1
|
Ng SIM, Chan MN. Beyond the formation: unveiling the atmospheric transformation of organosulfates via heterogeneous OH oxidation. Chem Commun (Camb) 2023; 59:13919-13938. [PMID: 37933441 DOI: 10.1039/d3cc03700b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Organosulfates (OSs), characterized with a sulfate ester group (R-OSO3-), are abundant constituents in secondary organic aerosols. Recent laboratory-based investigations have revealed that OSs can undergo efficient chemical transformation through heterogeneous oxidation by hydroxyl radicals (˙OH, interchangeably termed as OH in this article), which freshly derives functionalized and fragmented OSs. The reaction not only contributes to the presence of structurally transformed OSs in the atmosphere of which sources were unidentified, but it also leads to the formation of inorganic sulfates (e.g., SO42-) with profound implication on the form of aerosol sulfur. In this article, we review the current state of knowledge regarding the heterogeneous OH oxidation of OSs based on state-of-the-art designs of experiments, computational approaches, and chemical analytical techniques. Here, we discuss the formation potential of new OSs and SO42-, in light of the influence of diverse OS structures on the relative importance of different reaction pathways. We propose future research directions to advance our mechanistic understanding of these reactions, taking into account aerosol matrix effects, interactions with other atmospheric pollutants, and the incorporation of experimental findings into atmospheric chemical transport models.
Collapse
Affiliation(s)
- Sze In Madeleine Ng
- Earth System Science Programme, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China.
| | - Man Nin Chan
- Earth System Science Programme, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China.
- The Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Hong Kong, China
| |
Collapse
|
2
|
Wiegel AA, Liu MJ, Hinsberg WD, Wilson KR, Houle FA. Diffusive confinement of free radical intermediates in the OH radical oxidation of semisolid aerosols. Phys Chem Chem Phys 2018; 19:6814-6830. [PMID: 28218326 DOI: 10.1039/c7cp00696a] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multiphase chemical reactions (gas + solid/liquid) involve a complex interplay between bulk and interface chemistry, diffusion, evaporation, and condensation. Reactions of atmospheric aerosols are an important example of this type of chemistry: the rich array of particle phase states and multiphase transformation pathways produce diverse but poorly understood interactions between chemistry and transport. Their chemistry is of intrinsic interest because of their role in controlling climate. Their characteristics also make them useful models for the study of principles of reactivity of condensed materials under confined conditions. In previous work, we have reported a computational study of the oxidation chemistry of a liquid aliphatic aerosol. In this study, we extend the calculations to investigate nearly the same reactions at a semisolid gas-aerosol interface. A reaction-diffusion model for heterogeneous oxidation of triacontane by hydroxyl radicals (OH) is described, and its predictions are compared to measurements of aerosol size and composition, which evolve continuously during oxidation. These results are also explicitly compared to those obtained for the corresponding liquid system, squalane, to pinpoint salient elements controlling reactivity. The diffusive confinement of the free radical intermediates at the interface results in enhanced importance of a few specific chemical processes such as the involvement of aldehydes in fragmentation and evaporation, and a significant role of radical-radical reactions in product formation. The simulations show that under typical laboratory conditions semisolid aerosols have highly oxidized nanometer-scale interfaces that encapsulate an unreacted core and may confer distinct optical properties and enhanced hygroscopicity. This highly oxidized layer dynamically evolves with reaction, which we propose to result in plasticization. The validated model is used to predict chemistry under atmospheric conditions, where the OH radical concentration is much lower. The oxidation reactions are more strongly influenced by diffusion in the particle, resulting in a more liquid-like character.
