Abstract: A 2-D mixing-layer averaging model of long distant air pollution transport is presented. A case study is given for evaluating the concentration distributions of sulfur dioxide and sulfate in Northern China from a regional area source in Shanxi Province. The sensitivities of the model outputs to the parameters including dry deposit velocity, horizontal diffusivity, chemical transformation coefficient and mixing layer height are also examined. This model may be used as a practical tool for regional air quality evaluation.