Many problems about radiation monitoring of radon daughter dosimetry

People are exposed by natural radiation of which half quantity is occupied by the radon daughter dosimetry. 226Ra, parent nuclide of radon, is widely distributed in soil and affected very largely the human environment. There are two radiation monitorings, one is the epidemilogical approach and another the dosimetric approach. The results from two methods have not been the same in many studies, the differences of them were the important problem in the radiation monitoring. In the large scale research, the simple, cheap and easy passive type radon concentration meter is used. As the measured value is the radon concentration, the flow chart for deriving the concentration of radon daughter dosimetry has been given by UNSCEAR. There are three factors: the equilibrium factor, the occupancy factor and the dose rate transformation coefficient. These factors are explained in this paper about the change of them, the differences of them in each country and the relations among them. (S.Y.)