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Sarang K, Otto T, Gagan S, Rudzinski K, Schaefer T, Brüggemann M, Grgić I, Kubas A, Herrmann H, Szmigielski R. Aqueous-phase photo-oxidation of selected green leaf volatiles initiated by OH radicals: Products and atmospheric implications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 879:162622. [PMID: 36878296 DOI: 10.1016/j.scitotenv.2023.162622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 05/17/2023]
Abstract
C5- and C6- unsaturated oxygenated organic compounds emitted by plants under stress like cutting, freezing or drying, known as Green Leaf Volatiles (GLVs), may clear some of the existing uncertainties in secondary organic aerosol (SOA) budget. The transformations of GLVs are a potential source of SOA components through photo-oxidation processes occurring in the atmospheric aqueous phase. Here, we investigated the aqueous photo-oxidation products from three abundant GLVs (1-penten-3-ol, (Z)-2-hexen-1-ol, and (E)-2-hexen-1-al) induced by OH radicals, carried out in a photo-reactor under simulated solar conditions. The aqueous reaction samples were analyzed using advanced hyphenated mass spectrometry techniques: capillary gas chromatography mass spectrometry (c-GC-MS); and reversed-phase liquid chromatography high resolution mass spectrometry (LC-HRMS). Using carbonyl-targeted c-GC-MS analysis, we confirmed the presence of propionaldehyde, butyraldehyde, 1-penten-3-one, and 2-hexen-1-al in the reaction samples. The LC-HRMS analysis confirmed the presence of a new carbonyl product with the molecular formula C6H10O2, which probably bears the hydroxyhexenal or hydroxyhexenone structure. Density functional theory (DFT)-based quantum calculations were used to evaluate the experimental data and obtain insight into the formation mechanism and structures of the identified oxidation products via the addition and hydrogen-abstraction pathways. DFT calculations highlighted the importance of the hydrogen abstraction pathway leading to the new product C6H10O2. Atmospheric relevance of the identified products was evaluated using a set of physical property data like Henry's law constant (HLC) and vapor pressure (VP). The unknown product of molecular formula C6H10O2 has higher HLC and lower VP than the parent GLV and thus has potential to remain in the aqueous phase leading to possible aqueous SOA formation. Other observed carbonyl products are likely first stage oxidation products and precursors of aged SOA.
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Affiliation(s)
- Kumar Sarang
- Institute of Physical Chemistry Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Tobias Otto
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany
| | - Sahir Gagan
- Institute of Physical Chemistry Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Krzysztof Rudzinski
- Institute of Physical Chemistry Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Thomas Schaefer
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany
| | - Martin Brüggemann
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany
| | - Irena Grgić
- Department of Analytical Chemistry, National Institute of Chemistry, SI-1000 Ljubljana, Slovenia
| | - Adam Kubas
- Institute of Physical Chemistry Polish Academy of Sciences, 01-224 Warsaw, Poland.
| | - Hartmut Herrmann
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany.
| | - Rafal Szmigielski
- Institute of Physical Chemistry Polish Academy of Sciences, 01-224 Warsaw, Poland.
