Published: • Written by: Erik Rosen and Andrew Guido
Radon is a naturally occurring radioactive gas, created by the decay of uranium in the earth. While mostly harmless in outdoor air, it can seep into buildings as it rises through the earth, building up in increasing concentrations in the confined spaces of homes that are sealed tight for energy efficiency. Pathways for entry include cracks in the home’s foundation or basement slab, sump pits, gaps around pipes and cables, and crawl spaces. Operating appliances that draw air – such as exhaust/stove fans, water heaters, clothes dryers – create negative pressure and pull the radon up into the home’s living spaces. Colourless, odourless, and invisible, these radioactive alpha particles then attach to dust and other substances, and when breathed in, lodge in the lungs, damaging tissue and significantly increasing the risk for lung cancer. In fact, radon is the second leading cause of lung cancer worldwide, just behind cigarette smoking.
According to Health Canada, radon induced lung cancer deaths represent approximately 16% of all lung cancers, or 3,200 Canadians, and according to the US Environmental Protection Agency (EPA) 21,000 Americans die annually from radon exposure.”1 2
The World Health Organization (WHO) estimates “that radon causes between 3–14% of all lung cancers in a country, depending on the average radon level and the smoking prevalence in a country.”3
There is no predicting which homes have elevated radon levels and which don’t. Your home may be fine, while your next door neighbour’s isn’t. Even within a home, levels may vary significantly day to day and even hour to hour. The only way to know if cumulative and dangerous exposure is happening is by testing.
Canadian guidelines mandate some sort of radon mitigation if levels are in excess of 200 Becquerels per metre cubed (Bq/m³) over the course of at least 48 hours of continuous testing. If the reading is between 200-600 Bq/m³ the recommendation is that you remediate within two years. A reading above 600 Bq/m³ mandates remediation within one year, although clearly, any elevated readings should be addressed as soon as possible.
In the United States, which uses a different unit of measure called a picocurie, the EPA recommends homes be fixed if the radon level is 4 pCi/L (picocuries per liter) or more. Because there is no known safe level of exposure to radon, EPA also recommends that Americans consider fixing their home for radon levels between 2 pCi/L and 4 pCi/L.4
There are two basic methods of testing for radon:
It is important to follow all instructions when testing for radon, including keeping doors and windows closed for the duration of the test. This is the only way to ensure accuracy. You must use an approved device as well.
The good news is lowering radon levels is fairly easy. Health Canada recommends hiring a professional who is certified under the Canadian National Radon Proficiency Program (C-NRPP). The counterpart organization in the United States is the National Radon Proficiency Program (NRPP). Having a good technical understanding of radon and the various mitigation systems is vital to ensure the job is done properly, and your health is protected. You can find an approved device list at the respective website for both of these organizations.
The three main reduction methods – sometimes deployed jointly – are:
There are additional methods for radon mitigation that are currently in use. Your certified contractor will be able to advise you on the system that is best for your unique circumstances.
Erik Rosen is a former copywriter, journalist, and medical writer. He is currently the Director of Programs for the Building Biology Institute.
Andrew Guido is the President & Founder of ERTH. He is a Certified Building Biologist and Circadian (Lighting) Wellness Auditor.