1
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Jansen KT, Browne EC, Tolbert MA. Secondary Brown Carbon Aerosol Resists Bleaching by Ozone under Acidic Conditions. J Phys Chem A 2024. [PMID: 39078128 DOI: 10.1021/acs.jpca.4c02356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Light-absorbing organic aerosol (brown carbon, BrC) can affect Earth's radiative balance. However, owing to uncertainties in BrC sources, composition, and lifetime, the radiative impact of BrC is poorly constrained. In particular, the effects of heterogeneous oxidation and the influence of aerosol pH on the lifetime and light absorption properties of BrC are not well established. In a series of laboratory experiments, we characterize the changes in the chemical composition and optical properties of BrC aerosol upon heterogeneous oxidation by ozone (O3). BrC analogs were generated by reacting glyoxal with ammonium sulfate in bulk solutions. The resulting solutions were pH adjusted before being atomized and oxidized in a flow reactor, with online measurements of the aerosol optical and chemical properties to monitor changes from oxidation. For the conditions investigated here, we find that ozonolysis diminishes the ability of BrC material to absorb light, presumably due to the degradation of the BrC chromophores. While the BrC has a lifetime of 1-2 h due to ozonolysis, it effectively stops bleaching after <6 h of atmospheric processing, leaving behind an ozone (O3) resistant fraction of BrC. We observed a pH dependence on oxidation and bleaching with acidic BrC bleaching more slowly and remaining more absorbing than more basic samples. Given that submicron atmospheric aerosols are typically acidic and rapidly undergo partial bleaching, we suggest that the complex refractive index (RI; m) of secondary glyoxal-ammonium BrC should be modeled using data from the recalcitrant fraction of acidic aerosols. This study reports aerosols generated from a pH = 1.51 solution having a RI of m = 1.48 + 1.2 × 10-3 i and m = 1.53 + 2.9 × 10-4 i at 405 and 532 nm, respectively after aging with O3. A comprehensive treatment of BrC lifetime will require this process to be considered in conjunction with other bleaching mechanisms such as photolysis and reactions with OH.
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Affiliation(s)
- Kevin T Jansen
- Department of Chemistry, University of Colorado, 215 UCB, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, 216 UCB, Boulder, Colorado 80309, United States
| | - Eleanor C Browne
- Department of Chemistry, University of Colorado, 215 UCB, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, 216 UCB, Boulder, Colorado 80309, United States
| | - Margaret A Tolbert
- Department of Chemistry, University of Colorado, 215 UCB, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, 216 UCB, Boulder, Colorado 80309, United States
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2
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Zeng M, Wilson KR. Evaluating Possible Formation Mechanisms of Criegee Intermediates during the Heterogeneous Autoxidation of Squalene. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:11587-11595. [PMID: 38900151 DOI: 10.1021/acs.est.4c02590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Organic molecules in the environment oxidatively degrade by a variety of free radical, microbial, and biogeochemical pathways. A significant pathway is heterogeneous autoxidation, in which degradation occurs via a network of carbon and oxygen centered free radicals. Recently, we found evidence for a new heterogeneous autoxidation mechanism of squalene that is initiated by hydroxyl (OH) radical addition to a carbon-carbon double bond and apparently propagated through pathways involving Criegee Intermediates (CI) produced from β-hydroxy peroxy radicals (β-OH-RO2•). It remains unclear, however, exactly how CI are formed from β-OH-RO2•, which could occur by a unimolecular or bimolecular pathway. Combining kinetic models and multiphase OH oxidation measurements of squalene, we evaluate the kinetic viability of three mechanistic scenarios. Scenario 1 assumes that CI are formed by the unimolecular bond scission of β-OH-RO2•, whereas Scenarios 2 and 3 test bimolecular pathways of β-OH-RO2• to yield CI. Scenario 1 best replicates the entire experimental data set, which includes effective uptake coefficients vs [OH] as well as the formation kinetics of the major products (i.e., aldehydes and secondary ozonides). Although the unimolecular pathway appears to be kinetically viable, future high-level theory is needed to fully explain the mechanistic relationship between CI and β-OH-RO2• in the condensed phase.
