Research On Vehicle Pollutant Emission Simulation And Control Policy Application In Northeastern China Based On WRF-VEIN-CHIMERE Model

Since the implementation of The Twelfth Five-Year Plan for National Economic and Social Development in Northeast China,the growth rate of vehicles in this region has been much higher than that of Beijing and Shanghai.With the rapid growth of vehicle population,regional air pollution events caused by vehicle emissions have become more prominent among various environmental questions.Due to the unique geographical and climatic features of high latitudes,low temperature and frequent snowfall in Northeast China,vehicles emit more pollutants while driven in cold and icy roads compared to other regions.At the same time,the special geographical and climatic conditions make the physicochemical processes,the residence and transformation time of pollutants in the atmosphere different from other warm regions in China.Based on the Vehicle Emission Inventory model（VEIN）,this study optimizes the local parameters for vehicle emissions with considering the characteristics of low temperature and snowy environment in Northeast China,and then uses a combination of top-down and bottom-up methods to compile an up-to-date vehicle emission inventory（for the year of 2020）with high temporal and spatial resolution（1km×1km,1 hour）and covering more kinds of pollutants as high as 133.An innovative method with adapting video streams and AI recognition algorithm has been used to determine the hourly temporal allocation factors during the preprocessing progresses of our new compiled vehicle inventory.The R language was used to conduct the temporal and spatial（including horizontal and vertical distributions）allocations and the chemical species mapping works.The outputted model ready files were provided to the WRF-CHIMERE model to carry out the benchmark scenario simulation and to quantitatively evaluate the impacts of traffic emissions on regional air quality in Changchun.The new developed optimization technique for vehicle emission inventory in this study significantly improved the modelling accuracy of NO₂and O₃concentrations in the benchmark scenario,but limited in improving the simulation accuracy of PM_2.5,PM₁₀and CO.In order to explore the possible impacts of the implementation of different traffic restriction policies on the regional air environment,this study further set up two types of simulation scenarios with different level of vehicle restrictions and emission reductions（i.e.scenario 1 for restrictions on vehicles with two different tail numbers from 0 to 9 on each weekday,and scenario 2 for restrictions on vehicles with even or odd tail numbers on alternate days）.The contribution of different control policies to the reduction of major regional air pollutants concentrations were quantify calculated.The results indicated that,with comprehensive considering the actual environmental capacity of atmospheric pollutants,the national and local atmospheric pollution standards and vigorous regional development and economic growth in Changchun,the adoption of the traffic restriction policy in simulation scenario 1 for the whole year or during the periods of severe atmospheric pollution events in future would be the most suitable measure to alleviate the current traffic congestion and regional air pollution problems that faced by Changchun.