Radon is a colourless, odourless, tasteless and naturally occurring radioactive gas that is formed from the decay of the natural uranium found in soil and rocks.
Radon is found in outdoor air in low concentrations. In indoor environments, radon levels can be much higher. Long term exposure to high concentrations of radon increases a person's risk of developing lung cancer. Radon from natural sources can accumulate in buildings, especially in confined areas such as basements.
BCCDC and NCCEH have produced guidance on how to test radon levels:
- Protocols for Radon Testing in BC Homes (BCCDC, 2017) – includes where to test, test procedures, short-term test devices and a list of resources
- Radon Testing (BCCDC, 2016) – includes test protocol and a list of companies that supply radon testing devices
- Radon Testing and Remediation Programs: What Works? (NCCEH, 2008) – includes testing and remediation programs
- Radon Testing in BC Schools Protocol (BCCDC, 2012) – guidelines on type of detector to use, time and duration of monitoring, number of monitors needed per school, where to locate monitors, when to do a follow-up survey and mitigation solutions and costs
- Residential Indoor Radon Testing (NCCEH, 2009) – includes how radon gets into a home, testing methods, how to interpret results, a chart of the advantages and disadvantages of the principal types of passive radon detectors and a list of radon detector suppliers in Canada and the United States
Radon can be significantly reduced in existing homes using simple procedures and protocols. Modified building techniques can be applied to new homes at the construction stage to prevent radon entry. None of these techniques need be expensive. Home radon testing is offered by a number of companies.
Radon reduction techniques can involve the use of sealant products to close off cracks and gaps in basement floors and walls. Capping drains in the house often proves to be effective. Costs for such work amount to a few hundred dollars for material and labour. Where high radon levels do not respond to the mitigation techniques listed above, the installation of a sub-slab ventilation system that pumps the gas out from beneath the house before it gets in, has proven to be most effective.
For new homes, non-permeable membranes such as plastic sheets can be placed over the sand or gravel base before the concrete foundation is poured. The sheets will prevent radon gas getting in to the home. Attention should be paid to sealing the plastic to the footings and around service entrances. Such construction techniques reduce the likelihood of radon entering the home.
In 2007, BCCDC performed two studies in the interior of BC to measure radon in homes and radon in schools. Results of the study: