Mapping the Baseline of Terrestrial Gamma Radiation in China

Based on the previously constructed database on 226Ra, 232Th and 40K contents in dry soils and the estimated distribution of soil moisture contents, the terrestrial gamma radiation was further estimated by using the recommended dose rate conversion factors (DRCFs). For obtaining more detailed information on the distribution of terrestrial gamma radiation, the spatial data were further interpolated, and the digital map of terrestrial gamma radiation in China was finally produced by using the techniques of Geographic Information System (GIS). The results show that the values of terrestrial gamma dose rate vary significantly over different regions of China. The area-weighted terrestrial gamma radiation in China was about 62.0 nGy/h, which was in well agreement with the surveyed result in the late 1980s.