Effects of amines on formation of sub‐3 nm particles and their subsequent growth
Effects of amines on formation of sub‐3 nm particles and their subsequent growth
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DOI：
10.1029/2011gl050099
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发表时间：
2012-01
影响因子：
5.2
通讯作者：
Huan Yu;R. McGraw;Shan‐Hu Lee
中科院分区：
文献类型：
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作者：
Huan Yu;R. McGraw;Shan‐Hu Lee
现场观察和量子化学计算表明，胺可以是重要的纳米尺寸的颗粒的形成。胺和氨通常具有共同的大气排放源和相似的化学和物理性质。虽然氨对气溶胶成核的影响以前已经研究过，但缺乏涉及胺的均匀成核的实验室研究。本文研究了硫酸、水、氨和胺在大气条件下的多组分成核动力学。用化学电离质谱仪（CIMS）测量低浓度的气溶胶前体，以提供成核所需的约束前体浓度。用纳米差示迁移率分析仪（nano-DMA）测量大于102 nm的颗粒尺寸，并且用颗粒尺寸放大镜（PSM）测量大于101 nm的颗粒的数量浓度。我们的观察提供了实验室证据，胺确实可以参与气溶胶成核和增长的分子团簇水平。由于几种大气相关的胺化合物和氨导致的颗粒数浓度的增加与这些化合物的碱性有关，表明酸碱反应可能有助于形成亚3 nm颗粒。
Field observations and quantum chemical calculations suggest that amines can be important for formation of nanometer size particles. Amines and ammonia often have common atmospheric emission sources and the similar chemical and physical properties. While the effects of ammonia on aerosol nucleation have been previously investigated, laboratory studies of homogeneous nucleation involving amines are lacking. We have made kinetics studies of multicomponent nucleation (MCN) with sulfuric acid, water, ammonia and amines under conditions relevant to the atmosphere. Low concentrations of aerosol precursors were measured with chemical ionization mass spectrometers (CIMS) to provide constrained precursor concentrations needed for nucleation. Particle sizes larger than ∼2 nm were measured with a nano‐differential mobility analyzer (nano‐DMA), and number concentrations of particles larger than ∼1 nm were measured with a particle size magnifier (PSM). Our observations provide the laboratory evidence that amines indeed can participate in aerosol nucleation and growth at the molecular cluster level. The enhancement of particle number concentrations due to several atmospherically relevant amine compounds and ammonia were related to the basicity of these compounds, indicating that acid–base reactions may contribute to the formation of sub‐3 nm particles.