In this paper, particle dispersion and spatial distribution in a full scale (5.5 m Ã- 2.4 m Ã- 3.7 m) forced ventilated room are investigated using four different multiphase flow models, including passive scalar model, discrete particle phase model, mixture model and Eulerian model. The main differences between these four models lie in how the particles are modeled. A two layer k- turbulence model is used to calculate airflows. Simulated airflow characteristics and particle concentration are compared with corresponding experimental data. The results show that only discrete particle phase model could predict particle concentration distribution close to experimental values and satisfy the published validation criteria (ASTM D5157-97). The reasons for the failure and success of these models in the present case are discussed. Furthermore, the effects of turbulence models of airflows and treatment of boundary conditions on the particle concentration are also investigated.