Model Study Of Air Pollution In Hangzhou City Based On Community Multiscale Air Quality Modeling System

In recent years, the air quality in the Yangtze River Delta is becoming worse and worse. The formation process of atmospheric pollution was very complex, so the community multiscale air quality modeling system (CMAQ) was used to help develop efficient air pollution control policies. In this study, we investigated the temporal and spatial distribution of pollutants, and analysed the contribution rate of regional transport as well as the sharing rate from different departments. Further more, we assessed the effectiveness of policies to control emission and tried to find the most suitable object control strategies for the future.In this thesis, Hangzhou was selected as the research object. A "bottom-up" method combined with GIS technology was used to establish a homogenized emission inventory, which included nearly all species. Based on this high-resolution emissions inventory, combined with mesoscale meteorological model (WRF) and three nested grid method, CMAQ was applied to simulate the pollutant concentration in Hangzhou during Jan, May, Jun, Oct in2010. Monitoring data of five sites was selected to compare with the simulated data to assess the CMAQ model. The average bias of the simulation results is within a reasonable range, which fully proves the accuracy of the emission inventory. Verification results showed that CMAQ model can perfectly reflect the atmospheric pollution in Hangzhou.Simulation about the transport contribution from different regions shows that local emissions contribute only54.37%,58.67%,49.86%to the total NO2, SO2, PM2.5formation. Most pollutants are transported from other regions. It can be concluded that regional-joint control polices are required for the improvements of air quality. Research on the sharing rate of different departments to contamination indicates that vehicle exhaust was an important pollution source in Hangzhou, which contributes64.51%、22.41%、33.99%to NO2、SO2、PM2.5formation. Repectively, Controlling emissions from motor vehicles is one of the most effective measures to reduce air pollution in Hangzhou.Abatement policy scenario analysis shows that by the year of2015, nitrogen oxides and sulfides pollution will reduce significantly due to the total emission control policy of "the second Five Year" plan in Hangzhou, but the reduction of particulate matter will not be so obvious. In the future, more coordinates control policies should be implemented. Based on the motor vehicle emissions scenario, we conclude that it can effectively improve the air quality if we use petrol-electric for buses or liquefied natural gas (LNG) for heavy carts.