Collapse
Affiliation(s)
- Aaron A Wiegel
- Lawrence Berkeley National Laboratory, Chemical Sciences Division, Berkeley, CA 94702, USA.
| | - Matthew J Liu
- Lawrence Berkeley National Laboratory, Chemical Sciences Division, Berkeley, CA 94702, USA. and University of California, Berkeley, Department of Chemical and Biomolecular Engineering, Berkeley, CA 94702, USA
| | | | - Kevin R Wilson
- Lawrence Berkeley National Laboratory, Chemical Sciences Division, Berkeley, CA 94702, USA.
| | - Frances A Houle
- Lawrence Berkeley National Laboratory, Chemical Sciences Division, Berkeley, CA 94702, USA.
| |
Collapse
|
3
|
Liu MJ, Wiegel AA, Wilson KR, Houle FA. Aerosol Fragmentation Driven by Coupling of Acid–Base and Free-Radical Chemistry in the Heterogeneous Oxidation of Aqueous Citric Acid by OH Radicals. J Phys Chem A 2017; 121:5856-5870. [DOI: 10.1021/acs.jpca.7b04892] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Matthew J. Liu
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94702, United States
- Department
of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Aaron A. Wiegel
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94702, United States
| | - Kevin R. Wilson
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94702, United States
| | - Frances A. Houle
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94702, United States
| |
Collapse
|
4
|
Chim MM, Chow CY, Davies JF, Chan MN. Effects of Relative Humidity and Particle Phase Water on the Heterogeneous OH Oxidation of 2-Methylglutaric Acid Aqueous Droplets. J Phys Chem A 2017; 121:1666-1674. [DOI: 10.1021/acs.jpca.6b11606] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Man Mei Chim
- Earth System Science
Programme, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Chun Yin Chow
- Earth System Science
Programme, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - James F. Davies
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-8176, United States
| | - Man Nin Chan
- Earth System Science
Programme, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
- The Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Hong Kong, China
| |
Collapse
|
5
|
Richards-Henderson NK, Goldstein AH, Wilson KR. Sulfur Dioxide Accelerates the Heterogeneous Oxidation Rate of Organic Aerosol by Hydroxyl Radicals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:3554-3561. [PMID: 26953762 DOI: 10.1021/acs.est.5b05369] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
There remains considerable uncertainty in how anthropogenic gas phase emissions alter the oxidative aging of organic aerosols in the troposphere. Here we observe a 10-20 fold acceleration in the effective heterogeneous OH oxidation rate of organic aerosol in the presence of SO2. This acceleration originates from the radical chain reactions propagated by alkoxy radicals, which are formed efficiently inside the particle by the reaction of peroxy radicals with SO2. As the OH approaches atmospheric concentrations, the radical chain length increases, transforming the aerosol at rates predicted to be up to 10 times the OH-aerosol collision frequency. Model predictions, constrained by experiments over orders of magnitude changes in [OH] and [SO2], suggest that in polluted regions the heterogeneous processing of organic aerosols by OH ([SO2] ≥ 40 ppb) occur on similar time scales as analogous gas-phase oxidation reactions. These results provide evidence for a previously unidentified mechanism by which organic aerosol oxidation is enhanced by anthropogenic gas phase emissions.
Collapse
Affiliation(s)
- Nicole K Richards-Henderson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Allen H Goldstein
- Department of Environmental Science, Policy, and Management, University of California Berkeley , Berkeley, California 94720, United States
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| |
Collapse
|
6
|
Richards-Henderson NK, Goldstein AH, Wilson KR. Large enhancement in the heterogeneous oxidation rate of organic aerosols by hydroxyl radicals in the presence of nitric oxide. J Phys Chem Lett 2015; 6:4451-4455. [PMID: 26505970 DOI: 10.1021/acs.jpclett.5b02121] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In the troposphere, the heterogeneous lifetime of an organic molecule in an aerosol exposed to hydroxyl radicals (OH) is thought to be weeks, which is orders of magnitude slower than the analogous gas phase reactions (hours). Here, we report an unexpectedly large acceleration in the effective heterogeneous OH reaction rate in the presence of NO. This 10-50 fold acceleration originates from free radical chain reactions, propagated by alkoxy radicals that form inside the aerosol by the reaction of NO with peroxy radicals, which do not appear to produce chain terminating products (e.g., alkyl nitrates), unlike gas phase mechanisms. A kinetic model, constrained by experiments, suggests that in polluted regions heterogeneous oxidation plays a much more prominent role in the daily chemical evolution of organic aerosol than previously believed.
