Radon: The Invisible Killer

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

How to test for radon

There are two basic methods of testing for radon:

  • passive (non-electrified) do-it-yourself testing: this testing method features charcoal canisters that absorb radon over the course of several days. After the prescribed time, the kit is mailed to a laboratory where the particles emitted are counted by a sodium iodide counter. The lab will then notify you by mail of your results. These inexpensive test kits can be purchased over the counter at home improvement/hardware stores or directly from one of the following organizations:
  • active radon monitors: These systems are deployed by certified radon inspectors and continuously draw in air over the course of several days or more, recording levels throughout the day to come up with a highly accurate average reading.

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.

If your levels are too high

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:

  • Opening windows, or using a whole house ventilation system that balances indoor air pressure so soil gasses aren’t drawn into your home.
  • Sealing foundation cracks, pipe joints, and other possible entryways for radon.
  • Deploying a sub slab suction system. Also known as Active Soil Depressurization, this is the most commonly used and reliable method to reduce radon levels in the home. A pipe is installed through the foundation slab and a small fan continually runs, drawing the soil gasses up for venting outside. Depending on the size of the home and radon levels, multiple pipes may be sunk through the foundation.

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.

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