1
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Chen Y, Zaveri RA, Vandergrift GW, Cheng Z, China S, Zelenyuk A, Shilling JE. Nonequilibrium Behavior in Isoprene Secondary Organic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:14182-14193. [PMID: 37708377 DOI: 10.1021/acs.est.3c03532] [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: 09/16/2023]
Abstract
Recent studies have shown that instantaneous gas-particle equilibrium partitioning assumptions fail to predict SOA formation, even at high relative humidity (∼85%), and photochemical aging seems to be one driving factor. In this study, we probe the minimum aging time scale required to observe nonequilibrium partitioning of semivolatile organic compounds (SVOCs) between the gas and aerosol phase at ∼50% RH. Seed isoprene SOA is generated by photo-oxidation in the presence of effloresced ammonium sulfate seeds at <1 ppbv NOx, aged photochemically or in the dark for 0.3-6 h, and subsequently exposed to fresh isoprene SVOCs. Our results show that the equilibrium partitioning assumption is accurate for fresh isoprene SOA but breaks down after isoprene SOA has been aged for as short as 20 min even in the dark. Modeling results show that a semisolid SOA phase state is necessary to reproduce the observed particle size distribution evolution. The observed nonequilibrium partitioning behavior and inferred semisolid phase state are corroborated by offline mass spectrometric analysis on the bulk aerosol particles showing the formation of organosulfates and oligomers. The unexpected short time scale for the phase transition within isoprene SOA has important implications for the growth of atmospheric ultrafine particles to climate-relevant sizes.
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Affiliation(s)
- Yuzhi Chen
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Rahul A Zaveri
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Gregory W Vandergrift
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Zezhen Cheng
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Swarup China
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Alla Zelenyuk
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - John E Shilling
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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2
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Kaur Kohli R, Salas S, Shokoor B, Price CL, Davies JF. Chemically Resolved Evaporation Dynamics of Dicarboxylic Acid Mixtures in Solid Particles. Anal Chem 2023. [PMID: 37490783 DOI: 10.1021/acs.analchem.3c02475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
The evaporation rate and corresponding vapor pressure of dicarboxylic acids have been the subject of numerous scientific studies over the years, with reported values spanning several orders of magnitude. Recent work has identified the importance of considering the phase state of the material during evaporation, likely accounting for some of the variability in measured vapor pressures. In the homologous series of dicarboxylic acids, the phase state under dry conditions may be crystalline or amorphous, with particles of odd-carbon-numbered acids exhibiting tendencies to remain amorphous and spherical. Although measurements of vapor pressures for pure components make up most of the available literature data, for many applications, these compounds are not present in isolation. Additionally, many systems containing a semi-volatile material exist in a solid state, especially under dry and low relative humidity conditions. In this work, we explore the evaporation of compounds present in mixed solid-state particles. Specifically, we use single particle levitation coupled with mass spectrometry to measure the evolving composition of solid particles containing mixtures of glutaric acid and succinic acid, glutaric acid and adipic acid, and malonic acid and succinic acid. Under dry conditions, these systems exhibit non-spherical geometries consistent with crystallization of one or both components into an organic crystal. Our measurements allow the evaporation of each component in the mixture to be characterized independently and effective vapor pressures of the pure components to be inferred. The resulting vapor pressures are compared against pure component vapor pressures. We demonstrate that these mixtures exhibit thermodynamic ideality but can be influenced by limited diffusion in the solid phase. These are the first results in the literature that explore the thermodynamic and kinetic factors that control the evaporative evolution of mixed solid-state particles.
