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Radon Levels

Radon levels in Granby

Quebec · Sherbrooke metropolitan area · Health Canada home survey · 2013 data · 104 readings

By OpenStats · Built from official Canadian sources

Regional estimate
238.2Bq/m³Elevated
0600+Guideline200 Bq/m³
Mean indoor radon
238.2 Bq/m³
Quebec avg: 101 Bq/m³
Homes above 200 Bq/m³
24%
Provincial avg: 11%
Risk category
High
Reference: 200 Bq/m³

Reading this page

In Granby, average indoor radon is 238.2 Bq/m³ (above the Quebec average of 101 Bq/m³). 24% of tested homes exceed Health Canada's 200 Bq/m³ reference level.

Local geology (Mixed) contributes to regional variation. Geology helps explain area averages; individual home levels still depend on foundation type, ventilation, and soil contact.

How to read this

Figures come from Health Canada's Cross-Canada Survey of Radon Concentrations in Homes: long-term tests in participating dwellings, aggregated by geography. The 200 Bq/m³ guideline applies to the normal occupancy area (lowest lived-in level). A city mean is not a reading for your address.

Start with the mean and the share of homes at or above 200 Bq/m³, then check whether this page is labeled direct or regional. Direct means the survey geography matches this municipality or its named metro breakout. Regional means you are seeing a broader area average that may not match your street. Compare with the provincial reading only as context; house-to-house variation is usually larger than city-to-city gaps.

Prefer a three-month (or longer) alpha-track test that includes heating season. Short-term tests are screening tools. Place the detector on the lowest lived-in level, away from exterior walls and high airflow. For elevated results, hire a C-NRPP measurement or mitigation professional, then retest after any work. Full provenance: methodology.

Figure 1 · Geology

Mixed beneath Granby

Granby sits on Mixed bedrock or surficial deposits. Radon enters homes through cracks in foundations, sump pits, and utility penetrations. Geology explains regional averages, but individual home levels depend on construction, ventilation, and soil contact.

Granby vs Quebec

Granby mean radon238.2 Bq/m³
Quebec provincial average101 Bq/m³
Health Canada reference level200 Bq/m³
Homes above 200 Bq/m³24%

Mitigation recommended

Average indoor radon in this area exceeds Health Canada's 200 Bq/m³ reference level. If your home tests high, hire a C-NRPP certified mitigator.

  • 1Confirm levels with a long-term test kit (minimum 3 months)
  • 2If results exceed 200 Bq/m³, contact a C-NRPP certified professional
  • 3Sub-slab depressurization typically reduces levels by 80–90%
  • 4Retest after mitigation to verify the system works
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Source · Health Canada Radon and Thoron Data From Canadian Homes, CMA survey vintage 2012–2013 (Open Government Licence – Canada); metropolitan area proxy from Sherbrooke CMA (104 home readings). Last updated 2013. Refreshed on the site's automated schedule.