Ambient Measurements of Highly Oxidized Gas-Phase Molecules during the Southern Oxidant and Aerosol Study (SOAS) 2013
Ambient Measurements of Highly Oxidized Gas-Phase Molecules during the Southern Oxidant and Aerosol Study (SOAS) 2013
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DOI：
10.1021/acsearthspacechem.8b00028
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发表时间：
2018-07-01
影响因子：
3.4
通讯作者：
Worsnop, Douglas R.
中科院分区：
文献类型：
--
作者：
Massoli, Paola;Stark, Harald;Worsnop, Douglas R.
用高分辨率硝酸根离子飞行时间化学电离质谱仪(NO3-CIMS)对气相中的高氧化多功能分子(HOMS)进行了测量。这些测量是在2013年南方氧化剂和气溶胶研究(SOAS 2013)期间在阿拉巴马州的一个森林地点进行的，那里的排放主要是生物来源的挥发性有机化合物(BVOC)。主要的BVOC排放是由混合了各种萜类的异戊二烯表示的，与以前在单萜类为主的环境中部署N3-CIMS相比，使其成为一个独特的采样地点。在2013年的SOAS期间，NO3-CIMS检测到氧碳(O：C)比在0.5到1.4之间的HOM，这些HOM来自异戊二烯(C-5)和单萜烯(C-10)，以及另外数百个碳数在C-3和C-20之间的HOM。我们使用正矩阵分解(PMF)对复杂的数据集进行去卷积，并提取具有相似时间趋势的HOM类的信息。这一分析揭示了三个以异戊二烯为主的PMF因素和三个以单萜为主的PMF因素。在大多数因素中，我们观察到大量的异戊二烯和单萜烯衍生的有机硝酸酯(ONS)。ONS的大量存在与之前的研究一致，这些研究强调了NOx驱动的化学在该地点的重要性。异戊二烯占主导地位的一个因素与可能来自附近燃煤电厂的SO2羽流有很强的相关性，并且主要是来自(C5H10N2O8)的异戊二烯。这些结果表明，人为排放对该地区BVOC排放形成低挥发性化合物起到了重要作用。
We present measurements of highly oxidized multifunctional molecules (HOMs) detected in the gas phase using a high-resolution time-of flight chemical ionization mass spectrometer with nitrate reagent ion (NO3- CIMS). The measurements took place during the 2013 Southern Oxidant and Aerosol Study (SOAS 2013) at a forest site in Alabama, where emissions were dominated by biogenic volatile organic compounds (BVOCs). Primary BVOC emissions were represented by isoprene mixed with various terpenes, making it a unique sampling location compared to previous NO3- CIMS deployments in monoterpene-dominated environments. During SOAS 2013, the NO3- CIMS detected HOMs with oxygen-to-carbon (O:C) ratios between 0.5 and 1.4 originating from both isoprene (C-5) and monoterpenes (C-10) as well as hundreds of additional HOMs with carbon numbers between C-3 and C-20. We used positive matrix factorization (PMF) to deconvolve the complex data set and extract information about classes of HOMs with similar temporal trends. This analysis revealed three isoprene-dominated and three monoterpene-dominated PMF factors. We observed significant amounts of isoprene- and monoterpene-derived organic nitrates (ONs) in most factors. The abundant presence of ONs was consistent with previous studies that have highlighted the importance of NOx-driven chemistry at the site. One of the isoprene-dominated factors had a strong correlation with SO2 plumes likely advected from nearby coal-fired power plants and was dominated by an isoprene derived ON (C5H10N2O8). These results indicate that anthropogenic emissions played a significant role in the formation of low volatility compounds from BVOC emissions in the region.