Effects Of Different Emission Sources And Chemical Mechanisms On Ground-level Ozone Simulation In Shanghai

Ozone pollution has become the key issue that restricts the continuous improvement of air quality in my country,and it is urgent to carry out ozone pollution prevention and control of ozone pollution.The air quality models can describe complex physical and chemical reaction processes related to the ozone generation and elimination process,so it is widely used in the research on ozone pollution.However,there are still no specific criteria for the selection of emission sources and chemical mechanisms in the air quality model.The influence of the selection of different emission sources and chemical mechanisms on the simulation results is still unclear.Therefore,in this paper,we use two different emission sources(MEIC,EDGAR)and four different chemical mechanisms(RADM2,CB05,CBMZ,SAPRC99)in WRF-Chem model to calculate the values of O₃and other pollutants in the Shanghai area.Simulate and compare the simulated value with the observed data.The main conclusions of this research are as follows:(1)Using different emission sources and chemical mechanisms in WRF-Chem has less impact on the simulation results of meteorological elements,and the simulated meteorological data are more consistent with the observation results.(2)Using different emission sources(MEIC,EDGAR)and different chemical mechanisms(RADM2,CBMZ,SAPRC99)to simulate the average ratio of HCHO/NO₂in Shanghai is less than 1,so Shanghai is in the VOCs control area during this simulation period.The formation of ozone in Shanghai is mainly affected by the emission of VOCs.(3)Using RADM2 chemical mechanism to classify the organic matter of the emission sources MEIC and EDGAR.The reactivity of VOCs in the MEIC emission source is twice that of the VOCs in the EDGAR emission source.Therefore,the organic matter in the MEIC emission source can generate O₃Stronger.The VOCs reaction activity levels of emission sources obtained by using different chemical mechanisms(RADM2,SAPRC99,CB05)in MEIC sources are basically the same.The study also found that the major emission species that determine the production and consumption of O₃in Shanghai are olefins and aromatic hydrocarbons.(4)The spatial distribution of O₃concentration simulated by the three chemical mechanisms of RADM2,SAPRC99 and CBMZ is similar.In the Shanghai area,the O₃concentration simulated by the RADM2 mechanism is the largest,and the O₃concentration simulated by the SAPRC99 mechanism is the smallest.The atmospheric oxidation simulated by the CBMZ mechanism is the strongest,and the atmospheric oxidation simulated by the RADM2 mechanism is the weakest.(5)The change trends of NO₂and PM_2.5obtained by using different emission sources and chemical mechanism simulations are generally consistent,but there are big differences in numerical values.There is an obvious anti-phase relationship between the simulated value and the observed value of PM_2.5concentration.