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Affiliation(s)
- Meirong Zeng
- College of Smart Energy, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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3
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Nguyen TB, Bates KH, Buenconsejo RS, Charan SM, Cavanna EE, Cocker DR, Day DA, DeVault MP, Donahue NM, Finewax Z, Habib LF, Handschy AV, Hildebrandt Ruiz L, Hou CYS, Jimenez JL, Joo T, Klodt AL, Kong W, Le C, Masoud CG, Mayernik MS, Ng NL, Nienhouse EJ, Nizkorodov SA, Orlando JJ, Post JJ, Sturm PO, Thrasher BL, Tyndall GS, Seinfeld JH, Worley SJ, Zhang X, Ziemann PJ. Overview of ICARUS-A Curated, Open Access, Online Repository for Atmospheric Simulation Chamber Data. ACS EARTH & SPACE CHEMISTRY 2023; 7:1235-1246. [PMID: 37342759 PMCID: PMC10278178 DOI: 10.1021/acsearthspacechem.3c00043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 04/18/2023] [Accepted: 05/01/2023] [Indexed: 06/23/2023]
Abstract
Atmospheric simulation chambers continue to be indispensable tools for research in the atmospheric sciences. Insights from chamber studies are integrated into atmospheric chemical transport models, which are used for science-informed policy decisions. However, a centralized data management and access infrastructure for their scientific products had not been available in the United States and many parts of the world. ICARUS (Integrated Chamber Atmospheric data Repository for Unified Science) is an open access, searchable, web-based infrastructure for storing, sharing, discovering, and utilizing atmospheric chamber data [https://icarus.ucdavis.edu]. ICARUS has two parts: a data intake portal and a search and discovery portal. Data in ICARUS are curated, uniform, interactive, indexed on popular search engines, mirrored by other repositories, version-tracked, vocabulary-controlled, and citable. ICARUS hosts both legacy data and new data in compliance with open access data mandates. Targeted data discovery is available based on key experimental parameters, including organic reactants and mixtures that are managed using the PubChem chemical database, oxidant information, nitrogen oxide (NOx) content, alkylperoxy radical (RO2) fate, seed particle information, environmental conditions, and reaction categories. A discipline-specific repository such as ICARUS with high amounts of metadata works to support the evaluation and revision of atmospheric model mechanisms, intercomparison of data and models, and the development of new model frameworks that can have more predictive power in the current and future atmosphere. The open accessibility and interactive nature of ICARUS data may also be useful for teaching, data mining, and training machine learning models.
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Affiliation(s)
- Tran B. Nguyen
- Department
of Environmental Toxicology, University
of California Davis, Davis, California 95616, United States
| | - Kelvin H. Bates
- Department
of Environmental Toxicology, University
of California Davis, Davis, California 95616, United States
- Center
for the Environment, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Reina S. Buenconsejo
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Sophia M. Charan
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Eric E. Cavanna
- Information
and Educational Technology, University of
California Davis, Davis, California 95616, United States
| | - David R. Cocker
- Department
Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92507, United States
| | - Douglas A. Day
- Cooperative
Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Marla P. DeVault
- Cooperative
Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Neil M. Donahue
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Chemical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Engineering and Public Policy, Carnegie
Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Zachary Finewax
- Cooperative
Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Luke F. Habib
- Department
of Chemical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Anne V. Handschy
- Cooperative
Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Lea Hildebrandt Ruiz
- McKetta
Department of Chemical Engineering, The
University of Texas at Austin, Austin, Texas 78712, United States
| | - Chung-Yi S. Hou
- Data Stewardship Engineering Team, National
Center for Atmospheric Research, Boulder, Colorado 80307, United States
| | - Jose L. Jimenez
- Cooperative
Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Taekyu Joo
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Alexandra L. Klodt
- Department of Chemistry, University of
California Irvine, Irvine, California 92697, United States
| | - Weimeng Kong
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Chen Le
- Department
Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92507, United States
| | - Catherine G. Masoud
- McKetta
Department of Chemical Engineering, The
University of Texas at Austin, Austin, Texas 78712, United States
| | - Matthew S. Mayernik
- Data Stewardship Engineering Team, National
Center for Atmospheric Research, Boulder, Colorado 80307, United States
| | - Nga L. Ng
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- School of
Chemical and Biomolecular Engineering, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
- School of
Civil and Environmental Engineering, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - Eric J. Nienhouse
- Data Stewardship Engineering Team, National
Center for Atmospheric Research, Boulder, Colorado 80307, United States
| | - Sergey A. Nizkorodov
- Department of Chemistry, University of
California Irvine, Irvine, California 92697, United States
| | - John J. Orlando
- Atmospheric
Chemistry Observations and Modeling, National
Center for Atmospheric Research, Boulder, Colorado 80305, United States
| | - Jeroen J. Post
- Information
and Educational Technology, University of
California Davis, Davis, California 95616, United States
| | - Patrick O. Sturm
- Air Quality Research Center, University
of California Davis, Davis, California 95616, United States
| | - Bridget L. Thrasher
- Data Stewardship Engineering Team, National
Center for Atmospheric Research, Boulder, Colorado 80307, United States
| | - Geoffrey S. Tyndall
- Atmospheric
Chemistry Observations and Modeling, National
Center for Atmospheric Research, Boulder, Colorado 80305, United States
| | - John H. Seinfeld
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
- Division
of Engineering and Applied Science, Calif.
