Asbestos Fiber Deposition in a Human Tracheobronchial Cast. I. Experimental

Abstract

Hollow replicate casts of a human tracheobronchial (TB) tree were used to evaluate the conditions and mechanisms affecting fiber deposition. These casts were exposed to an aerodynamically classified crocidolite asbestos aerosol at cyclic inspiratory flow rates of 15 and 60 l/min. The deposited fibers were washed from the interior surfaces, and their dimensions were measured by scanning electron microscopy. Deposition efficiency was found to increase with fiber length and flow rate, and deposition densities were greater at the bifurcations than along the airway walls. Deposition densities were also high at two tracheal “hot spots”: the upper dorsal section and the lower ventral section.