1. Find the right number
Use the average in Bq/m³ for the complete test period. Do not treat one hourly peak on an electronic monitor as the annual average.
2. Check the test duration
If the test was shorter than 91 days, Health Canada recommends a long-term test before making corrective-action decisions. If the long-term average is above 200 Bq/m³, current guidance recommends taking action to reduce it.
3. Understand the timeframe
For any valid long-term average above 200 Bq/m³, Health Canada recommends corrective action within one year. The higher the concentration, the sooner action should be taken. This is a planned-action timeframe, not an emergency-response claim.
4. Prepare for a professional conversation
- Keep the full test report and device information.
- Note the test location, start and end dates and whether it ran during the heating season.
- Describe the basement, slab, crawlspace and any additions.
- Ask how the provider will diagnose the foundation and verify the installed system.