Community Radon Map
Info
Community Radon Map
Every point on this map is a radon measurement taken in someone's home, in Canada, and submitted anonymously — before or after mitigation. These citizen measurements are not certified: they outline at-risk sectors without guaranteeing any single building. The absence of data does not mean the absence of risk.
Radon is a naturally occurring radioactive gas that seeps into buildings from the ground. It's invisible and odorless. Prolonged exposure increases the risk of lung cancer.
Bq/m³ = becquerels per cubic meter. This is the unit used to measure radon concentration in the air. The higher the number, the higher the concentration.
New in Version 3.1
- Two new explainer videos (1 min 27) join the Understanding radon page: radon, testing and solutions, in pictures.
- Each video comes with a complete, timestamped transcript — the content stays accessible even without sound.
- Videos load only on click and stream from a CDN: pages stay light, even on mobile data.
Thresholds
What should you do? — Under 100 Bq/m³: acceptable. 100 to 200: worth monitoring, consider a long-term test (≥ 91 days). Above 200: Health Canada recommends mitigation.
Read the markers
Outer ring: thick dark = high · thin grey = to watch · none = low
Dashed outline = test under 91 days (indicative, less reliable)
Detector
Measured more than 200 Bq/m³?
Reducing radonget a detectorRadon levels vary by season. Tests under 91 days are labeled “indicative” and are less reliable.