A Deterministic Model for Estimating Indoor Radon Concentrations in South Korea

Estimating long-term exposure to indoor radon is necessary to determine the effects of indoor radon exposure on health. However, measuring long-term exposure to radon is labor intensive and costly. While developing models for estimating indoor radon concentrations are very difficult and unrealistic due to the many factors affecting radon concentrations, several studies have attempted to estimate indoor radon concentrations with mathematical models based on mass balance equations. However, these models are only applicable to specific regions or situations, and some require actual measurement data. This study sought to develop a widely applicable model for estimating mean annual indoor radon concentrations in actual residences considering seasonal variations in indoor radon. The model is based on a mass balance equation using data on geographical factors, building characteristics, meteorological factors, and nationwide radon surveys. The primary factor in our model is the infiltration factor, which can vary according to region, building materials, cracks, floor type, etc. In this study, infiltration factor was calculated according to the type of housing and groundwater usage, and the results thereof were applied to estimate indoor radon concentrations. Overall, measured concentrations and estimates of indoor radon concentrations using the infiltration factor were similar. This model showed better performance than our previous model, except for a few high concentration residences.