Reducing radon in buildings

Volume 17, Number 3, September 2012

Figure 1. Active sub-slab depressurization ductwork and radon monitor

Recent scientific research performed by Health Canada’s Radiation Protection Bureau estimates that approximately 3000 lung cancer deaths annually in Canada could be linked to indoor radon exposure. Approximately 7% of Canadian homes have radon levels above Health Canada’s guideline, according to a nationwide survey.

Radon is an odourless, tasteless, colourless radioactive gas that comes from the natural breakdown of uranium in the ground. It can enter buildings wherever there is contact with the ground, often through the foundation. Radon concentrations also vary strongly from building to building.

The National Research Council and Health Canada’s Radiation Protection Bureau are embarking on a multi-year laboratory study to minimize health risks from radioactive soil gases. Using the results of the study, researchers will provide practical solutions for adoption by homeowners, contractors, facility managers of small buildings, and those concerned with regulatory aspects.

The following key questions will be answered by NRC and Health Canada researchers during the next three years:

  • Will radon be re-entrained into buildings from radon mitigation exhaust fan discharges of neighbouring buildings? This aspect is especially important for densely built developments, where fresh air intakes, windows and doors usually are close to discharged air.
  • Can improved membranes and concrete assemblies featuring reduced permeability for radon also reduce the radon concentrations in basements or first floors?
  • Will a fan triggered by actual radon concentrations reduce indoor radon concentrations in basements or first floors and save energy at the same time?
  • Will the negative pressure created by a radon depressurization fan increase the risk of backdrafting from the combustion appliances in the basement and pollutant migrating from the garage attached to the building?

An integrated approach to finding solutions

Health Canada’s Radiation Protection Bureau is NRC’s research partner as well as the funding federal department. Its mandate is to minimize exposure of the Canadian population to radioactive contaminants.

The collaborative research into radon mitigation technologies and solutions will profit from NRC’s unique and comprehensive modelling expertise and NRC’s Indoor Air Research Laboratory, equipped with state-of-the-art tracer gas equipment and radon detectors (figure 1). The research team is working towards an integrated approach including ventilation and pressure management as a way to ensure that Canadian homes are safe, healthy and energy-efficient.

The described activities are performed under the Government of Canada’s Clean Air Regulatory Agenda, with the ultimate goal being to improve the health of all Canadians. NRC will support this goal by evaluating technical solutions and energy-efficient innovations that have a high chance of adoption by builders, retrofitters and homeowners and that are interesting to the Canadian building industry as a whole. NRC’s focus is also in supporting industry in developing more energy-efficient and durable fans. NRC’s mandate in this context includes facilitating the uptake of knowledge and technical solutions by all key players.

Health Canada and NRC will present mitigation scenarios and seek input from their stakeholders this fall, to guide their research.

For more information

Contact Liang (Grace) Zhou at or 613-991-1220.