NUKLEONIKA 2012, 57(3):411-420

 


STUDIES OF THE RADON PROGENY PARTICLE SIZE DISTRIBUTION
IN THE DOMESTIC ENVIRONMENT.
EPIDEMIOLOGICAL AND DOSIMETRIC DOSE ESTIMATES



Kalina Mamont-Cieśla, Olga Stawarz

Central Laboratory for Radiological Protection, 7 Konwaliowa Str., 03-194 Warsaw, Poland


Measurements of the short-lived radon progeny particle size distributions were performed under realistic natural conditions in 54 dwellings in 6 regions of Poland by means of the Radon Progeny Particle Size Spectrometer (RPPSS). The RPPSS comprises a one open face stage, a 4-stage diffusion battery and a 3-stage multi-hole inertial impactor. It was manufactured at the ARPaNSA (Melbourne, Australia), under supervision of Dr S. B. Solomon and supplied with his software. While using the continuous mode, the programme provides analysis of the potential alpha energy concentration on each stage, particle size distributions and weighted dose conversion factors based on the ICRP human respiratory tract model (HRTM) as implemented in the computer code RADEP (radon dose evaluation program). The unattached fraction indoors ranges from ca. 0 to 53% with an arithmetic mean and median of 17%. The equilibrium factor F was observed in the range from 7 to 64% with an arithmetic mean of 32% and median of 29%. The annual effective doses from radon progeny for the general population were estimated according to two models: epidemiological and dosimetric. The mean values of the ratios of the dosimetric to epidemiological dose estimates for the general population (breathing rate 0.78 m3/h) and workers (breathing rate 1.2 m3/h) are 1.0 and 1.4, respectively. The epidemiological dose estimates for the general population are smaller in comparison with the dosimetric estimates for the unattached fraction fp greater than 17%. It was shown that the dependence of the ratio of the doses estimated on the basis of two models on the unattached fraction fp is well described by a linear equation.


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