基于GPS浮动车法的机动车尾气排放量分布特征

Research on Distribution Characteristics of Motor Vehicle Exhaust Emissions Based on GPS Floating Car Method

以广州市城市干道东风路1902～1903路段为研究对象,根据交通流理论建立了速度-流量模型,采用GPS浮动车速度数据和视频检测流量数据计算了模型的关键参数——阻塞密度,实现了从速度到流量的推算,并采用COPERTⅣ模型计算了不同速度等级下的综合排放因子,通过源强法计算该路段00:01─24:00的小时排放量.对CO,NOx,VOC和PM综合排放因子的速度敏感性分析表明,当平均速度达50 kmh后,随速度的增加综合排放因子下降明显变缓;对小时排放量的分析表明,污染物排放量主要集中在车流量的高峰时段,且与车流密度有很好的线性相关性,相关系数均大于0.90.

Taking section 1902-1903 of Dongfeng Road（an urban arterial road of Guangzhou City） as the study object,a Speed-Flow model was established according to traffic flow theory.The congestion density,a key parameter of the model,was obtained according to the speed calculated from GPS data and flow count from a video stream,and the dynamic flow was calculated.The hourly motor vehicle exhaust emissions from 00：01 to 24：00 were calculated based on source intensity method and comprehensive vehicle emission factors for different speed grades calculated from the COPERT Ⅳ model.Sensitivity analysis between speed and the four pollutant emission factors for CO,NOx,VOC and PM showed that when the mean speed increased above 50 kmh,the decrease in combined vehicle emission factors slowed down significantly.The hourly emissions analysis showed that exhaust emissions were mainly concentrated during the peak traffic times and showed a good linear correlation with flow density,with correlation coefficients more than 0.90 for CO,NOx,VOC and PM.