Vertical distribution monitoring of near-surface atmospheric VOCs in Shenzhen based on UAV-borne
WANG Bi1, CHENG Yong1, YU Guang-he2, LI Xin2, WANG Hai-chao3, ZHENG Ze-long3, ZENG Li-wu1, HUANG Xiao-feng1
1. Laboratory of Atmospheric Observation Supersite, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China; 2. PKU~HKUST Shenzhen-Hong Kong Institution, Shenzhen 518057, China; 3. Guangdong Laboratory of Southern Marine Science and Engineering, School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai 519082, China
Abstract：From September 21 to 23, 2023, a study was conducted in Shenzhen using a multi-channel airborne sampling system on unmanned aerial vehicle (UAV) equipped with in-house NO2 and O3 integrated monitoring devices in seven gradient levels during morning and afternoon periods. This study aimed to investigate the vertical distribution characteristics, composition evolution, and their impact on ozone formation of volatile organic compounds (VOCs) from the surface to 480 meters. The results indicated that the concentrations of VOCs in the morning decreased with height, reflecting a significant influence of ground emissions, while it increased with height in the afternoon, influencing by regional transport. The main VOC species were OVOCs and alkanes, with their concentrations peaking at 160~240meters and 400meters due to emission sources, while other species exhibited minor fluctuations. The vertical distribution characteristics of the total ozone formation potential (OFP) were consistent with the total VOCs concentration. The major contributors to OFP were OVOCs (36.9%), olefins (25.2%), and aromatics (22.4%). Ratio analysis of typical and characteristic species suggested that secondary production, industrial processes, solvent usage sources, and vehicular emissions have a significant impact on the vertical distribution of VOCs. Furthermore, during the observation period, the NO2 concentration increased with altitude above 240 meters in morning and noon. The O3 concentration peaked at 160 meters during the morning, and showed an opposite trend to NO2 above 240 meters during the afternoon, influenced by the synergistic effects of VOCs and NO2.
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