The vertical observation of volatile organic compounds (VOCs) is an important means to clarify the mechanisms of ozone formation. To explore the vertical evolution characteristics of VOCs, a field campaign using a tethered balloon during summer photochemical pollution was conducted in Shijiazhuang from June 8 to July 3, 2019. A total of 192 VOC samples were collected, 23 vertical profiles were obtained, and the concentrations of 87 VOCs were measured. The range of the TVOC concentration was 41-48 ppbv below 600 m; it slightly increased above 600 m and rose to 58 ± 52 ppbv at 1000 m. The proportion of alkanes increased with height while the proportions of alkenes, halohydrocarbons, and acetylene decreased. The proportion of aromatics remained almost unchanged. A comparison with the results of a winter field campaign from January 8 to 16, 2019, showed that the concentrations of VOCs except for halohydrocarbons in winter were more than twice those in summer. Alkanes accounted for the same proportion in winter and summer. Alkenes, aromatics, and acetylene accounted for higher proportions in winter, while halohydrocarbons accounted for a higher proportion in summer. There were five VOC sources in the vertical direction. The proportions of gasoline vehicular emissions + industrial sources and coal burning were higher in winter. The proportions of biogenic sources + long-range transport, solvent usage, and diesel vehicular emissions were higher in summer. From the surface to 1000 m, the proportion of gasoline vehicular emissions + industrial sources gradually increased.

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华北平原夏季边界层挥发性有机物的垂直演化及与冬季的差异

挥发性有机化合物（VOCs）的垂直观测是阐明臭氧形成机制的重要手段。为探究VOCs的垂直演化特征，于2019年6月8日至7月3日在石家庄市开展了夏季光化学污染期间系留气球野外活动，共采集VOCs样品192份，获得23条垂直剖面图。测量了 87 种 VOC 的浓度。600 m以下TVOC浓度范围为41-48 ppbv；它在 600 m 以上略有增加，并在 1000 m 上升到 58 ± 52 ppbv。烷烃的比例随着高度的增加而增加，而烯烃、卤代烃和乙炔的比例下降。芳烃的比例几乎保持不变。与 2019 年 1 月 8 日至 16 日冬季田间运动结果的比较，结果表明，冬季除卤代烃外的VOCs浓度是夏季的两倍多。烷烃在冬季和夏季的比例相同。烯烃、芳烃和乙炔在冬季占比较高，而卤代烃在夏季占比较高。垂直方向有五个VOC源。冬季汽油车排放+工业源和燃煤的比例较高。夏季生物源+远距离运输、溶剂使用和柴油车排放的比例较高。从地表到1000米，汽油车排放+工业源的比例逐渐增加。烷烃在冬季和夏季的比例相同。烯烃、芳烃和乙炔在冬季占比较高，而卤代烃在夏季占比较高。垂直方向有五个VOC源。冬季汽油车排放+工业源和燃煤的比例较高。夏季生物源+远距离运输、溶剂使用和柴油车排放的比例较高。从地表到1000米，汽油车排放+工业源的比例逐渐增加。烷烃在冬季和夏季的比例相同。烯烃、芳烃和乙炔在冬季占比较高，而卤代烃在夏季占比较高。垂直方向有五个VOC源。冬季汽油车排放+工业源和燃煤的比例较高。夏季生物源+远距离运输、溶剂使用和柴油车排放的比例较高。从地表到1000米，汽油车排放+工业源的比例逐渐增加。垂直方向有五个VOC源。冬季汽油车排放+工业源和燃煤的比例较高。夏季生物源+远距离运输、溶剂使用和柴油车排放的比例较高。从地表到1000米，汽油车排放+工业源的比例逐渐增加。垂直方向有五个VOC源。冬季汽油车排放+工业源和燃煤的比例较高。夏季生物源+远距离运输、溶剂使用和柴油车排放的比例较高。从地表到1000米，汽油车排放+工业源的比例逐渐增加。