Single particle measurements of mixing between mimics for biomass burning and aged secondary organic aerosols
Single particle measurements of mixing between mimics for biomass burning and aged secondary organic aerosols
复制标题
生物质燃烧模拟物与老化二次有机气溶胶之间混合的单粒子测量
DOI：
10.1039/d2ea00017b
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Donahue, Neil
中科院分区：
文献类型：
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作者：
Habib, Luke;Donahue, Neil
通过半挥发性有机物的蒸发和冷凝，气溶胶种群之间的气相交换可能是聚集型颗粒物与缓慢凝聚的颗粒物混合的主要机制。由于扩散的限制，这种交换在高粘性、半固态或玻璃状颗粒中可能会受到阻碍。在这里，我们描述了精心准备的代表高粘性或潜在的“玻璃状”老化有机颗粒(非挥发性糖13C-葡萄糖、蔗糖和棉子糖与硫酸铵种子)和新鲜生物质燃烧颗粒(赤藓糖醇与黑碳种子)的实验，以开发有机气溶胶系统的模型相空间，并更好地了解粒子相状态何时阻碍混合。我们的假设是，在一定的相对湿度阈值下，这些限制会得到缓解，随着环境温度的下降，相对湿度阈值会增加。我们使用气溶胶质谱仪(AMS)结合事件触发(ET)和烟尘粒子(SP)模式，量化了10-25°C和5-90%RH的颗粒群的混合状态。观测到的单粒子质量谱被聚集在短时间片中，并用于执行相关参考光谱的线性组合，以确定每个组分对结果粒子信号的贡献。我们的结果表明，在测试的条件下，非挥发性糖颗粒对混合几乎没有扩散限制。
Gas-phase exchange between aerosol populations via evaporation and condensation of semi-volatile organics can be a major mechanism of mixing between accumulation-mode particles with slow coagulation. This exchange may be impeded in highly viscous, semi-solid, or glassy particles due to diffusion limitations. Here we describe experiments on carefully prepared particle populations representing highly viscous or potentially “glassy” aged organic particles (non-volatile sugars 13C-glucose, sucrose, and raffinose with ammonium sulfate seeds) and fresh biomass burning particles (erythritol with black carbon seeds) to develop a model phase space for organic aerosol systems and better understand when particle phase state impedes mixing. Our hypothesis is that these limitations are alleviated at some relative humidity threshold, which increases with decreasing ambient temperatures. We quantify the mixing state of these particle populations from 10–25 °C and 5–90% RH using an Aerosol Mass Spectrometer (AMS) combining Event Trigger (ET) and Soot Particle (SP) modes. The observed single particle mass spectra are aggregated in short time slices and used to perform a linear combination of relevant reference spectra to determine the contributions each constituent has on the resulting particle signal. Our results suggest that the non-volatile sugar particles have little to no diffusive limitations to mixing at the conditions tested.