Studying temporal variations of indoor radon as a vital step towards rational and harmonized international regulation

Abstract

Regulations and measurement protocols for indoor radon testing differ between Europe and the US, with Europe implementing a reference level as opposed to the American two-step approach based on an action level. Moreover, none of the afore-mentioned regulatory approaches considers the temporal uncertainty of radon, a factor that usually significantly exceeds instrumental uncertainty. Discussed hereafter is the innovative principle of indoor radon regulation that considers both temporal and instrumental uncertainties. A quantitative relation between Action and Reference levels is being established for the first time. A statistical method for assessing the coefficient of temporal radon variation K(t) depending on the mode and duration of measurements is discussed. New data on the values of K(t) in hot climates and unstable geology typical for Israel are obtained. It is also shown that the influence of meteorological factors, tidal forces and seismic activity on the behavior of indoor radon does not improve the measurement protocol. It is concluded that building a statistically representative array of calculated coefficients of temporal radon variation K(t) with a large number (200–300) of continuous annual indoor radon monitoring in different countries is a vital step towards establishing rational and harmonized international regulation.

Keywords

• Indoor radon
• Annual monitoring
• Temporal uncertainty
• Reference level
• Action level
• Measurement protocol