Interrelationship of indoor radon concentrations, soil-gas flux, and meteorological parameters

Passive electret-based radon flux monitors were deployed at 12-hour intervals for 1 year outside a single-family house, in order to access the variability and reliability of this method for estimation of indoor radon concentrations. Radon flux from the soil averaged 37 mBq/m2 . s and showed small diurnal and seasonal fluctuations. Continuous basement-level radon measurements were collected at 5-minute intervals during the same time period, inside the house. The corresponding measurements allowed a direct comparison of the relationship of radon flux from the soil, using this method, and actual indoor radon concentrations at the house. Indoor radon levels showed strong diurnal and seasonal cycles, with the indoor radon concentrations during the year ranging from 50 to 1570 Bq/m3 and averaging 360 Bq/m3. Meteorological measurements (barometric pressure, wind speed, temperature, and rainfall) collected at the site provided additional potentially correlative parameters to radon flux and indoor concentrations. While indoor radon levels at the house were not obviously affected by barometric pressure and wind speed, they were found to be strongly influenced by indoor and outdoor temperature differentials.