Effect of particle mass size distribution on the deposition of aerosols inthe human respiratory system

Elemental mass size distributions were experimentally determined in atmosph eric aerosols collected at four different locations in Budapest, Hungary, c omprising a urban background site, two downtown sites and a road tunnel. Ba sed on these distributions, deposition fractions for the various elements i n the respiratory system were calculated for a healthy Caucasian adult mate , female and 5-year-old child under sitting breathing conditions by a stoch astic lung deposition model. The highest deposition values were observed in the extrathoracic region regardless of subject's age and gender, and chemi cal species and size distributions. Deposition in the tracheobronchial tree and acinar region was much smaller than that in the extrathoracic region. Variations in the deposition fractions due to differences in the size distr ibutions were really significant only in the extrathoracic region. Surprisi ngly, the different size distributions yielded similar depositions in the t horacic region for a given gender as far as the shape of the deposition cur ve and the total amount are concerned. Regional deposition fractions were c ompared for the male, female and child, and for various size distributions (sampling location) and elements. (C) 2001 Elsevier Science Ltd. All rights reserved.