北京交通限行对城市次干道空气质量的影响

 为研究交通限行对城市次干道路域环境空气质量的影响，于2015年8月20日至9月30日对北京市典型次干道PM_2.5、NO₂、O₃、CH₄和非甲烷总烃等污染物进行连续监测，并同步观测车流量，研究阅兵期间交通限行措施对北京城市次干道车流量和空气质量的影响。结果表明，交通限行措施对小客车、中型客车和重型货车的车流量控制明显，分别降低了35.36%、45.12%和94.23%，而出租车和公交车的车流量有增高现象；交通限行期间及限行结束后次干道污染物浓度变化显著，交通限行结束后NO₂、非甲烷总烃浓度分别增加了127%和33.3%，O₃浓度下降了27.7%；次干道车流量与CH₄小时浓度呈显著负相关，与PM_2.5小时浓度、日均浓度有相关性；机动车贡献的NO₂、O₃浓度净值与车流量显著相关，交通限行对机动车贡献的NO₂浓度净值的平均削减幅度为51.25%，O₃增加幅度为82.99%；受交通限行和区域减排影响，PM_2.5削减幅度达34.72%。

Influence of Beijing vehicle restriction rule on air quality of hypo-artery road

In order to investigate the effect of traffic restriction on ambient air quality in urban hypo-artery road, concentrations of PM_2.5, NO₂, O₃, CH₄ and NMHC (non-methane hydrocarbons) were constantly monitored during Aug. to Sep. 2015. Meanwhile, traffic flow was calculated, and the impact from the 2015 Beijing Parade traffic restriction on vehicle operating conditions and air quality in urban roads were studied. The limiting effects were obviously shown on buses and heavy trucks; 35.36%, 45.12%, and 94.23% traffic reductions were found on minibuses, medium buses, and heavy trucks, respectively during that period; while taxis and public transport increased. Pollutant concentrations varied significantly during and after traffic restriction. There was less change in methane concentration while concentrations of nitrogen dioxide and non-methane hydrocarbon were increased by 127% and 33.3%, respectivey. The ozone concentration was decreased by 27.7%. Pearson analysis reflected that the traffic flow had 1) a significant negative correlation with CH₄ hourly concentration; 2) no significant correlation with PM_2.5 concentration. A comparative analysis between monitoring data from background control point suggests that the traffic flow has significant correlation with the net contributions of NO₂ and O₃ concentrations from motor vehicles. During the Parade traffic restriction period, the average cut range of NO₂ concentration on the monitored section was 51.25% while the average increase range of O₃ concentration was 82.99%. Under the restriction and regional comprehensive emission reduction measures, an average cut range of 34.72% on PM_2.5 was met.