Radon is a naturally occurring radioactive gas, colorless and odorless, produced from the decay of uranium which can infiltrate buildings indoors and cause lung cancer on prolonged exposure. Despite the most reliable radon measurement remains long-term passive sampling, the advent of low-cost and real-time radon sensors has enabled rapid expansion of radon monitoring. Despite the increasing availability of low-cost real-time radon monitoring devices, only limited data exists on their long-term performance. This study investigated whether real-time radon sensor performance evolves over prolonged operation and whether factors such as device brand, price, or detection method influence long-term sustainability of the device. We conducted a comparative longitudinal analysis of several real-time radon monitors initially tested between 2023-2024 and re-evaluated in 2025 under controlled conditions across various radon concentrations. After two years of operation, performance variations correlated with individual device models rather than market grade categories, with significant variability was observed within the same grade. Consumer-grade devices such as the RadonEye RD200 and RD200P2 maintained excellent accuracy and dynamic performance, while others including Airthings Wave Plus and EcoQube devices fell significantly below acceptable thresholds. These findings demonstrate that device grade alone is not a reliable indicator of long-term performance sustainability. Individual device design, calibration methodologies, and quality control processes appear to play determinant roles in maintaining measurement accuracy over extended periods, challenging conventional assumptions about the relationship between device cost and long-term reliability in radon monitoring applications. • We reevaluated performances of four types of real-time radon devices after two years • We hypothesized that radon real-time devices performances are decreasing over time • In line with previous studies, devices performances were better at high radon levels • Device price alone is not a reliable index of long-term performance sustainability
Rey et al. (Sun,) studied this question.