if you find high levels of radon in your home. It may require a special levy, especially if multiple units are affected.
Renters, especially those in basement suites, should contact their landlord if they find high levels of radon in their home. Under the BC Residential Tenancy Act, a landlord must keep a dwelling healthy and safe to live in, so talk to your landlord about testing for radon and addressing high levels. If your landlord is not taking mitigation measures, you can appeal to the Residential Tenancy Branch.
Radon mitigation is not usually complex, though, and a professional installer can complete the process fairly quickly. Costs usually range from $3,000 to $11,000 depending on the specifics required, with the average cost hovering near the low end. There is also a grant program available from the Canadian Lung Association for up to $1,500 for qualified low- to moderate-income applicants and those diagnosed with lung cancer.
What should I do about radon when buying or selling a home?
Homeseekers currently buying a home should ask the listing agent or seller of if a long-term radon test has been done and the results. If it hasn't, note that a week-long subject removal period or three-day rescission period aren’t enough for a long-term test. Currently, neither agents nor sellers are required to do long-term radon testing before selling a home, but levels above 200 Bq/m³ are considered a material latent defect and must be disclosed if known. Some home inspectors may do radon testing, but the days before you finalize a deal on a home won’t give you the full picture.
You could look at maps of the area to see how prevalent high levels of radon are in nearby homes, but as noted earlier this doesn’t necessarily mean your home will have similar levels of radon. Instead, soon after moving into any home, do a long-term radon test to determine if you need to install a mitigation system.
If you’re considering selling your home and have time, perform a long-term radon test to see if there are elevated radon levels. If so, installing a mitigation system may help make your home more desirable. And if levels aren’t high, you can happily disclose this to potential buyers.
While radon may sound scary, simple tests and a quick to install mitigation system – if levels are found to be high – can give you peace of mind, improve your health and help the resale value of your home.
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