Radon Kinetics in a Basement Space Measured with Different Devices

Abstract

Although indoor monitoring of radon and benchmarking of radon measurement devices remain important research topics, few intercomparisons of active radon measurement devices have been performed under realistic conditions, let alone dynamic ones enabling comparison of their transient behavior. Five different radon monitors were therefore placed in a poorly ventilated basement space under three different conditions: 24 h under a steady, elevated radon level, 24 h with fans turned on to produce a radon washout transient, and 9 d with fans turned off for a radon buildup transient. Resulting radon concentrations varied between ~200 and ~2,000 Bq m−3. Accuracy of the devices were evaluated using root-mean-square error, and ventilation data were fit to first order linear compartmental models. To more accurately model behaviors such as cyclic diurnal variations, the source term corresponding to entry of radon from soil into the basement was considered to be non-constant, as it is likely to vary drastically with both the indoor-outdoor pressure differential and soil concentration variations. The improved radon washout model fit very well with the measurements. Despite a wide variety in list prices, all devices performed similarly during transients and at different radon concentrations.

Radon-222 Charcoal Canister Steady State Model Calibrations Performed in a Highly Controlled Environmental Chamber and a Natural Indoor Environment

“…An affordably priced continuous radon monitor (RadonEye, RadonFTLab, Haebong-ro, Danwon-gu, Ansan-city, Gyeonggido, South Korea) was used to track hourly radon concentration in the basement space over time. This radon monitor was shown to perform well compared with industry standards and was secondarily calibrated to devices that were calibrated in a traceable manner (Carmona and Kearfott 2019; Chung et al 2021). Radon monitor measurements were assumed to be accurate representations of the ambient radon concentration.…”