Institute of Technology, Pasadena, California 91125, United States
| | - Steven J. Worley
- Data Stewardship Engineering Team, National
Center for Atmospheric Research, Boulder, Colorado 80307, United States
| | - Xuan Zhang
- Atmospheric
Chemistry Observations and Modeling, National
Center for Atmospheric Research, Boulder, Colorado 80305, United States
| | - Paul J. Ziemann
- Cooperative
Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
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4
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Zhang W, Zhao Z, Shen C, Zhang H. Unexpectedly Efficient Aging of Organic Aerosols Mediated by Autoxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:6965-6974. [PMID: 37083304 DOI: 10.1021/acs.est.2c09773] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Multiphase oxidative aging is a ubiquitous process for atmospheric organic aerosols (OA). But its kinetics was often found to be slow in previous laboratory studies where high hydroxyl radical concentrations ([•OH]) were used. In this study, we performed heterogeneous oxidation experiments of several model OA systems under varied aging timescales and gas-phase [•OH]. Our results suggest that OA heterogeneous oxidation may be 2-3 orders of magnitude faster when [•OH] is decreased from typical laboratory flow tube conditions to atmospheric levels. Direct laboratory mass spectrometry measurements coupled with kinetic simulations suggest that an intermolecular autoxidation mechanism mediated by particle-phase peroxy radicals greatly accelerates OA oxidation, with enhanced formation of organic hydroperoxides, alcohols, and fragmentation products. With autoxidation, we estimate that the OA oxidation timescale in the atmosphere may be from less than a day to several days. Thus, OA oxidative aging can have greater atmospheric impacts than previously expected. Furthermore, our findings reveal the nature of heterogeneous aerosol oxidation chemistry in the atmosphere and help improve the understanding and prediction of atmospheric OA aging and composition evolution.
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Affiliation(s)
- Wen Zhang
- Department of Chemistry, University of California, Riverside, California 92507, United States
| | - Zixu Zhao
- Department of Chemistry, University of California, Riverside, California 92507, United States
| | - Chuanyang Shen
- Department of Chemistry, University of California, Riverside, California 92507, United States
| | - Haofei Zhang
- Department of Chemistry, University of California, Riverside, California 92507, United States
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5
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Zeng M, Liu CL, Wilson KR. Catalytic Coupling of Free Radical Oxidation and Electrophilic Chlorine Addition by Phase-Transfer Intermediates in Liquid Aerosols. J Phys Chem A 2022; 126:2959-2965. [PMID: 35511037 DOI: 10.1021/acs.jpca.2c00291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
While examining the heterogeneous reaction of chlorine atoms with alkenes, in the presence of Cl2, we have observed an unexpectedly large enhancement of reactivity and the predominance of chlorinated reaction products even under high O2 conditions, where Cl atom recycling is expected to be minimal. These observations cannot be explained by known free radical oxidation or cycling mechanisms, but rather we find evidence for the multiphase catalytic coupling of free radical oxidation with electrophilic Cl2 addition. The mechanism entails the production of oxygenated reaction intermediates, which act as gas-liquid phase-transfer catalysts (gl-PTCs) by promoting the accommodation of gas-phase Cl2 by the aerosol, thereby enhancing electrophilic addition. Although the majority of PTCs typically couple chemistry between two immiscible liquid phases (aqueous/organic), there are few examples of PTCs that couple gas-liquid reactions. This work shows how multiphase reaction schemes of aerosols can be reimagined for understanding catalytic reaction mechanisms.
