New research suggests radon testing should be done year round

When spring arrives in the northern hemisphere, it traditionally means that radon testing season is coming to an end.

But the research titled “Radon exposure is rising steadily within the modern North American residential environment and is increasingly uniform across seasons” published in the Nature’s Scientific Reports indicates that every season may be radon testing season. Their study suggests minimal winter-to-summer radon variations in almost half of the properties tested. The other half of the properties showed higher levels of radon during the summer, or higher levels of radon during winter.

“The long-standing viewpoint that radon levels are higher during the cold winter months when people are keeping their houses closed and turning up the heat is an outdated 20^th-century perspective on radon,” reads the study.

Research states that radon levels are consistent throughout the entire year. This is believed to be caused by the rise of energy-efficient and environmentally friendly buildings that are extremely airtight and designed to prevent the escape of air conditioning during the summer or heat during the winter. Home factors studied include:

• ceiling height
• square footage
• number of stories
• lowest level such as basement, crawlspace, slab on grade, bi-level
• building material of lowest level such as dirt, earth, concrete, wood, cinder block
• occupant behaviour such as window opening

Surprisingly, there was not an observed significant difference in home radon levels based on the thermostat settings, based on time of day or whether the home was occupied.

Increase in radon levels in newer homes

A 31.5-percent increase in radon levels has been found in homes built since 1992 versus older structures. The issue is that these modern houses are too efficient at limiting the amount of unregulated air coming in or out of the house. New homes in North America are containing greater and greater radon levels.

Air tightness with increased air conditioning during the summer months collectively creates indoor air that is less diluted by outside air during the summer. According to the study, radon levels appear to be consistent throughout the course of the calendar year. The average radon levels during the individual seasons only changed by a difference of 7 to 25 becquerels per cubic metre. That is only a 5- to 23-percent fluctuation throughout the year. This indicates that seasons have very little impact on radon exposure in modern-day North America.

Radon levels will vary over time

Radon levels fluctuate. If you test in the winter months and have low radon levels, it is important to test again during summer months. Conversely, if you test for radon in the summer and levels are low it is recommended that you test again during the winter months. If neighbors in your area have low radon levels it does not mean your home does as well. Radon levels can vary from home to home and even between apartments in the same building.

What is radon

Radon is an odorless, colorless gas that forms when the uranium in natural stone below a home or building decays. The gas decays into “radon progeny” which are harmful radioactive atoms that get caught in our respiratory tract when we breathe. Over time this exposure causes lung cancer.

Radon is the number one cause of lung cancer in non-smokers and the number two cause of lung cancer nationwide. The amount of radon found in the indoor air of a dwelling, school or workplace can vary depending on ventilation, structural deficiencies, surrounding area geography and outdoor weather. It is recommended that all dwellings, schools and workplaces be tested for radon gas.

Energy efficiency and need for radon testing

At the 2022 Canadian Association of Radon Scientists and Technologists conference, Dr. Anne-Marie Nicol, associate-professor of Professional Practice at Simon Frazier University, and Dr. Noah Quastel, director of law and policy, healthy indoor environments for the British Columbia Lung Foundation presented gaps in the environmental efficiency programs in Canada. A potential consequence of grants for green home construction can be elevated radon levels in these energy efficient homes. Therefore, radon testing and mitigation should also be a focus of such programs.

Radon exposure is not merely a problem during the winter months. “As the research demonstrates, radon is a health risk during every season,” says Zan Jones, vice-president of sales and marketing for Radonova. “It is important that radon testing be conducted year-round without prioritizing certain months of the year over others. The airtight construction of modern homes has contributed to increased radon exposure in the summer months that were historically thought to have lower exposure.” With the onset of modern, energy efficient and sustainable building techniques, radon-related health problems will continue to trend upward if awareness does not continue to grow.