Analysis of simultaneous time series of indoor, outdoor and soil air radon concentrations, meteorological and seismic data

Abstract

It is well known that the temporal dynamic of indoor and outdoor radon concentrations show complex patterns, which are partly not easy to interpret. Clearly, for physical reasons, they must be related to possibly variable conditions of radon generation, migration and atmospheric dispersion and accumulation. The aim of this study was to analyse long-time series of simultaneously measured indoor and outdoor radon concentrations, together with environmental quantities, which may act as control variables of Rn. The study was performed in Chiba, Japan, using two ionization chambers for parallel indoor and outdoor radon concentrations measurements over 4 years. Meteorological and seismic data were obtained from the Japan Metrological Agency (JMA).

Outdoor Radon as a Tool to Estimate Radon Priority Areas—A Literature Overview

“…Although there are a few main processes that are responsible for the amount of radon concentration in air, there are many parameters influencing radon behaviour. This was also nicely demonstrated by Fourier analysis of indoor and outdoor time series, which has shown that there is more noise in the time series from outdoor than from indoor radon measurements [ 68 ].…”

“…On the other hand, at noon and during the afternoon there is the largest negative temperature gradient causing the strongest atmosphere mixing, causing the lowest radon concentrations [ 63 , 64 ]. Diurnal variation of the radon concentration has been a subject of many investigations [ 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ] and typical behaviour is presented in Figure 2 (taken from [ 66 ]).…”

“…A study has been performed monitoring continuously indoor and outdoor radon concentrations in one location in Chiba, Japan, for 4 years using the active device AlphaGUARD [ 68 ]. It was found that diurnal changes are more pronounced for outdoor radon than those of indoor radon [ 68 ]. Furthermore, monthly gradients are more pronounced for outdoor radon than for indoor radon.…”

“…The maximum observed outdoor radon concentration was in winter, while for indoor radon concentration in summer. In this study the data indicate that indoor and outdoor values are negatively correlated with Pearson correlation factor of -0.18 [ 68 ]. Differently, a linear relation was found between indoor and outdoor equilibrium equivalent concentrations of radon-222 with correlation coefficient of R = 0.9 [ 75 ].…”

Development of Predictive Model for Radon-222 Estimation in the Atmosphere using Stepwise Regression and Grid Search Based-Random Forest Regression

“…Theoretical models have been developed by several researchers in the literature to predict radon behaviour and concentration for various conditions and applications [17,18,[20][21][22]. Several studies in the literature have reported the variation of atmospheric radon and its progenies with changes in meteorological parameters like temperature, pressure, humidity and windspeed [23][24][25]. [26] used these meteorological variables as independent predictors in the development of a multiple linear regression model for estimation and prediction of the time series of radon and thoron progeny concentrations.…”