Regional and local new particle formation events observed in the Yangtze River Delta region, China
Regional and local new particle formation events observed in the Yangtze River Delta region, China
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长三角地区观测到的区域性和局部新粒子形成事件
DOI：
10.1002/2016jd026030
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发表时间：
2017-02-27
影响因子：
4.4
通讯作者：
Yu, Huan
中科院分区：
文献类型：
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作者：
Dai, Liang;Wang, Honglei;Yu, Huan
为研究中国污染大气中新粒子形成（NPF）的空间不均匀性，于2015年9 - 11月在长江三角洲地区的一个石化工业区附近的城市站点和一个区域背景站点进行了同步测量。在城市站点，我们观察到一种类型的本地NPF事件（事件数：n = 5），其中成核仅限于一个小区域，但平均持续6.8小时在白天。在局部和区域性事件中，发现5 nm粒子的形成率（J（5））与H2SO 4代用品（log J（5）与log[H2SO 4]斜率接近1）呈正相关。此外，与区域性事件相比，来自附近工业区的人为挥发性有机碳（VOC）羽流增强了局部事件中的J（5）。尺度相关的气溶胶动力学计算表明，与观测到的区域性事件相比，局地事件具有高成核率的特征（J（1.3）> 1000 cm（-3）s（-1）），亚3 nm颗粒的高生长速率（GR（sub-3）> 20 nm h（-1））和高数量浓度的成核模式颗粒（平均峰N5-20：6 × 10（4）cm（-3））。考虑到这些特征，人为起源的本地NPF事件也可能是城市和区域尺度云凝结核浓度的重要贡献者。此外，两个站点之间的同时区域NPF事件（事件数：n=7）的比较表明，区域NPF强度可能被低估的单点测量在城市站点，由于空气质量的异质性。
To study the spatial inhomogeneity of new particle formation (NPF) in the polluted atmosphere of China, we conducted simultaneous measurements at an urban site near a petrochemical industrial area and a regional background site in the Yangtze River Delta region from September to November 2015. At the urban site we observed a type of local NPF event (number of events: n = 5), in which nucleation was limited to a small area but persisted for 6.8 h on average during the daytime. Formation rates of 5 nm particles (J(5)) were found to be correlated positively with the H2SO4 proxy (log J(5) versus log[H2SO4] slope near 1) in both local and regional events. Furthermore, J(5) was enhanced by the anthropogenic volatile organic carbon (VOC) plumes from nearby industrial area in the local events compared to the regional events. Size-dependent aerosol dynamics calculation showed that in comparison with the observed regional events, the local events were featured with high nucleation rate (J(1.3) > 1000 cm(-3) s(-1)), high growth rate of sub-3 nm particles (GR(sub-3) > 20 nm h(-1)), and high number concentration of nucleation mode particles (mean peak N5-20: 6x10(4) cm(-3)). Considering these features, the local NPF events of anthropogenic origin may also be an important contributor to cloud condensation nuclei concentrations in urban and regional scales. In addition, the comparison of simultaneous regional NPF events between the two sites (number of events: n=7) suggested that regional NPF intensity may be underestimated by the single-point measurement at an urban site, due to the heterogeneity of air masses.