Biological variability of regional deposition of aerosol particles in the human respiratory tract.

Regional deposition of inhaled particles was studied experimentally for 9 health subjects breathing the same aerosol under the same breathing conditions in order to evaluate intersubject variability of regional deposition. A great intersubject variability of extrathoracic, tracheobronchial and alveolar deposition was found. The highest one was observed for particle deposition in the extrathoracic airways. This biological variability of regional deposition has to be taken into account for considerations of health related aspects of aerosol inhalation.