Evaluation of the Terrestrial 222Rn Flux from 210Pb Deposition Measurements

Abstract

The study of the 222Rn terrestrial flux (Bq/(m2·s) or Bq/(m2·h)) is a complex issue involving both radiation-protection and environmental aspects. While the radiation-protection aspects are quite obvious—it has been well known for several decades that soil is the major source of indoor radon—environmental issues such as the correlation with conventional pollutants (PM2.5, PM10, NOX, etc.) and the use of radon for the esmation of the natural component of GHG (CO2) emissions are relatively less discussed in spite of their growing relevance. In this work we present a method for the estimation of the average value of 222Rn flux from HPGe γ-spectrometry 210Pb measurements performed on wet and dry deposition samples gathered monthly in the period 2006–2020. The results obtained with this technique give an average radon flux in the period Φ = 57 ± 27 Bq/(m2·h), the value of which is comparable with those coming from other methods and direct radon flux measurements as well. The method can thus be used to obtain a worldwide map of the radon flux.