FIELD MEASUREMENT OF THE UNATTACHED FRACTION AND ACTIVITY CONCENTRATION RATIO OF RADON PROGENY IN TYPICAL DWELLINGS.

ABSTRACT

The unattached fraction (fp) and activity concentration ratio of radon progeny (${\boldsymbol C}_{{}{}^{\bf 218}\bf{Po}}{\boldsymbol C}_{{}{}^{\bf 214}\bf{Pb}}{\boldsymbol C}_{{}{}^{\bf 214}\bf{Bi}}$) are important for radon exposure dose evaluation. For getting these characteristic parameters in dwellings, a series of field measurement was carried out. For comparison, a semi-continuous measurement was carried out in an office room and outdoors. Results show that the average fp is 4.5% ± 2.2% and 3.8% ± 1.7% in city dwellings and in rural dwellings, respectively. The average activity concentration ratios are 10.940.70 for radon progeny and 10.070.06 for unattached radon progeny in city dwellings, while those in rural dwellings are 10.880.66 and 10.090.07. The average values of fp are 5.1% ± 0.9% and 5.4% ± 3.1% in the office room and in outdoors without significant difference. The average activity concentration ratios are 10.880.77 for radon progeny and 10.110.11 for unattached radon progeny in outdoors.