The prediction of particle dispersion by interactions with a turbulent gaseous fluid is an important, yet difficult, problem. This paper presents a new model to predict the motion of particles in a turbulent Row. This model, which solves for the probability density function (pdf) for particle velocity, treats the impact of the turbulence on the velocity pdf as a diffusion process. Particle concentrations are, in turn, found from the velocity distributions. Comparisons between the model predictions and both analytical and experimental results are presented. Results are reported for flows of homogeneous, isotropic turbulence; for grid-generated turbulence; and for round jets. This study includes a large range of particle diameters and densities. Good agreement is found between the predictions and measurements.