南京市交通流与NO2、CO时空分布特征关系研究

基于南京RFID基站2014年数据,获取南京市主城区范围内多条道路车流量、车速、车队构成信息,结合南京市国控空气质量监测站点NO_2、CO浓度数据,从时间、空间两个维度对交通流特征及污染物浓度趋势进行分析,并对其相关性进行讨论.结果表明,南京市2014年交通第一季度最通畅,第四季度车速最低;2月车流量最低,12月最高,且12月是周末流量最高的月份;工作日早晚高峰车流量与车速变化趋势明显,节假日平缓;夜间大型车辆占近25%.NO_2与CO浓度在2月下降明显,在10—12月攀升到较高水平,与交通流变化趋势同步;净浓度日变化趋势呈双峰,与车流量变化相关性系数在0.57~0.82之间;空间关系上,路网密集、交通拥堵区域污染物浓度明显高于其他区域,表明南京市交通流与气态污染物NO_2、CO变化趋势有高度时空关联.

Relationship between traffic flow and temporal and spatial variations of NO2 and CO in Nanjing

By applying NO₂ and CO data from national air quality monitoring station, traffic characteristics and temporal and spatial distributions of air pollutants were analyzed based on the traffic activities such as the traffic volume, speed and fleet composition of multiple roads in the main urban area of Nanjing acquired from the Radio Frequency Identification (RFID) in 2014. In addition, the correlation between traffic information and pollutants were also analyzed. The results showed that traffic speed was the highest in the first quarter and the lowest in the fourth quarter. The lowest traffic volume appeared in February and highest in December with the biggest weekend volumes. The traffic volume of weekdays varied more significantly than holidays, and heavy-duty vehicle accounted for nearly 25% at night. NO₂ and CO concentrations decreased significantly in February, and climbed to a high level from October to December with the same trend of traffic flow. There were two concentration peaks in the morning and evening while the correlation coefficients between the concentration and traffic flow were from 0.57 to 0.82. The concentrations of pollutants in the traffic congestion area were obviously higher than those in other regions, and there was a significant spatial correlation between them. This indicated that the traffic flow and NO₂ and CO concentrations were highly correlated in Nanjing.