Radonaide

The science behind the dangers of radon

Radon is a naturally occurring radioactive gas that can enter your home through the foundation or basement slab You cannot see it, smell it, or taste it — but the science behind its health effects is well established.

Radon is the leading cause of lung cancer in non-smokers and the second-leading cause of lung cancer overall in Canada.

1. What makes radon dangerous?

Radon-222 is produced naturally when uranium in soil and rock breaks down through a series of radioactive transformations.

The process works like this:

• Uranium in the ground: Uranium decays into other radioactive elements, including radium.
• Radon gas is released: Radon moves through soil and can seep into a building through foundation cracks, joints, sumps and service openings.
• Radioactive decay occurs in your lungs: Radon decays into radioactive particles that can deposit in the respiratory tract and damage lung tissue.

1. How radon damages your lungs

The main danger is not simply the gas itself. It is the radioactive decay products that radon produces.

• Inhalation: Radon and its decay products enter your airways as you breathe.
• Alpha radiation: Some decay products emit alpha particles, which deposit energy over a very short distance.
• Cellular damage: This radiation can damage DNA in lung cells.
• Cancer development: Over time, accumulated DNA damage can contribute to mutations and lung cancer.

The risk generally increases with both the radon concentration in the air and the length of time you are exposed. There is no established completely risk-free level of radon exposure.

Radon does not usually cause immediate symptoms. A person can live in a home with elevated levels for years without feeling anything unusual.

3. What do the numbers mean?

Radon concentration is measured in becquerels per cubic metre (Bq/m³). One becquerel represents one radioactive decay per second.

Health Canada’s guideline recommends taking corrective action when the average annual radon concentration exceeds 200 Bq/m³ in a normally occupied area. The higher the level, the sooner action should be taken. Reducing radon as far as reasonably practicable is the goal.

4. Why smoking makes radon even more dangerous

Smoking and radon exposure work together to increase lung cancer risk. People who smoke and are exposed to radon face substantially greater risk than non-smokers exposed to the same radon level.

This is why radon testing matters even if nobody in the household smokes. Non-smokers are not immune.

5. How radon mitigation works

A common mitigation method is active soil depressurization. A professionally installed system draws soil gas from beneath the basement floor and exhausts it outdoors through a pipe and fan, reducing the amount of radon entering the home.

The process is straightforward:

1. Test the home to establish its radon concentration.
2. Install an appropriate mitigation system if needed.
3. Allow the system to operate and verify its performance.
4. Retest to confirm that radon levels have been reduced.

Testing after mitigation is essential because the effectiveness of the system must be measured, not assumed.

6. The bottom line

The science is clear: radon is a proven human carcinogen, the risk comes from cumulative exposure, and homes cannot be judged safe based on appearance, age, location or a neighbour’s results.

You cannot detect radon with your senses. You have to test for it. If levels are elevated, mitigation can reduce exposure and help protect the people living in the home.

For further reading:
Health Canada: https://www.canada.ca/en/health-canada/services/health-risks-safety/radiation/radon/government-canada-radon-guideline.html
Government of Prince Edward Island: https://www.princeedwardisland.ca/en/information/health-and-wellness/radon