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| Titel |
Chemical composition and microphysical properties of secondary organic aerosols from tree emissions |
| VerfasserIn |
Angela Buchholz, Thomas Mentel, Astrid Kiendler-Scharr, Florian Rubach, Christian Spindler, Ralf Tillmann, Einhard Kleist, Jürgen Wildt |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046459
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| Zusammenfassung |
| Plant emitted volatile organic compounds (VOCs) are a major precursor of secondary organic
aerosols (SOA), an important constituent of atmospheric aerosols. We used the Juelich Plant
Atmosphere Chamber (JPAC) at the Research Center Juelich to investigate the microphysical
properties of aerosols. SOA particles were produced from the ozonolysis and reaction of OH
radicals with the complex VOC mixture emitted from trees typical for the boreal forest.
Hygroscopic growth factors (GF) were determined with a humidity tandem differential
mobility analyzer (HTDMA) for different particle sizes at RH = 2 - 97%. Cloud
condensation nuclei (CCN) activation was measured with a continuous flow CCN counter
(DMT). The chemical composition of the particles was determined with a High
Resolution ToF AMS. Additionally, the size distribution and number concentration
of the particles were measured. The gas phase was monitored with GC-MS and
PTR-MS.
Changing the emission pattern and strength changed the measured GF and the diameter of
the dry particles that were activated (D50). However, below 80% RH the GF changes are
within the range of the measurement error. The GF(RHÂ =Â 90%) were between 1.03 and 1.14,
and the D50(SS = 0.4%) in a range of 93 - 100nm. The average hygroscopicity parameter κ
(calculated according to Petters and Kreidenweis, 2007) was 0.03±0.01 at RHÂ =Â 90% and
0.08±0.02 at activation.
The aerosol mass spectra measured with the HR-Tof-AMS were analysed with positive
matrix factorisation (PMF). The contributions of the identified factors were correlated with
the detailed κ values.
Reference: Petters, M. D. and Kreidenweis, S. M. (2007). Atmos. Chem. Phys., 7,
1961-1971. |
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