Radon 101

What is Radon?

In the simplest terms, radon is a colourless, odourless, and tasteless gas. It occurs from  breakdown of the natural element uranium. When uranium decays, radon is released into the soil. Radon can then enter a building through the foundation. Depending on how much radon is entering the home, this can be a threat to the safety of those who are in the building. 


You can test for radon by either purchasing a do-it-yourself radon kit or by hiring a radon professional. A list of radon professionals who use the CT007-R can be accessed here.

How to Mitigate radon

If you discover that radon levels in your building are high, there are radon professionals who can help you mitigate the radon. A list of mitigators that use the CT007-R can be found here.

Health Canada recommends that building owners hire a mitigation professional certified under the Canadian National Radon Proficiency Program (C-NRPP) to help find the best way to reduce radon levels in the home.

The U.S. Environmental Protection Agency (EPA) recommends following the ANSI/AARST Radon Standards. They provide information on the processes, procedures and quality assurance systems to ensure standardized approaches for measurement and mitigation in both existing and new buildings

The amount of radon that enters a building can be reduced by decreasing the flow of soil gas through the foundation. The most common radon reduction system is by active soil depressurization (sub-soil depressurization). This type of system operates by pulling soil gas from beneath the foundation of a home and exhausting it outside.

Installation of this system generally consists of a pipe installed through the foundation floor connecting to an exterior wall, or through the roof. A small fan is attached to the pipe to draw the radon up from below the building, ventilating outdoors.

There are many other mitigation methods, the design of the system and method chosen is influenced by several factors including the building type and accessibility to critical foundation areas, the reduction in radon levels required, and associated costs i.e. energy and cosmetic aspects.

Play Video
Take a look at the video displayed above, where Abe Mendez – The Radon Specialist, (AARST-NRPP and NRSB certified) – demonstrates how he professionally installs a proper mitigation system using the Radon Sniffer in the process. During the mitigation process, the Radon Sniffer is typically used by professionals in the phase prior to the installation. A mitigator will use the Sniffer to find locations where radon is entering the building, AKA the radon “hotspot(s).” The contractor will perform their diagnostic tests in conjuction with the Radon Sniffer device to assess how the system will be installed.

How does radon enter a building

Radon gas is the product of uranium decay in soil and rocks, therefore, it enters a building through the foundation. Radon gas can manoeuvre through the soil and enter the building through cracks and crevices due to the stack effect.

The Stack Effect
The stack effect takes place when the temperature inside a building and the temperature outside are different. This causes a pressure difference that then results in air being sucked into the foundation of a building. The pressure inside the house is lower than the pressure outside, a vacuum is created. Radon and other gases may be contained within the new air that is entering the building.

Training and Certification

If you’re looking to expand your proficiency level in radon standards, or you are somebody who is interested in a career in radon check out the Canadian National Radon Proficiency Program here: C-NRPP, for certification requirements within Canada. For the United States check out the National Radon Proficiency Program NRPP, and the National Radon Safety Board NRSB for training and certification requirements.

Other Applications

As discussed previously the Radon Sniffer is a diverse tool, serving many different functions for radon professionals. One of its major advantages is the nozzle and hose, which allows mitigators to take measurements in specific, and/or difficult to reach spots. 

As an example, Collin Dumais from Radon West, brought the Sniffer on a commercial project at a university dormitory. After performing standard diagnostic testing, there was difficulty determining system design and location. Using the Sniffer, he was able to extend the nozzle behind a wall opening located in the bathroom, where they discovered pipping blocking access to the “hot spot” location. From there they were able to engineer a proper system that reduced the radon levels in the entire dwelling.

In another instance a mitigator used the device by first isolating the home and depressurizing the house. This allowed the mitigator to use the Radon Sniffer directly in air vents and other locations, without first needing to drill several communications test holes in the ground.

Bill Brodhead also outlines in his research publication ” Use of Sniffers in Radon Mitigation,” several other applications in which the Radon Sniffer may be used.

  • Before or after a radon system is installed to find a radon source or rule out a possible radon source
  • Locating a source, when a reduction system as been installed yet there is still an indication of high radon levels
  • Measuring the radon levels during installation to determine radon reduction from ventilation and worker exposure
Check out Bill Brodheads page on Sniffers and these slides from Bill’s presentation from the 2021 AARST International Radon and Vapor Intrusion Symposium.