The effect of filter storage conditions on degradation of organic Aerosols
The effect of filter storage conditions on degradation of organic Aerosols
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DOI：
10.1080/02786826.2023.2229881
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发表时间：
2023-06
影响因子：
5.2
通讯作者：
Chase K. Glenn;Omar El Hajj;R. Saleh
中科院分区：
文献类型：
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作者：
Chase K. Glenn;Omar El Hajj;R. Saleh
摘要目前的做法包括用铝箔包裹有机气溶胶（OA）过滤器样品，并储存在冰箱中，以避免样品在分析前降解。然而，缺乏证据支持这些做法。在这里，我们调查的热降解和光降解对甲苯燃烧OA，松树燃烧OA，和环境OA样品储存在培养皿中一个月，在三个不同的条件：覆盖铝箔和在冰箱（F），覆盖铝箔在室温下（RC），并在室温下（RUC）揭开。我们进行了三种类型的分析：热光学测量，电喷雾电离质谱，紫外-可见光谱。对于所有样品，我们观察到在RC和RUC条件下相对挥发性有机碳部分（OC 1）的温和减少。我们在本研究中没有考虑阳性伪影，因此，这种减少至少部分是由于吸附的蒸汽而不是颗粒的蒸发。除了在条件RC和RUC下松木燃烧OA的一些小分子大小化合物的损失（可能是由于蒸发）外，在任何储存条件下，相对于对照组，没有证据表明化学组成发生了显著的系统性变化。没有证据表明在RUC条件下任何样品发生了光漂白。相反，我们观察到的RC和RUC条件下的松树燃烧OA的吸收增加，可能是由于蒸发的小分子大小的物种相对较弱的吸收。版权所有© 2023美国气溶胶研究协会
Abstract Current practices involve wrapping organic aerosol (OA) filter samples with aluminum foil and storing in a freezer to avoid sample degradation prior to analysis. However, there is a lack of evidence supporting these practices. Here, we investigate the effect of thermal and photodegradation on toluene-combustion OA, pine-combustion OA, and ambient OA samples by storing them in petri dishes for one month at three different conditions: covered with aluminum foil and in a freezer (F), covered with aluminum foil at room temperature (RC), and uncovered at room temperature (RUC). We performed three types of analyses: thermal-optical measurements, electrospray ionization mass spectrometry, and UV-Vis spectroscopy. For all samples, we observed a mild reduction in the relatively volatile organic carbon fraction (OC1) in the RC and RUC conditions. We did not account for positive artifacts in this study, and therefore, this reduction was at least partially due to the evaporation of adsorbed vapors rather than particles. There was no evidence of significant systematic change in chemical composition relative to control for any of the storage conditions, except for loss of some small-molecular-size compounds in conditions RC and RUC for pine-combustion OA, likely due to evaporation. There was no evidence that photobleaching occurred in the RUC condition for any of the samples. On the contrary, we observed an increase in absorption in the RC and RUC conditions for pine-combustion OA, likely due to evaporation of small-molecular-size species with relatively weak absorption. Copyright © 2023 American Association for Aerosol Research GRAPHICAL ABSTRACT