Species differences in aerosol deposition.

A theory for scaling the collection efficiency of the lung and respiratory tract is developed by identifying the dimensionless groups of variables controlling the deposition of an inhaled aerosol. The theory predicts that collection efficiency is substantially independent of body size under physiologically equivalent conditions. Thus, total deposition depends primarily on differences in ventilation per gram body weight. Experiments on mice, hamsters, rats, rabbits and dogs simultaneously exposed to the same 198Au labelled 0.78 micron aerosol are in agreement with this prediction, but show wide variability of collection efficiency even in animals of nearly identical size.