First steps towards an All-European Indoor Radon Map

This is the authors' abstract. We don't add key points for this paper.

A hypothetical All-European Indoor Radon Map has been developed using summary statistics estimated from 1.2 million indoor radon samples. In this study we have used the arithmetic mean (AM) over grid cells of 10 km × 10 km to predict a mean indoor radon concentration at ground floor level in the grid cells where no or few data are available (N < 30). Four interpolation techniques have been tested: inverse distance weighted (IDW); ordinary kriging (OK); collocated cokriging with uranium concentration as secondary variable (CoCK); and regression kriging with topsoil geochemistry and bedrock geology as secondary variables (RK). Cross-validation exercises have been carried out to assess the uncertainties associated with each method. Of the four methods tested, RK has proved to be the best one for predicting mean indoor radon concentrations, and by combining the RK predictions with the AM of the grids with 30 or more measurements, an All-European Indoor Radon Map has been produced. This map represents the first step towards a European radon exposure, and further on a radon dose map.