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Affiliation(s)
- Meirong Zeng
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Chen-Lin Liu
- Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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6
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Kohli RK, Davies JF. Measuring the Chemical Evolution of Levitated Particles: A Study on the Evaporation of Multicomponent Organic Aerosol. Anal Chem 2021; 93:12472-12479. [PMID: 34455787 DOI: 10.1021/acs.analchem.1c02890] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Single-particle levitation methods provide an effective platform for probing the physical properties of atmospheric aerosol via micrometer-sized particles. Until recently, chemical composition measurements on levitated particles were limited to spectroscopy, yielding only basic chemical information. Here, we describe, benchmark, and discuss the applications of an approach for probing the physical properties and chemical composition of single levitated particles using high-resolution mass spectrometry (MS). Using a linear quadrupole electrodynamic balance (LQ-EDB) coupled to paper spray mass spectrometry, we report accurate measurements of the evolving size within 5 nm (using broadband light scattering) and relative composition (using MS) of evaporating multicomponent levitated particles in real time. Measurements of the evaporation dynamics of semivolatile organic particles containing a range of n-ethylene glycols (n = 3, 4, and 6) in various binary and ternary mixtures were made under dry conditions and compared with predictions from a gas-phase diffusion evaporation model. Under assumptions of ideal mixing, excellent agreement for both size and composition evolution between measurements and models were obtained for these mixtures. At increased relative humidity, the presence of water in particles causes the assumption of ideality to break down, and the evaporative mass flux becomes a function of the mole fraction and activity coefficient. Through compositionally resolved evaporation measurements and thermodynamic models, we characterize the activity of organic components in multicomponent particles. Our results demonstrate that the LQ-EDB-MS platform can identify time-dependent size and compositional changes with high precision and reproducibility, yielding an effective methodology for future studies on chemical aging and gas-particle partitioning in suspended particles.
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Affiliation(s)
- Ravleen Kaur Kohli
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - James F Davies
- Department of Chemistry, University of California, Riverside, California 92521, United States
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7
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Li J, Knopf DA. Representation of Multiphase OH Oxidation of Amorphous Organic Aerosol for Tropospheric Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:7266-7275. [PMID: 33974411 DOI: 10.1021/acs.est.0c07668] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Organic aerosol (OA) is ubiquitous in the atmosphere and, during transport, can experience chemical transformation with consequences for air quality and climate. Prediction of the chemical evolution of OA depends on its reactivity with atmospheric oxidants such as the OH radical. OA particles undergo amorphous phase transitions from liquid to solid (glassy) states in response to temperature changes, which, in turn, will impact its reactivity toward OH oxidation. To improve the predictability of OA reactivity toward OH oxidation, the reactive uptake coefficients (γ) of OH radicals reacting with triacontane and squalane serving as amorphous OA surrogates were measured at temperatures from 213-293 K. γ increases strongest with temperature when the organic species is in the liquid phase, compared to when being in the semisolid or solid phase. The resistor model is applied, accounting for the amorphous phase state changes using the organic species' glass transition temperature and fragility, to evaluate the physicochemical parameters of the temperature dependent OH uptake process. This allows for the derivation of a semiempirical formula, applicable to models, to predict the degree of oxidation and chemical lifetime of the condensed-phase organic species for typical tropospheric temperature and humidity when OA particle viscosity is known.
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Affiliation(s)
- Jienan Li
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794, United States
| | - Daniel A Knopf
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794, United States
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8
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Zeng M, Wilson KR. Efficient Coupling of Reaction Pathways of Criegee Intermediates and Free Radicals in the Heterogeneous Ozonolysis of Alkenes. J Phys Chem Lett 2020; 11:6580-6585. [PMID: 32787230 DOI: 10.1021/acs.jpclett.0c01823] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In the gas phase, ozonolysis of olefins is known to be a significant source of free radicals. However, for heterogeneous and condensed phase ozone reactions, the importance of reaction pathways that couple Criegee intermediates (CI) with hydroxyl (OH), alkoxy, and peroxy free radicals remains uncertain. Here we report experimental evidence for substantial free radical oxidation during the heterogeneous reaction of O3 with cis-9-tricosene (Tri) aerosol. A kinetic model with three coupled submechanisms that include O3, CI, and free radical reactions is used to explain how the observed Tri reactivity and its product distributions depend upon [O3], [OH], and the presence of CI scavengers. During multiphase ozonolysis, the kinetic model predicts that only ∼30% of the alkene is actually consumed by O3, while the remaining ∼70% is consumed by free radicals that cycle through pathways involving CI. These results reveal the importance of free radical oxidation during heterogeneous ozonolysis, which has been previously difficult to isolate due to the complex coupling of CI and OH reaction pathways.
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Affiliation(s)
- Meirong Zeng
- Chemical Sciences 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
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9
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Evidence that Criegee intermediates drive autoxidation in unsaturated lipids. Proc Natl Acad Sci U S A 2020; 117:4486-4490. [PMID: 32071215 DOI: 10.1073/pnas.1920765117] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Autoxidation is an autocatalytic free-radical chain reaction responsible for the oxidative destruction of organic molecules in biological cells, foods, plastics, petrochemicals, fuels, and the environment. In cellular membranes, lipid autoxidation (peroxidation) is linked with oxidative stress, age-related diseases, and cancers. The established mechanism of autoxidation proceeds via H-atom abstraction through a cyclic network of peroxy-hydroperoxide-mediated free-radical chain reactions. For a series of model unsaturated lipids, we present evidence for an autoxidation mechanism, initiated by hydroxyl radical (OH) addition to C=C bonds and propagated by chain reactions involving Criegee intermediates (CIs). This mechanism leads to unexpectedly rapid autoxidation even in the presence of water, implying that as reactive intermediates, CI could play a much more prominent role in chemistries beyond the atmosphere.
