Laboratory study of aging of secondary organic aerosol formed from the photooxidation of aromatic hydrocarbons

在偏远地区观测到的含氧有机气溶胶（OOA）被认为包括老化的二次有机气溶胶（SOA）；然而，与SOA化学老化相关的反应过程迄今尚不清楚。我们使用气溶胶质谱、液相色谱/质谱和碘量分光光度法分析了芳香烃光氧化形成的SOA颗粒。这些结果表明，SOA老化主要是通过羧酸的形成进行的，并且在实验室室中SOA老化的速度受到酮基氧化的限制。

Oxygenated organic aerosol(OOA) observed in remote areas is believed to comprise aged secondary organic aerosol(SOA); however, the reaction processes relevant to SOA chemical aging have hitherto been unclear. We analyzed SOA particles formed from the photooxidation of aromatic hydrocarbons using an Aerosol mass spectrometry, liquid chromatography/mass spectrometry, and iodometric spectrophotometry. These results indicate that SOA aging proceeds mainly by formation of carboxylic acids, and that the rate of SOA aging in laboratory chambers is limited by the oxidation of ketone groups.