Stability of α-Pinene and d -Limonene Ozonolysis Secondary Organic Aerosol Compounds Toward Hydrolysis and Hydration
Stability of α-Pinene and d -Limonene Ozonolysis Secondary Organic Aerosol Compounds Toward Hydrolysis and Hydration
复制标题
α-蒎烯和 d-柠檬烯臭氧分解二次有机气溶胶化合物对水解和水合的稳定性
DOI：
10.1021/acsearthspacechem.1c00171
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发表时间：
2021
影响因子：
3.4
通讯作者：
Nizkorodov, Sergey A.
中科院分区：
文献类型：
--
作者：
Wong, Cynthia;Vite, Daniel;Nizkorodov, Sergey A.
二次有机气溶胶（SOA）是挥发性有机化合物（VOCs）经气相氧化后形成的，可在大气中停留数天，有时甚至数周。SOA的形成迅速，通常在VOC排放后的几个小时内，然后SOA在大气中的整个生命周期中可以经历慢得多的物理和化学过程。水，以水蒸气，气溶胶液态水，云和雾的形式，可以通过改变形成和短期老化机制强烈影响SOA的组成;然而，水如何影响长期SOA老化知之甚少。本工作的目的是系统地探讨长期老化过程中水对α-蒎烯和d-柠檬烯SOA化学组成的影响。SOA样品在氧化流动反应器中产生，并收集在箔衬底上。样品在97%相对湿度的水蒸气中老化7-14天或在水溶液中老化1-2天，然后用直接注入电喷雾电离高分辨率质谱法分析，以深入了解老化前后SOA的化学组成。对峰强度和观察到的分子式的模式进行了检查，以获得水驱动化学的证据。我们发现，在长期暴露于水蒸气和液态水的过程中，SOA的化学成分确实发生了变化，但变化的程度出奇的小。这表明与所研究的单萜SOA的其他老化机制相比，暴露于水不是长期老化过程的强驱动因素。
Secondary organic aerosol (SOA), formed through the gas-phase oxidation of volatile organic compounds (VOCs), can reside in the atmosphere for several days and sometimes for weeks. The formation of SOA takes place rapidly, often within hours after VOC emissions, and SOA can then undergo much slower physical and chemical processes throughout its lifetime in the atmosphere. Water, in the form of water vapor, aerosol liquid water, and cloud and fogwater, can strongly impact the composition of SOA by altering formation and short-term aging mechanisms; however, less is known about how water impacts long-term SOA aging. The goal of this work is to systematically explore the effects of water on the chemical composition of α-pinene andd-limonene SOA during long-term aging processes. SOA samples were generated in an oxidation flow reactor and collected on foil substrates. Samples were aged in the presence of water vapor at 97% relative humidity for 7–14 days or an aqueous solution for 1–2 days, then analyzed with direct infusion electrospray ionization high-resolution mass spectrometry to gain insight into the chemical composition of SOA before and after aging. The patterns of peak intensities and observed molecular formulas were examined for evidence of water-driven chemistry. We found that chemical composition of the SOA did change during long-term exposure to water vapor and liquid water, but the extent of the change was surprisingly small. This indicates that the exposure to water is not a strong driver of long-term aging processes compared to other mechanisms of aging for the monoterpene SOA studied.