This article is part of the New Advances in Organic Aerosol Chemistry special issue. Organic compounds make up a major fraction of fine atmospheric particle mass worldwide. In North America and Europe, as environmental regulations have cleaned up atmospheric sulfur,(1) understanding the sources and fate of aerosol organics has become critically important to air quality management.(2,3) Organic aerosol chemistry also impacts climate: besides their contributions to aerosol mass, organic compounds impact aerosol optical properties and the ability of the particles to nucleate cloud droplets [cloud condensation nuclei (CCN) activity] or ice particles.(4−7) Biogenic organic compounds were a major component of fine particle mass in pre-industrial times, and given the scarcity of paleoclimate records of aerosols, we rely on models of new particle formation, growth, and transformations to establish a reference state for assessments of climate change.(8) Wildfires are a large source of atmospheric organic aerosol that will continue to increase as the climate changes.(9) We present in this virtual special issue a collection of exciting new advances in organic aerosol chemistry. The manuscripts fall into four broad and interconnected categories: (1) novel insights into secondary organic aerosol (SOA) formation, (2) impact of organics on aerosol physical properties relevant for climate, (3) organics and the aerosol–cloud life cycle, and (4) field observations of organic aerosols and their transformations. Combustion processes, from fossil fuel combustion to biomass burning to cooking, are important sources of organic aerosols. Bikkina et al.(10) and Garofalo et al.(11) report the results of field investigations of the chemistry of aerosol particles in smoke plumes emitted from biomass burning. The tracer study of Bikkina et al. highlights the chemical differences of smoke from burning different fuel types in Southeast Asia (forest fires) versus the Indo-Gangetic Plain (crop residue and wood burning). Garofalo et al., studying wildfires in the Western U.S., demonstrate that the evolution of aerosols in wildfire plumes is a result of simultaneous dilution-driven evaporation and oxidation-induced condensation. Takhar et al. report on the chemistry and volatility of fresh and photochemically aged organic aerosol from cooking oils.(12) Zhang et al. measured atmospheric aerosols resulting from a fireworks display in Albany, NY, using aerosol mass spectrometry. Although fireworks are well-known sources of inorganic aerosols, including toxic metals,(13) this study also reports on the organic component of the firework aerosol. Several of the manuscripts in this collection present new perspectives on SOA formation from biogenic volatile organic precursors and the SOA life cycle. Faiola et al. report the impact of stress from aphid infestations on the volatile organic compound (VOC) emissions from Scots pine trees and the associated SOA formation.(14) Their whole-plant paradigm provides a counterpoint to the single-VOC approach traditionally taken for SOA formation studies. Joo et al.(15) and Finewax et al.(16) investigated SOA formation in laboratory studies from two VOCs that have been observed during biomass burning (resorcinol and 3-methylfuran), with a focus on NO₃ radicals. The formation mechanisms of organic nitrate species and highly oxidized molecules from the reaction of Δ-3-carene with NO₃ radicals were studied by Draper and co-workers.(17) Using the Community Multiphase Air Quality (CMAQ) model, Zare et al.(18) compared the relative importance of multiphase chemistry and vapor-pressure-driven pathways for the contribution of organic nitrates to SOA, finding that most of that SOA mass is no longer identifiable as organic nitrates as a result of in-particle hydrolysis, making this chemistry tricky to diagnose in field studies. Walhout et al. took a novel approach to studying the photolytic aging of SOA derived from α-pinene,(19) extending the aging to a 4 day period and analyzing the products using a combination of offline mass spectrometry techniques as well as attenuated total reflectance–Fourier transform infrared spectroscopy and ultraviolet/visible (UV/vis) spectrophotometry. Lutz and co-workers characterized the gas–particle partitioning of biogenic organic acid species in the boreal forest of Hyytiälä, Finland, using an advanced mass spectrometry technique for the study of organic aerosols.(20) Xu et al. investigated the gas–particle partitioning of formic acid, which has many sources but is an oxidation product of organic aerosol, via continuous measurements in suburban Shanghai.