Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China.
State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
J Environ Sci (China). 2017 Jan;51:342-351. doi: 10.1016/j.jes.2016.05.039. Epub 2016 Aug 18.
Knowledge of particle number size distribution (PND) and new particle formation (NPF) events in Southern China is essential for mitigation strategies related to submicron particles and their effects on regional air quality, haze, and human health. In this study, seven field measurement campaigns were conducted from December 2013 to May 2015 using a scanning mobility particle sizer (SMPS) at four sites in Southern China, including three urban sites and one background site. Particles were measured in the size range of 15-615nm, and the median particle number concentrations (PNCs) were found to vary in the range of 0.3×10-2.2×10cm at the urban sites and were approximately 0.2×10cm at the background site. The peak diameters at the different sites varied largely from 22 to 102nm. The PNCs in the Aitken mode (25-100nm) at the urban sites were up to 10 times higher than they were at the background site, indicating large primary emissions from traffic at the urban sites. The diurnal variations of PNCs were significantly influenced by both rush hour traffic at the urban sites and NPF events. The frequencies of NPF events at the different sites were 0%-30%, with the highest frequency occurring at an urban site during autumn. With higher SO concentrations and higher ambient temperatures being necessary, NPF at the urban site was found to be more influenced by atmospheric oxidizing capability, while NPF at the background site was limited by the condensation sink. This study provides a unique dataset of particle number and size information in various environments in Southern China, which can help understand the sources, formation, and the climate forcing of aerosols in this quickly developing region, as well as help constrain and validate NPF modeling.
了解中国南方地区颗粒物数浓度粒径分布（PND）和新粒子生成（NPF）事件对于制定与亚微米颗粒物及其对区域空气质量、雾霾和人类健康影响相关的减排策略至关重要。本研究于 2013 年 12 月至 2015 年 5 月在中国南方四个站点（三个城市站点和一个背景站点）利用扫描式迁移率颗粒物粒径谱仪（SMPS）进行了七次现场测量活动。测量的粒子粒径范围为 15-615nm，城市站点的中值粒子数浓度（PNC）范围为 0.3×10-2.2×10cm，背景站点的 PNC 约为 0.2×10cm。不同站点的峰值粒径变化范围较大，为 22-102nm。城市站点的艾肯模态（25-100nm）PNC 是背景站点的 10 倍以上，表明城市站点的交通存在大量的一次排放。城市站点 PNC 的日变化受到交通高峰时段和 NPF 事件的显著影响。不同站点的 NPF 事件频率为 0%-30%，秋季城市站点的频率最高。城市站点 NPF 受到大气氧化能力的影响较大，而背景站点的 NPF 受到凝结汇的限制，需要较高的 SO2浓度和环境温度。本研究提供了中国南方不同环境下粒子数和粒径的独特数据集，有助于了解该快速发展地区气溶胶的来源、形成和气候强迫，同时也有助于约束和验证 NPF 模型。
