Evidence for a significant proportion of Secondary Organic Aerosol from isoprene above a maritime tropical forest
Evidence for a significant proportion of Secondary Organic Aerosol from isoprene above a maritime tropical forest
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DOI：
10.5194/acp-11-1039-2011
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发表时间：
2011-01-01
影响因子：
6.3
通讯作者：
Coe, H.
中科院分区：
文献类型：
--
作者：
Robinson, N. H.;Hamilton, J. F.;Coe, H.
异戊二烯是最丰富的非甲烷生物源挥发性有机化合物（BVOC），但从异戊二烯氧化二次有机气溶胶（SOA）形成的过程才刚刚开始被理解和选择性量化的大气颗粒物负担仍然很困难。在2008年夏季，使用气溶胶质谱和离线详细表征，使用全面的二维气相色谱法研究了位于马来西亚婆罗洲丹浓谷，异戊二烯高排放区的热带雨林上方的有机气溶胶。观测结果表明，大气亚微米有机气溶胶中有相当一部分（质量分数高达15%）在热解吸后被观测为甲基呋喃（MF）。这一观察与建立气相异戊二烯氧化产物甲基乙烯基酮（MVK）和甲基丙烯醛（MACR）的同时测量。在异戊二烯的实验室氧化过程中也进行了MF的观察。正矩阵分解的AMS有机质谱时间序列产生了一个强大的因素，占平均23%（0.18 μ g m（-3）），达到高达53%（0.50 μ g m（-3））的总有机负载，确定（和高度相关）的强MF信号。假设该因子通常代表异戊二烯SOA，则异戊二烯衍生气溶胶在该区域起着重要作用。与其他研究的测量结果比较表明，这种类型的异戊二烯SOA在其他异戊二烯占主导地位的环境中发挥作用，尽管具有不同的意义。
Isoprene is the most abundant non-methane biogenic volatile organic compound (BVOC), but the processes governing secondary organic aerosol (SOA) formation from isoprene oxidation are only beginning to become understood and selective quantification of the atmospheric particulate burden remains difficult. Organic aerosol above a tropical rainforest located in Danum Valley, Borneo, Malaysia, a high isoprene emission region, was studied during Summer 2008 using Aerosol Mass Spectrometry and offline detailed characterisation using comprehensive two dimensional gas chromatography. Observations indicate that a substantial fraction (up to 15% by mass) of atmospheric sub-micron organic aerosol was observed as rnethylfuran (MF) after thermal desorption. This observation was associated with the simultaneous measurements of established gas-phase isoprene oxidation products methylvinylketone (MVK) and methacrolein (MACR). Observations of MF were also made during experimental chamber oxidation of isoprene. Positive matrix factorisation of the AMS organic mass spectral time series produced a robust factor which accounts for an average of 23% (0.18 mu g m(-3)), reaching as much as 53% (0.50 mu g m(-3)) of the total oraganic loading, identified by (and highly correlated with) a strong MF signal. Assuming that this factor is generally representative of isoprene SOA, isoprene derived aerosol plays a significant role in the region. Comparisons with measurements from other studies suggest this type of isoprene SOA plays a role in other isoprene dominated environments, albeit with varying significance.