TY  - JOUR
A1  - Kim, Jaeseok
A1  - Ahlm, Lars
A1  - Yli-Juuti, Taina
A1  - Lawler, Michael Joseph
A1  - Keskinen, Helmi
A1  - Tröstl, Jasmin
A1  - Schobesberger, Siegfried
A1  - Duplissy, Jonathan
A1  - Amorim, Antonio
A1  - Bianchi, Federico
A1  - Donahue, Neil McPherson
A1  - Flagan, Richard C.
A1  - Hakala, Jani
A1  - Heinritzi, Martin
A1  - Jokinen, Tuija
A1  - Kürten, Christoph Andreas
A1  - Laaksonen, Ari
A1  - Lehtipalo, Katrianne
A1  - Miettinen, Pasi
A1  - Petäjä, Tuukka
A1  - Rissanen, Matti P.
A1  - Rondo, Linda
A1  - Sengupta, Kamalika
A1  - Simon, Mario
A1  - Tomé, Antonio
A1  - Williamson, Christina
A1  - Wimmer, Daniela
A1  - Winkler, Paul M.
A1  - Ehrhart, Sebastian
A1  - Ye, Penglin
A1  - Kirkby, Jasper
A1  - Curtius, Joachim
A1  - Baltensperger, Urs
A1  - Kulmala, Markku
A1  - Lehtinen, Kari E. J.
A1  - Smith, James N.
A1  - Riipinen, Ilona
A1  - Virtanen, Annele
T1  - Hygroscopicity of nanoparticles produced from homogeneous
nucleation in the CLOUD experiments
T2  - Atmospheric chemistry and physics / Discussions
N2  - Sulfuric acid, amines and oxidized organics have been found to be important compounds in the nucleation and initial growth of atmospheric particles. Because of the challenges involved in determining the chemical composition of objects with very small mass, however, the properties of the freshly nucleated particles and the detailed pathways of their formation processes are still not clear. In this study, we focus on a challenging size range, i.e., particles that have grown to diameters of 10 and 15 nm following nucleation, and measure their water uptake. Water uptake is useful information for indirectly obtaining chemical composition of aerosol particles. We use a nanometer-hygroscopicity tandem differential mobility analyzer (nano-HTDMA) at subsaturated conditions (ca. 90 % relative humidity at 293 K) to measure the hygroscopicity of particles during the seventh Cosmics Leaving OUtdoor Droplets (CLOUD7) campaign performed at CERN in 2012. In CLOUD7, the hygroscopicity of nucleated nanoparticles was measured in the presence of sulfuric acid, sulfuric acid–dimethylamine, and sulfuric acid–organics derived from α-pinene oxidation. The hygroscopicity parameter κ decreased with increasing particle size, indicating decreasing acidity of particles. No clear effect of the sulfuric acid concentration on the hygroscopicity of 10 nm particles produced from sulfuric acid and dimethylamine was observed, whereas the hygroscopicity of 15 nm particles sharply decreased with decreasing sulfuric acid concentrations. In particular, when the concentration of sulfuric acid was 5.1 × 106 molecules cm−3 in the gas phase, and the dimethylamine mixing ratio was 11.8 ppt, the measured κ of 15 nm particles was 0.31 ± 0.01: close to the value reported for dimethylaminium sulfate (DMAS) (κDMAS ∼ 0.28). Furthermore, the difference in κ between sulfuric acid and sulfuric acid–imethylamine experiments increased with increasing particle size. The κ values of particles in the presence of sulfuric acid and organics were much smaller than those of particles in the presence of sulfuric acid and dimethylamine. This suggests that the organics produced from α-pinene ozonolysis play a significant role in particle growth even at 10 nm sizes.
Y1  - 2016
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/39566
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-395660
N1  - © Author(s) 2016. CC Attribution 3.0 License
VL  - 16
SP  - 293
EP  - 304
PB  - European Geosciences Union
CY  - Katlenburg-Lindau
ER  -