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2
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Vodopivec AA, Chen Y, Russo PS, Hung FR. Molecular Dynamics Simulations of Nanostructures Formed by Hydrophobins and Oil in Seawater. J Phys Chem B 2021; 125:7886-7899. [PMID: 34236182 DOI: 10.1021/acs.jpcb.1c02040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Classical molecular dynamics simulations using the Martini coarse-grained force field were performed to study oil nanodroplets surrounded by fungal hydrophobin (HP) proteins in seawater. The class I EAS and the class II HFBII HPs were studied along with two model oils, namely, benzene and n-decane. Both HPs exhibit free energy minima at the oil-seawater interface, which is deeper in benzene compared to the n-decane systems. Larger constraint forces are required to keep both HPs within the n-decane phase compared to inside benzene, with HFBII being more affine to benzene compared to EAS. Smaller surface tensions are observed at benzene-seawater interfaces coated with HPs compared to their n-decane counterparts. In the latter the surface tension remains unchanged upon increases in the concentration of HPs, whereas in benzene systems adding more HPs lead to decreases in surface tension. EAS has a larger tendency to cluster together in the interface compared to HFBII, with both HPs having larger coordination numbers when surrounding benzene droplets compared to when they are around n-decane nanoblobs. The HP-oil nanostructures in seawater examined have radii of gyration ranging between 2 and 12 nm, where the n-decane structures are larger and have more irregular shapes compared to the benzene systems. The n-decane molecules within the nanostructures form a compact spherical core, with the HPs partially covering its surface and clustering together, conferring irregular shapes to the nanostructures. The EAS with n-decane structures are larger and have more irregular shapes compared to their HFBII counterparts. In contrast, in the HP-benzene structures both HPs tend to penetrate the oil part of the droplet. The HFBII-benzene structures having the larger oil/HP ratios examined tend to be more compact and spherical compared to their EAS counterparts; however, some of the HFBII-benzene systems that have smaller oil/HP ratios have a more elongated structure compared to their EAS counterparts. This simulation study provides insights into HP-oil nanostructures that are smaller than the oil droplets and gas bubbles recently studied in experiments and, thus, might be challenging to examine with experimental techniques.
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Affiliation(s)
- Andrés A Vodopivec
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Yuwu Chen
- Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Paul S Russo
- School of Materials Science and Engineering and School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Francisco R Hung
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
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Ruiz-Lopez MF, Francisco JS, Martins-Costa MTC, Anglada JM. Molecular reactions at aqueous interfaces. Nat Rev Chem 2020; 4:459-475. [PMID: 37127962 DOI: 10.1038/s41570-020-0203-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2020] [Indexed: 12/16/2022]
Abstract
This Review aims to critically analyse the emerging field of chemical reactivity at aqueous interfaces. The subject has evolved rapidly since the discovery of the so-called 'on-water catalysis', alluding to the dramatic acceleration of reactions at the surface of water or at its interface with hydrophobic media. We review critical experimental studies in the fields of atmospheric and synthetic organic chemistry, as well as related research exploring the origins of life, to showcase the importance of this phenomenon. The physico-chemical aspects of these processes, such as the structure, dynamics and thermodynamics of adsorption and solvation processes at aqueous interfaces, are also discussed. We also present the basic theories intended to explain interface catalysis, followed by the results of advanced ab initio molecular-dynamics simulations. Although some topics addressed here have already been the focus of previous reviews, we aim at highlighting their interconnection across diverse disciplines, providing a common perspective that would help us to identify the most fundamental issues still incompletely understood in this fast-moving field.
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5
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Martins‐Costa MTC, Anglada JM, Francisco JS, Ruiz‐López MF. Theoretical Investigation of the Photoexcited NO
2
+H
2
O reaction at the Air–Water Interface and Its Atmospheric Implications. Chemistry 2019; 25:13899-13904. [DOI: 10.1002/chem.201902769] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Marilia T. C. Martins‐Costa
- Laboratoire de Physique et Chimie Théoriques, UMR CNRS 7019University of Lorraine, CNRS, BP 70239 54506 Vandoeuvre-lès-Nancy France
| | - Josep M. Anglada
- Departament de Química Biològica (IQAC), CSIC c/ Jordi Girona 18 08034 Barcelona Spain
| | - Joseph S. Francisco
- Department of Earth and Environmental Science and Department of ChemistryUniversity of Pennsylvania Philadelphia PA 19104-6316 USA
| | - Manuel F. Ruiz‐López
- Laboratoire de Physique et Chimie Théoriques, UMR CNRS 7019University of Lorraine, CNRS, BP 70239 54506 Vandoeuvre-lès-Nancy France
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Broderick A, Rocha MA, Khalifa Y, Shiflett MB, Newberg JT. Mass Transfer Thermodynamics through a Gas-Liquid Interface. J Phys Chem B 2019; 123:2576-2584. [PMID: 30803233 DOI: 10.1021/acs.jpcb.9b00958] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular level information about thermodynamic variations (enthalpy, entropy, and free energy) of a gas molecule as it crosses a gas-liquid interface is strongly lacking from an experimental perspective under equilibrium conditions. Herein, we perform in situ measurements of water interacting with the ionic liquid (IL) 1-butyl-3-methylimidazolium acetate, [C4mim][Ace], using ambient pressure X-ray photoelectron spectroscopy in order to assess the interfacial uptake of water quantitatively as a function of temperature, pressure, and water mole fraction ( xw). The surface spectroscopy results are compared to existing bulk water absorption experiments, showing that the amount of water in the interfacial region is consistently greater than that in the bulk. The enthalpy and entropy of water sorption vary significantly between the gas-liquid interface and the bulk as a function of xw, with a crossover that occurs near xw = 0.6 where the water-IL mixture converts from being homogeneous ( xw < 0.6) to nanostructured ( xw > 0.6). Free energy results reveal that water at the gas-IL interface is thermodynamically more favorable than that in the bulk, consistent with the enhanced water concentration in the interfacial region. The results herein show that the efficacy for an ionic liquid to absorb a gas phase molecule is not merely a function of bulk solvation parameters but also is significantly influenced by the thermodynamics occurring across the gas-IL interface during the mass transfer process.
