重庆市典型道路机动车排放NO_(2)污染特征

Research on the pollution characteristics of NO_(2) emitted by motor vehicles on typical roads in Chongqing

为研究城市道路机动车排放NO_(2)浓度的变化,选取重庆市大渡口区4条道路进行1周的自动在线监测,结合道路RFID基站的车流量及车型信息,分析NO_(2)浓度与车流变化特征及其相关性。结果表明:4条道路NO_(2)日均浓度为29~57µg/m^(3),均低于GB 3095—2012《环境空气质量标准》二级标准限值;NO_(2)小时浓度变化趋势为20:00左右峰值浓度明显高于08:00峰值浓度,最小值出现在14:00左右。4条道路车流量呈明显的早晚高峰趋势,周末的车流量比工作日平均车流量下降20%~40%,出现比例较高的车型为小型客车、出租车、公交车、轻型货车。NO_(2)小时浓度变化与车流量变化规律基本一致,均呈现较为明显的早晚高峰趋势,但晚高峰时段NO_(2)峰值浓度的出现稍微滞后于车流量峰值的出现。

To study the change of the concentrations of NO_(2) emitted by motor vehicles on the urban road,4 roads in Dadukou District,Chongqing Municipality were selected for one-week automatic online monitoring.Combined with the information of traffic flow and vehicles collected by RFID Base Stations on the road,the change features of NO_(2) concentration and traffic flow,as well as their correlation were analyzed.The results showed that the daily averaged concentration of NO_(2) on 4 roads was 29-57µg/m^(3),all lower than Level 2 standard threshold of Ambient Air Quality Standard(GB 3095-2012).The hourly concentration of NO_(2) peak value at about 20:00 was significantly higher than that at 08:00,with the minimum value appearing at around 14:00.The traffic flow of 4 roads had the obvious trend of morning and evening rush hours.The traffic flow at weekends was 20%-40%lower than the average traffic flow on workdays.The vehicle models with a high proportion included minibus,taxi,bus,and light truck.The change of the hourly concentration of NO_(2) was consistent with that of traffic flow.Both of them had the obvious trend of morning and evening rush hours,but during the evening rush hours,the peak concentration of NO_(2) appeared slightly later than the peak value of traffic flow.