Radon Exposure

Radon-222 is a colourless, odourless, naturally occurring radioactive noble gas formed by uranium-238 decay in soils and rocks; it accumulates in basements and ground-floor rooms of poorly ventilated buildings. Inhaled radon progeny (²¹⁸Po, ²¹⁴Po) deposit alpha-emitting particles in bronchial epithelium, causing the DNA damage that drives lung cancer. Radon is the second leading cause of lung cancer overall (after tobacco) and the leading cause in never-smokers. A 2005 pooled analysis of 13 European case-control studies (7,148 cases) showed an 8% (95% CI 3–16%) increase in lung-cancer risk per 100 Bq/m³ long-term residential exposure. The WHO 2009 handbook recommends a reference level of 100 Bq/m³, not exceeding 300 Bq/m³. Germany's Strahlenschutzgesetz (StrlSchG, in force 2018) sets a 300 Bq/m³ reference value for dwellings and workplaces. Mitigation: sub-slab depressurisation, sealing, increased ventilation.