江苏如东沿海经济开发区夏季O_(3)污染特征及来源分析

Characteristics and Sources of O_(3) Pollution in the Rudong Coastal Economic Park in Summer

为探究如东沿海经济开发区夏季大气中的O_(3)污染成因,基于2022年6月园区大气超级站的监测数据,较为全面地分析了O_(3)污染来源、水平及二次生成潜势等。结果表明:2022年6月园区O_(3)超标天数占比为34.5%,共计10 d,污染严重程度为2018—2022年同期最高水平(151μg/m3);分析4个污染过程发现,高温低湿、静稳天气易诱发O_(3)污染事件,结合污染天气象条件发现,当温度>25℃且相对湿度<75%时极易发生O_(3)污染;污染天VOCs组分贡献率主要受芳香烃、烯烃及烷烃影响,其中邻二甲苯、甲苯、间-对二甲苯是O_(3)管控的关键活性物种;后向轨迹聚类分析显示,园区O_(3)污染主要受到上海、江西和苏南本地气团输送的影响,主导轨迹出现概率分别为30%、27%和24%,其余小部分时段可能受到来自中国北部和东部的下沉气流影响。为科学管控园区夏季O_(3)污染,应加强监测并协同管控本地关键VOCs物种。

In order to explore the causes of ozone(O_(3))pollution in the Rudong Coastal Economic Park in summer,the pollution level,secondary generation potential and source analysis of O_(3) were analyzed using the monitoring data of the super station in June 2022.The results showed that:In June 2022,there were 10 days of O_(3) pollution in the park(accounting for 34.5%of June),and the monthly average O_(3) concentration rose to 151μg/m3,which led to the highest level of pollution in the same period from 2018 to 2022.O_(3) pollution was easily induced under high temperature,low humidity and stationary weather conditions based on the analysis of four pollution processes.Combined with the meteorological conditions on polluted days,it was found that most of the O_(3) pollution occurred at temperatures>25℃and relative humidity<75%.The contribution rate of components of VOCs were mainly affected by aromatic hydrocarbons,olefins and alkanes in polluted days,among them,o-xylene,toluene and m-p-xylene substances were key active species for O_(3) control.The backward trajectory clustering analysis showed that O_(3) pollution in the park was mainly transported by air masses from Shanghai,Jiangxi,and southern Jiangsu region,with the dominant trajectory occurred probabilities of 30%,27%and 24%,respectively.The remaining small period might be affected by the downdraft from northern and eastern China.To scientifically control O_(3) pollution in the park in summer,the local key VOCs species should be intensively monitored and collaboratively controlled.