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Affiliation(s)
- Alicia Broderick
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - M Alejandra Rocha
- Department of Chemical and Petroleum Engineering , University of Kansas , Lawrence , Kansas 66045 , United States
| | - Yehia Khalifa
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Mark B Shiflett
- Department of Chemical and Petroleum Engineering , University of Kansas , Lawrence , Kansas 66045 , United States
| | - John T Newberg
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
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Enami S, Ishizuka S, Colussi AJ. Chemical signatures of surface microheterogeneity on liquid mixtures. J Chem Phys 2019; 150:024702. [PMID: 30646725 DOI: 10.1063/1.5055684] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Many chemical reactions in Nature, the laboratory, and chemical industry occur in solvent mixtures that bring together species of dissimilar solubilities. Solvent mixtures are visually homogeneous, but are not randomly mixed at the molecular scale. In the all-important binary water-hydrotrope mixtures, small-angle neutron and dynamic light scattering experiments reveal the existence of short-lived (<50 ps), short-ranged (∼1 nm) concentration fluctuations. The presence of hydrophobic solutes stabilizes and extends such fluctuations into persistent, mesoscopic (10-100 nm) inhomogeneities. While the existence of inhomogeneities is well established, their impacts on reactivity are not fully understood. Here, we search for chemical signatures of inhomogeneities on the surfaces of W:X mixtures (W = water; X = acetonitrile, tetrahydrofuran, or 1,4-dioxane) by studying the reactions of Criegee intermediates (CIs) generated in situ from O3(g) addition to a hydrophobic olefin (OL) solute. Once formed, CIs isomerize to functionalized carboxylic acids (FC) or add water to produce α-hydroxy-hydroperoxides (HH), as detected by surface-specific, online pneumatic ionization mass spectrometry. Since only the formation of HH requires the presence of water, the dependence of the R = HH/FC ratio on water molar fraction x w expresses the accessibility of water to CIs on the surfaces of mixtures. The finding that R increases quasi-exponentially with x w in all solvent mixtures is consistent with CIs being preferentially produced (from their OL hydrophobic precursor) in X-rich, long-lived OL:X m W n interfacial clusters, rather than randomly dispersed on W:X surfaces. R vs x w dependences therefore reflect the average ⟨m, n⟩ composition of OL:X m W n interfacial clusters, as weighted by cluster reorganization dynamics. Water in large, rigid clusters could be less accessible to CIs than in smaller but more flexible clusters of lower water content. Since mesoscale inhomogeneities are intrinsic to most solvent mixtures, these phenomena should be quite general.
