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| Titel |
Oil palm BVOC emissions and their potential for aerosol formation |
| VerfasserIn |
Pawel K. Misztal, Eiko Nemitz, J. Neil Cape, Ben Langford, Gavin J. Phillips, Chiara DiMarco, Mhairi Coyle, Susan Owen, Mathew R. Heal, C. Nicholas Hewitt |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250040485
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| Zusammenfassung |
| During ambient measurements at oil palm plantation (OP3/ACES projects) which took place
from May to June 2008 we recorded by direct eddy covariance technique with proton transfer
reaction mass spectrometry (PTR-MS) large emission fluxes of isoprene (mid-day mean 8.6
mg m-2 h-1), estragole (0.81 mg m-2 h-1), acetone (0.1 mg m-2 h-1), hexanals (0.05 mg
m-2 h-1) and remaining compounds (~ 1 mg m-2 h-1). However, secondary products of
isoprene oxidation such as MVK+MACR exhibited high deposition rates (1 cm
s-1) which were close to maximal theoretical values. In addition, methanol and,
to some extent, other VOC compounds exhibited negative fluxes during the day.
Despite several times higher emissions of isoprene from oil palm than from a nearby
rainforest, it is uncertain how these differences would impact on the formation of
aerosols. There have been recently many speculations about actual contribution of
isoprene emissions to aerosol formation, for example whether they could inhibit the
creation of aerosols due to scavenging of hydroxyl radicals, in contradiction to
an earlier OH-radical recycling hypothesis. Regardless, mass aerosol yields from
isoprene have been thought low (up to ~2%), which can however make up significant
overall loading at large emissions such as encountered at oil palm. Although oil palm
was not found to be a monoterpene emitter, it appears that the largest contributor
to aerosol production from oil palms might be floral emissions of estragole with
its aerosol yield from photooxidation of this compound being similar to that of
monoterpenes (~40%). In addition, other VOCs might have also an effect. We show the
parameterisation for emission and deposition of particular VOCs and relate them to
aerosol yields found in literature. Overall, it seems that the net aerosol formation
potential with regards to VOCs emitted from oil palm may not be much different to
that of rainforest, despite differences in the VOC mix emitted by these land uses. |
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