Formation and Evolution of aqSOA from Aqueous-Phase Reactions of Phenolic Carbonyls: Comparison between Ammonium Sulfate and Ammonium Nitrate Solutions
Formation and Evolution of aqSOA from Aqueous-Phase Reactions of Phenolic Carbonyls: Comparison between Ammonium Sulfate and Ammonium Nitrate Solutions
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DOI：
10.1021/acs.est.8b03441
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发表时间：
2018-08-21
影响因子：
11.4
通讯作者：
Chan, Chak K.
中科院分区：
文献类型：
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作者：
Huang, Dan Dan;Zhang, Qi;Chan, Chak K.
我们调查硫酸盐和硝酸盐对二次有机气溶胶的形成和演变的水相（aqSOA）从光氧化的两个酚羰基从木材燃烧排放的影响。在硫酸铵和硝酸铵溶液中，甘草醛（C_9H_10O_4）和乙酰甘草酮（C_10H_12O_4）均能有效地光氧化生成aqSOA，质量产率为30%~ 120%。通过气溶胶质谱仪获得的有机质谱上的正矩阵分解揭示了aqSOA的化学演变中的官能化、低聚化和碎片化过程的组合。官能化和低聚反应占主导地位，在第一个4小时的反应，酚低聚物及其衍生物显着有助于aqSOA的形成，和氧化的第一代产品导致了丰富的含氧开环产品。在硝酸盐溶液中的降解率的双甘醛和乙酰双甘酮的1.5和3.5倍，比在硫酸盐溶液中的速率快，和aqSOA产量在硝酸盐实验中的两倍高，在硫酸盐实验。硝酸盐可能促进了反应，因为它是OH自由基的光解源，而硫酸盐不是，突出了气溶胶相硝酸盐通过促进有机前体的光氧化在aqSOA形成中的重要性。
We investigate the effects of sulfate and nitrate on the formation and evolution of secondary organic aerosol formed in the aqueous phase (aqSOA) from photooxidation of two phenolic carbonyls emitted from wood burning. aqSOA was formed efficiently from the photooxidation of both syringaldehyde (C9H10O4) and acetosyringone (C10H12O4) in ammonium sulfate and ammonium nitrate solutions, with mass yields ranging from 30% to 120%. Positive matrix factorization on the organic mass spectra acquired by an Aerosol Mass Spectrometer revealed a combination of functionalization, oligomerization, and fragmentation processes in the chemical evolution of aqSOA. Functionalization and oligomerization dominated in the first 4 h of reaction, with phenolic oligomers and their derivatives significantly contributing to aqSOA formation; and oxidation of the first-generation products led to an abundance of oxygenated ring-opening products. Degradation rates of syringaldehyde and acetosyringone in nitrate solutions were 1.5 and 3.5 times faster than rates in sulfate solutions, and aqSOA yields in nitrate experiments are twice as high as in sulfate experiments. Nitrate likely promoted the reactions because it is a photolytic source of OH radicals, while sulfate is not, highlighting the importance of aerosol-phase nitrate in the formation of aqSOA by facilitating the photooxidation of organic precursors.