Task 4.2: Relationship between indoor radon concentration and geogenic radon

The aim of this task is to estimate relationships between indoor Rn or derived quantities such as the probability of exceeding a reference level within an area, and quantities related to geogenic Rn such as the Rn potential or uranium concentration in the ground (see  Task 3.2), as some concepts for mapping the geogenic Rn potential and RPA crucially depend on such relationships.
As RPAs are often estimated from quantities other than indoor Rn, such as geogenic Rn, the correlation and a statistical relationship between indoor Rn and the RPA predictor quantity (or quantities) therefore needs to be established, because only indoor Rn is directly linked to reference values according to the EU-BSS. In most cases, the statistical relationships between indoor Rn and geogenic quantities are weak. These relationships have been studied for many years as regression and classification type approaches. The physical and statistical reasons for the weak relationships will be evaluated and explained and their consequences assessed. In this task, existing models and methodologies will be reviewed and reported, in particular, statistical procedures which have sometimes proved a weak point in such analyses in the past.