DEPOSITION MODELING OF REFRACTORY CERAMIC FIBERS IN THE RAT LUNG

An earlier mathematical model (Asgharian and Yu, J. Aerosol Sci. 20, 355-366, 1989) has been modified to calculate the deposition of refractory ceramic fibers (RCF) in the rat lung. Using the anatomical whole lung model and lobar lung model proposed by Schum and Yeb (Bull. Math. Biol. 42, 1-15, 1980), fractional deposition efficiency and size distribution of deposited fibers in various regions of the lung were determined. It was found that a large fraction of long and thick fibers deposited in the nasopharynx and the tracheobronchial tree by the mechanisms of impaction and interception, while the geometric mean diameter and length of the fibers deposited in the pulmonary region decreased considerably from their respective values in the aerosol state. The calculated size distribution in the pulmonary region of the accessory lobe was found in good agreement with the data obtained in recent exposure experiments.