(21) Cui et al. present a unique long-term (1991–2015) record of biogenic SOA tracers in aerosols sampled at Cape Grim, Australia.(22) Aerosols serve as nuclei for the formation of cloud droplets and atmospheric ice particles, and chemistry occurring in cloudwater can contribute to organic aerosol mass.(23) Surface-active organic material or surfactants can partition to the gas–aerosol interface, potentially forming coatings on particles and altering their CCN ability by reducing the interfacial tension.(5,6) In a laboratory study using sum frequency generation, Bé et al. studied the partitioning of β-caryophyllene ozonolysis products to the gas–aqueous interface and their interfacial organization.(24) In an effort to better understand surfactant film formation on marine aerosols, Cheng et al. characterized the interfacial behavior of a series of surfactant molecules on artificial seawater using a Langmuir trough and infrared reflection absorption spectroscopy.(25) Nandy et al. studied the influence of organic material from the sea surface microlayer on aerosol phase behavior (liquid–liquid phase separation and crystallization).(26) Barati et al. investigated the CCN activity of organic aerosols, including cholesterol and water-soluble organic compounds,(27) and Ganguly et al. report on the potential for aerosols containing nano- and microplastics to nucleate ice.(28) The hygroscopicity of mixed organic–inorganic aerosols containing oxalate metal complexes was investigated by Ma et al.(29) Bianco et al. detected chemical tracers for SOA, brown carbon, and nitroaromatics in cloud droplets collected on a mountaintop using mass spectrometry.(30) Zhang and co-workers found evidence of cloud processing of aerosols in a field study at the Whiteface Mountain Observatory.(31) Fankhauser et al. showed in a modeling study that bacteria, which have been observed in ambient aerosols and cloudwater, may metabolize small organic compounds in the particle or droplet in which they reside but are not likely to impact atmospheric composition as a result of their scarcity and the physical separation between droplets.(32) Organosulfur compounds are observed ubiquitously in atmospheric aerosols,(33−35) although their sources are not fully understood.(36) Organosulfates are believed to impact aerosol CCN activity, possibly as a result of their surface-active nature(37,38) and aerosol pH.(39) In a computational study using density functional theory and classical nucleation theory, Burrell et al. explored new particle formation involving methanesulfonic acid and amines.(40) Fleming et al.(41) discovered a new pathway for the formation of light-absorbing organosulfate species from SOA material,(37) and Huang et al. report the formation of organosulfur compounds in particles containing Fe³⁺ and isoprene oxidation products methyl vinyl ketone and methacrolein.(42) Light-absorbing aerosol organics or aerosol “brown carbon” both alter the Earth’s radiative balance(43,44) and promote chemistry in the particle phase via photosensitization.(45−51) Trofimova et al. explore the contribution of charge-transfer complexes to light absorption by aerosol brown carbon.(52) Many light-absorbing organic compounds in atmospheric aerosols are also surface-active(53−55) or otherwise influence aerosol phase behavior. Beier and co-workers report a dramatic surface tension decrease of brown carbon mixtures under photooxidation.(56) Gubbins et al. demonstrated that adding alcohols to glyoxal–ammonium sulfate solutions known to form light-absorbing organics increases the viscosity of the mixture with an increasing concentration and O:C ratio.(57) DeRieux et al.(58) and De Haan et al.(59) both investigate the interplay between aerosol phase state and in-particle brown carbon formation by reactions of amines. Similarly, Zhang et al.(60) and Olson et al.(61) investigated the formation of SOA from isoprene epoxydiols (IEPOX), finding that IEPOX SOA formation increases particle viscosity, which, in turn, suppresses further IEPOX uptake and IEPOX SOA formation. Collectively, the manuscripts in this virtual special issue represent the next generation of ideas and techniques in this field. Further research, enabled by recent advances in aerosol technology and a collaborative and inclusive research culture, will be needed to tackle the urgent challenges in global air pollution and climate that we face today. Views expressed in this editorial are those of the author and not necessarily the views of the ACS. This article references 61 other publications.

