Radon decay products attachment rate

Average dose conversion factor, DCF, for the inhalation of unattached, DCFu, and aerosol-attached, DCFae. radon decay products in air of different locations arranged according to aerosol conditions. ITbb ITbb Ai = 0- 0 0.15 0.05 is the relative cancer sensitivity distribution of the bronchial, Wbb. and alveolar, u)ai> regions of the thoracic lung, v = inhalation rate, Z = aerosol particle concentration. The indices i = n, a and c represent the nucleation (Aitken nuclei), accumulation and coarse particle modes... 

Surface deposition is the most important parameter in reduction of the free and aerosol attached radon decay products in room air. If V is the volume of a room and S is the surface area available for deposition (walls, furniture etc), the rate of removal (plateout rate) q is vg S/V, always assuming well mixed room air. vg is the deposition velocity. 

Porstendorfer, J. and T. Mercer, Diffusion Coefficient of Radon Decay Products and their Attachment Rate to the Atmosphere Aerosol, in Natural Radiation Environment III. (T. F. Gesell and W. M. Lowder, eds.), CONF-780422, Vol. 1, pp. 281-293, National Technical Information Service, Springfield, Virginia (1980). 

A plot of the attachment coefficient, p, of radon decay product ions is shown in Figure 2.3 (Chamberlain, 1991). The line is Equation (2.2) with the diffusion coefficient value, D = 7 X 10 m s Vm = 44 ms and a = 1. In the natural aerosol size distribution, typical of well-populated country districts, Junge s (1963) natural aerosol size distribution includes particles such as sea salt and resuspended dust which extend the distribution at the large-diameter end, the rate constant for attachment = 2.1 x 10 s , and since A = 1.7 x 10 m for the Junge s aerosol, the corresponding value of the attachment coefficient is P = 1.2x10 m s . Measured values for the attachment coefficient p for outdoor aerosols... 

Porstendorfer, C., Mercer, X (1980). Diffusion coefficient of radon decay products and their attachment rate to the atmospheric aerosol. In Gesell, T.F., Lowder, W.M. (Eds.), Natural Radiation Environment III, vol. 1. National Technical Information Service, Springfield, VA, CONF-780422, pp. 281-293. 

As an example, the activity size distributions of the aerosol-attached fraction of all shortlived radon decay products are shown in Figure 6.13. The errors (dashed lines) included the statistical errors of the counting rates and the uncertainties in the efficiencies of the detector of the on-line a-cascade impactor in the several stages. The fitted distribution and its parameters are also shown in Figure 6.13. The AMAD of Po is about 10% smaller and Og is about... 

This paper deals with the plate-out characteristics of a variety of materials such as metals, plastics, fabrics and powders to the decay products of radon and thoron under laboratory-controlled conditions. In a previous paper, the author reported on measurements on the attachment rate and deposition velocity of radon and thoron decay products (Bigu, 1985). In these experiments, stainless steel discs and filter paper were used. At the time, the assumption was made that the surface a-activity measured was independent of the chemical and physical nature, and conditions, of the surface on which the products were deposited. The present work was partly aimed at verifying this assumption. 

Porstendorfer, J., Reineking, A. Becker, K.H. (1987) Free fractions, attachment rates and plate-out rates of radon daughters in houses. In Radon and its Decay Products, ed. P.K. Hopke, Washington D.C., American Chemical Society, pp. 285-300. 

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