Collapse
Affiliation(s)
- Nicole K Richards-Henderson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Allen H Goldstein
- Department of Environmental Science, Policy and Management, University of California Berkeley , Berkeley, California 94720, United States
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| |
Collapse
|
7
|
Kroll JH, Lim CY, Kessler SH, Wilson KR. Heterogeneous Oxidation of Atmospheric Organic Aerosol: Kinetics of Changes to the Amount and Oxidation State of Particle-Phase Organic Carbon. J Phys Chem A 2015; 119:10767-83. [PMID: 26381466 DOI: 10.1021/acs.jpca.5b06946] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Atmospheric oxidation reactions are known to affect the chemical composition of organic aerosol (OA) particles over timescales of several days, but the details of such oxidative aging reactions are poorly understood. In this study we examine the rates and products of a key class of aging reaction, the heterogeneous oxidation of particle-phase organic species by the gas-phase hydroxyl radical (OH). We compile and reanalyze a number of previous studies from our laboratories involving the oxidation of single-component organic particles. All kinetic and product data are described on a common basis, enabling a straightforward comparison among different chemical systems and experimental conditions. Oxidation chemistry is described in terms of changes to key ensemble properties of the OA, rather than to its detailed molecular composition, focusing on two quantities in particular, the amount and the oxidation state of the particle-phase carbon. Heterogeneous oxidation increases the oxidation state of particulate carbon, with the rate of increase determined by the detailed chemical mechanism. At the same time, the amount of particle-phase carbon decreases with oxidation, due to fragmentation (C-C scission) reactions that form small, volatile products that escape to the gas phase. In contrast to the oxidation state increase, the rate of carbon loss is nearly uniform among most systems studied. Extrapolation of these results to atmospheric conditions indicates that heterogeneous oxidation can have a substantial effect on the amount and composition of atmospheric OA over timescales of several days, a prediction that is broadly in line with available measurements of OA evolution over such long timescales. In particular, 3-13% of particle-phase carbon is lost to the gas phase after one week of heterogeneous oxidation. Our results indicate that oxidative aging represents an important sink for particulate organic carbon, and more generally that fragmentation reactions play a major role in the lifecycle of atmospheric OA.
Collapse
Affiliation(s)
| | | | | | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| |
Collapse
|
8
|
Houle FA, Hinsberg WD, Wilson KR. Oxidation of a model alkane aerosol by OH radical: the emergent nature of reactive uptake. Phys Chem Chem Phys 2015; 17:4412-23. [DOI: 10.1039/c4cp05093b] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactive uptake of OH by organic aerosol particles is situational and related to internal diffusion distances between OH sticking events.
Collapse
Affiliation(s)
- F. A. Houle
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | | | - K. R. Wilson
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| |
Collapse
|
9
|
Nah T, Zhang H, Worton DR, Ruehl CR, Kirk BB, Goldstein AH, Leone SR, Wilson KR. Isomeric Product Detection in the Heterogeneous Reaction of Hydroxyl Radicals with Aerosol Composed of Branched and Linear Unsaturated Organic Molecules. J Phys Chem A 2014; 118:11555-71. [DOI: 10.1021/jp508378z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | - David R. Worton
- Aerosol Dynamics Inc., Berkeley, California 94710, United States
| | | | | | | | | | | |
Collapse
|
10
|
Zhang H, Ruehl CR, Chan AWH, Nah T, Worton DR, Isaacman G, Goldstein AH, Wilson KR. OH-Initiated Heterogeneous Oxidation of Cholestane: A Model System for Understanding the Photochemical Aging of Cyclic Alkane Aerosols. J Phys Chem A 2013; 117:12449-58. [DOI: 10.1021/jp407994m] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Haofei Zhang