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10
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Peng Z, Jimenez JL. Radical chemistry in oxidation flow reactors for atmospheric chemistry research. Chem Soc Rev 2020; 49:2570-2616. [DOI: 10.1039/c9cs00766k] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We summarize the studies on the chemistry in oxidation flow reactor and discuss its atmospheric relevance.
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Affiliation(s)
- Zhe Peng
- Cooperative Institute for Research in Environmental Sciences and Department of Chemistry
- University of Colorado
- Boulder
- USA
| | - Jose L. Jimenez
- Cooperative Institute for Research in Environmental Sciences and Department of Chemistry
- University of Colorado
- Boulder
- USA
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11
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Bianchini RH, Roman MJ, Costen ML, McKendrick KG. Real-space laser-induced fluorescence imaging applied to gas-liquid interfacial scattering. J Chem Phys 2019. [DOI: 10.1063/1.5110517] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Robert H. Bianchini
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Maksymilian J. Roman
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Matthew L. Costen
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Kenneth G. McKendrick
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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12
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Jacobs MI, Xu B, Kostko O, Wiegel AA, Houle FA, Ahmed M, Wilson KR. Using Nanoparticle X-ray Spectroscopy to Probe the Formation of Reactive Chemical Gradients in Diffusion-Limited Aerosols. J Phys Chem A 2019; 123:6034-6044. [DOI: 10.1021/acs.jpca.9b04507] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Michael I. Jacobs
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Bo Xu
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Oleg Kostko
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Aaron A. Wiegel
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Frances A. Houle
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Musahid Ahmed
- Chemical Sciences 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
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13
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Houle FA, Wiegel AA, Wilson KR. Predicting Aerosol Reactivity Across Scales: from the Laboratory to the Atmosphere. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:13774-13781. [PMID: 30412390 DOI: 10.1021/acs.est.8b04688] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
To fully utilize the results of laboratory-based studies of the chemistry of model atmospheric aerosol reactions, it is important to understand how to relate them to the conditions found in nature. In this study, we have taken a validated reaction-diffusion mechanism for oxidation of C30H62 aerosol by OH under flow tube conditions and examined its predictions for another experimental regime (continuous flow stirred tank reactor) and for the atmosphere, spanning alkane aerosol viscosities from liquid to semisolid. The results show that under OH-concentration-limited and aerosol-mixing-limited conditions, it should be possible to select laboratory experimental conditions where many aspects of the particle phase and volatile product chemistry under atmospheric conditions can be revealed. If the OH collision and organic diffusion rates are comparable, however, reactivity is highly sensitive to the details of both OH concentration and internal mixing. The characteristics of the transition between limiting conditions provide key insights into which parts of the reaction mechanism dominate in the various kinetic regimes.
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Affiliation(s)
- Frances A Houle
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , 1 Cyclotron Road , Berkeley , California 94720 , United States
| | - Aaron A Wiegel
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , 1 Cyclotron Road , Berkeley , California 94720 , United States
| | - Kevin R Wilson
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , 1 Cyclotron Road , Berkeley , California 94720 , United States
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14
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Lester Y, Sabach S, Zivan O, Dubowski Y. Key environmental processes affecting the fate of the insecticide chloropyrifos applied to leaves. CHEMOSPHERE 2017; 171:74-80. [PMID: 28006666 DOI: 10.1016/j.chemosphere.2016.12.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/29/2016] [Accepted: 12/04/2016] [Indexed: 06/06/2023]
Abstract
Chlorpyrifos (CP) is still a commonly employed organophosphorus insecticide worldwide. In semi-arid and Mediterranean climates, applied CP is expected to remain on leaves surfaces for relatively long time due to the lack of summer rains and common use of drip irrigation. The present work examines the loss rate of CP from leaves via different surface processes: evaporation, direct photolysis and reactions with ozone and OH radicals. Laboratory experiments showed that evaporation rate constant of CP increased from 0.109 to 0.492 h-1 with the increase in wind speed up to 4 m/s. First-order rate constant of direct photolysis, measured using a solar simulator, was k'UV = 1.15 (±0.01) x 10-20 cm2 photon-1. Second-order rate constants for the reaction of CP with ozone and OH were measured as 6 × 10-20 and 6 × 10-12 cm3 molecule-1 s-1, respectively. The above rate constants were applied successfully in an outdoor experiment to predict the disappearance of chloropyrifos under specific environmental conditions. Further modeling showed that the insecticide half-life time on exposed surfaces under typical Mediterranean environment will be in the range of 0.9-6.9 h. Evaporation is expected to be the dominant removal path under most environmental conditions, followed by direct photolysis and reaction with OH.
