The role of ions in new particle formation in the CLOUD chamber-猫眼课题宝

DOI：

10.5194/acp-17-15181-2017

发表时间：

2017-12

期刊：

Atmospheric Chemistry and Physics

影响因子：

6.3

通讯作者：

中科院分区：

地球科学1区

文献类型：

作者：

R. Wagner;Chao Yan;K. Lehtipalo;J. Duplissy;T. Nieminen;J. Kangasluoma;L. Ahonen;L. Dada;J. Kontkanen;H. Manninen;A. Dias;A. Amorim;P. Bauer;A. Bergen;Anne-Kathrin Bernhammer;Federico Bianchi-;S. Brilke;S. Mazon;Xuemeng Chen;D. Draper;L. Fischer;C. Frege;C. Fuchs;O. Garmash;H. Gordon;J. Hakala;L. Heikkinen;M. Heinritzi;V. Hofbauer;C. Hoyle;J. Kirkby;A. Kürten;A. Kvashnin;T. Laurila;M. Lawler;H. Mai;V. Makhmutov;R. Mauldin;U. Molteni;L. Nichman;W. Nie;A. Ojdanic;A. Onnela;F. Piel;L. Quéléver;M. Rissanen;N. Sarnela;S. Schallhart;K. Sengupta;M. Simon;D. Stolzenburg;Y. Stozhkov;J. Tröstl;Y. Viisanen;A. Vogel;A. Wagner;M. Xiao;P. Ye;U. Baltensperger;J. Curtius;N. Donahue;R. Flagan;M. Gallagher;A. Hansel;J. Smith;A. Tomé;P. Winkler;D. Worsnop;M. Ehn;M. Sipilä;V. Kerminen;T. Petäjä;M. Kulmala

摘要。大气中二次粒子的形成占全球云凝结核的一半以上。在欧洲核子研究中心CLOUD（宇宙离开室外液滴）室进行的实验强调了离子对新粒子形成的重要性，但量化它们在大气中的影响仍然具有挑战性。通过使用由两个纳米粒子计数器组成的新型仪器装置，其中一个配备了离子过滤器，我们能够进一步研究新粒子形成的离子相关机制。2015年秋季，我们在CLOUD进行了单萜烯、硫酸、氮氧化物、氨四种不同化学成分体系的实验。我们在精确控制和大气相关的条件下测量了离子对成核速率的影响。我们的研究结果表明，当电荷是稳定新形成的团簇所必需的，即在中性团簇不稳定的条件下，离子增强了成核过程。对于由离子诱导成核形成的带电团簇，我们第一次能够测量它们由于与相反带电离子的重组而逐渐中和。大部分簇在直径1.5 nm处携带电荷。然而，根据粒子的生长速率和离子浓度，带电团簇在生长到2.5 nm之前大部分被离子离子重组中和。在这个尺寸下，超过90%的颗粒是中性的。换句话说，颗粒可能来源于离子诱导成核，尽管在直径大于2.5 nm的地方检测到它们是中性的。在芬兰Hyytiala的观测显示，在类似条件下，与CLOUD测量相比，离子浓度和离子诱导成核的贡献更低。虽然这可以部分解释为观察到离子诱导的分数随着离子浓度的降低而减少，但需要进一步的研究来解决差异的来源。

Abstract. The formation of secondary particles in the atmosphere accounts for more than half of global cloud condensation nuclei. Experiments at the CERN CLOUD (Cosmics Leaving OUtdoor Droplets) chamber have underlined the importance of ions for new particle formation, but quantifying their effect in the atmosphere remains challenging. By using a novel instrument setup consisting of two nanoparticle counters, one of them equipped with an ion filter, we were able to further investigate the ion-related mechanisms of new particle formation. In autumn 2015, we carried out experiments at CLOUD on four systems of different chemical compositions involving monoterpenes, sulfuric acid, nitrogen oxides, and ammonia. We measured the influence of ions on the nucleation rates under precisely controlled and atmospherically relevant conditions. Our results indicate that ions enhance the nucleation process when the charge is necessary to stabilize newly formed clusters, i.e., in conditions in which neutral clusters are unstable. For charged clusters that were formed by ion-induced nucleation, we were able to measure, for the first time, their progressive neutralization due to recombination with oppositely charged ions. A large fraction of the clusters carried a charge at 1.5 nm diameter. However, depending on particle growth rates and ion concentrations, charged clusters were largely neutralized by ion–ion recombination before they grew to 2.5 nm. At this size, more than 90 % of particles were neutral. In other words, particles may originate from ion-induced nucleation, although they are neutral upon detection at diameters larger than 2.5 nm. Observations at Hyytiala, Finland, showed lower ion concentrations and a lower contribution of ion-induced nucleation than measured at CLOUD under similar conditions. Although this can be partly explained by the observation that ion-induced fractions decrease towards lower ion concentrations, further investigations are needed to resolve the origin of the discrepancy.

The role of ions in new particle formation in the CLOUD chamber

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