The driving factors of new particle formation and growth in the polluted boundary layer
The driving factors of new particle formation and growth in the polluted boundary layer
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DOI：
10.5194/acp-21-14275-2021
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发表时间：
2021-09-27
影响因子：
6.3
通讯作者：
Dommen, Josef
中科院分区：
文献类型：
--
作者：
Xiao, Mao;Hoyle, Christopher R.;Dommen, Josef
新颗粒物形成(NPF)是大气颗粒物的重要来源，影响气候和空气质量。了解城市气溶胶所涉及的机制对于制定有效的缓解策略非常重要。然而，污染边界层中报告的NPF率跨度超过4个数量级，这种差异背后的原因是激烈的科学辩论的主题。据推测，多种大气水蒸气参与了NPF，包括硫酸、氨、胺和有机物，但它们的相关作用尚不清楚。我们用模拟污染边界层条件的人为水汽混合物研究了云室中的NPF。我们证明，污染环境中的NPF在很大程度上是由硫酸碱团簇的形成驱动的，胺的存在、高氨浓度和较低的温度使其稳定。尽管芳香族氧化产物的挥发性极低，但在选定的城市环境中，它们在NPF中扮演的角色很小，但对于颗粒生长和新形成的颗粒的生存来说可能是重要的。我们的测量定量地解释了高度多样化的城市环境中的NPF，并解释了其巨大的观测变异性。在受控实验室条件下获得的这种定量信息将有助于解释未来对污染大气中NPF率的环境观测。
New particle formation (NPF) is a significant source of atmospheric particles, affecting climate and air quality. Understanding the mechanisms involved in urban aerosols is important to develop effective mitigation strategies. However, NPF rates reported in the polluted boundary layer span more than 4 orders of magnitude, and the reasons behind this variability are the subject of intense scientific debate. Multiple atmospheric vapours have been postulated to participate in NPF, including sulfuric acid, ammonia, amines and organics, but their relative roles remain unclear. We investigated NPF in the CLOUD chamber using mixtures of anthropogenic vapours that simulate polluted boundary layer conditions. We demonstrate that NPF in polluted environments is largely driven by the formation of sulfuric acid-base clusters, stabilized by the presence of amines, high ammonia concentrations and lower temperatures. Aromatic oxidation products, despite their extremely low volatility, play a minor role in NPF in the chosen urban environment but can be important for particle growth and hence for the survival of newly formed particles. Our measurements quantitatively account for NPF in highly diverse urban environments and explain its large observed variability. Such quantitative information obtained under controlled laboratory conditions will help the interpretation of future ambient observations of NPF rates in polluted atmospheres.