Bernard F, Ciuraru R, Boréave A, George C
Univ Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, F-69626, Villeurbanne, France.
Environ Sci Technol. 2016 Aug 16;50(16):8678-86. doi: 10.1021/acs.est.6b03520. Epub 2016 Aug 4.
In this study, we evaluated photosensitized chemistry at the air-sea interface as a source of secondary organic aerosols (SOA). Our results show that, in addition to biogenic emissions, abiotic processes could also be important in the marine boundary layer. Photosensitized production of marine secondary organic aerosol was studied in a custom-built multiphase atmospheric simulation chamber. The experimental chamber contained water, humic acid (1-10 mg L(-1)) as a proxy for dissolved organic matter, and nonanoic acid (0.1-10 mM), a fatty acid proxy which formed an organic film at the air-water interface. Dark secondary reaction with ozone after illumination resulted in SOA particle concentrations in excess of 1000 cm(-3), illustrating the production of unsaturated compounds by chemical reactions at the air-water interface. SOA numbers via photosensitization alone and in the absence of ozone did not exceed background levels. From these results, we derived a dependence of SOA numbers on nonanoic acid surface coverage and dissolved organic matter concentration. We present a discussion on the potential role of the air-sea interface in the production of atmospheric organic aerosol from photosensitized origins.
在本研究中，我们评估了作为二次有机气溶胶（SOA）来源的海 - 气界面处的光敏化学过程。我们的结果表明，除了生物源排放外，非生物过程在海洋边界层中也可能很重要。在一个定制的多相大气模拟室中研究了海洋二次有机气溶胶的光敏生成过程。实验室内含有水、作为溶解有机物替代物的腐殖酸（1 - 10 mg L(-1)）以及壬酸（0.1 - 10 mM），壬酸是一种脂肪酸替代物，在气 - 水界面形成有机膜。光照后与臭氧的暗二次反应导致SOA颗粒浓度超过1000 cm(-3)，这表明在气 - 水界面通过化学反应生成了不饱和化合物。仅通过光敏作用且在没有臭氧的情况下，SOA数量未超过背景水平。根据这些结果，我们得出了SOA数量对壬酸表面覆盖率和溶解有机物浓度的依赖性。我们讨论了海 - 气界面在由光敏源产生大气有机气溶胶过程中的潜在作用。
