Radon hazard and risk in Sussex, England and the factors affecting radon levels in dwellings in chalk terrain

A survey was undertaken of radon levels in 1013 dwellings in Sussex, UK. A number of dwellings were identified with high radon levels in an area previously considered to offer low radon risk from geological sources. Multiple regression was used to determine the relative influence of the various geographical and building-related factors on indoor radon levels. The radon hazard, independent of building-related effects, was determined for each surveyed location by standardising radon measurements to a 'model' dwelling. These were entered into a geographic information system and related to surface geology. The highest radon levels were found to be associated with the youngest Chalk formations, Tertiary deposits and Clay-with-flints Quaternary deposits in the area. Radon potentials were also determined for the area which can be used to estimate radon risk and assist in environmental planning and development control.