Evolution of particle composition in CLOUD nucleation experiments
Creators: name: Keskinen, Helmi
name: Virtanen, Annele
name: Joutsensaari, Jorma
name: Tsagkogeorgas, Georgios
name: Duplissy, Jonathan
name: Schobesberger, Siegfried
name: Gysel, Martin
name: Riccobono, Francesco
name: Slowik, Jay Gates
name: Bianchi, Federico
name: Yli-Juuti, Taina
name: Lehtipalo, Katrianne
name: Rondo, Linda
name: Breitenlechner, Martin
name: Kupc, Agnieszka
name: Almeida, João
name: Amorim, Antonio
name: Dunne, Eimear M.
name: Downard, Andrew J.
name: Ehrhart, Sebastian
name: Franchin, Alessandro
name: Kajos, Maija K.
name: Kirkby, Jasper
name: Kürten, Andreas
name: Nieminen, Tuomo
name: Makhmutov, Vladimir
name: Mathot, Serge
name: Miettinen, Pasi
name: Onnela, Antti
name: Petäjä, Tuukka
name: Praplan, Arnaud
name: Santos, Felipe D.
name: Schallhart, Simon
name: Sipilä, Mikko
name: Stozhkov, Yuri
name: Tomé, Antonio
name: Vaattovaara, Petri
name: Wimmer, Daniela
name: Prévôt, André
name: Dommen, Josef
name: Donahue, Neil M.
name: Flagan, Richard C.
name: Weingartner, Ernest
name: Viisanen, Yrjö
name: Riipinen, Ilona
name: Hansel, Armin
name: Curtius, Joachim
name: Kulmala, Markku
name: Worsnop, Douglas R.
name: Baltensperger, Urs
name: Wex, Heike
name: Stratmann, Frank
name: Laaksonen, Ari
Publisher: name: Copernicus
Year: 2013
Subjects: subject: 550 - Geowissenschaften

description: Sulphuric acid, ammonia, amines, and oxidised organics play a crucial role in nanoparticle formation in the atmosphere. In this study, we investigate the composition of nucleated nanoparticles formed from these compounds in the CLOUD (Cosmics Leaving Outdoor Droplets) chamber experiments at CERN (Centre européen pour la recherche nucléaire). The investigation was carried out via analysis of the particle hygroscopicity, ethanol affinity, oxidation state, and ion composition. Hygroscopicity was studied by a hygroscopic tandem differential mobility analyser and a cloud condensation nuclei counter, ethanol affinity by an organic differential mobility analyser and particle oxidation level by a high-resolution time-of-flight aerosol mass spectrometer. The ion composition was studied by an atmospheric pressure interface time-of-flight mass spectrometer. The volume fraction of the organics in the particles during their growth from sizes of a few nanometers to tens of nanometers was derived from measured hygroscopicity assuming the Zdanovskii–Stokes–Robinson relationship, and compared to values gained from the spectrometers. The ZSR-relationship was also applied to obtain the measured ethanol affinities during the particle growth, which were used to derive the volume fractions of sulphuric acid and the other inorganics (e.g. ammonium salts). In the presence of sulphuric acid and ammonia, particles with a mobility diameter of 150 nm were chemically neutralised to ammonium sulphate. In the presence of oxidation products of pinanediol, the organic volume fraction of freshly nucleated particles increased from 0.4 to ~0.9, with an increase in diameter from 2 to 63 nm. Conversely, the sulphuric acid volume fraction decreased from 0.6 to 0.1 when the particle diameter increased from 2 to 50 nm. The results provide information on the composition of nucleated aerosol particles during their growth in the presence of various combinations of sulphuric acid, ammonia, dimethylamine and organic oxidation products.