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虚拟特刊：有机气溶胶化学的新进展

本文是 有机气溶胶化学的新进展特刊。在全世界，有机化合物占大气微粒总量的主要部分。在北美和欧洲，由于环境法规已清除了大气中的硫，（1）了解气溶胶有机物的来源和去向对于空气质量管理至关重要。（2,3）有机气溶胶化学也影响气候：除了其贡献外对于气溶胶质量，有机化合物会影响气溶胶的光学特性以及颗粒使云滴（云凝结核（CCN）活性）或冰颗粒成核的能力。（4-7）生物有机化合物是细颗粒质量的主要组成部分。工业化前的时期，鉴于古气候的气溶胶记录稀少，我们依赖于新颗粒形成，生长，（8）野火是大气中有机气溶胶的主要来源，并将随着气候变化而继续增加。（9）在此虚拟特刊中，我们介绍了一系列令人振奋的新内容。有机气溶胶化学的进步。这些手稿分为四大类和相互关联的类别：（1）对次生有机气溶胶（SOA）形成的新颖见解；（2）有机物对与气候相关的气溶胶物理特性的影响；（3）有机物和气溶胶-云的生命周期， （4）有机气溶胶及其转化的现场观察。从化石燃料燃烧到生物质燃烧再到烹饪的燃烧过程是有机气溶胶的重要来源。Bikkina等人（10）和Garofalo等人（10）。（11）报告了对生物质燃烧产生的烟羽中气溶胶颗粒化学性质的现场调查结果。Bikkina等人的示踪剂研究。着重介绍了东南亚燃烧不同类型燃料（森林大火）与印度恒河平原（作物残渣和木材燃烧）产生的烟雾的化学差异。Garofalo等人研究了美国西部的野火，证明野火羽流中的气溶胶演变是同时稀释驱动的蒸发和氧化引起的冷凝作用的结果。Takhar等。报告了食用油中新鲜和光化学老化的有机气溶胶的化学和挥发性。（12）Zhang等。使用气溶胶质谱法测量了纽约州奥尔巴尼烟花汇演产生的大气气溶胶。尽管烟花是众所周知的无机气溶胶的来源，包括有毒金属，[13]但本研究还报告了烟花气溶胶的有机成分。该集合中的一些手稿提出了从生物挥发性有机前体形成SOA以及SOA生命周期的新观点。Faiola等。报告蚜虫侵染的压力对苏格兰松树挥发性有机化合物（VOC）排放及相关SOA形成的影响。（14）它们的全植物范式与传统上用于SOA形成研究的单一VOC方法相反。Joo等人（15）和Finewax等人（16）在实验室研究中研究了在生物质燃烧过程中观察到的两种VOC（间苯二酚和3-甲基呋喃）中SOA的形成，重点是NO （13）该研究还报告了烟花烟雾的有机成分。该集合中的一些手稿提出了从生物挥发性有机前体形成SOA以及SOA生命周期的新观点。Faiola等。报告蚜虫侵染的压力对苏格兰松树挥发性有机化合物（VOC）排放及相关SOA形成的影响。（14）它们的全植物范式与传统上用于SOA形成研究的单一VOC方法相反。Joo等人（15）和Finewax等人（16）在实验室研究中研究了在生物质燃烧过程中观察到的两种VOC（间苯二酚和3-甲基呋喃）中SOA的形成，重点是NO （13）该研究还报告了烟花烟雾的有机成分。该集合中的一些手稿提出了从生物挥发性有机前体形成SOA以及SOA生命周期的新观点。Faiola等。报告蚜虫侵染的压力对苏格兰松树挥发性有机化合物（VOC）排放及相关SOA形成的影响。（14）它们的全植物范式与传统上用于SOA形成研究的单一VOC方法相反。Joo等人（15）和Finewax等人（16）在实验室研究中研究了在生物质燃烧过程中观察到的两种VOC（间苯二酚和3-甲基呋喃）中SOA的形成，重点是NO 该集合中的一些手稿提出了从生物挥发性有机前体形成SOA以及SOA生命周期的新观点。Faiola等。报告蚜虫侵染的压力对苏格兰松树挥发性有机化合物（VOC）排放及相关SOA形成的影响。（14）它们的全植物范式与传统上用于SOA形成研究的单一VOC方法相反。Joo等人（15）和Finewax等人（16）在实验室研究中研究了在生物质燃烧过程中观察到的两种VOC（间苯二酚和3-甲基呋喃）中SOA的形成，重点是NO 该集合中的一些手稿提出了从生物挥发性有机前体形成SOA以及SOA生命周期的新观点。Faiola等。报告蚜虫侵染的压力对苏格兰松树挥发性有机化合物（VOC）排放及相关SOA形成的影响。（14）它们的全植物范式与传统上用于SOA形成研究的单一VOC方法相反。Joo等人（15）和Finewax等人（16）在实验室研究中研究了在生物质燃烧过程中观察到的两种VOC（间苯二酚和3-甲基呋喃）中SOA的形成，重点是NO 报告蚜虫侵染的应力对苏格兰松树挥发性有机化合物（VOC）排放及其相关SOA形成的影响。（14）它们的全植物范式与传统上用于SOA形成研究的单一VOC方法相反。