Aerosol deposition in the dog respiratory tract

Respiratory tract deposition of monodisperse aerosols have been measured in the dog, both in vivo and in excised lungs. Three particle sizes, 0.35, 0.50 and 1.0 micron, were used, with respiratory frequencies from 8 to 25 respirations/min and tidal volumes from 100 to 600 ml. The deposition fractions measured were compared with deposition fractions for one normal human subject using the same aerosols. In vivo deposition fractions for the dog were greater than those for man at comparable conditions, and greater than those for the excised lungs at the same conditions. Although sites of deposition were not directly measured, some conclusions about the appropriateness of animal aerosol toxicity studies for assessing human risk are presented. The hypothesis of geometric similarity of mammalian lungs is examine for dog and man.