This study is concerned with the three-dimensional numerical simulation of an airjet, loaded with spherical glass particles, issuing with velocity U-0 from a nozzle of diameter D 12 mm into the air co-flowing,with velocity U-a. The flow direction is vertically downward. The Reynolds number U0D/nu, is 2 x 10(4), and the velocity ratio Ua/U-0 is 0.27. The particle diameter is 100 mu m, and the Stokes number is 200. The particle mass loading ratio ranges from 0 to 0.4. The particle-laden air jet is simulated by the three-dimensional vortex method proposed in a prior study The simulation demonstrates that the air turbulence modulations due to the particles, such as the relaxation of the velocity decay, the decrement of the momentum diffusion in the radial direction at the fully developed region, and the reduction of the turbulent intensity and Reynolds shear stress, are successfully captured by the method. The effect of the particle mass loading ratio on the air turbulence modulations is investigated. (c) 2006 Elsevier B.V. All rights reserved.