From Babel to the Round Table of Camelot: On Setting up a Common Language and Objective for European Radon Risk Mapping. Part I. Radon Risk Maps, Different Maps for Different Purposes

Radon is a naturally occurring radioactive gas known to be, by far, the main contributor to exposure from natural background radiations received by the population. It is also considered to be the leading cause of lung cancer, only second to smoking. This has stimulated most European countries to adopt a number of regulations and launch surveys to identify radon-prone areas. A recent report on the European efforts for delineating areas with increased radon levels has shown a large variety of means and methods used to measure and report radon levels. Like all maps, Radon maps serve certain purposes, related to interests: displaying the actual exposure will result in a different map from one which aims to predict the risk which results from the geological structure of a region, or a map aimed at monitoring tectonic activity through variations in Radon exhalation, etc. It is the purpose of this paper to explore the variety of these maps and propose some definitions to make it easier to distinguish between various radon-risk maps. The possibility of preparing some harmonised radon map at the European level will also be discussed.JRC.H.4-Transport and air qualit