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Affiliation(s)
- Ravleen Kaur Kohli
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Stephanie Salas
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Bilal Shokoor
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - Chelsea L Price
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
| | - James F Davies
- Department of Chemistry, University of California Riverside, Riverside, California 92521, United States
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3
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Jia L, Xu Y. A core-shell box model for simulating viscosity dependent secondary organic aerosol (CSVA) and its application. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 789:147954. [PMID: 34062465 DOI: 10.1016/j.scitotenv.2021.147954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/06/2021] [Accepted: 05/17/2021] [Indexed: 06/12/2023]
Abstract
Secondary organic aerosol (SOA) plays a key role in air pollution and global climate change. However, the understanding and modelling of SOA properties and evolution are still limited. In this paper, we developed a novel kinetic Core-Shell box model for Viscosity dependent SOA simulation (CSVA), which includes explicit gas-phase reactions (MCM), homogeneous nucleation by H2SO4-NH3-H2O, viscosity dependent mass transfer between gas and particle phases (organic and aqueous phases) and particle-phase reactions. The gas-particle mass transfer is represented by chainlike reactions analogizing to electrical resistance. The CSVA model is verified and applied to chamber experiments of toluene oxidation systems. The monomers and dimers of SOA are determined by coupling the high-resolution Orbitrap mass spectra and MCM mechanism. The majority of dimers are confirmed to be peroxyhemiacetals formed by reactions of hydroperoxides with aldehydes in the particle phase. The results show that CSVA can well capture the following processes: (1) relative humidity (RH) dependent nucleation of the H2SO4-NH3-H2O system, (2) particle size-dependent hygroscopic growth of inorganics (e.g., NaCl and (NH4)2SO4) and organics (levoglucosan and SOA), (3) NOx dependent SOA formation, (4) viscosity-induced evolution of particle size distribution, and (5) effect of RH on SOA formation. In particular, our model reproduces the phenomenon that the evolution of SOA particle size distribution from a one-peak mode into a two-peak mode is due to viscosity.
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Affiliation(s)
- Long Jia
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Department of Atmospheric Chemistry and Environmental Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - YongFu Xu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Department of Atmospheric Chemistry and Environmental Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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4
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Kiland KJ, Maclean AM, Kamal S, Bertram AK. Diffusion of Organic Molecules as a Function of Temperature in a Sucrose Matrix (a Proxy for Secondary Organic Aerosol). J Phys Chem Lett 2019; 10:5902-5908. [PMID: 31517491 DOI: 10.1021/acs.jpclett.9b02182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Knowledge of diffusion coefficients as a function of temperature in secondary organic aerosol (SOA) or proxies of SOA is needed to predict atmospheric chemistry, climate, and air quality. We determined diffusion coefficients as a function of temperature of a fluorescent organic molecule in a sucrose matrix (a proxy for SOA). Diffusion coefficients were a strong function of temperature (e.g., at water activity = 0.43, diffusion coefficients decreased by a factor of ∼40 as the temperature decreased by 20 K). Interestingly, the apparent activation energy for diffusion of the fluorescent organic molecule was similar to the apparent activation for diffusion of water in the sucrose matrix. On the basis of these measurements, the mixing time of organic molecules by diffusion in some types of SOA particles will often be >1 h in the free troposphere, if a sucrose matrix is an accurate proxy for these types of SOA.
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Affiliation(s)
- Kristian J Kiland
- Department of Chemistry , The University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Adrian M Maclean
- Department of Chemistry , The University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Saeid Kamal
- Department of Chemistry , The University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Allan K Bertram
- Department of Chemistry , The University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
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5
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Wang Y, Liu P, Li YJ, Bateman AP, Martin ST, Hung HM. The Reactivity of Toluene-Derived Secondary Organic Material with Ammonia and the Influence of Water Vapor. J Phys Chem A 2018; 122:7739-7747. [DOI: 10.1021/acs.jpca.8b06685] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yan Wang
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts United States
| | | | - Yong Jie Li
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau, China
| | | | | | - Hui-Ming Hung
- Department of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan
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6
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The Influence of Absolute Mass Loading of Secondary Organic Aerosols on Their Phase State. ATMOSPHERE 2018. [DOI: 10.3390/atmos9040131] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Absolute secondary organic aerosol (SOA) mass loading (CSOA) is a key parameter in determining partitioning of semi- and intermediate volatility compounds to the particle phase. Its impact on the phase state of SOA, however, has remained largely unexplored. In this study, systematic laboratory chamber measurements were performed to elucidate the influence of CSOA, ranging from 0.2 to 160 µg m−3, on the phase state of SOA formed by ozonolysis of various precursors, including α-pinene, limonene, cis-3-hexenyl acetate (CHA) and cis-3-hexen-1-ol (HXL). A previously established method to estimate SOA bounce factor (BF, a surrogate for particle viscosity) was utilized to infer particle viscosity as a function of CSOA. Results show that under nominally identical conditions, the maximum BF decreases by approximately 30% at higher CSOA, suggesting a more liquid phase state. With the exception of HXL-SOA (which acted as the negative control), the phase state for all studied SOA precursors varied as a function of CSOA. Furthermore, the BF was found to be the maximum when SOA particle distributions reached a geometric mean particle diameter of 50–60 nm. Experimental results indicate that CSOA is an important parameter impacting the phase state of SOA, reinforcing recent findings that extrapolation of experiments not conducted at atmospherically relevant SOA levels may not yield results that are relevant to the natural environment.
