Level of external natural radiation and absorbed dose to population in Shandong province

Two thousand sites over Shandong Province (one in each 10 km mesh) were chosen for determination of natural radiation level and the absorbed dose to the population. Crystal scintillation radiometers calibrated with spherical ionization chamber were used in the determination. The ranges and mean values of absorbed dose rates in air from natural penetrating radiation for indoors, outdoors and roads are (10.8-34.8) x 10-8 Gy.h-1 and 14.5 x 10-8 Gy.h-1; (4.8-25.8) x 10-8 Gy.h-1 and 10.8 x 10-8 Gy.h-1 and (5.9-16.9) x 10-8 Gy.h-1 and 10.2 x 10-8 Gy.h-1, respectively. The mean annual effective dose equivalent for each person in this province is estimated to be 9.18 x 10-4 Sv, and the annual collective dose equivalent 6.82 x 104 man.Sv