Large estragole fluxes from oil palms in Borneo
Large estragole fluxes from oil palms in Borneo
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DOI：
10.5194/acp-10-4343-2010
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发表时间：
2010-01-01
影响因子：
6.3
通讯作者：
Cape, J. N.
中科院分区：
文献类型：
--
作者：
Misztal, P. K.;Owen, S. M.;Cape, J. N.
在两次实地活动中（OP 3和ACES），2008年在婆罗洲运行，（甲基chavicol; IUPAC系统名1-烯丙基-4-甲氧基苯;化学文摘社编号：140-67-0）（0.81 mg m（-2）h（-1）和3.2 ppbv的平均中午通量和混合比分别）和随后从花围。然而，我们没有在附近的雨林中检测到这种化合物。雌酮是非洲油棕榈象甲（Elaeidobius kamerunicus）的一种已知引诱剂，该象甲为油棕榈（Elaeis guineensis）授粉。近来人们对草唑的生物源排放产生了兴趣，但它通常不包括在生物源排放和大气化学的大气模型中，尽管它具有较高的光氧化二次有机气溶胶形成潜力，并且与OH自由基具有较高的反应性。我们报告的第一个直接冠层尺度的测量，从热带油棕榈的虚拟间断涡动协方差技术和比较，与以前报道的数据，从黄松的雌酮排放量。花，而不是叶子，似乎是从油棕的主要来源，我们得到一个全球估计的雌蒿甲醚排放量从油棕种植园类似的0.5 Tg y（-1）。观测到的生态系统平均通量（0.44毫克米（-2）小时（-1））和平均环境体积混合比（3.0 ppbv）的草唑是迄今为止最高的报告。中午混合比的值与总平均值相差不大，因为与其他VOC（例如异戊二烯）不同，主峰发生在晚上而不是中午。尽管如此，我们表明，可以使用修改后的G 06算法的排放参数化的estragole通量。然而，该模型低估了下午的峰值，即使类似的方法对异戊二烯很有效。我们的测量结果表明，这种生物源化合物可能会对区域大气化学产生影响，以前没有考虑在模型中，并可能在未来变得更加重要，由于油棕种植园面积的扩大。
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 similar to 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.