The Effect Of Traffic Policy On Air Quality In Shanghai

The number of motor vehicles in Shanghai has been sharply rising with the improvement of social and economic level in recent years.The rapid growth in motor vehicle ownership has provided convenience to people's lives,but it has also brought externalities at the same time such as traffic jams,air pollution and so on.More and more studies have proved that motor vehicles are the important source of air pollutants,such as CO,NO_X,particulate matter and VOCs,which seriously threaten public health and life.Therefore,it is of great significance to study emission reduction effect of vehicle-related policies for further mitigating air pollution and improving air quality.The emission reduction effects of three policies are analyzed in this thesis,including nonlocal vehicle restriction policy,elimination of old cars and yellow-label vehicles policy and promotion of new energy vehicles policy.Existing studies on the effect of traffic policy on air quality have mainly focused on the odd–even day traffic restriction policy or one-day-per-week restriction policy while the impact of local short-period(several hours)traffic restriction on urban air quality is largely unknown.To investigate the impact of nonlocal vehicle restriction policy on mitigating environmental pollution,regression discontinuity(RD)method was used to make quantitative analysis.The results show that the pollutant concentration was higher on ground-level roads on the restriction days than those in the nonrestriction days.Meanwhile,the extension of the restriction period exposed the commuters to high pollution for a longer time on the ground.Furthermore,nonlocal vehicle restriction policy in Shanghai did play a role in improving air quality when extending evening rush period in the short term.As time goes on,the improved effect will disappear in the long term.As for the two other traffic policies,COPERT software was used to establish emission inventory of motor vehicles in Shanghai by localized all parameters.The emission reduction effect of elimination of old cars and yellow-label vehicles policy and promotion of new energy vehicles policy implemented in Shanghai during this period were analyzed using emission factors of all kinds of pollutants obtained by COPERT software.The results show that elimination of old cars and yellow-label vehicles policy has reduced 583 tons CO,11765 tons NO_X and 1349 tons PM respectively.Promotion of new energy vehicles policy has reduced 603 tons CO,12172tons NO_X and 1396 tons PM respectively.In addition,this paper also discusses the potential implementation and of one-day-per-week restriction policy in Shanghai.The distribution of tail number of motor vehicles in Shanghai was obtained by field investigation.Based on this distribution,reasonable planning was conducted to ensure the stability of daily traffic flow.Also,through monthly or seasonal rotation,second purchase behavior can be avoided which would weaken the improvement of air quality.