Estimation of Automobile Exhaust Gas Concentration Around Expressway

本研究的目的是估算汽车尾气环境浓度，为沿着高速公路的城市规划和环境影响评价提供基础资料。当风向稍微偏离道路方向时，气体浓度在道路的下风向变小，在道路的迎风面变大.利用风洞试验研究了道路结构对沿着空气污染的影响，结果表明，道路结构在其周围形成了复杂的流场和特征浓度分布.由于采用烟羽模型模拟汽车尾气扩散现象，难以估计道路结构对汽车尾气扩散的影响.将风洞试验结果与羽流模型试验结果进行了比较和讨论，在水平道路情况下，两者的结果是一致的。风洞试验是评价道路结构对汽车尾气扩散影响的有效方法。

The purpose of this study is to estimate the environmental concentration of automobile exhaust gas and to get the basic information of city planning and method of environmental impact assessment along highways.Results :1. When the wind shift a little from the road direction, gas concentration become less on the downward side of the road and high on the windward side of the road, respectively.2. As result of investigating the effect of the road structure on air pollution along highways by using the wind tunnel, the road structure makes complex stream and characteristic concentration distribution around it.3. As result of simulating diffusion phenomena by the plume model, it is difficult to estimate the effect of the road structure on diffusion of automobile exhaust gas.4. We compared the result of wind tunnel experiments with the data of plume model and discussed.Both results are consistent in case of level road. Wind tunnel experiments are the effective method to evaluate the effect of the road structure on the diffusion of automobile exhaust gas.