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| Titel |
Large estragole fluxes from oil palms in Borneo |
| VerfasserIn |
P. K. Misztal, S. M. Owen, A. B. Guenther, R. Rasmussen, C. Geron, P. Harley, G. J. Phillips, A. Ryan, D. P. Edwards, C. N. Hewitt, E. Nemitz, J. Siong, M. R. Heal, J. N. Cape |
| 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 ; 10, no. 9 ; Nr. 10, no. 9 (2010-05-07), S.4343-4358 |
| Datensatznummer |
250008432
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| Publikation (Nr.) |
 copernicus.org/acp-10-4343-2010.pdf |
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| Zusammenfassung |
| During two field campaigns (OP3 and ACES), which ran in Borneo in 2008, we
measured large emissions of estragole (methyl chavicol; IUPAC systematic
name 1-allyl-4-methoxybenzene; CAS number 140-67-0) in ambient air above oil
palm canopies (0.81 mg m−2 h−1 and 3.2 ppbv for mean midday fluxes
and mixing ratios respectively) and subsequently from flower enclosures.
However, we did not detect this compound at a nearby rainforest. Estragole
is a known attractant of the African oil palm weevil (Elaeidobius kamerunicus), which pollinates
oil palms (Elaeis guineensis). There has been recent interest in the biogenic emissions of
estragole but it is normally not included in atmospheric models of biogenic
emissions and atmospheric chemistry despite its relatively high potential
for secondary organic aerosol formation from photooxidation and high
reactivity with OH radical. We report the first direct canopy-scale
measurements of estragole fluxes from tropical oil palms by the virtual
disjunct eddy covariance technique and compare them with previously reported
data for estragole emissions from Ponderosa pine. Flowers, rather than
leaves, appear to be the main source of estragole from oil palms; we derive
a global estimate of estragole emissions from oil palm plantations of ~0.5 Tg y−1. The observed ecosystem mean fluxes (0.44 mg m−2 h−1)
and mean ambient volume mixing ratios (3.0 ppbv) of estragole are
the highest reported so far. The value for midday mixing ratios is not much
different from the total average as, unlike other VOCs (e.g. isoprene), the
main peak occurred in the evening rather than in the middle of the day.
Despite this, we show that the estragole flux can be parameterised using a modified
G06 algorithm for emission. However, the model underestimates the afternoon
peak even though a similar approach works well for isoprene. Our
measurements suggest that this biogenic compound may have an impact on
regional atmospheric chemistry that previously has not been accounted for in
models and could become more important in the future due to expansion of the
areas of oil palm plantation. |
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