Development Of Emission Inventory Processing System And Study Of The Impact Of Chemical Mechanisms On Simulation

Air quality models（AQMs）are widely used to understand and predict changes（e.g.,transport,deposition,and reaction）of air pollutants at different spatial and temporal scales,providing an effective way for studying atmospheric pollution processes.Emission inventory,as input to the models,provides AQMs with information on emissions of gaseous and aerosol species.However,due to the mismatch of spatial and temporal resolution and pollutant types,the emission inventories available are not compatible when applied to AQMs.As a major component of AQMs,atmospheric chemical mechanism describes the complex chemical processes in the atmosphere,and different chemical mechanisms often lead to various results in simulations.We developed the open-source,multi-scale Emission Inventory Processing System（EMIPS）based on the Meteo Info software platform using the Jython programming language for providing model-ready emissions data for AQMs.EMIPS is highly applicable,scalable,and easy to use,provides a graphical user interface,adopts a modular design concept,and can run on any operating system with Java environment.The core functions of EMIPS include preprocessing,spatial allocation,temporal allocation,chemical speciation,vertical allocation,and coupling emission inventories from different sources.We detail the implementation of each function with practical examples and explain the use and operational efficiency of EMIPS in the body of this paper.We conducted a numerical experiment using the Weather Research and Forecasting model coupled to Chemistry（WRF-Chem）to examine the emissions data obtained with EMIPS.Simulations of the four pollutants(PM_2.5,PM₁₀,NO₂,and O₃)over China in January 2017 are described in detail in this paper.And the comparison of simulations with observations indicates the model can reproduce the temporal and spatial patterns of pollutants,suggesting that EMIPS is capable of supporting atmospheric chemistry modelingMoreover,we simulated O₃ and its precursors in several areas of China using WRF-Chem with different chemical mechanisms（CBMZ,MOZART,and SAPRC99）.The main conclusions are as follows,（1）for NO₂,the simulated concentrations of the three mechanisms can be roughly ranked as CBMZ>SAPRC99>MOZART,and the simulated effect is in reverse order,（2）for O₃,the simulated concentrations of the three mechanisms can be roughly ranked as SAPRC99>CBMZ>MOZART,CBMZ achieved the best simulation effect,while SAPRC99 and MOZART have better simulation effect on different areas respectively,（3）the simulation results indicate that most of the areas are VOCs-limited during this period.