Joo等人（15）和Finewax等人（16）在实验室研究中研究了在生物质燃烧过程中观察到的两种VOC（间苯二酚和3-甲基呋喃）中SOA的形成，重点是NO 报告蚜虫侵染的压力对苏格兰松树挥发性有机化合物（VOC）排放及相关SOA形成的影响。（14）它们的全植物范式与传统上用于SOA形成研究的单一VOC方法相反。Joo等人（15）和Finewax等人（16）在实验室研究中研究了在生物质燃烧过程中观察到的两种VOC（间苯二酚和3-甲基呋喃）中SOA的形成，重点是NO_3个部首。Δ-3-碳烯与NO ₃反应生成有机硝酸盐类和高氧化分子的机理Draper及其同事研究了这些自由基。（17）Zare等人（18）使用社区多相空气质量（CMAQ）模型，比较了多相化学和蒸汽压驱动途径对有机物贡献的相对重要性。硝酸盐转化为SOA，发现大部分SOA质量由于颗粒内水解而不再可识别为有机硝酸盐，这使得这种化学方法很难在现场研究中进行诊断。Walhout等。采取了一种新颖的方法来研究源自α-derived烯的SOA的光解老化，（19）将老化延长至4天，并使用离线质谱技术和衰减的全反射率结合傅里叶变换红外分析了产品光谱和紫外/可见（UV / vis）分光光度法。Lutz及其同事利用先进的质谱技术研究了芬兰Hyytiälä北方森林中生物有机酸种类的气体-颗粒分配。（20）Xu等。通过对上海郊区的连续测量，研究了甲酸的气-粒分配，该甲酸有多种来源，但是有机气溶胶的氧化产物。（21）Cui等。提出了在澳大利亚开普格里姆采样的气溶胶中生物SOA示踪剂的一项独特的长期（1991-2015）记录。[22]气溶胶充当形成云滴和大气冰粒的核，并且云水中发生的化学反应可能有助于（23）表面活性有机材料或表面活性剂可以分配到气溶胶界面，Bé等人（5,6）在一项利用和频产生的实验室研究中发现，在粒子上可能形成涂层并通过降低界面张力来改变其CCN能力。[24]为了更好地了解海洋气溶胶上表面活性剂膜的形成，研究了β-石竹烯臭氧分解产物在气-水界面及其界面组织中的分配。Nandy等人（25）用Langmuir槽和红外反射吸收光谱法表征了一系列表面活性剂分子在人造海水上的界面行为。（25）Nandy等。研究了来自海表微层的有机物质对气溶胶相行为（液相-液相分离和结晶化）的影响。（26）Barati等。研究了有机气溶胶的CCN活性，包括胆固醇和水溶性有机化合物，（27）和Ganguly等。（28）Ma等人研究了含有草酸盐金属配合物的有机-无机混合气溶胶的吸湿性（29）。使用质谱法检测了山顶上收集的云滴中SOA，褐碳和硝基芳烃的化学示踪剂。（30）Zhang和他的同事在白脸山天文台的野外研究中发现了气溶胶的云处理证据。（31） Fankhauser等。在模型研究中表明，在周围的气溶胶和云水中已经观察到细菌，可能会代谢它们所在的颗粒或液滴中的小有机化合物，但由于其稀缺性和液滴之间的物理分离而不太可能影响大气成分。（32）在大气气溶胶中普遍观察到有机硫化合物，（33− 35）尽管其来源尚未完全理解。（36）据信有机硫酸盐可能影响其气溶胶CCN活性，这可能是由于其表面活性性质（37,38）和气溶胶pH值所致。（39）在使用密度的计算研究中功能理论和经典成核理论，Burrell等。（40）Fleming等人（41）发现了一种从SOA材料中形成吸光有机硫酸盐类物质的新途径（37）和Huang等人。³⁺和异戊二烯氧化产物甲基乙烯基酮和甲基丙烯醛。（42）吸收光的气溶胶有机物或气溶胶“棕碳”都改变了地球的辐射平衡（43,44），并通过光敏作用促进了粒子相中的化学反应。（45-51） Trofimova等。探索电荷转移复合物对气溶胶褐碳吸收光的贡献。（52）大气气溶胶中的许多光吸收有机化合物也具有表面活性（53-55），否则会影响气溶胶的相行为。Beier和他的同事报告说，在光氧化作用下，棕色碳混合物的表面张力显着降低。（56）Gubbins等。证明在已知形成吸光性有机物的乙二醛-硫酸铵溶液中添加醇类会随着浓度和O：C比的增加而增加混合物的粘度。（57）DeRieux等人（58）和De Haan等人（59）都研究了气态相态与通过胺反应形成的颗粒状褐碳之间的相互作用。同样，Zhang等人（60）和Olson等人（61）研究了由异戊二烯环氧二醇（IEPOX）形成SOA的过程，发现IEPOX SOA的形成增加了颗粒的粘度，进而抑制了IEPOX的吸收和IEPOX SOA的产生。编队。该虚拟特刊中的手稿共同代表了该领域的下一代思想和技术。在气雾剂技术的最新发展以及协作和包容性研究文化的推动下，需要进行进一步的研究，以应对当今我们面临的全球空气污染和气候的紧迫挑战。本社论中表达的观点只是作者的观点，不一定是ACS的观点。本文引用了其他61种出版物。