Air pollution dispersion is a typical geographic process. A reasonable way to simulate air pollution dispersion is to modeling the dispersion and presents the results in a geographically referenced virtual environment. In this research, we apply the concept of virtual geographic environments (VGE), which is coined in the community of geographic information science, to facilitate air pollution dispersion by integrating MM5 and VGE. Because MM5 is computation intensive, the CUGrid is used in this research to decrease the computation time. Our research focuses on three key points, which are the platform design, MM5 integration and computation on CUGrid, and geographical visualization of air pollution dispersion in VGE. Based on the prototype system, a case of simulating air pollution dispersion in Pearl River Delta is employed to validate and test the rationality of the methodology. As shown in this case study, VGE can provide a good way to visualize air pollution dispersion and the CUGrid can decrease model computation time significantly.