摘要
基于2019年10月广东省鹤山大气超级监测站的观测数据分析了臭氧浓度特征与单颗粒气溶胶中的有机物组分.结果表明,PM_(2.5)中OC的含量显著大于EC,OC/EC比值为0.7~10.4,其中,OC/EC>2的比例占91%,表明有机碳主要来自二次生成.高臭氧浓度下二次组分(Sec)单颗粒和老化有机无机碳(ECOC-aged)单颗粒的数浓度显著增加,Sec和ECOC-aged单颗粒中含乙酸根(^(59)CH_(3)CO_(2)^(-))和乙醛酸(^(73)C_(2)HO_(3)^(-))的单颗粒数浓度呈单峰分布,两种有机单颗粒的增加都发生在下午臭氧浓度升高光化学反应较强的时段,表明大气氧化性增强有利于含氧有机物的生成.此外,Sec单颗粒中两种有机单颗粒的峰值出现在16:00,而ECOC-aged单颗粒中两种有机单颗粒的峰值出现在18:00之后,这种差异产生的原因可能与含氧有机物氧化形成的过程有关,ECOC-aged粒子中的含氧有机物主要来自光化学反应生成的低挥发有机物的气固分配过程,含氧有机物峰值的出现要晚于臭氧的浓度峰值.综上,本研究发现高臭氧浓度时段细颗粒物中二次有机碳显著增加,单颗粒中含氧有机物浓度上升,但同样大气氧化环境下不同单颗粒中含氧有机物的生成过程并不一致,相关结果为进一步探讨大气氧化性与二次有机气溶胶的生成提供了新思路.
This study measured ozone concentration and the organics-containing single particles in October 2019 in Heshan,Guangdong.The mass concentration of organic carbon(OC)was much higher than elemental carbon(EC)in PM_(2.5),and the ration of OC/EC ranged from 0.7 to 10.4,which more than 91%of OC/EC ratio was higher than 2,suggesting the majority of OC was from secondary formation process.The particle counts of Sec and ECOC-aged single particles increased under high ozone concentration,and the acetate(^(59)CH_(3)CO_(2)^(-))and glyoxylate(^(73)C_(2)HO_(3)^(-))containing particles in Sec and ECOC-aged particles also showed obvious increase in the afternoon when photochemistry was strong.This suggested the enhanced photochemical oxidative capacity was favorable for the production of oxygenated organics.In addition,the peaks of two oxygenated organics in Sec single particles appeared at 16:00 while they showed high particle counts after 18:00,and this might be due to the different formation processes of organics in Sec and ECOC-aged particles.The oxygenated organics in ECOC-aged particles were mainly from gas to particle portioning process of low volatility organics from photochemistry,which resulted the postpone peaks compared with ozone.In summary,this study found that the secondary organic carbon in fine particles increased significantly during the period of high ozone concentration,and the particle counts of oxygenated organics in single particles also increased.The results provide new insights into further research on atmospheric oxidation capacity and the formation of secondary organic aerosols.
作者
廖彤
吴梦曦
刘素琳
廉秀峰
蔡日东
陈多宏
成春雷
杨帆
李梅
LIAO Tong;WU Mengxi;LIU Sulin;LIAN Xiufeng;CAI Ridong;CHEN Duohong;CHENG Chunlei;YANG Fan;LI Mei(Guangdong Ecological and Environmental Monitoring Center,Guangzhou 510308;Institute of Mass Spectrometry and Atmospheric Environment,Guangdong-Hongkong-Macao Joint Laboratory of Collaborative Innovation for Environmental Quality,Guangdong Provincial Engineering Research Center for Online Source Apportionment System of Air Pollution,Jinan University,Guangzhou 510632;Environmental Monitoring Station of Pudong New District,Shanghai 201200)
出处
《环境科学学报》
CAS
CSCD
北大核心
2023年第1期181-191,共11页
Acta Scientiae Circumstantiae
基金
广东省自然科学基金面上项目(No.2021A1515011206)
浦东新区生态环境局科研专项项目(No.PDHJ20210008)。
关键词
臭氧
光化学反应
大气氧化性
含氧有机物
二次有机气溶胶
ozone
photochemistry
atmospheric oxidation
oxygenated organics
secondary organic aerosol
