Secondary organic aerosol formation and composition from the photo-oxidation of methyl chavicol (estragole)
Secondary organic aerosol formation and composition from the photo-oxidation of methyl chavicol (estragole)
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DOI：
10.5194/acp-14-5349-2014
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发表时间：
2013-12
影响因子：
6.3
通讯作者：
K. L. Pereira;J. Hamilton;A. Rickard;W. Bloss;M. S. Alam;M. Camredon;Amalia Muñoz;M. Vázquez;E. Borrás;M. Ródenas
中科院分区：
文献类型：
--
作者：
K. L. Pereira;J. Hamilton;A. Rickard;W. Bloss;M. S. Alam;M. Camredon;Amalia Muñoz;M. Vázquez;E. Borrás;M. Ródenas
抽象的。棕榈油用于生物燃料和食品的需求不断增加，导致油棕农业迅速扩张。甲基chavicol（也称为estragole和1-烯丙基-4-甲氧基苯）是一种氧化的生物挥发性有机化合物（VOC），最近被确定为马来西亚婆罗洲油棕种植园的主要花卉排放物。观测到的甲基胡椒酚的排放可能会影响区域大气化学，但对其形成二次有机气溶胶（SOA）的能力知之甚少。作为甲基胡椒酚大气化学（ATMECH）项目的一部分，在欧洲光反应器室中研究了甲基胡椒酚的光氧化。气溶胶样品使用颗粒进入液体采样器（PILS）收集，并使用广泛的仪器进行离线分析，包括：高效液相色谱质谱（HPLC-ITMS），高效液相色谱四极杆飞行时间质谱（HPLC-QTOFMS）和傅里叶变换离子回旋共振质谱（FTICR-MS）。对于212和460 ppbv（十亿分之一体积）的初始VOC混合比，SOA产率分别确定为18和29%;使用约5：1的VOC：NOx比。总共观察到59种SOA化合物，并使用高分辨率串联质谱鉴定了10种化合物的结构。羟基和/或硝基官能团的芳香环的加成似乎是气溶胶形成的重要机理途径。这导致形成具有低挥发性和高O：C比的化合物，其中由于环的稳定性，主要观察到官能化而不是片段化。所观察到的SOA物质可以被表征为半挥发性至低挥发性的含氧有机气溶胶（SVOOA和LVOOA）组分，因此在气溶胶形成和生长中可能是重要的。
Abstract. The increasing demand for palm oil for uses in biofuel and food products is leading to rapid expansion of oil palm agriculture. Methyl chavicol (also known as estragole and 1-allyl-4-methoxybenzene) is an oxygenated biogenic volatile organic compound (VOC) that was recently identified as the main floral emission from an oil palm plantation in Malaysian Borneo. The emissions of methyl chavicol observed may impact regional atmospheric chemistry, but little is known of its ability to form secondary organic aerosol (SOA). The photo-oxidation of methyl chavicol was investigated at the European Photoreactor chamber as a part of the atmospheric chemistry of methyl chavicol (ATMECH) project. Aerosol samples were collected using a particle into liquid sampler (PILS) and analysed offline using an extensive range of instruments including; high-performance liquid chromatography mass spectrometry (HPLC-ITMS), high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-QTOFMS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The SOA yield was determined as 18 and 29% for an initial VOC mixing ratio of 212 and 460 ppbv (parts per billion by volume) respectively; using a VOC:NOx ratio of ~5:1. In total, 59 SOA compounds were observed and the structures of 10 compounds have been identified using high-resolution tandem mass spectrometry. The addition of hydroxyl and/or nitro-functional groups to the aromatic ring appears to be an important mechanistic pathway for aerosol formation. This results in the formation of compounds with both low volatility and high O:C ratios, where functionalisation rather than fragmentation is mainly observed as a result of the stability of the ring. The SOA species observed can be characterised as semi-volatile to low-volatility oxygenated organic aerosol (SVOOA and LVOOA) components and therefore may be important in aerosol formation and growth.