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Affiliation(s)
- Shinichi Enami
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan
| | - Shinnosuke Ishizuka
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan
| | - Agustín J Colussi
- Linde Center for Global Environmental Science, California Institute of Technology, Pasadena, California 91125, USA
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Martins-Costa MTC, Anglada JM, Francisco JS, Ruiz-López MF. Photochemistry of SO 2 at the Air-Water Interface: A Source of OH and HOSO Radicals. J Am Chem Soc 2018; 140:12341-12344. [PMID: 30226769 DOI: 10.1021/jacs.8b07845] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photochemistry of sulfur dioxide in the near UV-vis energy range has been studied in aqueous environments. The combination of previously reported experimental measurements with accurate quantum chemical calculations achieved in this work reveals that the process represents an important source of OH radicals in the troposphere. It implicates the reaction of the lowest triplet excited state of SO2 with a water molecule. When the process occurs in the gas-phase, photochemical OH production is only significant under high humidity conditions and high SO2 concentrations as those measured in polluted urban areas. However, the OH production rate increases by several orders of magnitude when the process takes place at the surface of water droplets. The present study indicates therefore that the atmospheric importance of sulfur dioxide goes beyond its well-known role as acid rain and aerosol formation precursor.
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Affiliation(s)
- Marilia T C Martins-Costa
- Laboratoire de Physique et Chimie Théoriques , UMR CNRS 7019, University of Lorraine , BP 70239, 54506 Vandoeuvre-lès-Nancy , France
| | - Josep M Anglada
- Departament de Química Biològica (IQAC-CSIC) , c/Jordi Girona 18 , E-08034 Barcelona , Spain
| | - Joseph S Francisco
- College of Arts and Sciences , University of Nebraska-Lincoln , 1223 Oldfather Hall Lincoln , Lincoln , Nebraska 68588-0312 , United States
| | - Manuel F Ruiz-López
- Laboratoire de Physique et Chimie Théoriques , UMR CNRS 7019, University of Lorraine , BP 70239, 54506 Vandoeuvre-lès-Nancy , France
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Vereecken L, Glowacki DR, Pilling MJ. Theoretical Chemical Kinetics in Tropospheric Chemistry: Methodologies and Applications. Chem Rev 2015; 115:4063-114. [DOI: 10.1021/cr500488p] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Luc Vereecken
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - David R. Glowacki
- PULSE
Institute and Department of Chemistry, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
- Department
of Computer Science, University of Bristol, Bristol BS8 1UB, United Kingdom
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Richards-Henderson NK, Pham AT, Kirk BB, Anastasio C. Secondary organic aerosol from aqueous reactions of green leaf volatiles with organic triplet excited states and singlet molecular oxygen. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:268-76. [PMID: 25426693 DOI: 10.1021/es503656m] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Vegetation emits a class of oxygenated hydrocarbons--the green leaf volatiles (GLVs)--under stress or damage. Under foggy conditions GLVs might be a source of secondary organic aerosol (SOA) via aqueous reactions with hydroxyl radical (OH), singlet oxygen ((1)O2*), and excited triplet states ((3)C*). To examine this, we determined the aqueous kinetics and SOA mass yields for reactions of (3)C* and (1)O2* with five GLVs: methyl jasmonate (MeJa), methyl salicylate (MeSa), cis-3-hexenyl acetate (HxAc), cis-3-hexen-1-ol (HxO), and 2-methyl-3-butene-2-ol (MBO). Second-order rate constants with (3)C* and (1)O2* range from (0.13-22) × 10(8) M(-1) s(-1) and (8.2-60) × 10(5) M(-1) s(-1) at 298 K, respectively. Rate constants with (3)C* are independent of temperature, while values with (1)O2* show significant temperature dependence (Ea = 20-96 kJ mol(-1)). Aqueous SOA mass yields for oxidation by (3)C* are (84 ± 7)%, (80 ± 9)%, and (38 ± 18)%, for MeJa, MeSa, and HxAc, respectively; we did not measure yields for other conditions because of slow kinetics. The aqueous production of SOA from GLVs is dominated by (3)C* and OH reactions, which form low volatility products at a rate that is approximately half that from the parallel gas-phase reactions of GLVs.