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Environmental Sciences, Policy, and Management, University of California, Berkeley, California 94720, United States
| | - Christopher R. Ruehl
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Arthur W. H. Chan
- Department
of Environmental Sciences, Policy, and Management, University of California, Berkeley, California 94720, United States
| | - Theodora Nah
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - David R. Worton
- Department
of Environmental Sciences, Policy, and Management, University of California, Berkeley, California 94720, United States
- Aerosol
Dynamics Inc., Berkeley, California 94720, United States
| | - Gabriel Isaacman
- Department
of Environmental Sciences, Policy, and Management, University of California, Berkeley, California 94720, United States
| | - Allen H. Goldstein
- Department
of Environmental Sciences, Policy, and Management, University of California, Berkeley, California 94720, United States
- Environmental
and Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
| | - Kevin R. Wilson
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| |
Collapse
|
11
|
Shiraiwa M, Zuend A, Bertram AK, Seinfeld JH. Gas-particle partitioning of atmospheric aerosols: interplay of physical state, non-ideal mixing and morphology. Phys Chem Chem Phys 2013; 15:11441-53. [PMID: 23748935 DOI: 10.1039/c3cp51595h] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atmospheric aerosols, comprising organic compounds and inorganic salts, play a key role in air quality and climate. Mounting evidence exists that these particles frequently exhibit phase separation into predominantly organic and aqueous electrolyte-rich phases. As well, the presence of amorphous semi-solid or glassy particle phases has been established. Using the canonical system of ammonium sulfate mixed with organics from the ozone oxidation of α-pinene, we illustrate theoretically the interplay of physical state, non-ideality, and particle morphology affecting aerosol mass concentration and the characteristic timescale of gas-particle mass transfer. Phase separation can significantly affect overall particle mass and chemical composition. Semi-solid or glassy phases can kinetically inhibit the partitioning of semivolatile components and hygroscopic growth, in contrast to the traditional assumption that organic compounds exist in quasi-instantaneous gas-particle equilibrium. These effects have significant implications for the interpretation of laboratory data and the development of improved atmospheric air quality and climate models.
Collapse
Affiliation(s)
- Manabu Shiraiwa
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | | | | | | |
Collapse
|
12
|
Ruehl CR, Nah T, Isaacman G, Worton DR, Chan AWH, Kolesar KR, Cappa CD, Goldstein AH, Wilson KR. The Influence of Molecular Structure and Aerosol Phase on the Heterogeneous Oxidation of Normal and Branched Alkanes by OH. J Phys Chem A 2013; 117:3990-4000. [DOI: 10.1021/jp401888q] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher R. Ruehl
- Chemical Sciences Division,
Lawrence Berkeley National Laboratory, Berkeley, California 94720,
United States
- Department of Environmental Sciences, Policy, & Management, University of California, Berkeley, California 94720, United States
| | - Theodora Nah
- Chemical Sciences Division,
Lawrence Berkeley National Laboratory, Berkeley, California 94720,
United States
- Department of Chemistry, University
of California, Berkeley, California 94720, United States
| | - Gabriel Isaacman
- Department of Environmental Sciences, Policy, & Management, University of California, Berkeley, California 94720, United States
| | - David R. Worton
- Department of Environmental Sciences, Policy, & Management, University of California, Berkeley, California 94720, United States
- Aerosol Dynamics Inc., Berkeley,
California 94710, United States
| | - Arthur W. H. Chan
- Department of Environmental Sciences, Policy, & Management, University of California, Berkeley, California 94720, United States
| | - Katheryn R. Kolesar
- Department of Civil & Environmental Engineering, University of California, Davis, California 95616, United States
