Morphology and Viscosity Changes after Reactive Uptake of Isoprene Epoxydiols in Submicrometer Phase Separated Particles with Secondary Organic Aerosol Formed from Different Volatile Organic Compounds
Morphology and Viscosity Changes after Reactive Uptake of Isoprene Epoxydiols in Submicrometer Phase Separated Particles with Secondary Organic Aerosol Formed from Different Volatile Organic Compounds
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DOI：
10.1021/acsearthspacechem.1c00156
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发表时间：
2022-03
影响因子：
3.4
通讯作者：
Ziying Lei;Nicole E. Olson;Yue Zhang;Yuzhi Chen;A. Lambe;Jing Zhang;Natalie J. White;J. Atkin;M. M. Banaszak Holl-M.;Zhenfa Zhang;A. Gold;J. Surratt;A. Ault
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文献类型：
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作者：
Ziying Lei;Nicole E. Olson;Yue Zhang;Yuzhi Chen;A. Lambe;Jing Zhang;Natalie J. White;J. Atkin;M. M. Banaszak Holl-M.;Zhenfa Zhang;A. Gold;J. Surratt;A. Ault
二次有机气溶胶(SOA)是由挥发性有机化合物(VOCs)氧化形成的，是大气细颗粒物(PM2.5)的重要组成部分，普遍存在于无机-有机亚微米混合颗粒物中。由不同的生物和人为VOCs形成的SOA导致了独特的气溶胶物理化学性质，从而改变了气候影响(即，水吸收)。了解挥发性有机化合物衍生的半挥发性氧化产物对无机-soa混合颗粒的反应吸收仍然有限，特别是对于大气中最大尺寸(按数量计算)的颗粒(∼100 nm)。这些粒子的研究具有挑战性，因为SOA可能非常粘性(即，固体或半固体)，而混合粒子可能具有复杂的形态(例如，核壳)。在这里，我们表明，在酸催化反应性吸收异戊二烯环氧二醇(IEPOX)后，初始核-壳(无机-有机)粒子的粘度和形态发生了很大变化，并且这种差异高度依赖于挥发性有机化合物前体(α-蒎烯、β-石竹烯、异戊二烯和甲苯)。原子力显微镜测量表明，在50%相对湿度(RH)下，两种较高相对分子质量的前体(α-Pinene和β-石竹烯)的表面活性物质的粘度较小，而来自较低分子质量的前体(异戊二烯和甲苯)的表面活性物质的粘度没有明显变化。无机-二氧化硫颗粒粘度和形态的演变可能会改变对空气质量和气候的预测影响。
Secondary organic aerosol (SOA), formed from the oxidation of volatile organic compounds (VOCs), is a large contributor to atmospheric fine particulate matter (PM2.5) and is commonly present in mixed inorganic–organic submicron particles. SOA formed from varying biogenic and anthropogenic VOCs results in unique aerosol physicochemical properties that modify climate impacts (i.e., water uptake). Understanding reactive uptake of VOC-derived semivolatile oxidation products to inorganic-SOA mixed particles remains limited, particularly for particles at the most abundant sizes (by number) in the atmosphere (∼100 nm). These particles are challenging to study as SOA can be quite viscous (i.e., solid or semisolid), and mixed particles can have complex morphologies (e.g., core–shell). Herein, we show that the viscosity and morphology of initially core–shell (inorganic–organic) particles changed substantially after acid-catalyzed reactive uptake of isoprene epoxydiols (IEPOX), and that differences were highly dependent on VOC precursor (α-pinene, β-caryophyllene, isoprene, and toluene). SOA from two higher molecular weight precursors (α-pinene and β-caryophyllene) were less viscous after IEPOX uptake at 50% relative humidity (RH), while SOA viscosities from lower molecular weight precursors (isoprene and toluene) did not change appreciably, based on atomic force microscopy (AFM) measurements. The evolution of inorganic-SOA particle viscosity and morphology could alter the predicted impacts of SOA on air quality and climate.