咸宁市大气臭氧敏感性和污染来源解析

Analysis of the ozone sensitivity and source appointment in Xianning,Hubei Province

为掌握咸宁市臭氧(O_(3))污染状况,基于统计分析方法研究咸宁市2018年O_(3)地面观测数据,发现该年3~10月均有O_(3)浓度超标日发生,其中6、8、9、10月有浓度较高且持续时间较长的严重污染,高浓度时段集中于4~7月的每日12:00~20:00,浓度峰值出现时间约为16:00前后.使用OBM模型模拟,借助EKMA曲线、RIR分析等识别O_(3)敏感性,发现咸宁属于VOCs控制区,O_(3)生成对人为源VOCs中的二甲苯类芳香烃和烯烃类较敏感,这两类物种浓度均削减10%后分别得到RIR值为0.271和0.238.开展离线VOCs监测,经PMF方法解析得到5类源,其中工业排放为O_(3)污染主要贡献源,二甲苯类芳香烃绝大部分来自溶剂使用,烯烃类主要来自燃烧源.当O_(3)超标时,相比于非超标日,植物源、溶剂使用和燃烧源的贡献率均有增加,其中植物源的贡献增量较大,而机动车尾气和工业排放的贡献率却有一定程度的降低.

This research introduced statistical analysis methods and surface ozone data in 2018 to gain the knowledge about the ozone pollution characteristics in Xianning,Hubei Province.The ozone concentrations exceeded the national standards at days from March to October,especially in June,August,September and October when persistent heavy ozone pollution occurred.From April to July,the daily ozone high concentrations occurred between 12:00 and 20:00,and usually achieved the daily peak around 16:00.The Observation-Based Model(OBM)is designed and tools such as Empirical Kinetic Modeling Approach(EKMA)and Relative Incremental Reactivity(RIR)were included to calculate the ozone chemical sensitivity.It was found that the ozone formation in Xianning was VOCs-limited and seemed to be more sensible to two important anthropogenic VOCs species-xylene(XYL)and alkene(OLEP).After 10% cut of the emissions of xylene and alkene VOC species,the RIR values produced 0.271 and 0.238,respectively.Offline VOCs monitoring data was used in the PMF method and 5types of sources are appointed.It is found that industrial emissions contributed most to ozone pollution.xylene and alkene mainly came from solvent usage and combustion sources,respectively,which were the main VOC pollutants that should be controlled.During the ozone exceeding days,there were 9.8%,1.8% and 1.9% more contributions from vegetation,solvent and biomass burning,while 2.4% and 10.9% less contributions from vehicles and industrial sections.