| As one of the air pollution transmission channel cities in Beijing-Tianjin-Hebei and surrounding area?"2+26"cities?,the air quality of Anyang City has been improved by continuously pushing forward the battle of air pollution prevention and control.However,ozone?O3?pollution gradually intensified and the number of pollution days gradually increased,which has become the second environmental problem that affecting the air quality of Anyang City.In this paper,the characteristics of O3 pollution and its influencing factors in Anyang City were studied.Specifically,the temporal and spatial characteristics,meteorological factors,transport factors and the influence of VOCs on O3 concentration in Anyang City were deeply understood.At the same time,combined with the research results and the actual situation of Anyang City,more scientific and effective suggestions are put forward in order to provide a scientific reference for the treatment and control of O3 pollution in this region.Firstly,in this study,based on hourly air quality and meteorological data of Anyang City from 2014 to 2018,the characteristics of O3 pollution and the correlation with meteorological factors at different stations in the city were analyzed.The results showed that O3 pollution in anyang city from 2014 to 2018 showed an overall trend of fluctuation and increased,and the occurrence time of exceeded standards was constantly ahead of time.The level and rising range of O3 concentrations at each station in the urban area were different,which were shown as Cotton Research Institute>Ginkgo Community>Tiefo Temple,with the 90th percentile annual average growth of4.8?g·m-3,8.5?g·m-3and 11.7?g·m-3,respectively.There was a significant correlation between O3 concentration and meteorological factors,such as temperature and humidity.The pollution event of high concentration O3 was mainly related to air temperature>23?,relative humidity<58%and wind speed of 5 m·s-1 in SSW?south-southwest?direction,and the annual average temperature was consistent with the variation of O3 concentration.Secondly,the transport paths of air masses in different seasons were identified by backward trajectory clustering analysis,and the potential sources were further identified by combining O3 concentration.The results showed that the impact of air mass transport in different seasons was significant.In spring,the potential source areas were in the west of Hubei and the Yangtze River Delta.In summer,which were mainly distributed around Anyang City.In autumn,which were mainly distributed in the central part of north Hubei and the border areas of Shanxi,Shaanxi and Inner Mongolia.The case analysis of heavy pollution process of O3 showed that the concentration of O3in Tiefo temple station responded fastest in the whole pollution process,and it could have a great impact on the urban area along with the continuous westerly wind.Due to the influence of dry and hot air masses in the west of China,the high concentration of O3 in Anyang City is more likely to exceed the standard when the 500 hpa upper air was affected by the continuous weak trough weather.Finally,we observed and analyzed the concentration of precursor volatile organic compounds?VOCs?during the high O3 pollution period in summer.Th e results showed that the concentration of TVOCs in Anyang City was?29.47±20.83?×10-9 during the high O3 pollution period in summer.The O3 formation potential?OFP?of each species from high to low was aromatic hydrocarbon(32.94?g·m-3),alkene(31.94?g·m-3),alkane(21.25?g·m-3),OVOCs(8.02?g·m-3),halohydrocarbon(1.77?g·m-3)and sulfide(0.85?g·m-3),which is quite different from the concentration variation.Based on the PMF receptor model,five source s of VOCs were recognized,i.e.,industrial emission?39.54%?,vehicular emissi on?23.64%?,combustion sources?14.78%?,solvent utilization?11.88%?,and bi ogenic emission?10.16%?.The contribution ratio was close to the trend of OF P.The prevention of O3pollution in Anyang should be considered with the co mprehensive treatment of PM2.5,meanwhile,strengthen regional information sha ring,joint defense and joint control,and establish a long-term mechanism.The key point of the VOCs emission control is industrial emission,vehicular emis sion and solvent utilization. |
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