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7
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Bell DM, Imre D, T. Martin S, Zelenyuk A. The properties and behavior of α-pinene secondary organic aerosol particles exposed to ammonia under dry conditions. Phys Chem Chem Phys 2017; 19:6497-6507. [DOI: 10.1039/c6cp08839b] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chemical transformations and aging of secondary organic aerosol (SOA) particles can alter their physical and chemical properties, including particle morphology.
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8
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Steimer SS, Berkemeier T, Gilgen A, Krieger UK, Peter T, Shiraiwa M, Ammann M. Shikimic acid ozonolysis kinetics of the transition from liquid aqueous solution to highly viscous glass. Phys Chem Chem Phys 2016; 17:31101-9. [PMID: 26536455 DOI: 10.1039/c5cp04544d] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Ageing of particulate organic matter affects the composition and properties of atmospheric aerosol particles. Driven by temperature and humidity, the organic fraction can vary its physical state between liquid and amorphous solid, or rarely even crystalline. These transitions can influence the reaction kinetics due to limitations of mass transport in such (semi-) solid states, which in turn may influence the chemical ageing of particles containing such compounds. We have used coated wall flow tube experiments to investigate the reaction kinetics of the ozonolysis of shikimic acid, which serves as a proxy for oxygenated, water-soluble organic matter and can form a glass at room temperature. Particular attention was paid to how the presence of water influences the reaction, since it acts a plasticiser and thereby induces changes in the physical state. We analysed the results by means of a traditional resistor model, which assumes steady-state conditions. The ozonolysis rate of shikimic acid is strongly increased in the presence of water, a fact we attribute to the increased transport of O3 and shikimic acid through the condensed phase at lower viscosities. The analysis using the resistor model suggests that the system undergoes both surface and bulk reaction. The second-order rate coefficient of the bulk reaction is 3.7 (+1.5/-3.2) × 10(3) L mol(-1) s(-1). At low humidity and long timescales, the resistor model fails to describe the measurements appropriately. The persistent O3 uptake at very low humidity suggests contribution of a self-reaction of O3 on the surface.
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Affiliation(s)
- Sarah S Steimer
- Paul Scherrer Institute, Laboratory of Radio- and Environmental Chemistry, 5232 Villigen PSI, Switzerland. and ETH Zurich, Institute for Atmospheric and Climate Science, 8092 Zurich, Switzerland
| | - Thomas Berkemeier
- Max Planck Institute for Chemistry, Multiphase Chemistry Department, 55128 Mainz, Germany
| | - Anina Gilgen
- ETH Zurich, Institute for Atmospheric and Climate Science, 8092 Zurich, Switzerland
| | - Ulrich K Krieger
- ETH Zurich, Institute for Atmospheric and Climate Science, 8092 Zurich, Switzerland
| | - Thomas Peter
- ETH Zurich, Institute for Atmospheric and Climate Science, 8092 Zurich, Switzerland
| | - Manabu Shiraiwa
- Max Planck Institute for Chemistry, Multiphase Chemistry Department, 55128 Mainz, Germany
| | - Markus Ammann
- Paul Scherrer Institute, Laboratory of Radio- and Environmental Chemistry, 5232 Villigen PSI, Switzerland.
