上海高架道路上空空气质量分析

Analysis on Air Quality of Overhead Road in Shanghai

机动车尾气排放对大气环境污染有重要贡献,以机动车密集的上海市高架道路为研究对象,利用差分光学吸收光谱(DOAS)技术,结合路边NOx自动分析仪采样测量方法,对道路上空大气中NOx、SO2、O3、C6H6和C7H8进行了连续一周实时、在线测量.研究结果显示高架道路上方ρ(NOx)明显高于周围大气环境(ρ表示浓度),与车流量有较为明显的关系,日均值平均比同期国控点值高1.88倍.ρ(SO2)日均值低于同期国控点测量结果,并且与车流量没有明显关系.ρ(O3)处于较低水平,最大小时值为0.078 mg/m3,是因为机动车排放的NO对O3有较大的消耗作用.相比于C6H6,ρ(C7H8)有较高的值,最大小时值为0.037 mg/m3,并且与车流量和气象条件之间有一定联系,而ρ(C6H6)则一直处于较低的水平,最大小时值为0.010 mg/m3.实验结果显示,机动车尾气排放对NOx有较大贡献,而对SO2和C6H6没有明显贡献.

Traffic emission contributes significantly to atmospheric pollution.It is focused on an overhead road with a high density of traffic.NOx,SO2,O3,C6H6 and C7H8 in the atmosphere over the road were measured continuously by using Differential Optical Absorption Spectroscopy technique and NOx automatic analyzer for a week.It was shown that the concentration of NOx over the road was higher than ambient air and the relationship to vehicle flow was high.The daily average ratio of NOx of the overhead road to the whole city was 1.88.As for SO2,its daily average concentration was lower than whole city＇s daily average and had a lower relationship to vehicle flow.Concentration of O3was always low,the maximum hour＇s average concentration was 0.078mg/m3 as NO emission from vehicles played an important role in the O3 consumption.Compared with C6H6,concentration of C7H8 was high,its maximum hour＇s average concentration was 0.037mg/m3 and showed the relationship to vehicle flow and weather condition to a certain extent,but the concentration of C6H6 was very low during the experiment,its maximum hour＇s average concentration was 0.010mg/m3.The results showed that traffic emission had contributed significantly to NOx and less to SO2and C6H6.