Chemical Composition and Optical Properties of Secondary Organic Aerosol from Photooxidation of Volatile Organic Compound Mixtures
Chemical Composition and Optical Properties of Secondary Organic Aerosol from Photooxidation of Volatile Organic Compound Mixtures
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DOI：
10.1021/acsestair.3c00041
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发表时间：
2024-02
期刊：
影响因子：
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通讯作者：
Yumeng Cui;Kunpeng Chen;Haofei Zhang;Y. Lin;Roya Bahreini
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作者：
Yumeng Cui;Kunpeng Chen;Haofei Zhang;Y. Lin;Roya Bahreini
二次有机气溶胶（SOA）的化学和光学特性已通过环境箱实验得到广泛研究，部分结果已在大气模式中参数化，以帮助理解其辐射效应和气候影响。虽然大多数室的研究调查气溶胶形成的一个单一的挥发性有机化合物（VOC），来自VOC混合物的反应性中间体之间的潜在相互作用还没有得到很好的理解。在这项研究中，我们研究了SOA形成的纯和混合物的人为（苯酚和1-甲基萘）和/或生物（长叶烯）挥发性有机化合物使用连续流，高氮氧化物的光氧化室实验，以更好地模拟环境条件。SOA的光学性质，包括单次散射散射（SSA），质量吸收系数（MAC），和折射率（RI）在375 nm处，和化学组成，包括含氧有机化合物，有机氮化合物（包括有机硝酸盐和硝基有机物）的形成，和主要发色团的分子结构，进行了探索。此外，在多VOC系统中的SOA的虚折射率值预测使用线性组合的假设，并与测量值进行了比较。当两种挥发性有机化合物同时氧化时，我们发现SOA的化学组成发生了变化，这一变化导致了SOA光学特性的非线性效应。不同的系统之间的非线性效应不同。
The chemical and optical properties of secondary organic aerosols (SOA) have been widely studied through environmental chamber experiments, and some of the results have been parametrized in atmospheric models to help understand their radiative effects and climate influence. While most chamber studies investigate the aerosol formed from a single volatile organic compound (VOC), the potential interactions between reactive intermediates derived from VOC mixtures are not well understood. In this study, we investigated the SOA formed from pure and mixtures of anthropogenic (phenol and 1-methylnaphthalene) and/or biogenic (longifolene) VOCs using continuous-flow, high-NOx photooxidation chamber experiments to better mimic ambient conditions. SOA optical properties, including single scattering albedo (SSA), mass absorption coefficient (MAC), and refractive index (RI) at 375 nm, and chemical composition, including the formation of oxygenated organic compounds, organic-nitrogen compounds (including organonitrates and nitro-organics), and the molecular structure of the major chromophores, were explored. Additionally, the imaginary refractive index values of SOA in the multi-VOC system were predicted using a linear-combination assumption and compared with the measured values. When two VOCs were oxidized simultaneously, we found evidence for changes in SOA chemical composition compared to SOA formed from single-VOC systems, and this change led to nonlinear effects on SOA optical properties. The nonlinear effects were found to vary between different systems.