对颗粒物面源模式做了深入研究，确定了颗粒物粒子面源开始沉降的位置。颗粒物粒子在面源内部不考虑沉降问题，面源源块内颗粒物浓度等于单位面积污染物源强与地面反射系数之积除以地面风速。面源源块外面开始考虑粒子沉降，采用虚点源后置法，参考颗粒物点源的部分反射倾斜烟云模式，全面给出了面源的颗粒物模式。面源边缘浓度采用线性内插方法处理，以免计算结果不连续。面源中心点位置应该在水平x，y方向平移一个微小距离，以消除计算点和面源中心点重合的可能。

The area source model of particulates was deeply researched, and the places of the initial precipitation of the area sources of particulates were determined. The precipitation of the particulates into the inside of the area source would not be considered. The concentration of the particulates in the inside of the area source block equalled the source intensity of the pollutants of the unit area that was multiplied by the reflection coefficient of the ground surface and divided by the wind speed of the ground surface.

The particulate precipitation of the outside of the area source would be considered. Using the back set method of the virtual point source, and referring to the tilt smoke and cloud model of the part reflex of the point source, the area source model of the particulates was fully given. The edge concentration of the area source was processed by the part of the linear insertion, lest the discontinuity of the calculated results. The central point place of the area sources should be moved horizontally a micro-distance at X and Y directions so that the possibility of the coincidence of both the calculated point and the central point of the area sources would be eliminated.