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Affiliation(s)
- Yaal Lester
- The Water Research Center, Tel Aviv University, 69978, Tel Aviv, Israel.
| | - Sara Sabach
- Faculty of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Ohad Zivan
- Faculty of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Yael Dubowski
- Faculty of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa, Israel
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15
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Lee L, Wilson K. The Reactive–Diffusive Length of OH and Ozone in Model Organic Aerosols. J Phys Chem A 2016; 120:6800-12. [DOI: 10.1021/acs.jpca.6b05285] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lance Lee
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Kevin Wilson
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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16
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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.
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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
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17
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Chapleski RC, Zhang Y, Troya D, Morris JR. Heterogeneous chemistry and reaction dynamics of the atmospheric oxidants, O3, NO3, and OH, on organic surfaces. Chem Soc Rev 2016; 45:3731-46. [DOI: 10.1039/c5cs00375j] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Heterogeneous chemistry of the most important atmospheric oxidants, O3, NO3, and OH, plays a central role in regulating atmospheric gas concentrations, processing aerosols, and aging materials.
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Affiliation(s)
| | - Yafen Zhang
- Department of Chemistry
- Virginia Tech
- Blacksburg
- USA
| | - Diego Troya
- Department of Chemistry
- Virginia Tech
- Blacksburg
- USA
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18
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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.
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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
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19
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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.
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Affiliation(s)
| | | | | | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
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20
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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
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21
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Enami S, Hoffmann MR, Colussi AJ. In situ mass spectrometric detection of interfacial intermediates in the oxidation of RCOOH(aq) by gas-phase OH-radicals. J Phys Chem A 2014; 118:4130-7. [PMID: 24841316 DOI: 10.1021/jp503387e] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Products and intermediates of the oxidation of aqueous alkanoic acids initiated by gas-phase hydroxyl radicals, ·OH(g), at the air-water interface were detected by mass spectrometry in a novel setup under various experimental conditions. Exposure of submillimolar RCOOH (R = methyl, n-pentyl, n-heptyl) aqueous microjets to ∼10 ns ·OH(g) pulses from the 266 nm laser flash photolysis of O3(g)/O2(g)/H2O(g) mixtures yielded an array of interfacial species that were unambiguously and simultaneously identified in situ by online electrospray mass spectrometry. We found that peroxyl radicals R(-H)(COO(-))OO· react within 50 μs to produce alcohols R(-H)(COO(-))OH and carbonyls R(-2H)(COO(-))═O via competitive Russell and Bennett-Summers mechanisms. We confirmed the formation of hydroperoxides R(-H)(COO(-))OOH in experiments performed in D2O. To our knowledge, this is the first report on the prompt and simultaneous detection of products and peroxyl/peroxide intermediates in the heterogeneous oxidation of aqueous organics initiated by ·OH(g).
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Affiliation(s)
- Shinichi Enami
- The Hakubi Center for Advanced Research, Kyoto University , Kyoto 606-8302, Japan
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22
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Petrick LM, Sabach S, Dubowski Y. Degradation of VX surrogate profenofos on surfaces via in situ photo-oxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:8751-8758. [PMID: 23876145 DOI: 10.1021/es4016537] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Surface degradation of profenofos (PF), a VX nerve gas surrogate, was investigated using in situ photo-oxidation that combines simple instrumentation and ambient gases (O2 and H2O) as a function of exposure conditions ([O3], [OH], UV light λ = 185 and/or 254 nm, relative humidity) and PF film surface density (0.38-3.8 g m(-2)). PF film 0.38 g m(-2) fully degraded after 60 min of exposure to both 254 and 185 nm UV light in humidified air and high ozone. The observed pseudo-first-order surface reaction rate constant (kobs = 0.075 ± 0.004 min(-1)) and calculated hydroxyl concentration near the film surface ([OH]g = (9 ± 2) × 10(7) molecules cm(-3)) were used to determine the second-order rate constant for heterogeneous reaction of PF and OH (k(OH)PF = (5 ± 1) × 10(-12) cm(3) molec(-1) s(-1)). PF degradation in the absence of 185 nm light or without humidity was lower (70% or 90% degradation, respectively). With denser PF films ranging from 2.3 to 3.8 g m(-2), only 80% degradation was achieved until the PF droplet was redissolved in acetonitrile which allowed >95% PF degradation. Surface product analysis indicated limited formation of the nontoxic phosphoric acid ester but the formation of nonvolatile chemicals with increased hydrophilicity and addition of OH.