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Affiliation(s)
- Nicole K Richards-Henderson
- Department of Land, Air and Water Resources, University of California - Davis , 1 Shields Avenue, Davis, California 95616, United States
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11
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Liyana-Arachchi TP, Zhang Z, Ehrenhauser FS, Avij P, Valsaraj KT, Hung FR. Bubble bursting as an aerosol generation mechanism during an oil spill in the deep-sea environment: molecular dynamics simulations of oil alkanes and dispersants in atmospheric air/salt water interfaces. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:53-64. [PMID: 24296764 DOI: 10.1039/c3em00391d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Potential of mean force (PMF) calculations and molecular dynamics (MD) simulations were performed to investigate the properties of oil n-alkanes [i.e., n-pentadecane (C15), n-icosane (C20) and n-triacontane (C30)], as well as several surfactant species [i.e., the standard anionic surfactant sodium dodecyl sulfate (SDS), and three model dispersants similar to the Tween and Span species present in Corexit 9500A] at air/salt water interfaces. This study was motivated by the 2010 Deepwater Horizon (DWH) oil spill, and our simulation results show that, from the thermodynamic point of view, the n-alkanes and the model dispersants have a strong preference to remain at the air/salt water interface, as indicated by the presence of deep free energy minima at these interfaces. The free energy minimum of these n-alkanes becomes deeper as their chain length increases, and as the concentration of surfactant species at the interface increases. The n-alkanes tend to adopt a flat orientation and form aggregates at the bare air/salt water interface. When this interface is coated with surfactants, the n-alkanes tend to adopt more tilted orientations with respect to the vector normal to the interface. These simulation results are consistent with the experimental findings reported in the accompanying paper [Ehrenhauser et al., Environ. Sci.: Processes Impacts 2013, in press, (DOI: 10.1039/c3em00390f)]. The fact that these long-chain n-alkanes show a strong thermodynamic preference to remain at the air/salt water interfaces, especially if these interfaces are coated with surfactants, makes these species very likely to adsorb at the surface of bubbles or droplets and be ejected to the atmosphere by sea surface processes such as whitecaps (breaking waves) and bubble bursting. Finally, the experimental finding that more oil hydrocarbons are ejected when Corexit 9500A is present in the system is consistent with the deeper free energy minima observed for the n-alkanes at the air/salt water interface at increasing concentrations of surfactant species.
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Habartová A, Valsaraj KT, Roeselová M. Molecular Dynamics Simulations of Small Halogenated Organics at the Air–Water Interface: Implications in Water Treatment and Atmospheric Chemistry. J Phys Chem A 2013; 117:9205-15. [DOI: 10.1021/jp405292k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alena Habartová
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Kalliat T. Valsaraj
- Cain
Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Martina Roeselová
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
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Liyana-Arachchi TP, Hansel AK, Stevens C, Ehrenhauser FS, Valsaraj KT, Hung FR. Molecular modeling of the green leaf volatile methyl salicylate on atmospheric air/water interfaces. J Phys Chem A 2013; 117:4436-43. [PMID: 23668770 DOI: 10.1021/jp4029694] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Methyl salicylate (MeSA) is a green leaf volatile (GLV) compound that is emitted in significant amounts by plants, especially when they are under stress conditions. GLVs can then undergo chemical reactions with atmospheric oxidants, yielding compounds that contribute to the formation of secondary organic aerosols (SOAs). We investigated the adsorption of MeSA on atmospheric air/water interfaces at 298 K using thermodynamic integration (TI), potential of mean force (PMF) calculations, and classical molecular dynamics (MD) simulations. Our molecular models can reproduce experimental results of the 1-octanol/water partition coefficient of MeSA. A deep free energy minimum was found for MeSA at the air/water interface, which is mainly driven by energetic interactions between MeSA and water. At the interface, the oxygenated groups in MeSA tend to point toward the water side of the interface, with the aromatic group of MeSA lying farther away from water. Increases in the concentrations of MeSA lead to reductions in the height of the peaks in the MeSA-MeSA g(r) functions, a slowing down of the dynamics of both MeSA and water at the interface, and a reduction in the interfacial surface tension. Our results indicate that MeSA has a strong thermodynamic preference to remain at the air/water interface, and thus chemical reactions with atmospheric oxidants are more likely to take place at this interface, rather than in the water phase of atmospheric water droplets or in the gas phase.
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