Modeling retention of inhaled particles in rat lungs including toxic and overloading effects

A theoretical model describing the retention of insoluble particles in rat lungs after prolonged exposure to an aerosol is presented. The retention kinetics of particle deposition have been determined based on the particle deposition flux and residence time of the aerosol in all generations of the respiratory system, accounting for both mucociliary and pulmonary clearance effects. The model predictions are in good agreement with inhalation data from the literature of diesel soot particles of mass median diameter 0.25 μm, titanium dioxide particles of aerodynamic diameter 1.5 μm, and quartz particles of aerodynamic diameter 2.5 μm. The model indicates that particle retention in the lungs is strongly influenced by the particle toxicity and concentration in the inhaled air.