This study numerically investigates particle dispersion and deposition in a scaled ventilated chamber. Three-dimensional airflow simulations at two different Reynolds numbers such as 150 and 300 were performed using a lattice Boltzmann (LB) method, while a Lagrangian particle tracking method was employed to compute particle dynamics in the airflow. Instead of the commonly used lattice Bhatnagar-Gross-Krook (LBGK) model, a massively parallel code using multiple-relaxation-time LB (MRT-LB) method due to its better performance on numerical stability was developed for three-dimensional particle dynamics problems. Good agreement was observed between present airflow simulation and FLUENT results. It was also found that the three-dimensional and two-dimensional airflow patterns in ventilated chamber were very distinct from each other, indicating that two-dimensional computation is not appropriate for such kind of problem, even at low Reynolds numbers. For the particle dispersion and deposition study, six particle size groups ranging from 0.051 to 10 mu m were used. The particle results were verified by comparing them with FLUENT discrete phase model (DPM) prediction. Then the characteristics of particle dispersion and deposition were analyzed. (C) 2011 Elsevier Ltd. All rights reserved.