What High Radon Readings Mean For Your Health

Posted in Radon Testing, on October 27, 2025

An elevated reading from radon testing is a signal that you need to make changes to your home’s air quality environment. At SafeAir, we’ve been helping families navigate high radon readings for over a decade. Radon gas is a colourless, odourless, invisible radioactive gas that affects approximately 1 in 8 homes in Ontario. Air quality testing in Toronto can help alert you to this harmful gas’s presence, as well as other pollutants that could negatively affect your health and safety. 

Understanding Radon and Its Sources

Radon gas is formed by natural deposits of uranium in the earth. As the uranium breaks down, it releases radon, which comes up through the rock and soil and dissipates into the atmosphere, where it poses minimal risk. But homes with sub-grade basements create a pocket of negative pressure in the ground and can actually draw radon into your home. Radon enters your home through several means, such as:

• Cracks or gaps in the foundation.
• Sump pumps.
• Old windows or doors. 
• Groundwater. 
• Some types of stone fixtures or details. 

What Constitutes a “High” Radon Reading

The long-term effects of radon exposure are concerning, especially since there are no signs or symptoms until it’s too late. Health Canada classifies readings over 200 Bq/m³ as “high” and recommends homeowners implement mitigation strategies if their home returns a test above this value. 

• Various features can affect the likelihood of a high radon reading, such as: 
• Location: Parts of Ontario test statistically higher than others. 
• Ventilation (or lack thereof) in the basement or lower level. 
• Season and weather. 
• Local geology. 

How High Radon Levels Affect Your Health

Exposure to concentrated levels of radon gas causes lung and respiratory damage in the long term. As the radon gas decays in your lungs, it causes scarring and cellular changes that dramatically increase your risk of lung cancer; in fact, radon exposure is the leading cause of lung cancer after cigarette smoking. If you already smoke, your risk increases exponentially, making it one of the most dangerous, but invisible, health issues in our homes. 

Steps to Take After High Radon Readings

If you receive a worrisome radon test result, what’s next? SafeAir generally recommends that our clients do several things to reduce their exposure and prevent radon from entering their home. 

• If you’ve done a DIY radon test, we suggest following up with a professional test. Radon can fluctuate, and short-term tests can be unreliable. A follow-up test ensures accuracy and gives you more information to act on. 
• We can help introduce you to certified radon mitigation experts for a professional assessment. They’ll help you create a strategy to eliminate or reduce radon in your home based on the latest science. 
• Some homes with very high levels of radon gas may need to install tools or systems like sub-slab depressurization or specialized water filters. These are highly effective tools that may eliminate your risk. 
• Retesting may seem like an additional step, but it’s an important one to ensure your solutions are working! Ongoing monitoring can alert you to changes and ensure that you are testing lower than 200 Bq/m³. 

Act Quickly and Breathe Easier With SafeAir

SafeAir is a trusted expert in air quality testing in Toronto. With over a decade of experience helping families eliminate allergens, pollutants, and toxic gases like radon from their homes, our knowledgeable team has helped thousands of people breathe easier — both literally and figuratively. 

Because radon exposure’s effects accumulate over time, having your home tested today is critical. Radon testing is a safe and non-invasive test that happens over a few months using a small device similar to a fire alarm, just without the beeping! If your home is affected by high radon readings, reduction is achievable, affordable, and highly effective, making it an easy way to improve your health in the long term. Don’t wait — contact SafeAir today for a radon test in Toronto or to learn more about a customized radon reduction solution. 

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