The Study Of Comprehensive Air Pollution Characteristics And Regional Emissions Contribution In Dongguan City

In recent years,the atmospheric complex pollution situation characterized by high concentration of ozone and fine particles is becoming more and more serious.It is the prerequisite to study the pollution characteristics and contribution sources of O₃ and PM_2.5 to effectively control atmospheric pollution.The WRF-CMAQ air quality simulation system was established,and the air quality of the Pearl River Delta in 2014 was simulated.The simulation results were compared with the measured meteorological data and surface air quality data,and the reliability of the simulation system was verified.This paper analyzes the temporal and spatial distribution characteristics of O₃ and PM_2.5 pollution in Dongguan City by using air quality monitor and model simulation data in Dongguan City,which is relatively serious in the Pearl River Delta.Based on the high dimensional Kriging interpolation algorithm,the response surface model?RSM?between O₃,PM_2.5 concentration and its precursor emission was established,and the reliability of RSM system was evaluated by external verification method.On the basis of this,the ozone-based peak rate assessment method was used to identify the main controlling factor of ozone pollution in Dongguan City,and analyze the regional sources and emission reduction contribution of O₃ and PM_2.5 pollution in Dongguan.The results show that the reliability of WRF-CMAQ-RSM simulation system can meet the needs of atmospheric complex pollution characteristic and regional emission contribution analysis.The summer and autumn are the high incidence of ozone pollution in Dongguan City.The diurnal variation characteristics of the summer and autumn are obvious single peak type.In October,there is a slight "weekend effect" phenomenon,and the high value area appears in the north and west of Dongguan respectively.The PM_2.5 pollution in Dongguan City has obvious seasonal characteristics,and the diurnal variation characteristics of the PM_2.5 pollution in the summer show a single peak type change,but in other seasons show peak-valley type change,the high value area all appears in the west of Dongguan.Through the method of ozone peak rate assessment,we found that Dongguan City is a typical VOCs-limited area in the high incidence season of ozone pollution and controling VOCs emissions can more effectively reduce the local O₃ concentration.O₃ pollution in Dongguan city is affected by local emissions and regional emissions,the contribution of all anthropogenic emissions in the Pearl River Delta accounted for about 56.1%,Dongguan and Huizhou are the largest contribution region in July and Octorber respectively.VOCs emission reduction of Pearl River Delta can decrease Dongguan O₃ concentration in the low,medium and high three kinds of emission reduction scenarios,while the NOx emission reduction in the low emission scenarios increased O₃ concentration,the medium and high emission reduction scenarios can make the O₃ concentration continue to decline.With the increasing intensity of joint regional control,O₃ generation in Dongguan can be transformed from VOCs-limited to NOx-limited.PM_2.5 pollution in Dongguan is a regional pollution,local pollution emissions contribution accounted for about 37.9% and the surrounding urban area pollution transmission contribution accounted for about 46.2%.Under the low,medium and high emission reduction scenarios,the PM_2.5 pollution control measures of Pearl River Delta reduced the PM_2.5 concentration in Dongguan by 3.56,14.78 and 30.60 ?g/m3 respectively,among which Dongguan,Huizhou and Shenzhen were the top three emission reduction contributors,much greater than other regions.