Monoterpene SOA – Contribution of first-generation oxidation products to formation and chemical composition
Monoterpene SOA – Contribution of first-generation oxidation products to formation and chemical composition
复制标题
DOI：
10.1016/j.atmosenv.2015.10.080
复制
发表时间：
2016-04
影响因子：
5
通讯作者：
A. Mutzel;M. Rodigast;Y. Iinuma;O. Böge;H. Herrmann
中科院分区：
文献类型：
--
作者：
A. Mutzel;M. Rodigast;Y. Iinuma;O. Böge;H. Herrmann
对第一代萜烯氧化产物的连续反应的研究为二次有机气溶胶(SOA)的形成提供了洞察力。为此，我们考察了与α-品烯、β-品烯和柠檬烯的OH自由基反应，以及作为β-品烯氧化产物的诺品酮和作为α-品烯氧化产物的品红醛和桃金娘烯醛的OH-氧化反应。β-蒎烯的SOA产率(0.50)远高于α-Pinene(0.35)和柠檬烯/OH体系(0.30)。这与文献中描述的臭氧分解SOA的产率相反。β-Pinene的生长曲线表明了二次反应的贡献，如诺酮的二次反应。这一贡献(17%)和诺皮酮的高SOA产率(0.24%)可能导致了观察到的β-Pinene的高SOA形成潜力。从β-蒎烯中观察到的大部分C90氧化产物可以归因于诺皮酮的连续反应，而在蒎醛中，只有少数α-Pinene氧化产物被鉴定出来。在β-Pinene氧化过程中，诺皮酮对松酸(51%)、高松油酸(74%)和3-甲基-1，2，3-丁烷-三羧酸(MBTCA，88%)的生成有显著贡献。松醛的氧化预计会产生重要的SOA标志物，但只确定了微不足道的量。这表明它们的形成必须通过不同的途径进行，而不是通过α-Pinene的进一步氧化。在α-蒎烯氧化反应中，只有较多的松烯酸和甲基叔丁基三氯乙酸生成，产率为57%，而松醛/OH反应的产率为33%。缺少重要的SOA标记化合物可能是导致松醛的SOA产率较低(0.07)的原因。基于较低的辛烯酸产率，α-蒎烯辛酸的贡献仅为4.5%。在α-蒎烯氧化的气相产物中鉴定出桃金娘烯醛。大多数α-Pinene SOA标记化合物确实是由桃金娘烯醛氧化形成的，特别是叔丁酸(84%)、品酸(76%)和二烯酸醋酸酯(DTAA；40%)。一般来说，桃金娘醛对α-Pinene SOA的贡献率估计高达23%。在检测到的化合物中，高松油酸被确认为一种新的标记化合物，它是由β-Pinene/OH和诺皮酮/OH形成的，而不是由α-Pinene/OH形成。在由诺皮酮氧化形成的β-Pinene/OH体系中，还发现了一条新的生成MBTCA的反应途径，而在α-Pinene体系中，由松醛氧化生成了MBTCA。
Investigation of the consecutive reactions of first-generation terpene oxidation products provides insight into the formation of secondary organic aerosol (SOA). To this end, OH radical reactions with α-pinene, β-pinene, and limonene were examined along with the OH-oxidation of nopinone as a β-pinene oxidation product and pinonaldehyde and myrtenal as α-pinene oxidation products. The SOA yield of β-pinene (0.50) was much higher than that of α-pinene (0.35) and the limonene/OH system (0.30). This is opposite to the ozonolysis SOA yields described in the literature. The growth curve of SOA from β-pinene shows the contribution of secondary reactions, such as further reaction of nopinone. This contribution (17%) and the high SOA yield of nopinone (0.24) might lead to the high SOA formation potential observed for β-pinene. The majority of the C9oxidation products observed from β-pinene can be attributed to the consecutive reaction of nopinone, whereas in the case of pinonaldehyde, only a few α-pinene oxidation products were identified. Nopinone contributes significantly to the formation of pinic acid (51%), homoterpenylic acid (74%), and 3-methyl-1,2,3-butane-tricarboxylic acid (MBTCA, 88%) during β-pinene oxidation. The oxidation of pinonaldehyde was expected to produce important SOA markers, but only negligible amounts were identified. This indicates that their formation by oxidation of α-pinene must proceed via different pathways from the further oxidation of pinonaldehyde. Only pinonic acid and MBTCA were found in considerable amounts and were formed in α-pinene oxidation with 57% yield, while that for the pinonaldehyde/OH reaction was 33%. The lack of important SOA marker compounds might cause the low SOA yield (0.07) observed for pinonaldehyde. Based on the low SOA yield, pinonaldehyde contributes only 4.5% to α-pinene SOA. Myrtenal was identified among the gas-phase products of α-pinene oxidation. A majority of α-pinene SOA marker compounds was indeed formed by myrtenal oxidation, especially terebic acid (84%), pinic acid (76%), and diaterpenylic acid acetate (DTAA; 40%). In general, the contribution of myrtenal to α-pinene SOA is estimated to be as high as 23%. Among the detected compounds, homoterpenylic acid was positively identified as a new SOA marker compound, which was formed from β-pinene/OH and nopinone/OH but not from α-pinene/OH. A new reaction pathway yielding MBTCA was also identified in the β-pinene/OH system formed by the oxidation of nopinone, while in the case of α-pinene, the oxidation of pinonaldehyde yielded MBTCA.