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Enhanced organic mass fraction and decreased hygroscopicity of cloud condensation nuclei (CCN) during new particle formation events

Dusek, Ulrike; Frank, Göran LU ; Curtius, J.; Drewnick, F.; Schneider, J.; Kürten, A.; Rose, Diana; Andreae, Meinrat O.; Borrmann, S. and Pöschl, Ulrich (2010) In Geophysical Research Letters 37.
Abstract
In a forested near-urban location in central Germany, the

CCN efficiency of particles smaller than 100 nm decreases

significantly during periods of new particle formation. This

results in an increase of average activation diameters, ranging

from 5 to 8% at supersaturations of 0.33% and 0.74%,

respectively. At the same time, the organic mass fraction in

the sub-100-nm size range increases from approximately 2/3

to 3/4. This provides evidence that secondary organic aerosol

(SOA) components are involved in the growth of new

particles to larger sizes, and that the reduced CCN efficiency

of small particles is caused by the low hygroscopicity of

... (More)
In a forested near-urban location in central Germany, the

CCN efficiency of particles smaller than 100 nm decreases

significantly during periods of new particle formation. This

results in an increase of average activation diameters, ranging

from 5 to 8% at supersaturations of 0.33% and 0.74%,

respectively. At the same time, the organic mass fraction in

the sub-100-nm size range increases from approximately 2/3

to 3/4. This provides evidence that secondary organic aerosol

(SOA) components are involved in the growth of new

particles to larger sizes, and that the reduced CCN efficiency

of small particles is caused by the low hygroscopicity of

the condensing material. The observed dependence of

particle hygroscopicity (k) on chemical composition can

be parameterized as a function of organic and inorganic

mass fractions (forg, finorg) determined by aerosol mass

spectrometry: k = korg forg + kinorg finorg. The obtained value

of korg ~ 0.1 is characteristic for SOA, and kinorg ~ 0.7 is

consistent with the observed mix of ammonium, sulfate

and nitrate ions. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Geophysical Research Letters
volume
37
publisher
American Geophysical Union
external identifiers
  • scopus:76349099359
ISSN
1944-8007
DOI
10.1029/2009GL040930
project
MERGE
language
English
LU publication?
yes
id
2c182326-7859-4e46-8b09-9f4a20a8a2bc (old id 1615201)
date added to LUP
2010-06-16 13:22:10
date last changed
2018-05-29 11:49:41
@article{2c182326-7859-4e46-8b09-9f4a20a8a2bc,
  abstract     = {In a forested near-urban location in central Germany, the<br/><br>
CCN efficiency of particles smaller than 100 nm decreases<br/><br>
significantly during periods of new particle formation. This<br/><br>
results in an increase of average activation diameters, ranging<br/><br>
from 5 to 8% at supersaturations of 0.33% and 0.74%,<br/><br>
respectively. At the same time, the organic mass fraction in<br/><br>
the sub-100-nm size range increases from approximately 2/3<br/><br>
to 3/4. This provides evidence that secondary organic aerosol<br/><br>
(SOA) components are involved in the growth of new<br/><br>
particles to larger sizes, and that the reduced CCN efficiency<br/><br>
of small particles is caused by the low hygroscopicity of<br/><br>
the condensing material. The observed dependence of<br/><br>
particle hygroscopicity (k) on chemical composition can<br/><br>
be parameterized as a function of organic and inorganic<br/><br>
mass fractions (forg, finorg) determined by aerosol mass<br/><br>
spectrometry: k = korg forg + kinorg finorg. The obtained value<br/><br>
of korg ~ 0.1 is characteristic for SOA, and kinorg ~ 0.7 is<br/><br>
consistent with the observed mix of ammonium, sulfate<br/><br>
and nitrate ions.},
  author       = {Dusek, Ulrike and Frank, Göran and Curtius, J. and Drewnick, F. and Schneider, J. and Kürten, A. and Rose, Diana and Andreae, Meinrat O. and Borrmann, S. and Pöschl, Ulrich},
  issn         = {1944-8007},
  language     = {eng},
  publisher    = {American Geophysical Union},
  series       = {Geophysical Research Letters},
  title        = {Enhanced organic mass fraction and decreased hygroscopicity of cloud condensation nuclei (CCN) during new particle formation events},
  url          = {http://dx.doi.org/10.1029/2009GL040930},
  volume       = {37},
  year         = {2010},
}