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| Titel |
New particle formation from the oxidation of direct emissions of pine seedlings |
| VerfasserIn |
L. Q. Hao, P. Yli-Pirilä, P. Tiitta, S. Romakkaniemi, P. Vaattovaara, M. K. Kajos, J. Rinne, J. Heijari, A. Kortelainen, P. Miettinen, J. H. Kroll, J. K. Holopainen, J. N. Smith, J. Joutsensaari, M. Kulmala  , D. R. Worsnop, A. Laaksonen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 9, no. 20 ; Nr. 9, no. 20 (2009-10-28), S.8121-8137 |
| Datensatznummer |
250007715
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| Publikation (Nr.) |
 copernicus.org/acp-9-8121-2009.pdf |
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| Zusammenfassung |
| Measurements of particle formation following the gas phase oxidation of
volatile organic compounds (VOCs) emitted by Scots pine (Pinus sylvestris L.) seedlings are
reported. Particle formation and condensational growth both from ozone
(O3) and hydroxyl radical (OH) initiated oxidation of pine emissions
(about 20-120 ppb) were investigated in a smog chamber. During experiments,
tetramethylethylene (TME) and 2-butanol were added to control the
concentrations of O3 and OH. Particle formation and condensational
growth rates were interpreted with a chemical kinetic model. Scots pine
emissions mainly included α-pinene, β-pinene, Δ3-carene,
limonene, myrcene and β-phellandrene, composing more
than 95% of total emissions. Modeled OH concentrations in the O3-
and OH-induced experiments were on the order of ~106 molecules cm−3.
Our results demonstrate that OH-initiated oxidation of VOCs plays
an important role in the nucleation process during the initial new particle
formation stage. The highest average particle formation rate of 360 cm−3 s−1
was observed for the OH-dominated nucleation events and
the lowest formation rate of less than 0.5 cm−3 s−1 was observed
for the case with only O3 present as an oxidant. In contrast to the
particle formation process, ozonolysis of monoterpenes appears to be much
more efficient to the aerosol growth process following nucleation. Higher
contributions of more oxygenated products to the SOA mass loadings from
OH-dominated oxidation systems were found as compared to the ozonolysis
systems. Comparison of mass and volume distributions from the aerosol mass
spectrometer and differential mobility analyzer yields estimated SOA
effective densities of 1.34±0.06 g cm−3 for the OH+O3
oxidation systems and 1.38±0.03 g cm−3 for the O3 dominated
chemistry. |
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