Health Canada's Radon Guideline, Explained

Health Canada's guideline sets 200 Bq/m³ (becquerels per cubic metre) as the action level for radon in indoor air. Below that, no action is required. Between 200 and 600 Bq/m³, the guideline recommends remediation within two years. Above 600 Bq/m³, it recommends remediation within one year.

These are not emergency deadlines — radon exposure is a cumulative, decades-long risk, not an acute one. The guideline reflects that timeline while still giving a clear point to act by.

There's no exposure level with zero risk — radon risk scales with concentration and time. Health Canada's 200 Bq/m³ threshold represents a level where the balance of risk and mitigation cost is considered reasonable to act on, not a line where risk suddenly appears.