“…The 222 Rn in soil gas measurements and their evaluation were carried out by the Geological Institute of the University of Bonn considering the geological formations and structural circumstances and are published in Kemski et al (1996Kemski et al ( , 2001Kemski et al ( , 2002Kemski et al ( , 2004Kemski et al ( , 2009) and Lehmann et al (2001). Both factors influence the geogenic 222 Rn potential which has a fundamental impact on the indoor 222 Rn activity.…”