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Radon Levels

Radon levels in Thunder Bay

Ontario · Thunder Bay metropolitan area · Health Canada home survey · 2013 data · 92 readings

By OpenStats · Built from official Canadian sources

Direct municipal data
159.1Bq/m³Guideline watch
0600+Guideline200 Bq/m³
Mean indoor radon
159.1 Bq/m³
Ontario avg: 94 Bq/m³
Homes above 200 Bq/m³
30.4%
Provincial avg: 9%
Risk category
High
Reference: 200 Bq/m³

Reading this page

In Thunder Bay, average indoor radon is 159.1 Bq/m³ (above the Ontario average of 94 Bq/m³). 30.4% 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 Thunder Bay

Thunder Bay 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.

Thunder Bay vs Ontario

Thunder Bay mean radon159.1 Bq/m³
Ontario provincial average94 Bq/m³
Health Canada reference level200 Bq/m³
Homes above 200 Bq/m³30.4%

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
Partner

Find a certified radon mitigator

30.4% of tested homes in Thunder Bay exceed the 200 Bq/m³ guideline (average 159.1 Bq/m³). Start with a C-NRPP certified professional; test kits and monitors are listed below.

Learn more →

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Source · Health Canada Radon and Thoron Data From Canadian Homes, CMA survey vintage 2012–2013 (Open Government Licence – Canada). Last updated 2013. Refreshed on the site's automated schedule.