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Affiliation(s)
- Lauren M Petrick
- Technion Center of Excellence in Exposure Science and Environmental Health (TCEEH), Technion-Israel Institute of Technology , Haifa, Israel.
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23
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Nah T, Kessler SH, Daumit KE, Kroll JH, Leone SR, Wilson KR. OH-initiated oxidation of sub-micron unsaturated fatty acid particles. Phys Chem Chem Phys 2013; 15:18649-63. [DOI: 10.1039/c3cp52655k] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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King KL, Paterson G, Rossi GE, Iljina M, Westacott RE, Costen ML, McKendrick KG. Inelastic scattering of OH radicals from organic liquids: isolating the thermal desorption channel. Phys Chem Chem Phys 2013; 15:12852-63. [DOI: 10.1039/c3cp51708j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Slade JH, Knopf DA. Heterogeneous OH oxidation of biomass burning organic aerosol surrogate compounds: assessment of volatilisation products and the role of OH concentration on the reactive uptake kinetics. Phys Chem Chem Phys 2013; 15:5898-915. [DOI: 10.1039/c3cp44695f] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Lee L, Wooldridge P, Nah T, Wilson K, Cohen R. Observation of rates and products in the reaction of NO3with submicron squalane and squalene aerosol. Phys Chem Chem Phys 2013. [DOI: 10.1039/c2cp42500a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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27
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Harmon CW, Ruehl CR, Cappa CD, Wilson KR. A statistical description of the evolution of cloud condensation nuclei activity during the heterogeneous oxidation of squalane and bis(2-ethylhexyl) sebacate aerosol by hydroxyl radicals. Phys Chem Chem Phys 2013; 15:9679-93. [DOI: 10.1039/c3cp50347j] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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28
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Isaacman G, Chan AWH, Nah T, Worton DR, Ruehl CR, Wilson KR, Goldstein AH. Heterogeneous OH oxidation of motor oil particles causes selective depletion of branched and less cyclic hydrocarbons. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:10632-10640. [PMID: 22947099 DOI: 10.1021/es302768a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Motor oil serves as a useful model system for atmospheric oxidation of hydrocarbon mixtures typical of anthropogenic atmospheric particulate matter, but its complexity often prevents comprehensive chemical speciation. In this work we fully characterize this formerly "unresolved complex mixture" at the molecular level using recently developed soft ionization gas chromatography techniques. Nucleated motor oil particles are oxidized in a flow tube reactor to investigate the relative reaction rates of observed hydrocarbon classes: alkanes, cycloalkanes, bicycloalkanes, tricycloalkanes, and steranes. Oxidation of hydrocarbons in a complex aerosol is found to be efficient, with approximately three-quarters (0.72 ± 0.06) of OH collisions yielding a reaction. Reaction rates of individual hydrocarbons are structurally dependent: compared to normal alkanes, reaction rates increased by 20-50% with branching, while rates decreased ∼20% per nonaromatic ring present. These differences in rates are expected to alter particle composition as a function of oxidation, with depletion of branched and enrichment of cyclic hydrocarbons. Due to this expected shift toward ring-opening reactions heterogeneous oxidation of the unreacted hydrocarbon mixture is less likely to proceed through fragmentation pathways in more oxidized particles. Based on the observed oxidation-induced changes in composition, isomer-resolved analysis has potential utility for determining the photochemical age of atmospheric particulate matter with respect to heterogeneous oxidation.
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Affiliation(s)
- Gabriel Isaacman
- Environmental Science, Policy, and Management, University of California, Berkeley, California, United States.
