Abstract
In this study, the results concerning the activity size distribution of the long-lived (Pb-210) radon decay product aerosols and the thoron decay product aerosols (Pb-212) and (Be-7) of the outdoor atmosphere are presented. Also, the mass size distribution of the aerosol particles is determined. The low-pressure Berner cascade impactor Model 20/0.015 was used as a sampling device. The activity size distribution of these radionuclides was determined by one log-normal distribution (accumulation mode) whereas the mass size distribution was by two log-normal distributions (accumulation and coarse mode). The activity median aerodynamic diameter (AMAD) of Pb-212 was found to be 305 nm with a geometric standard deviation ((g)) of 2.41. The specific air activity concentration of Pb-212 was found to be 0.14 0.012 Bq m(3). An AMAD of Pb-210 of 610 nm with (g) of 1.8 was determined, whereas that of 550 nm with (g) of 1.97 was determined for Be-7. The specific air activity concentration of Pb-210 and Be-7 was found to be 0.00162.510(4) and 0.00348 410(4) Bq m(3), respectively. Using a dosimetric model, the total deposition fraction as well as the total equivalent dose has been evaluated considering the observed parameters of the activity size distribution of Pb-212. At a total deposition fraction of 21 , the total equivalent dose was found to be 0.41 Sv.