In Ontario, the average indoor radon level is about 77 Bq/m³, slightly below the national average but still a health concern. Approximately 1 in 6 homes (16%) exceed Health Canada’s guideline of 200 Bq/m³, and many others fall between 100-199 Bq/m³, above the WHO’s recommended limit. Rural areas and older, detached homes show higher concentrations than urban or multi-unit dwellings. While Ontario’s levels are moderate compared to regions like Atlantic Canada or Interior B.C., no area is radon-free. Regular testing and mitigation remain essential for maintaining safe indoor air.

(Source: Cross-Canada Radon Survey 2024 - https://crosscanadaradon.ca/survey)