南京北郊低对流层挥发性有机物垂直分布特征及对臭氧生成的潜在影响  

Vertical Distribution Characteristics of Lower Troposphere VOCs and Its Potential Effect on Ozone Formation in the Northern Suburb of Nanjing City,Jiangsu Province,China

作　　者：施双双 朱彬[3] 沈利娟 杨思琪 王红磊[3] SHI Shuang-shuang;ZHU Bin;SHEN Li-juan;YANG Si-qi;WANG Hong-lei(Key Laboratory of Ecosystem Carbon Source and Sink of China Meteorological Administration,Wuxi University,Wuxi 214105,Jiangsu,China;School of Atmosphere and Remote Sensing,Wuxi University,Wuxi 214105,Jiangsu,China;Key Laboratory for Aerosol-cloud-precipitation of China Meteorological Administration,Nanjing University of Information Science&Technology,Nanjing 210044,Jiangsu,China)

机构地区：[1]无锡学院中国气象局生态系统碳源汇重点开放实验室,江苏无锡214105 [2]无锡学院大气与遥感学院,江苏无锡214105 [3]南京信息工程大学中国气象局气溶胶-云-降水重点开放实验室,江苏南京210044

出　　处：《地球科学与环境学报》2024年第4期513-527,共15页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(44275115);无锡学院引进人才科研启动专项经费项目(2023r036)。

摘　　要：在各地臭氧(O_(3))污染呈现多发态势的背景下,垂直方向上挥发性有机物(VOCs)对O_(3)生成的潜在贡献尚不明晰。利用南京北郊2020年10月17日至11月15日低对流层(高度为0~1000 m)强化探空数据,探讨了VOCs垂直分布特征及其对O_(3)生成的潜在影响。结果表明:①VOCs总含量(体积分数,下同)随着高度的升高而降低((73.4±26.1)×10^(-9)~(50.4±20.3)×10^(-9)),各高度上烷烃占比最大(64.3%~71.6%),烯烃占比随着高度的升高而逐渐减小(3.4%~9.9%),芳香烃、卤代烃和乙炔占比无显著变化;交通排放和低边界层致使早、晚VOCs廓线垂直梯度大,低层VOCs积累且烷烃占比增大,而午后VOCs各组分垂直分布较均匀。②受大气层结影响,白天混合层内以烷烃和烯烃的光化学反应为主,OH自由基损失率(L_(OH))分别为3.3和2.7 s^(-1),占比分别为42.8%和35.1%;稳定边界层和残余层内均以烷烃和芳香烃的光化学反应为主。③午后混合层内VOCs的OH自由基损失率、臭氧生成潜势(OFP)与O_(3)含量成正相关关系,代表局地VOCs和O_(3)关系特征;早晨稳定边界层和残余层内无显著相关性;光化学反应活性较大的VOCs组分对O_(3)生成的潜在贡献主要集中在低层,以乙烯和丙烯为主;低对流层上部对O_(3)光化学生成的潜在贡献主要以低活性的烷烃为主,二甲苯/乙苯比值(X/E)分析表明,高层气团老化程度较高,可反映区域大气特征。限制化工厂排放、提升机动车排放标准和燃油质量是改善南京地区O_(3)污染的关键。Ozone pollution shows a trend of increasing,but the potential contribution of volatile organic compounds(VOCs)to ozone formation in the vertical direction is still unclear.The vertical distribution characteristics of VOCs and its impact on ozone formation were studied based the enhanced sounding data in the lower troposphere(0-1000 m)from October 17 to November 15,2020 observed in the northern suburbs of Nanjing city,Jiangsu province.The results show that①the volume fraction of VOCs((73.4±26.1)×10^(-9)-(50.4±20.3)×10^(-9))decreases with the increase of height,and alkanes account for the largest proportion(64.3%-71.6%)at each height,and the proportion of olefin(3.4%-9.9%)gradually decrease with the increase of height;there is no significant change in the proportion of aromatics,halohydrocarbons and acetylene;the VOCs accumulate in the lower layer in the morning and evening with a great gradient,and the proportion of alkane increases due to the traffic emissions and lower boundary layer;the VOCs profiles are uniform in the afternoon.②Affected by atmospheric junction,the alkanes and olefin dominate the photochemical reactions in the mixing layer,with the loss rate of OH radicals(L_(OH))of 3.3 and 2.7 s^(-1),accounting for 42.8%and 35.1%,respectively;alkanes and aromatics are the dominant species in the stable boundary layer and residual layer.③The L_(OH)and ozone formation potential(OFP)of VOCs in the afternoon mixing layer are positively correlated with the ozone volume fraction,which represent the relationship between local VOCs and ozone;however,there is no significant correlation between L_(OH),OFP and ozone in the stable boundary layer and residual layer in the morning;the contributions of VOCs components with high reaction activity to OFP are occurred in the low layer,and ethene and propene are the representative components;alkane makes greater contribution to the photochemical generation of ozone in the upper atmosphere,and the analysis result of X/E ratio reflects higher aging and the characteristi

关 键 词：挥发性有机物 垂直分布 臭氧 对流层 光化学反应活性 南京 

分 类 号：X51[环境科学与工程—环境工程]