DEPOSITION MODELING OF REFRACTORY CERAMIC FIBERS IN THE RAT LUNG

An earlier mathematical model (Asgharian and Yu, J. Aerosol Sci. 20, 3 55-366, 1989) has been modified to calculate the deposition of refract ory ceramic fibers (RCF) in the rat lung. Using the anatomical whole l ung model and lobar lung model proposed by Schum and Yeb (Bull. Math. Biol. 42, 1-15, 1980), fractional deposition efficiency and size distr ibution of deposited fibers in various regions of the lung were determ ined. It was found that a large fraction of long and thick fibers depo sited in the nasopharynx and the tracheobronchial tree by the mechanis ms of impaction and interception, while the geometric mean diameter an d length of the fibers deposited in the pulmonary region decreased con siderably from their respective values in the aerosol state. The calcu lated size distribution in the pulmonary region of the accessory lobe was found in good agreement with the data obtained in recent exposure experiments.