| | - Christopher D. Cappa
- Department of Civil & Environmental Engineering, University of California, Davis, California 95616, United States
| | - Allen H. Goldstein
- Department of Environmental Sciences, Policy, & Management, University of California, Berkeley, California 94720, United States
- Department of Civil & Environmental Engineering, University of California, Berkeley, California 94720, United States
- Environmental
Energy Technologies
Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
| | - Kevin R. Wilson
- Chemical Sciences Division,
Lawrence Berkeley National Laboratory, Berkeley, California 94720,
United States
| |
Collapse
|
13
|
Kessler SH, Nah T, Daumit KE, Smith JD, Leone SR, Kolb CE, Worsnop DR, Wilson KR, Kroll JH. OH-Initiated Heterogeneous Aging of Highly Oxidized Organic Aerosol. J Phys Chem A 2012; 116:6358-65. [DOI: 10.1021/jp212131m] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sean H. Kessler
- Department of Chemical
Engineering, Massachusetts Institute of Technology, Cambridge Massachusetts 02139, United States
| | - Theodora Nah
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley California
94720, United States
- Department of Chemistry, University of California, Berkeley,
California 94720, United States
| | - Kelly E. Daumit
- Department of Civil
and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
| | - Jared D. Smith
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley California
94720, United States
| | - Stephen R. Leone
- Department of Chemistry, University of California, Berkeley,
California 94720, United States
| | - Charles E. Kolb
- Center for
Aerosol and Cloud
Chemistry, Aerodyne Research Inc., Billerica,
Massachusetts 01821, United States
| | - Douglas R. Worsnop
- Center for
Aerosol and Cloud
Chemistry, Aerodyne Research Inc., Billerica,
Massachusetts 01821, United States
| | - Kevin R. Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley California
94720, United States
| | - Jesse H. Kroll
- Department of Chemical
Engineering, Massachusetts Institute of Technology, Cambridge Massachusetts 02139, United States
- Department of Civil
and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
| |
Collapse
|
14
|
Abbatt JPD, Lee AKY, Thornton JA. Quantifying trace gas uptake to tropospheric aerosol: recent advances and remaining challenges. Chem Soc Rev 2012; 41:6555-81. [DOI: 10.1039/c2cs35052a] [Citation(s) in RCA: 161] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
15
|
Pratt KA, Prather KA. Mass spectrometry of atmospheric aerosols--recent developments and applications. Part II: On-line mass spectrometry techniques. MASS SPECTROMETRY REVIEWS 2012; 31:17-48. [PMID: 21449003 DOI: 10.1002/mas.20330] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 08/19/2010] [Accepted: 08/19/2010] [Indexed: 05/30/2023]
Abstract
Many of the significant advances in our understanding of atmospheric particles can be attributed to the application of mass spectrometry. Mass spectrometry provides high sensitivity with fast response time to probe chemically complex particles. This review focuses on recent developments and applications in the field of mass spectrometry of atmospheric aerosols. In Part II of this two-part review, we concentrate on real-time mass spectrometry techniques, which provide high time resolution for insight into brief events and diurnal changes while eliminating the potential artifacts acquired during long-term filter sampling. In particular, real-time mass spectrometry has been shown recently to provide the ability to probe the chemical composition of ambient individual particles <30 nm in diameter to further our understanding of how particles are formed through nucleation in the atmosphere. Further, transportable real-time mass spectrometry techniques are now used frequently on ground-, ship-, and aircraft-based studies around the globe to further our understanding of the spatial distribution of atmospheric aerosols. In addition, coupling aerosol mass spectrometry techniques with other measurements in series has allowed the in situ determination of chemically resolved particle effective density, refractive index, volatility, and cloud activation properties.
