Radon entry, migration and reduction in houses with cellars

Soil radon entry to a house and indoor concentration level are affected by many factors, such as the infiltration characteristics of the house, air tightness of the substructure of the house, air permeability of the soil, radon content in the soil and many others. Amongst them, the structure of the house, particularly its substructure is certainly one of the most crucial factors. It determines radon entry routes and indoor radon distribution, and consequently, affects the effectiveness of radon control measures applied in the house. The paper focuses on houses with cellars, a type of dwelling in Derbyshire, North England where high indoor radon levels have been found in over 20% homes. Based on the results of an initial study, a conceptual house was constructed bearing the major features of such types of houses. A modelling strategy was established which integrated two previously developed computer models. Such integration made it possible to simulate a complete course of radon migration, from its generation by soil grains, transport with soil gas and decay in soil matrix to its entry through the substructure of the house and moving from one room to another, and finally its dispersion into atmosphere. Using this modelling strategy, a parametric study was carried out to examine the effects of some crucial aspects on the indoor radon level throughout the house, including the ambient temperature, the wind speed and direction and most importantly the cellar ventilation, a simple remedial solution to radon reduction for this type of house. © 2002 Elsevier Science Ltd. All rights reserved.