Fig. 3.
Arithmetic means (AM) over 10 km × 10 km cells of long-term radon concentration in ground-floor rooms of 32 European countries (ETRS89-LAEA frame). Latest update, August 2017. (The cell mean is neither an estimate of the population exposure, nor of the risk.) Source: European Commission, DG JRC (Tollefsen et al., 2010-02).