BEHAVIOR OF RADON AND ITS PROGENY IN A JAPANESE OFFICE

The properties of Rn-222, its progeny, and aerosol particles have been measured in an office for one year and three months. It was observed that the diurnal variations of Rn-222 concentration in two office room s depend on the operation of air conditioners. The concentrations of R n-222 during holidays were observed to be considerably higher than tho se on weekdays. Taking the actual exposure time into consideration, th e actual Rn-222 concentrations applicable to dosimetry for workers in the two office rooms were about 65% and 70% of the values which could be estimated using passive monitors. No dear diurnal variations and no significant differences between holidays and weekdays were observed i n the equilibrium factor in the office rooms. It was suggested that a value of the equilibrium factor could be treated as a representative v alue for dosimetry regardless of the period of measurement.