Simulation Study On The Air Pollution Transport Characteristics Of Typical Weather In East Asia In Spring

In recent years,with the rapid economic development of the mainland of China especially the eastern coastal areas,new urbanization, industrialization road and excessive dependence on energy and resource a large number of pollutants emit into the atmosphere which brings about air pollution. Improving the quality of atmospheric environment must takes the inter-regional transport and impactinto account. Air quality models as an extremely effective tools were widely used in regional air pollution study. This article analyzed the spatial distribution of atmospheric pollutants in East Asia and summarized characteristics of transportation,transformation and source apportionment especially the affect of weather processes on air quality using the SMOKE/WRF/CMAQ model system.The main conclusions were as follows:1Compared to the observed data from monitoring sites, aerial survey, expedition ship, CMAQ modeling system demonstrated it’s ability to simulate the spatial distribution of the atmospheric pollutants, especially the impact of typical weather conditions (strong cold front process) on the air quality.2Analysis results showed pronounced a clear seasonal distribution of air pollutants in the horizontal and vertical direction.Concentrations of gasous pollutants in the vertical direction decreased with height on the whole and mainly concentrated below3000m; distribution of gasous pollutants coincided well with that of sources in horizontal direction,both increasd from edge to center of the city.3Both surface monitoring data and modeling results showed that there was a high concentration of air pollution aera before the cold front but drastically decreased after the front moved through. The cold front uplifted the pollutants to the height range of800-500hPa and pollutants were transported quickly in the middle troposphere to the west Pacific ocean. Mid-latitude warm conveyor belt air has an important impact on long-range transport of air pollutants in coastal areas of eastern Asia.4Concentrations of SO2,O3,NOx,PM2.5at Changdao decreased90.87%,34.1%,50.56%, 72.69%respectively while concentrations of SO2,O3,NOx,PM2.5at Hongze lake decreased82.53%,50.45%,65.11%,36.8%respectively. Under the high pressure behind the cold front,air pollutants accumulated and concentrations rebounded again.5For a complete cold front process,air pollutants may experience a cycle of "local accumulation—rising ahead of front—advective transport in upper air—diluted by strong gust of wind—local accumulation". The movement and evolution of large-scale weather systems is the main reason why the air quality performs regional and procedural features.6Analysis of trajectory clusters and source receptor apportionment found that Shandong Peninsula offshore pollutants mainly came from Shan dong, Beijing,Tianjin,Hebei,Jiangsu and Liaoning Province; the contribution rate from Beijing-Tianjin-Hebei region and background,boundary conditions gradually increased as the altitude increased at different receptor sites.7Based on the monitored data of references,EANET and the CMAQ (4.7.1) model scenario simulation,we analyzed the two countries (?)(SO2) interannual variation and contribution of pollutant emissions in China to the Japan regional air quality downwind. Results showed that two countries’s air quality in recent years were gradually improved each year; The coefficient between pollutant emissions of China and (?)(SO2) at Japanese site were smaller.