Gas-phase products and secondary aerosol yields from the photooxidation of 16 different terpenes
Gas-phase products and secondary aerosol yields from the photooxidation of 16 different terpenes
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DOI：
10.1029/2006jd007050
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发表时间：
2006-09-07
影响因子：
4.4
通讯作者：
Seinfeld, John H.
中科院分区：
文献类型：
--
作者：
Lee, Anita;Goldstein, Allen H.;Seinfeld, John H.
[1] 异戊二烯、八种单萜、三种氧化单萜和四种倍半萜的光氧化是在加州理工学院室内室设施中在大气相关的 HC: NOx 比率下单独进行的，以使用 PTR-MS 监测 SOA 和气相氧化产物的时间演变和产率。在PTR-MS中校准了多种氧化产物，包括甲醛、乙醛、甲酸、丙酮、乙酸、诺皮酮、异丁烯醛+甲基乙烯基酮；其他氧化产物是从已知的碎片模式推断出来的，例如蒎醛；和其他产物根据质荷比 (m/z) 进行鉴定。形成了众多的不明产物，第一代、第二代产物的演化过程清晰可见。不同萜烯的 SOA 产率范围为 1% 至 68%，总气相加颗粒相产物约占反应碳的 50% - 100%。倍半萜烯的碳质量平衡最差，这表明观察到的产物被低估，或者形成了额外的产物但 PTR-MS 未检测到。检测到了异戊二烯光氧化的几种第二代产物，包括 m/z 113 以及对应于乙醇醛、羟基丙酮、甲基乙二醛和羟基羰基的离子。已识别和未识别产物的详细时间序列和相对产率有助于阐明未识别产物的反应途径和结构。在黄松人工林的树冠内部和上方也观察到了这些实验中的许多未识别产物，证实可以使用 PTR-MS 在环境空气中检测到许多萜烯氧化产物，并且表明同时存在 SOA 形成。
[ 1] The photooxidation of isoprene, eight monoterpenes, three oxygenated monoterpenes, and four sesquiterpenes were conducted individually at the Caltech Indoor Chamber Facility under atmospherically relevant HC: NOx ratios to monitor the time evolution and yields of SOA and gas-phase oxidation products using PTR-MS. Several oxidation products were calibrated in the PTR-MS, including formaldehyde, acetaldehyde, formic acid, acetone, acetic acid, nopinone, methacrolein + methyl vinyl ketone; other oxidation products were inferred from known fragmentation patterns, such as pinonaldehyde; and other products were identified according to their mass to charge (m/z) ratio. Numerous unidentified products were formed, and the evolution of first- and second-generation products was clearly observed. SOA yields from the different terpenes ranged from 1 to 68%, and the total gas-plus particle-phase products accounted for similar to 50 - 100% of the reacted carbon. The carbon mass balance was poorest for the sesquiterpenes, suggesting that the observed products were underestimated or that additional products were formed but not detected by PTR-MS. Several second-generation products from isoprene photooxidation, including m/z 113, and ions corresponding to glycolaldehyde, hydroxyacetone, methylglyoxal, and hydroxycarbonyls, were detected. The detailed time series and relative yields of identified and unidentified products aid in elucidating reaction pathways and structures for the unidentified products. Many of the unidentified products from these experiments were also observed within and above the canopy of a Ponderosa pine plantation, confirming that many products of terpene oxidation can be detected in ambient air using PTR-MS, and are indicative of concurrent SOA formation.