Effect of dimethylamine on the gas phase sulfuric acid concentration measured by Chemical Ionization Mass Spectrometry.
Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H2SO4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantitative detection of H2SO4in the presence of dimethylamine by CIMS at atmospherically relevant concentrations. For the first time in the CLOUD experiment, the monomer sulfuric acid concentration was measured by a CIMS and by two CI-APi-TOF (Chemical Ionization-Atmospheric Pressure interface-Time Of Flight) mass spectrometers. In addition, neutral sulfuric acid clusters were measured with the CI-APi-TOFs. The CLOUD7 measurements show that in the presence of dimethylamine (<5 to 70 pptv) the sulfuric acid monomer measured by the CIMS represents only a fraction of the total H2SO4, contained in the monomer and the clusters that is available for particle growth. Although it was found that the addition of dimethylamine dramatically changes the H2SO4cluster distribution compared to binary (H2SO4-H2O) conditions, the CIMS detection efficiency does not seem to depend substantially on whether an individual H2SO4monomer is clustered with a DMA molecule. The experimental observations are supported by numerical simulations based on A Self-contained Atmospheric chemistry coDe coupled with a molecular process model (Sulfuric Acid Water NUCleation) operated in the kinetic limit.
Institute for Atmospheric and Environmental Sciences Goethe University Frankfurt am Main Frankfurt am Main Germany.
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Rondo
CERN Geneva Switzerland.
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S
Ehrhart
Institute for Atmospheric and Environmental Sciences Goethe University Frankfurt am Main Frankfurt am Main Germany.
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A
Kürten
Department of Physics University of Helsinki Helsinki Finland.
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A
Adamov
Laboratory of Atmospheric Chemistry Paul Scherrer Institute Villigen Switzerland; Institute for Atmospheric and Climate Science ETH Zurich Zurich Switzerland.
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F
Bianchi
Institute for Ion Physics and Applied Physics University of Innsbruck Innsbruck Austria.
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M
Breitenlechner
Department of Physics University of Helsinki Helsinki Finland.
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J
Duplissy
Department of Physics University of Helsinki Helsinki Finland.
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A
Franchin
Laboratory of Atmospheric Chemistry Paul Scherrer Institute Villigen Switzerland.
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J
Dommen
Center for Atmospheric Particle Studies Carnegie Mellon University Pittsburgh Pennsylvania USA.
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NM
Donahue
Kuopio Unit Finnish Meteorological Institute Kuopio Finland; School of Earth and Environment University of Leeds Leeds UK.
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Dunne
Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena California USA.
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RC
Flagan
Department of Physics University of Helsinki Helsinki Finland.
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J
Hakala
Institute for Ion Physics and Applied Physics University of Innsbruck Innsbruck Austria.
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A
Hansel
Department of Physics University of Helsinki Helsinki Finland; Department of Applied Physics University of Eastern Finland Kuopio Finland.
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H
Keskinen
Department of Applied Physics University of Eastern Finland Kuopio Finland.
J
J
Kim
Department of Physics University of Helsinki Helsinki Finland.
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T
Jokinen
Department of Physics University of Helsinki Helsinki Finland.
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K
Lehtipalo
Institute for Atmospheric and Environmental Sciences Goethe University Frankfurt am Main Frankfurt am Main Germany.
M
M
Leiminger
Department of Physics University of Helsinki Helsinki Finland; Kuopio Unit Finnish Meteorological Institute Kuopio Finland.
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A
Praplan
Laboratory of Atmospheric Chemistry Paul Scherrer Institute Villigen Switzerland.
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F
Riccobono
Department of Physics University of Helsinki Helsinki Finland.
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MP
Rissanen
Department of Physics University of Helsinki Helsinki Finland.
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N
Sarnela
Department of Physics University of Helsinki Helsinki Finland; Department of Atmospheric Sciences University of Washington Seattle Washington USA.
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S
Schobesberger
Institute for Atmospheric and Environmental Sciences Goethe University Frankfurt am Main Frankfurt am Main Germany.
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M
Simon
Department of Physics University of Helsinki Helsinki Finland.
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M
Sipilä
Department of Applied Physics University of Eastern Finland Kuopio Finland; Department of Chemistry University of California Irvine California USA.
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JN
Smith
CENTRA-SIM University of Lisbon and University of Beira Interior Lisbon Portugal.
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A
Tomé
Laboratory of Atmospheric Chemistry Paul Scherrer Institute Villigen Switzerland.
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J
Tröstl
Leibniz Institute for Tropospheric Research Leipzig Germany.
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G
Tsagkogeorgas
Department of Applied Physics University of Eastern Finland Kuopio Finland; Department of Environmental Science University of Eastern Finland Kuopio Finland.
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P
Vaattovaara
Faculty of Physics University of Vienna Vienna Austria.
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PM
Winkler
Institute for Atmospheric and Environmental Sciences Goethe University Frankfurt am Main Frankfurt am Main Germany.
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C
Williamson
Department of Physics University of Helsinki Helsinki Finland.
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D
Wimmer
Laboratory of Atmospheric Chemistry Paul Scherrer Institute Villigen Switzerland.
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U
Baltensperger
Institute for Atmospheric and Environmental Sciences Goethe University Frankfurt am Main Frankfurt am Main Germany; CERN Geneva Switzerland.
J
J
Kirkby
Department of Physics University of Helsinki Helsinki Finland.
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M
Kulmala
Department of Physics University of Helsinki Helsinki Finland.
T
T
Petäjä
Department of Physics University of Helsinki Helsinki Finland; Aerodyne Research, Inc. Billerica Massachusetts USA.
D R
DR
Worsnop
Institute for Atmospheric and Environmental Sciences Goethe University Frankfurt am Main Frankfurt am Main Germany.
J
J
Curtius
CLOUD experiment; Chemical Ionization‐Atmospheric Pressure interface‐Time Of Flight Mass Spectrometer; nucleation