Performance evaluation of radon active sensors and passive dosimeters at low and high radon concentrations

Radon is a naturally occurring radioactive gas that has the potential to accumulate in buildings and over time, causes lung cancer in humans. Present methods for radon measurements are disparate, which pose challenges to benchmark radon concentrations and to accurately assess the population's received dose. This paper presents a comprehensive performance evaluation of radon dosimeters and three grades of active radon sensors: consumer-, medium- and research -grade. The measurements were performed at relatively low (300 Bq/m3) and high (2 ' 000-3 ' 000 Bq/m3) radon levels. Tests were conducted in an atomic shelter, with stable temperature and humidity conditions. The active sensors differed in absolute accuracy and dynamic performance (time -dependent correlations) according to their grade. Research -grade sensors performed marginally better than medium -grade sensors, and significantly better than consumer -grade sensors. Relative to the reference, the error (percentage difference between the reference and the sensors) was below 5 % for research- and medium -grade sensors, and nearly 10 % for consumer -grade sensors at high radon levels. Performance of sensors diminished at low radon levels, except for research -grade sensors. Passive dosimeters generally performed better at high radon levels than at low ones. Their longer exposure time was associated with increased measurement reliability. These results highlight the need for understanding the purpose of measurements in order to select an adequate radon detector, and ultimately, reduce measurement and interpretation errors. This study raises awareness among researchers, radon professionals and the general public regarding the performances of different active radon sensors and passive dosimeters. It also sheds light on their respective scope of application.