Activity size distributions of the radon product decay aerosols

Activity size distributions of the radon product decay aerosols 3.4.1. Lead-214 and aerosol size distributions 

The a-activity of an atmospheric aerosol sample initially decays with the 26.8 min half-life of after 3 h, the rate approaches that of 10.64 h Pb (Papastefanou and Bondietti, 1987). The measured alphas in the sample are actually derived from the decay products of these 

Mean observed Pb and Pb activity size distributions and frequency of dominance (44 measurements) 

The Pb activity median aerodynamic diameters, AMADs, determined with the low pressure impactors (LPI) varied from 0.10 to 0.37 pm (mean value 0.16 pm). For Pb, the AMADs varied from 0.07 to 0.245 pm (mean value, 0.13 pm). These AMAD calculations were made assuming log-normal distributions. An abbreviated version of these results is presented in Table 2.3 (Papastefanou and Bondietti, 1987). 

Summary of mean monthly activity median aerodynamic diameters (AMADs) and geometric standard deviations (ffg) of radon ( Rn) and thoron ( °Rn) decay products size distributions in ambient aerosols 

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