Canadian Association of Radon Scientists and Technologists

Helping Canadians Reduce Radon Risk

Four steps to Reduce your Radon Exposure:

Radon poses a significant health threat as the leading cause of lung cancer in non-smokers. No area is radon free - it is naturally occurring radioactive gas that is invisible to the human senses. The only way to know the radon level in a building (home, school or workplace) is to test.

We recommend testing for radon in the first heating season in your home and retesting every five years, or sooner if you complete major renovations.  There are multiple ways you can test. You can purchase a do-it-yourself kit or contact a C-NRPP Measurement certified professional to do it for you. If you do the test yourself, make sure you read and follow the instructions.    

Purchase a DIY radon detector or contact one of our members to help.

Long-Term Testing

CARST recommends following Health Canada recommendations and testing during the heating season with a minimum 91 day test.

A long-term test provides a year-long average of your radon exposure. Radon levels can fluctuate on a day to day and season to season basis.  A long-term radon test provides an average level. 

This testing also provides information on how your home’s radon levels put you at risk for lung cancer, since prolonged exposure to radon increases risk of lung cancer.                                                                   

If you do the test yourself, make sure you read and follow the instructions.

Short-Term Testing

A short-term radon measurement test must be a minimum duration of 48 hours up to 91 days. These tests provide relatively quick results and can act as a screening tool.

Health Canada recommends that a long-term test be conducted before making a decision to mitigate.

If you have installed a mitigation system into your home, a certified mitigator should do a short-term radon test to ensure the system is effective in lowering the radon levels in the home.  The test duration should last for a minimum of 48 hours and it should be started at least 24 hours after the fan for the system has been turned on.

The homeowner should then follow up with a long-term test during the next winter season after the mitigation system was installed.

Step 2: Return detector

To get accurate results, the radon measurement device must stay undisturbed in one location for the duration of the test. Ensure that you keep the return packaging for the device to return to the lab it was purchased from.

Mark the date to return to the lab for analysis, or call your professional to come back and pick it up at the end of the testing period.

Step 3: Examining the Results

The laboratory will report your radon test results after analyzing the device.

Health Canada recommends that all Canadian buildings aim to maintain radon levels below 200 Bq/m3 to minimize health risks. While further reduction is possible, it's ultimately the homeowner's choice. If long-term measurements exceed 200 Bq/m3, Health Canada offers guidelines for mitigation timelines.

 Radon Concentration  Recommended Remedial Action Time
 Greater than 600 Bq/m3   In less than 1 year
 Between 200 Bq/m3 and 600 Bq/m3   In less than 2 years
 Between outdoor levels and 200 Bq/m3   At homeowner's discretion

     Note:  Average outdoor radon concentration=15 Bq/m3 

Step 4: Lowering Radon Levels

If you have tested your home and discovered it requires radon mitigation, hire a C-NRPP Mitigation Professional with proper training and hands-on experience to reduce the radon levels.

Radon Mitigation can include measures which will include sealing, removing or ventilating.

Sealing the building foundation will attempt to prevent radon entry.

Removing radon from below the building to reduce the amount of radon entering the building from ground contact.

Ventilating the building air will provide dilution of the inside air reducing radon concentrations.

Active Soil Depressurization (ASD) - a radon mitigation system which removes the radon from below a building and provides a pathway for it to exit outside.    ASD is the most effective method of reducing radon levels in a home.

In Health Canada’s Active Soil Depressurization (ASD) Field Study of 52 homes, 

they found a 90.7% reduction in radon with an ASD system.

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