Enhanced secondary organic aerosol formation during dust episodes by photochemical reactions in the winter in Wuhan  

作　　者：Kai Xu Yafei Liu Chenlu Li Chen Zhang Xingang Liu Qijie Li Min Xiong Yujun Zhang Shijie Yin Yu Ding 

机构地区：[1]State Key Laboratory of Water Environment Simulation,School of Environment,Beijing Normal University,Beijing 100875,China [2]Wuhan Municipality Environmental Monitoring Center,Wuhan 430015,China [3]College of Environment and Ecology,Chongqing University,Chongqing 400030,China

出　　处：《Journal of Environmental Sciences》2023年第11期70-82,共13页环境科学学报（英文版）

基　　金：supported by the National Key R&D Programme of China(No.2019YFC0214200);the National Research Programme for Key Issues in Air Pollution Control(No.DQGG0532).

摘　　要：To investigate the effect of frequently occurring mineral dust on the formation of secondary organic aerosol(SOA),106 volatile organic compounds(VOCs),trace gas pollutants and chemical components of PM_(2.5) were measured continuously in January 2021 in Wuhan,Central China.The observation period was divided into two stages that included a haze period and a following dust period,based on the ratio of PM_(2.5) and PM_(10) concentrations.The average ratio of secondary organic carbon(SOC)to elemental carbon(EC)was 1.98 during the dust period,which was higher than that during the haze period(0.69).The contribution of SOA to PM_(2.5) also increased from 2.75% to 8.64%.The analysis of the relationships between the SOA and relative humidity(RH)and the odd oxygen(e.g.,O_(X)=O_(3)+NO_(2))levels suggested that photochemical reactions played a more important role in the enhancement of SOA production during the dust period than the aqueous-phase reactions.The heterogeneous photochemical production of OH radicals in the presence of metal oxides during the dust period was believed to be enhanced.Meanwhile,the ratios of trans-2-butene to cis-2-butene and m-/p-xylene to ethylbenzene(X/E)dropped significantly,confirming that stronger photochemical reactions occurred and SOA precursors formed efficiently.These results verified the laboratory findings that metal oxides in mineral dust could catalyse the oxidation of VOCs and induce higher SOA production.

关 键 词：VOCS Mineral dust Metal oxides SOA Photochemical reactions 

分 类 号：X513[环境科学与工程—环境工程]