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29
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Renbaum-Wolff L, Smith GD. "Virtual injector" flow tube method for measuring relative rates kinetics of gas-phase and aerosol species. J Phys Chem A 2012; 116:6664-74. [PMID: 22702447 DOI: 10.1021/jp303221w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A new method for measuring gas-phase and aerosol reaction kinetics is described in which the gas flow, itself, acts as a "virtual injector" continuously increasing the contact time in analogy to conventional movable-injector kinetics techniques. In this method a laser is directed down the length of a flow tube, instantly initiating reaction by photodissociation of a precursor species at every point throughout the flow tube. Key tropospheric reactants such as OH, Cl, NO(3), and O(3) can be generated with nearly uniform concentrations along the length of the flow tube in this manner using 355 nm radiation from the third harmonic of a Nd:YAG laser. As the flow travels down the flow tube, both the gas-phase and particle-phase species react with the photogenerated radicals or O(3) for increasingly longer time before exiting and being detected. The advantages of this method are that (1) any wall loss of gas-phase and particle species is automatically accounted for, (2) the reactions are conducted under nearly pseudo-first-order conditions, (3) the progress of the reaction is followed as a continuous function of reaction time instead of reactant concentration, (4) data collection is quick with an entire decay trace being collected in as little as 1 min, (5) relative rates of several species can be measured simultaneously, and (6) bimolecular rate constants at least as small as k = 10(-17) (cm(3)/molecule)/s, or aerosol uptake coefficients at least as small as γ = 10(-4), can be measured. Using the virtual injector technique with an aerosol chemical ionization mass spectrometer (CIMS) as a detector, examples of gas-phase relative rates and uptake by oleic acid particles are given for OH, Cl, NO(3), and O(3) reactions with most agreeing to within 20% of published values, where available.
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30
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Wilson KR, Smith JD, Kessler SH, Kroll JH. The statistical evolution of multiple generations of oxidation products in the photochemical aging of chemically reduced organic aerosol. Phys Chem Chem Phys 2012; 14:1468-79. [DOI: 10.1039/c1cp22716e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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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.
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Affiliation(s)
- Kerri A Pratt
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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32
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Yu JZ, Huang XHH, Ho SSH, Bian Q. Nonpolar organic compounds in fine particles: quantification by thermal desorption–GC/MS and evidence for their significant oxidation in ambient aerosols in Hong Kong. Anal Bioanal Chem 2011; 401:3125-39. [DOI: 10.1007/s00216-011-5458-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 09/18/2011] [Accepted: 09/28/2011] [Indexed: 11/28/2022]
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33
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Waring C, Bagot PAJ, Costen ML, McKendrick KG. Reactive Scattering as a Chemically Specific Analytical Probe of Liquid Surfaces. J Phys Chem Lett 2011; 2:12-18. [PMID: 26295207 DOI: 10.1021/jz1013032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this Perspective, we highlight some recent progress in the reactive scattering of "chemical probe" species such as atoms or small radicals from liquid surfaces. We emphasize in particular the evolution of this area from purely dynamical studies of the scattering mechanism. The mechanistic understanding that has now been gained is sufficiently mature to allow the same methods to be used as an effective analytical tool. The use of this approach to measure liquid-surface composition and structure is illustrated through the scattering of O((3)P) atoms from a common, imidazolium-based family of ionic liquids.
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Affiliation(s)
- Carla Waring
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Paul A J Bagot
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Matthew L Costen
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Kenneth G McKendrick
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
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34
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Liu CL, Smith JD, Che DL, Ahmed M, Leone SR, Wilson KR. The direct observation of secondary radical chain chemistry in the heterogeneous reaction of chlorine atoms with submicron squalane droplets. Phys Chem Chem Phys 2011; 13:8993-9007. [DOI: 10.1039/c1cp20236g] [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]
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35
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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]
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36
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Leone SR, Ahmed M, Wilson KR. Chemical dynamics, molecular energetics, and kinetics at the synchrotron. Phys Chem Chem Phys 2010; 12:6564-78. [PMID: 20419177 DOI: 10.1039/c001707h] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Scientists at the Chemical Dynamics Beamline of the Advanced Light Source in Berkeley are continuously reinventing synchrotron investigations of physical chemistry and chemical physics with vacuum ultraviolet light. One of the unique aspects of a synchrotron for chemical physics research is the widely tunable vacuum ultraviolet light that permits threshold ionization of large molecules with minimal fragmentation. This provides novel opportunities to assess molecular energetics and reaction mechanisms, even beyond simple gas phase molecules. In this perspective, significant new directions utilizing the capabilities at the Chemical Dynamics Beamline are presented, along with an outlook for future synchrotron and free electron laser science in chemical dynamics. Among the established and emerging fields of investigations are cluster and biological molecule spectroscopy and structure, combustion flame chemistry mechanisms, radical kinetics and product isomer dynamics, aerosol heterogeneous chemistry, planetary and interstellar chemistry, and secondary neutral ion-beam desorption imaging of biological matter and materials chemistry.
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Affiliation(s)
- Stephen R Leone
- Department of Chemistry, University of California, Berkeley, CA 94720, USA.
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37
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Kroll JH, Smith JD, Che DL, Kessler SH, Worsnop DR, Wilson KR. Measurement of fragmentation and functionalization pathways in the heterogeneous oxidation of oxidized organic aerosol. Phys Chem Chem Phys 2009; 11:8005-14. [DOI: 10.1039/b905289e] [Citation(s) in RCA: 256] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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