Abstract
Total deposition data were used to estimate the efficiency of the alveolar region of the human respiratory tract to collect aerosol particles. When inspired at a flow rate of 250 cm3s−1 (1000 cm3s−1) through the mouth particles of 2.6 µm (1.7 µm) aerodynamic diameter are the largest particles which pass through the extrathoracic and bronchial regiom without being deposited. They are deposited in the alveolar region only.