Performance Evaluation of Electronic Radon Monitors Available to the General Public

In recent years, consumer-grade electronic radon monitors (ERMs) have become increasingly popular for measuring radon in residences and public buildings. Many of these devices are designed for use by the general public, with features and price points that make them accessible alternatives to passive detection methods such as alpha track detectors. However, the influx of new devices into the market and the absence of independent performance evaluations have raised concerns about the reliability of manufacturer claims. This study evaluated the performance of 15 different consumer-grade ERMs at prices less than $400 Canadian (CAD) and which were readily available through online marketplaces under radon exposure conditions ranging from 110 to 2,400 Bq m -3 . Short-term (2- to 3-wk) tests were conducted in radon chambers at Health Canada and Radiation Safety Institute of Canada facilities. Long-term (13-wk) tests were conducted at the underground low-background counting room at SNOLAB. Testing revealed two distinct groups of high- and low-performance ERMs, with absolute mean differences (AMDs) either less than 22% or ranging from 28-238%, compared to reference devices. Long-term testing showed that most ERMs demonstrated improved accuracy with prolonged exposures. This study also highlights the impact of several environmental and technical factors on ERM performance and emphasizes the need to consider performance indicators beyond accuracy. These findings underscore the critical need for independent third-party testing to validate the performance of ERMs, alongside the establishment of robust standards and regulatory frameworks to ensure the reliability of radon measurements, protect public health, and foster consumer confidence.