重庆市典型道路机动车排放NO2污染特征

为研究城市道路机动车排放NO₂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NO₂浓度与车流变化特征及其相关性。结果表明：4条道路NO₂日均浓度为29~57 μg/m³，均低于GB 3095—2012《环境空气质量标准》二级标准限值；NO₂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。NO₂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NO₂峰值浓度的出现稍微滞后于车流量峰值的出现。

Research on the pollution characteristics of NO2 emitted by motor vehicles on typical roads in Chongqing

To study the change of the concentrations of NO2 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 NO2 concentration and traffic flow, as well as their correlation were analyzed. The results showed that the daily averaged concentration of NO2 on 4 roads was 29-57 μg/m3, all lower than Level 2 standard threshold of Ambient Air Quality Standard (GB 3095-2012). The hourly concentration of NO2 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 NO2 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 NO2 appeared slightly later than the peak value of traffic flow.