Abstract: To study synoptic patterns and pollutant transports in regional air environmental processes in North China, a pollution process from October 2nd to 12th, 2003 was discussed as an example. Results show that the south-west pathway is dominant in the API increasing phase, while the pollutants disperse from north to south during the API decreasing phase, and the air quality of most cities turns good in the influence of zonal fronts. Statistics of all air environmental processes from september to December were discussed. When large-scale high pressure controls North China, and if the center lies in the south part of Shanxi and Hebei is influenced with low pressure system (weak trough), the synoptic situation results in a south-west air stream over this region. Results show that south-west pathway is the main transport to cause the regional pollution process with the influence of topography and synoptic patterns. 