Radon entry indoors due to soil gas and tap water in a temperate climate: impact of infiltration rate and seismicity

Abstract

Abstract Radon entry rates indoors were monitored using prototype devices approaching a dwelling with a cellar basement at 1 m depth. The radon concentrations in soil gas were also measured at 1 m depth. Integrated measurements were performed, and the results correlated with meteorological parameters. The influence of the difference in outdoor and device-soil temperature was discussed, and the infiltration rate was calculated. The effect of the soil temperature gradient on the soil radon entry rate was analyzed. The indoor radon entry rate due to the soil gas was 7.0 ± 2.7 Bq m− 3 h− 1. The radon entry rate.was 5.0 ± 0.8 Bq m− 3 h− 1 due to diffusion. The advection-drive flow of soil gas is ranged up to ± 4.0 Bq m− 3 h− 1. The infiltration rate of the model dwelling was 0.7 (± 0.5) x10− 1 h− 1 if only the stack effect occurred. The soil radon entry is increased by one order of magnitude when the ventilation is low or seismic faulting appears. The radon levels in tap water were measured, and the radon entry rate was estimated at 1.3 ± 0.7 Bq m− 3 h− 1. The soil radon appeared like the building materials rate, having 1/3 of the total, while outdoor air was slightly lower (28%), with tap water at 5%. The resident's mortality risk occurred at < 2.5% for typical dwellings in temperate climate areas founded on sand-gravel underground. The risk rises to 34% with an extremely low ventilation rate and high radon entry from the soil and building materials.