| Xigu District of Lanzhou city is the largest gathering area of petrochemical enterprises in Lanzhou city.The large amount of nitrogen oxides and VOCs emitted in Xigu District are the important precursors of ozone,which will affect the generation and sensitivity of near surface ozone in Xigu District and even the main urban area of Lanzhou city.Therefore,it is of great significance to study the contribution of petrochemical industry in Xigu District of Lanzhou city to the near surface ozone concentration and the impact of ozone sensitivity,so as to understand the formation of local ozone pollution in Lanzhou City and put forward corresponding control measures.Firstly,the relevant information of key industrial sources of petrochemical industry in Xigu District of Lanzhou city is investigated,then the emission list of pollution sources of petrochemical industry in Xigu District of Lanzhou city is made,which is coupled with the processed MEIC list to obtain the high-precision grid emission list of pollution sources in the study area.Then,based on the emission inventory and the meteorological data simulated by WRF,using CMAQ model,set the standard scenario of keeping the emission source unchanged and the limiting scenario of shutting down the emission sources of petrochemical industry in Xigu District of Lanzhou city to simulate the primary ozone pollution process in the main urban area of Lanzhou city.The main conclusions are as follows:?1?According to the information of key industrial sources of petrochemical industry in Xigu District of Lanzhou City and relevant"guidelines",the pollution sources emission list of petrochemical industry in Xigu District of Lanzhou city is compiled,and then it is Coupling with the processed MEIC list.Finally,the high-precision pollution sources emission list available for CMAQ model is obtained by using the smoke model.?2?Analyze the monitoring data of Lanzhou state control monitoring station in2018.The time of serious ozone pollution?June 8-13?was selected as the research period;The correlation between ozone concentration near the ground and temperature and relative humidity was analyzed,The results show that higher temperature and lower relative humidity are favorable meteorological conditions for ozone concentration accumulation near the ground.?3?Evaluate the simulation results.The results show that the average relative deviation of WRF model is between-3.79%and 18.28%,and the correlation coefficient is between 0.86 and 0.90,The simulation results can be used as meteorological field input CMAQ model,During the simulation period,there is no obvious cold air activity,the weather is clear and the sunshine hours are long,the ground has weak divergence and subsidence movement,which is conducive to the formation of ozone pollution near the ground;The standardized mean deviation of CMAQ simulation value is between-68.77%and-35.99%,the correlation coefficient is between 0.64 and 0.81,the standardized mean deviation of daytime simulation value is between-52.58%and-5%,and the standardized mean deviation of nighttime simulation value is between-96.69%and-68.58%,CMAQ model can better simulate the variation characteristics of ozone concentration near the ground in the study area,and the simulation effect is better in the daytime.?4?According to the simulation results of the standard scenario,the characteristics of ozone pollution near the ground in the main urban area of Lanzhou were analyzed.The results show that the high value area of near surface ozone concentration is mainly concentrated in the central part of Xigu District and the surrounding area of the main urban area,while the near surface ozone concentration in the central part of Chengguan District is often low;The average p?H2O2?/p?HNO3?of national monitoring stations is less than 0.35,among which the p?H2O2?/p?HNO3?of LANLIAN hotel is 0.0012-0.1364,the p?H2O2?/p?HNO3?of Lanzhou education port is 0.0001-0.0059,the p?H2O2?/p?HNO3?of Biological Products Institute is0.0000-0.0019,the p?H2O2?/p?HNO3?of railway design and Research Institute is0.0001-0.0074,Therefore,they are all in the control area of VOCs;Most of the main urban areas of Lanzhou city are VOCs control areas.The edge of the main urban area changes into transition areas or NOx control areas from 13:00 to 15:00,and back to VOCs control areas from 15:00 to 18:00;The vertical transport process and vertical diffusion process are the main source processes of ozone concentration near the ground,the positive contribution rate of vertical transport process is between 27.26%and 91.99%,and the positive contribution rate of vertical diffusion process is between0.29%and 59.15%;the horizontal transport process and gas-phase chemical reaction process are the main sink processes,the negative contribution rate of horizontal transport process is between 24.89%and 91.92%,and the gas-phase transformation The negative contribution rate of the reaction process is between 5.51%and 62.54%.?5?According to the simulation results of the limited scenario,the contribution of petrochemical production industry to the near surface ozone concentration and the impact of ozone sensitivity in the main urban area of Lanzhou are analyzed.The results show that the emission sources of petrochemical industry in Xigu District of Lanzhou City have a greater impact on the near surface ozone concentration in Xigu District,but a smaller impact on the near surface ozone concentration in Chengguan District,Anning District and Qilihe district;The contribution values of petrochemical industry in Xigu District of Lanzhou city to the average near ground ozone concentration of Lanzhou Refinery Hotel,Lanzhou education port,Institute of biological products and railway design and Research Institute are 27.15?g/m3,11.43?g/m3,9.94?g/m3 and 10.11?g/m3,with the contribution rates of 48.74%,21.05%,23.98%and 25.89%,Therefore,the emission sources of petrochemical production industry in Xigu District of Lanzhou City contribute more to the near surface ozone concentration of LANLIAN Hotel?Xigu District?,but less to other stations;The emission sources of petrochemical industry in Xigu District of Lanzhou City have great influence on the sensitivity of LANLIAN Hotel?Xigu District?,which makes it easier for LANLIAN Hotel?Xigu District?to be transformed into a transition zone or NOx control zone;The emission sources of petrochemical production industry in Xigu District of Lanzhou City have great influence on the near surface ozone sensitivity in the north of Anning District,the north of Chengguan District and the south of Qilihe district,which makes these areas more easily transformed into transition areas or NOx control areas. |
PDF Full Text Request