Making the Radon Potential Map of Great Britain—An Insight Into the Methodology

Abstract

Radon is a naturally occurring radioactive gas recognised as the second largest cause of lung cancer in the UK population. Radon maps are developed to identify areas with elevated radon potential to provide protection against the health risks associated with radon exposure. An updated 25-m resolution radon potential map of Great Britain was developed using an improved methodology combining 561,000 indoor radon measurements and a hierarchy of up to 9,323 geological classifications. The radon potential for each geological classification was estimated as the percentage of homes at or above the UK radon action level of 200 Bq m⁻³. The spatial variation in radon potential was mapped across 75.7% of Great Britain using 810 combined bedrock and superficial geology classes for which 30 or more indoor radon measurements were available. A further 8.8% of Great Britain was mapped using bedrock and superficial geology classes for which a minimum of 10 measurements were available. In areas with very small numbers of radon measurements, the revised modelling used successively less complex geological classes to compile the average radon potential. These classes are based on bedrock stratigraphy with lithology, bedrock stratigraphy or bedrock lithology. The updated radon potential map of Great Britain revealed some changes in radon potential when compared with previously published maps. The number of homes in radon Affected Areas in England and Scotland increased by 3.3% and 2.1%, respectively, whereas the number in Wales decreased by 4%. These changes were determined by the updated methodology and considering the additional measurements and improved geological classifications.