Measurement report: Vertical distribution of biogenic and anthropogenic secondary organic aerosols in the urban boundary layer over Beijing during late summer
Measurement report: Vertical distribution of biogenic and anthropogenic secondary organic aerosols in the urban boundary layer over Beijing during late summer
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DOI：
10.5194/acp-21-12949-2021
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发表时间：
2021-09
影响因子：
6.3
通讯作者：
H. Ren;Wei Hu;Lianfang Wei;Siyao Yue;Jian Zhao;Linjie Li;Libin Wu;Wan-yu Zhao;Lujie Ren;Mingjie Kang;Q. Xie;Sihui Su;Xiaole Pan;Zifa Wang;Yele Sun;K. Kawamura;P. Fu
中科院分区：
文献类型：
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作者：
H. Ren;Wei Hu;Lianfang Wei;Siyao Yue;Jian Zhao;Linjie Li;Libin Wu;Wan-yu Zhao;Lujie Ren;Mingjie Kang;Q. Xie;Sihui Su;Xiaole Pan;Zifa Wang;Yele Sun;K. Kawamura;P. Fu
抽象。二次有机气溶胶（SOA）在大气化学中起着重要的作用。然而，对城市边界层（UBL）中SOA的垂直廓线却知之甚少。这种知识差距限制了化学传输模型中的SOA模拟。2015年8月15日至9月10日，在北京325 m气象塔上同步采集了8、120和260 m处的气溶胶样品。2015年中国胜利日阅兵期间实施了严格的排放控制。在这里，我们观察到，生物SOA示踪剂的总浓度随高度增加。来自异戊二烯氧化的SOA的分数随高度增加，而来自单萜和倍半萜的SOA的分数降低，并且2，3-二羟基-4-氧代戊酸（DHOPA），甲苯氧化的人为SOA的示踪剂，也随高度增加。SOA示踪剂的复杂垂直剖面突出了在UBL内表征SOA的必要性。估算的次生有机碳（SOC）的质量浓度范围为341至673 ng C m−3。异戊二烯和甲苯的估计SOC分数与高度的增加被认为是更相关的区域运输，而单萜和倍半萜的估计SOC与高度的减少更容易受到本地排放。游行期间的排放控制减少了4%-35%的SOC，甲苯SOC的减少比其他SOC。这项研究表明，SOA的垂直分布内的UBL是复杂的，和SOA的浓度和来源的垂直剖面应考虑在现场和模拟研究在未来。
Abstract. Secondary organic aerosol (SOA) plays a significant role in atmospheric chemistry. However, little is known about the vertical profiles of SOA in the urban boundary layer (UBL). This knowledge gap constrains the SOA simulation in chemical transport models. Here, the aerosol samples were synchronously collected at 8, 120, and 260 m based on a 325 m meteorological tower in Beijing from 15 August to 10 September 2015. Strict emission controls were implemented during this period for the 2015 China Victory Day parade. Here, we observed that the total concentration of biogenic SOA tracers increased with height. The fraction of SOA from isoprene oxidation increased with height, whereas the fractions of SOA from monoterpenes and sesquiterpenes decreased, and 2,3-dihydroxy-4-oxopentanoic acid (DHOPA), a tracer of anthropogenic SOA from toluene oxidation, also increased with height. The complicated vertical profiles of SOA tracers highlighted the need to characterize SOA within the UBL. The mass concentration of estimated secondary organic carbon (SOC) ranged from 341 to 673 ng C m−3. The increase in the estimated SOC fractions from isoprene and toluene with height was found to be more related to regional transport, whereas the decrease in the estimated SOC from monoterpenes and sesquiterpene with height was more subject to local emissions. Emission controls during the parade reduced SOC by 4 %–35 %, with toluene SOC decreasing more than the other SOC. This study demonstrates that vertical distributions of SOA within the UBL are complex, and the vertical profiles of SOA concentrations and sources should be considered in field and modeling studies in the future.