机动车多点源排放空气污染物浓度解析模式

针对公路机动车排放源和环境特点，建立了风速和扩散系数随高度变化的公路机动车多源排放空气污染平流扩散方程。提出了在地面和对流层边界对污染物为全反射条件下的定解问题。引用Green函数的概念，提出了公路机动车多源扩散方程的求解思路，利用微分方程的特征理论，求得了Green函数的横风和垂直向分量。通过Green函数分量与排放源强的线性组合，得到了公路机动车排放为多点源、线源和面源时污染物浓度三维分布的解析解。指出了广泛使用的高斯扩散模式在公路机动车排气污染物浓度计算中的局限性。

Analytical solutions of atmospheric diffusion equation with multi sources from roads

Based on the material balance law, the advection-diffusion equation with the multi-sources and height-dependent wind speed and eddy diffusivities are established. Depending on the interactions between the vehicular emission pollutants and the bounding surfaces, the homogeneous Neumann (total reflection) boundary conditions are proposed. A methodology based on the superposition of Green's functions is proposed for vehicular multiple source dispersion. With the Green's function concept, three-(dimensional) analytical solutions of the diffusion can be split three components: a source strength, a crosswind sub-Green function, and a vertical sub-Green function. By means of the eigenvalue theory of partial differential equation, the crosswind and vertical sub-Green functions (dispersion factors) corresponding to the boundary types are derived. By choosing appropriate sub-Green functions and source strength, three-dimensional analytical ambient concentration distributions of air pollutants from different highway vehicular emission types such as multiple point, line, and area releases are given. In addition, this study points out that the Gaussian plume model has its limitation in the application for highway vehicular pollutant dispersion. 1 fig, 12 refs.