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| Titel |
Photochemical production of aerosols from real plant emissions |
| VerfasserIn |
Th. F. Mentel, J. Wildt, A. Kiendler-Scharr, E. Kleist, R. Tillmann, M. Maso, R. Fisseha, Th. Hohaus, H. Spahn, R. Uerlings, R. Wegener, P. T. Griffiths, E. Dinar, Y. Rudich, A. Wahner |
| 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. 13 ; Nr. 9, no. 13 (2009-07-07), S.4387-4406 |
| Datensatznummer |
250007491
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| Publikation (Nr.) |
 copernicus.org/acp-9-4387-2009.pdf |
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| Zusammenfassung |
| Emission of biogenic volatile organic compounds (VOC) which on oxidation
form secondary organic aerosols (SOA) can couple the vegetation with the
atmosphere and climate. Particle formation from tree emissions was
investigated in a new setup: a plant chamber coupled to a reaction chamber
for oxidizing the plant emissions and for forming SOA. Emissions from the
boreal tree species birch, pine, and spruce were studied. In addition,
α-pinene was used as reference compound. Under the employed
experimental conditions, OH radicals were essential for inducing new
particle formation, although O3 (≤80 ppb) was always present and a
fraction of the monoterpenes and the sesquiterpenes reacted with ozone
before OH was generated. Formation rates of 3 nm particles were linearly
related to the VOC carbon mixing ratios, as were the maximum observed volume and
the condensational growth rates. For all trees, the threshold of new
particle formation was lower than for α-pinene. It was lowest for
birch which emitted the largest fraction of oxygenated VOC (OVOC),
suggesting that OVOC may play a role in the nucleation process. Incremental
mass yields were ≈5% for pine, spruce and α-pinene, and
≈10% for birch. α-Pinene was a good model compound to
describe the yield and the growth of SOA particles from coniferous
emissions. The mass fractional yields agreed well with observations for
boreal forests. Despite the somewhat enhanced VOC and OH concentrations our
results may be up-scaled to eco-system level. Using the mass fractional
yields observed for the tree emissions and weighting them with the abundance
of the respective trees in boreal forests SOA mass concentration
calculations agree within 6% with field observations. For a future VOC
increase of 50% we predict a particle mass increase due to SOA of 19%
assuming today's mass contribution of pre-existing aerosol and oxidant
levels. |
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