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.

vehicles restriction rule  /  hypo-artery road  /  air quality  /  PM_2.5  /  ozone