Radon Levels in London

Name: London Radon Levels
Creator: OpenStats
License: https://open.canada.ca/en/open-government-licence-canada

Ontario · London metropolitan area · Health Canada home survey · 2013 data · 80 readings

By OpenStats · Built from official Canadian sources

Direct municipal data

85.1Bq/m³Low

0600+Guideline200 Bq/m³

Mean indoor radon

85.1 Bq/m³

Ontario avg: 99 Bq/m³

Homes above 200 Bq/m³

7.5%

Provincial avg: 9%

Risk category

Low

Reference: 200 Bq/m³

Reading this page

In London, the published mean indoor radon reading is 85.1 Bq/m³, based on Health Canada survey sampling from 80 home readings in the London metropolitan area. 7.5% of tested homes in this sample exceed the 200 Bq/m³ guideline, and the highest single reading recorded was 340 Bq/m³.

Local geology is recorded as mixed. Geology helps explain regional averages; individual homes still vary with foundation type, ventilation, and soil contact, so a moderate regional average does not rule out a high reading in any single home.

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 London

London 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.

London vs Ontario

London mean radon85.1 Bq/m³

Ontario provincial average99 Bq/m³

Health Canada reference level200 Bq/m³

Homes above 200 Bq/m³7.5%

Test to confirm your level

Regional averages are moderate, but radon varies house to house. Health Canada recommends all Canadians test their homes.

1Use a long-term test kit during heating season (October–April)
2Place the detector away from drafts, windows, and exterior walls
3If results are below 200 Bq/m³, retest every 2 years
4If results exceed 200 Bq/m³, consult a C-NRPP certified mitigator

Order a long-term radon test kit

Average indoor radon in London is 85.1 Bq/m³, and 7.5% of tested homes exceed the 200 Bq/m³ guideline. A three-month alpha-track test on the lowest occupied level is the right first step.

Shop radon test kits on Amazon.ca →

As an Amazon Associate, OpenStats earns from qualifying purchases.

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.