Aerosol dispersion in human lung: comparison between numerical simulations and experiments for bolus tests

Bolus inhalations of 0.87-micron-diameter particles were administered to 10 healthy subjects, and data were compared with numerical simulations based on a one-dimensional model of aerosol transport and deposition in the human lung (J. Appl. Physiol. 77: 2889-2898, 1994). Aerosol boluses were inhaled at a constant flow rate into various volumetric lung depths up to 1,500 ml. Parameters such as bolus half-width, mode shift, skewness, and deposition were used to characterize the bolus and to display convective mixing. The simulations described the experimental results reasonably well. The sensitivity of the simulations to different parameters was tested. Simulated half-width appeared to be insensitive 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 experiments with a fixed penetration volume and various flow rates. Comparison showed good agreement, which may be explained by the fact that half-width, mode shift, and skewness were little affected by the flow rate.