Construction Of CMAQ Pollution Source Inventory Based On ISAT Model

The air pollution source inventory is the basis of air quality simulation,and it has a crucial impact on the accuracy and reliability of the entire model results.Therefore,the preprocessing method of the inventory,how to improve the resolution of the pollution sources inventory and complete the docking with the model is particularly important.Based on socioeconomic data,the construction of pollution source emission inventories is of great significance for the joint prevention and control of air pollution between regions,the formulation and introduction of policy measures.Changchun City is the natural geographic center of Northeast China,and it has a very important strategic position in the entire Jilin Province and even the Northeast Plain.This thesis is based on the 2017 MEIC inventory,combined with the local anthropogenic activity data in Changchun City obtained from field research,and uses the ISAT model to allocate the inventory with high precision in time and space.The results show that the anthropogenic emissions of seven pollutants CO,NH₃,NO₂,PM_2.5,PM₁₀,SO₂,and VOCs in Changchun City in 2017 were 1.089 million tons,73,000 tons,186,700 tons,65,000 tons,85,000 tons,69,600 tons,and 213,300 tons,respectively.The contribution rate of industrial sources to NO₂,PM₁₀,SO₂,and VOCs is the largest,at 50.2%,46.1%,68.7%,64.2%,and the contribution rate of residential sources to CO,PM_2.5 is the largest,at 50.8%,57.2%,NH₃ mainly comes from agricultural emission sources,and agriculture contributes 95.4%to it.In terms of the monthly distribution of the inventory,there is no obvious temporal change in transportation sources between months.Residential sources and agricultural sources are affected by seasonal climate,and the monthly changes are more obvious.In general,emissions intensities across sectors are lower from May to September,while higher in winter and spring.In the hourly distribution of the inventory,emissions from power sources show an M-shaped change trend,the emission intensity of the transportation and industrial sources are stronger during the day than at night,and the hourly emission change of the residential source is related to the temperature during the day.The emission intensity is higher in the morning and evening.In terms of the spatial distribution of the inventory,except for agricultural sources,the high-concentration areas of the other four types of sources are mainly located in Chaoyang District,Green Park and other areas in the center of Changchun City,and high-weight areas of agricultural sources are Yushu City,which is in the northeast of Changchun City.The WRF model has good simulation results for both temperature and pressure.The trends of the simulated values and the monitored values are basically the same.For temperature,the WRF model can simulate the temperature peaks well in April and October.For air pressure,the simulated values of the model are generally low.As for the particulate matter of the CMAQ model,the concentration value of simulation is low,but it can simulate the diurnal variation characteristics of urban sites and suburban background sites well.The simulation effect in January is the best,and the simulation effect in October is relatively poor.This may be due to the fact that the inventory does not consider of some factors such as straw burning.In general,the model simulation performance is good and meets the accuracy requirements of the model simulation.The simulation results show that the concentration of particulate matter in one day,the highest value appears at 8-11 am in the morning,and the lowest value appears at16-18 o’clock in the afternoon.Between seasons,PM_2.5,SO₂,NO₂ all showed the highest concentration in winter,followed by spring and autumn,and the lowest concentration in summer.O₃ was the opposite.The highest concentration occurred in July,and the lowest concentration happened in January.In terms of spatial distribution,the patterns of PM_2.5,SO₂ and NO₂ are relatively similar.There are obvious high and low boundaries of pollutant concentration between cities（mainly located in the Fourth Ring Road）and suburban areas.The high concentration areas are located in Lvyuan District and Kuancheng District.In the spatial distribution pattern,the simulation results of O₃ mainly shows that the concentration in suburbs is higher than that in urban areas,and the high concentration areas are located in Nong’an County and Jiutai City.