Collapse
Affiliation(s)
- Kerri A Pratt
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | | |
Collapse
|
16
|
Xiao S, Bertram AK. Reactive uptake kinetics of NO3 on multicomponent and multiphase organic mixtures containing unsaturated and saturated organics. Phys Chem Chem Phys 2011; 13:6628-36. [PMID: 21369605 DOI: 10.1039/c0cp02682d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We investigated the reactive uptake of NO(3) (an important night-time oxidant in the atmosphere) on binary mixtures containing an unsaturated organic (methyl oleate) and saturated molecules (diethyl sebacate, dioctyl sebacate, and squalane) which we call matrix molecules. These studies were carried out to better understand the reactivity of unsaturated organics in multicomponent and multiphase atmospheric particles. For liquid binary mixtures the reactivity of methyl oleate depended on the matrix molecule. Assuming a bulk reaction, H(matrix)√(D(matrix)k(oleate)) varied by a factor of 2.7, and assuming a surface reaction H(matrix)(S)K(matrix)(S)k(oleate)(S) varied by a factor of 3.6, where H(matrix)√(D(matrix)k(oleate) and H(matrix)(S)K(matrix)(S)k(oleate)(S) are constants extracted from the data using the resistor model. For solid-liquid mixtures, the reactive uptake coefficient depended on exposure time: the uptake decreased by a factor of 10 after exposure to NO(3) for approximately 90 min. By assuming either a bulk or surface reaction, the atmospheric lifetime of methyl oleate in different matrices was estimated for moderately polluted atmospheric conditions. For all liquid mixtures, the lifetime was in the order of a few minutes (with an upper limit of 35 min). These lifetimes can be used as lower limits to the lifetimes in semi-solid mixtures. Our studies emphasize that the lifetime of unsaturated organics (similar to methyl oleate) is likely short if the particle matrix is in a liquid state.
Collapse
Affiliation(s)
- S Xiao
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | | |
Collapse
|
17
|
Iannone R, Xiao S, Bertram AK. Potentially important nighttime heterogeneous chemistry: NO3 with aldehydes and N2O5 with alcohols. Phys Chem Chem Phys 2011; 13:10214-23. [DOI: 10.1039/c1cp20294d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
18
|
Waring C, King KL, Bagot PAJ, Costen ML, McKendrick KG. Collision dynamics and reactive uptake of OH radicals at liquid surfaces of atmospheric interest. Phys Chem Chem Phys 2011; 13:8457-69. [DOI: 10.1039/c0cp02734k] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
19
|
Pope FD, Gallimore PJ, Fuller SJ, Cox RA, Kalberer M. Ozonolysis of maleic acid aerosols: effect upon aerosol hygroscopicity, phase and mass. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:6656-6660. [PMID: 20701273 DOI: 10.1021/es1008278] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The hygroscopicity and mass loss of aerosols initially composed of maleic acid have been investigated before and after reaction with ozone. The phase of the aerosol, solid or aqueous, during the reaction with ozone strongly affects the composition of the processed aerosol. Furthermore the loss of aerosol mass, via the production of volatile ozonolysis products, does not occur until the processed aerosol has existed as an aqueous phase aerosol. The loss rate of the aerosol mass appears to follow unimolecular first order kinetics which is consistent with the rate determining step being the cleavage of a weak hydroperoxide, or peroxide, bond (approximately 104 kJ mol(-1)). This speculative rate determining step, which is not based on chemical analysis, is possibly a universal feature in the ozonolysis of organic aerosol containing the alkene functionality.
Collapse
Affiliation(s)
- F D Pope
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | | | | | | | | |
Collapse
|
20
|
Abstract
Atmospheric aerosol particles play pivotal roles in climate and air quality. Just as chemically reduced gases experience oxidation in the atmosphere, it is now apparent that solid and liquid atmospheric particulates are also subject to similar oxidative processes. The most reactive atmospheric gas-phase radicals, in particular the hydroxyl radical, readily promote such chemistry through surficial interactions. This Review looks at progress made in this field, discussing the radical-initiated heterogeneous oxidation of organic and inorganic constituents of atmospheric aerosols. We focus on the kinetics and reaction mechanisms of such processes as well as how they can affect the physico-chemical properties of particles, such as their composition, size, density and hygroscopicity. Potential impacts on the atmosphere include the release of chemically reactive gases such as halogens, aldehydes and organic acids, reactive loss of particle-borne molecular tracer and toxic species, and enhanced hygroscopic properties of aerosols that may improve their ability to form cloud droplets.
Collapse
|
21
|
Renbaum LH, Smith GD. Organic nitrate formation in the radical-initiated oxidation of model aerosol particles in the presence of NOx. Phys Chem Chem Phys 2009; 11:8040-7. [DOI: 10.1039/b909239k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|