Fine-Scale Spatial Distribution of Indoor Radon and Identification of Potential Ingress Pathways

• Published in: Atmosphere Vol. 16; no. 8; p. 943
• Main Authors: Pressyanov, Dobromir, Dimitrov, Dimitar
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 06.08.2025
• Subjects: Activated carbon; Adsorption; Calibration; Case studies; Detectors; Floors; Gas detectors; Humidity; Indoor environments; Measurement techniques; Radon; Radon content; Radon detectors; Radon levels; Sensors; Spatial discrimination; Spatial distribution; Spatial resolution; Temperature effects; Ventilation; Voids; Germany
• ISSN: 2073-4433; 2073-4433
• DOI: 10.3390/atmos16080943

A new generation of compact radon detectors with high sensitivity and fine spatial resolution (1–2 cm scale) was used to investigate indoor radon distribution and identify potential entry pathways. Solid-state nuclear track detectors (Kodak-Pathe LR-115 type II, Dosirad, France), combined with activated carbon fabric (ACC-5092-10), enabled sensitive, spatially resolved radon measurements. Two case studies were conducted: Case 1 involves a room with elevated radon levels suspected to originate from the floor. Case 2 involves a house with persistently high indoor radon concentrations despite active basement ventilation. In the first case, radon emission from the floor was found to be highly inhomogeneous, with concentrations varying by more than a factor of four. In the second, unexpectedly high radon levels were detected at electrical switches and outlets on walls in the living space, suggesting radon transport through wall voids and entry via non-hermetic electrical fittings. These novel detectors facilitate fine-scale mapping of indoor radon concentrations, revealing ingress routes that were previously undetectable. Their use can significantly enhance radon diagnostics and support the development of more effective mitigation strategies.