2022年凯里臭氧污染过程及成因分析

Analysis on the characterization and cause of an autumn high-level ozone episode in Kaili

2022年10月20-25日,凯里市首次出现持续臭氧污染事件。基于常规污染物监测资料和气象数据,结合ERA5再分析数据研究了此次污染过程中各污染物浓度的变化特征。结果表明,此次臭氧污染呈现明显的区域污染特征。在臭氧污染期间,凯里城区臭氧(O3)平均浓度达123.76±59.76μg m-3,较污染前的O3平均浓度(61.57±29.49μg m-3)大幅上升101.01%;臭氧前体物,包括氮氧化物(NOx)、非甲烷总烃(NMHC)、一氧化碳(CO)在臭氧污染期间的平均浓度与污染前的相比几乎不变;细颗粒物(PM2.5)和可吸入颗粒物(PM10)的平均浓度在臭氧污染期间上涨7.69%和10.26%。另外,风场资料显示,在偏弱的东北风的作用下,凯里市的O3浓度变化明显受到外来输送的影响。本研究探索了凯里市秋季臭氧污染的成因,为开展区域臭氧污染季节臭氧及其前体物的协同控制提供科学支撑。

Kaili suffered from ozone pollution for the first time from October 20 to 25,2022.Based on the conventional pollutant monitoring data and meteorological data,combined with the ERA5 reanalysis data,we investigated the variation characteristics of the concentrations of air pollutants during the high-level ozone episode in this study.The results indicated that this ozone pollution exhibits obvious regional pollution characteristics.During the ozone pollution period,the average ozone concentration in the urban area of Kaili reached 123.76±59.76μg·m-3,which was a significant increase of 101.01%compared to the average concentration(61.57±29.49μg·m-3)before the pollution.The average concentrations of ozone precursors,including nitrogen oxides(NO x),non-methane hydrocarbon compound(NMHC),and carbon monoxide(CO),remained almost unchanged during the ozone pollution period compared to those before the pollution.The average concentrations of fine particulate matter(PM 2.5)and inhalable particulate matter(PM 10)increased by 7.69%and 10.26%during the ozone pollution period.Additionally,wind data indicated that under the influence of weak northeast winds,the changes in ozone concentration in Kaili were significantly influenced by external transport.We explored in this study the causes of autumn ozone pollution in Kaili and hoped to provide scientific support for the coordinated control of seasonal ozone and its precursors in the region.