Accurate modeling of air flow and aerosol transport in the alveolated airways is essential for quantitative predictions of pulmonary aerosol deposition. However, experimental validation of such modeling studies has been scarce. The objective of this study is to validate computational fluid dynamics (CFD) predictions of flow field and particle trajectory with experiments within a scaled-up model of alveolated airways. Steady flow (Re = 0.13) of silicone oil was captured by particle image velocimetry (PIV), and the trajectories of 0.5 and 1.2 mm spherical iron beads (representing 0.7-14.6 mu m aerosol in vivo) were obtained by particle tracking velocimetry (PTV). At 12 selected cross sections, the velocity profiles obtained by CFD matched well with those by PIV (within 1.7% on average). The CFD predicted trajectories also matched well with PTV experiments. These results showed that air flow and aerosol transport in models of human alveolated airways can be Simulated by CFD techniques with reasonable accuracy. (C) 2009 Elsevier Ltd. All rights reserved.