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@ARTICLE{Worringen:276329,
author = {Worringen, A. and Kandler, K. and Benker, N. and Dirsch, T.
and Mertes, S. and Schenk, L. and Kästner, U. and Frank, F.
and Nillius, B. and Bundke, Ulrich and Rose, D. and Curtius,
J. and Kupiszewski, P. and Weingartner, E. and Vochezer, P.
and Schneider, J. and Schmidt, S. and Weinbruch, S. and
Ebert, M.},
title = {{S}ingle-particle characterization of ice-nucleating
particles and ice particle residuals sampled by three
different techniques},
journal = {Atmospheric chemistry and physics},
volume = {15},
number = {8},
issn = {1680-7324},
address = {Katlenburg-Lindau},
publisher = {EGU},
reportid = {FZJ-2015-06789},
pages = {4161 - 4178},
year = {2015},
abstract = {In the present work, three different techniques to separate
ice-nucleating particles (INPs) as well as ice particle
residuals (IPRs) from non-ice-active particles are compared.
The Ice Selective Inlet (ISI) and the Ice Counterflow
Virtual Impactor (Ice-CVI) sample ice particles from
mixed-phase clouds and allow after evaporation in the
instrument for the analysis of the residuals. The Fast Ice
Nucleus Chamber (FINCH) coupled with the Ice Nuclei Pumped
Counterflow Virtual Impactor (IN-PCVI) provides
ice-activating conditions to aerosol particles and extracts
the activated particles for analysis. The instruments were
run during a joint field campaign which took place in
January and February 2013 at the High Alpine Research
Station Jungfraujoch (Switzerland). INPs and IPRs were
analyzed offline by scanning electron microscopy and
energy-dispersive X-ray microanalysis to determine their
size, chemical composition and mixing state. Online analysis
of the size and chemical composition of INP activated in
FINCH was performed by laser ablation mass spectrometry.
With all three INP/IPR separation techniques high abundances
(median $20–70\%)$ of instrumental contamination artifacts
were observed (ISI: Si-O spheres, probably calibration
aerosol; Ice-CVI: Al-O particles; FINCH + IN-PCVI: steel
particles). After removal of the instrumental contamination
particles, silicates, Ca-rich particles, carbonaceous
material and metal oxides were the major INP/IPR particle
types obtained by all three techniques. In addition,
considerable amounts (median abundance mostly a few percent)
of soluble material (e.g., sea salt, sulfates) were
observed. As these soluble particles are often not expected
to act as INP/IPR, we consider them as potential measurement
artifacts. Minor types of INP/IPR include soot and
Pb-bearing particles. The Pb-bearing particles are mainly
present as an internal mixture with other particle types.
Most samples showed a maximum of the INP/IPR size
distribution at 200–400 nm in geometric diameter. In a few
cases, a second supermicron maximum was identified.
Soot/carbonaceous material and metal oxides were present
mainly in the sub-micrometer range. Silicates and Ca-rich
particles were mainly found with diameters above 1 μm
(using ISI and FINCH), in contrast to the Ice-CVI which also
sampled many submicron particles of both groups. Due to
changing meteorological conditions, the INP/IPR composition
was highly variable if different samples were compared.
Thus, the observed discrepancies between the different
separation techniques may partly result from the
non-parallel sampling. The differences of the particle group
relative number abundance as well as the mixing state of
INP/IPR clearly demonstrate the need of further studies to
better understand the influence of the separation techniques
on the INP/IPR chemical composition. Also, it must be
concluded that the abundance of contamination artifacts in
the separated INP and IPR is generally large and should be
corrected for, emphasizing the need for the accompanying
chemical measurements. Thus, further work is needed to allow
for routine operation of the three separation techniques
investigated.},
cin = {IEK-8},
ddc = {550},
cid = {I:(DE-Juel1)IEK-8-20101013},
pnm = {243 - Tropospheric trace substances and their
transformation processes (POF3-243)},
pid = {G:(DE-HGF)POF3-243},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000353838000012},
doi = {10.5194/acp-15-4161-2015},
url = {https://juser.fz-juelich.de/record/276329},
}