TY  - JOUR
A1  - Wagner, Robert
A1  - Yan, Chao
A1  - Lehtipalo, Katrianne
A1  - Duplissy, Jonathan
A1  - Nieminen, Tuomo
A1  - Kangasluoma, Juha
A1  - Ahonen, Lauri R.
A1  - Dada, Lubna
A1  - Kontkanen, Jenni
A1  - Manninen, Hanna Elina
A1  - Dias, Antonio
A1  - Amorim, Antonio
A1  - Bauer, Paulus Salomon
A1  - Bergen, Anton
A1  - Bernhammer, Anne-Kathrin
A1  - Bianchi, Federico
A1  - Brilke, Sophia
A1  - Buenrostro Mazon, Stephany
A1  - Chen, Xuemeng
A1  - Draper, Danielle C.
A1  - Fischer, Lukas
A1  - Frege, Carla
A1  - Fuchs, Claudia
A1  - Garmash, Olga
A1  - Gordon, Hamish
A1  - Hakala, Jani
A1  - Heikkinen, Liine
A1  - Heinritzi, Martin
A1  - Hofbauer, Victoria
A1  - Hoyle, Christopher Robert
A1  - Kirkby, Jasper
A1  - Kürten, Christoph Andreas
A1  - Kvashnin, Alexander N.
A1  - Laurila, Tiia
A1  - Lawler, Michael Joseph
A1  - Mai, Huajun
A1  - Makhmutov, Vladimir
A1  - Mauldin, Roy Lee
A1  - Molteni, Ugo
A1  - Nichman, Leonid
A1  - Nie, Wei
A1  - Ojdanic, Andrea
A1  - Onnela, Antti
A1  - Piel, Felix
A1  - Quéléver, Lauriane L. J.
A1  - Rissanen, Matti P.
A1  - Sarnela, Nina
A1  - Schallhart, Simon
A1  - Sengupta, Kamalika
A1  - Simon, Mario
A1  - Stolzenburg, Dominik
A1  - Stozhkov, Yuri
A1  - Tröstl, Jasmin
A1  - Viisanen, Yrjö
A1  - Vogel, Alexander L.
A1  - Wagner, Andrea Christine
A1  - Xiao, Mao
A1  - Ye, Penglin
A1  - Baltensperger, Urs
A1  - Curtius, Joachim
A1  - Donahue, Neil McPherson
A1  - Flagan, Richard C.
A1  - Gallagher, Martin William
A1  - Hansel, Armin
A1  - Smith, James N.
A1  - Tomé, Antonio
A1  - Winkler, Paul M.
A1  - Worsnop, Douglas R.
A1  - Ehn, Mikael
A1  - Sipilä, Mikko
A1  - Kerminen, Veli-Matti
A1  - Petäjä, Tuukka
A1  - Kulmala, Markku
T1  - The role of ions in new-particle formation in the CLOUD chamber
T2  - Atmospheric chemistry and Physics. Discussions
N2  - 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 nano-particle 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 where 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 1.2 nm diameter. However, depending on particle growth rates and ion concentrations, charged clusters were largely neutralized by ion–ion recombination before they grew to 2.2 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 2.2 nm. Observations at Hyytiälä, 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.
Y1  - 2017
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/44556
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-445567
SN  - 1680-7375
SN  - 1680-7367
N1  - © Author(s) 2017. CC BY 4.0 License.
VL  - 17
SP  - 1
EP  - 27
PB  - EGU
CY  - Katlenburg-Lindau
ER  -