Unexpectedly acidic nanoparticles formed in dimethylamine-ammonia-sulfuric-acid nucleation experiments at CLOUD

Show full item record



Permalink

http://hdl.handle.net/10138/169635

Citation

Lawler , M J , Winkler , P M , Kim , J , Ahlm , L , Trostl , J , Praplan , A P , Schobesberger , S , Kuerten , A , Kirkby , J , Bianchi , F , Duplissy , J , Hansel , A , Jokinen , T , Keskinen , H , Lehtipalo , K , Leiminger , M , Petäjä , T , Rissanen , M , Rondo , L , Simon , M , Sipilä , M , Williamson , C , Wimmer , D , Riipinen , I , Virtanen , A & Smith , J N 2016 , ' Unexpectedly acidic nanoparticles formed in dimethylamine-ammonia-sulfuric-acid nucleation experiments at CLOUD ' , Atmospheric Chemistry and Physics , vol. 16 , no. 21 , pp. 13601-13618 . https://doi.org/10.5194/acp-16-13601-2016

Title: Unexpectedly acidic nanoparticles formed in dimethylamine-ammonia-sulfuric-acid nucleation experiments at CLOUD
Author: Lawler, Michael J.; Winkler, Paul M.; Kim, Jaeseok; Ahlm, Lars; Trostl, Jasmin; Praplan, Arnaud P.; Schobesberger, Siegfried; Kuerten, Andreas; Kirkby, Jasper; Bianchi, Federico; Duplissy, Jonathan; Hansel, Armin; Jokinen, Tuija; Keskinen, Helmi; Lehtipalo, Katrianne; Leiminger, Markus; Petäjä, Tuukka; Rissanen, Matti; Rondo, Linda; Simon, Mario; Sipilä, Mikko; Williamson, Christina; Wimmer, Daniela; Riipinen, Ilona; Virtanen, Annele; Smith, James N.
Contributor: University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Department of Physics
University of Helsinki, Stockholm University
Date: 2016-11-03
Language: eng
Number of pages: 18
Belongs to series: Atmospheric Chemistry and Physics
ISSN: 1680-7316
URI: http://hdl.handle.net/10138/169635
Abstract: New particle formation driven by acid-base chemistry was initiated in the CLOUD chamber at CERN by introducing atmospherically relevant levels of gas-phase sulfuric acid and dimethylamine (DMA). Ammonia was also present in the chamber as a gas-phase contaminant from earlier experiments. The composition of particles with volume median diameters (VMDs) as small as 10 nm was measured by the Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS). Particulate ammonium-to-dimethylaminium ratios were higher than the gas-phase ammonia-to-DMA ratios, suggesting preferential uptake of ammonia over DMA for the collected 10-30 nm VMD particles. This behavior is not consistent with present nanoparticle physicochemical models, which predict a higher dimethylaminium fraction when NH3 and DMA are present at similar gas-phase concentrations. Despite the presence in the gas phase of at least 100 times higher base concentrations than sulfuric acid, the recently formed particles always had measured base : acid ratios lower than 1 : 1. The lowest base fractions were found in particles below 15 nm VMD, with a strong size-dependent composition gradient. The reasons for the very acidic composition remain uncertain, but a plausible explanation is that the particles did not reach thermodynamic equilibrium with respect to the bases due to rapid heterogeneous conversion of SO2 to sulfate. These results indicate that sulfuric acid does not require stabilization by ammonium or dimethylaminium as acid-base pairs in particles as small as 10 nm.
Subject: SECONDARY ORGANIC AEROSOL
CI-API-TOF
PARTICLE FORMATION
ATMOSPHERIC PARTICLES
ALKYLAMINIUM SULFATES
CHEMICAL-COMPOSITION
MASS-SPECTROMETRY
GROWTH-RATES
OXIDATION
PHASE
114 Physical sciences
Rights:


Files in this item

Total number of downloads: Loading...

Files Size Format View
acp_16_13601_2016.pdf 1.537Mb PDF View/Open

This item appears in the following Collection(s)

Show full item record