AEROSOL DISPERSION IN HUMAN LUNG - COMPARISON BETWEEN NUMERICAL SIMULATIONS AND EXPERIMENTS FOR BOLUS TESTS

Bolus inhalations of 0.87-mu m-diameter particles were administered to 10 healthy subjects, and data were compared with numerical simulation s based on a one-dimensional model of aerosol transport and deposition in the human lung (J. Appl. Physiol. 77: 2889-2898, 1994). Aerosol bo luses were inhaled at a constant flow rate into various volumetric lun g depths up to 1,500 ml. Parameters such as bolus half-width, mode shi ft, skewness, and deposition were used to characterize the bolus and t o display convective mixing. The simulations described the experimenta l results reasonably well. The sensitivity of the simulations to diffe rent parameters was tested. Simulated half-width appeared to be insens itive to altered values of the deposition term, whereas it was greatly affected by modified values of the apparent diffusion in the alveolar zone of the lung. Finally, further simulations were compared in exper iments with a fixed penetration volume and various flow rates. Compari son showed good agreement, which mag be explained by the fact that hal f-width, mode shift, and skewness were little affected by the flow rat e.