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9
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Li YJ, Liu P, Gong Z, Wang Y, Bateman AP, Bergoend C, Bertram AK, Martin ST. Chemical Reactivity and Liquid/Nonliquid States of Secondary Organic Material. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:13264-74. [PMID: 26465059 DOI: 10.1021/acs.est.5b03392] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The reactivity of secondary organic material (SOM) of variable viscosity, ranging from nonliquid to liquid physical states, was studied. The SOM, produced in aerosol form from terpenoid and aromatic precursor species, was reacted with ammonia at variable relative humidity (RH). The ammonium-to-organic mass ratio (MNH4+/MOrg) increased monotonically from <5% RH to a limiting value at a threshold RH, implicating a transition from particle reactivity limited by diffusion at low RH to one limited by other factors at higher RH. For the studied size distributions and reaction times, the transition corresponded to a diffusivity above 10-17.5 ± 0.5 m2 s-1. The threshold RH values for the transition were <5% RH for isoprene-derived SOM, 35-45% RH for SOM derived from α-pinene, toluene, m-xylene, and 1,3,5-trimethylbenzene, and >90% for β-caryophyllene-derived SOM. The transition RH for reactivity differed in all cases from the transition RH of a nonliquid to a liquid state. For instance, for α-pinene-derived SOM the transition for chemical reactivity of 35-45% RH can be compared to the nonliquid to liquid transition of 65-90% RH. These differences imply that chemical transport models of atmospheric chemistry should not use the SOM liquid to nonliquid phase transition as one-to-one surrogates of SOM reactivity.
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Affiliation(s)
- Yong Jie Li
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau , Avenida da Universidade, Taipa, Macau, China
| | - Pengfei Liu
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Zhaoheng Gong
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Yan Wang
- Department of Environmental Health, Harvard T.H. Chan School of Public Health , Boston, Massachusetts 02115, United States
| | - Adam P Bateman
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Clara Bergoend
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
- Department of Energy and Environment, National Institute of Applied Science of Lyon , Villeurbanne 69100, France
| | - Allan K Bertram
- Department of Chemistry, University of British Columbia , Vancouver, British Columbia V6T 1Z1, Canada
| | - Scot T Martin
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
- Department of Earth and Planetary Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
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10
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Kolesar KR, Li Z, Wilson KR, Cappa CD. Heating-Induced Evaporation of Nine Different Secondary Organic Aerosol Types. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:12242-12252. [PMID: 26393817 DOI: 10.1021/acs.est.5b03038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The volatility of the compounds comprising organic aerosol (OA) determines their distribution between the gas and particle phases. However, there is a disconnect between volatility distributions as typically derived from secondary OA (SOA) growth experiments and the effective particle volatility as probed in evaporation experiments. Specifically, the evaporation experiments indicate an overall much less volatile SOA. This raises questions regarding the use of traditional volatility distributions in the simulation and prediction of atmospheric SOA concentrations. Here, we present results from measurements of thermally induced evaporation of SOA for nine different SOA types (i.e., distinct volatile organic compound and oxidant pairs) encompassing both anthropogenic and biogenic compounds and O3 and OH to examine the extent to which the low effective volatility of SOA is a general phenomenon or specific to a subset of SOA types. The observed extents of evaporation with temperature were similar for all the SOA types and indicative of a low effective volatility. Furthermore, minimal variations in the composition of all the SOA types upon heating-induced evaporation were observed. These results suggest that oligomer decomposition likely plays a major role in controlling SOA evaporation, and since the SOA formation time scale in these measurements was less than a minute, the oligomer-forming reactions must be similarly rapid. Overall, these results emphasize the importance of accounting for the role of condensed phase reactions in altering the composition of SOA when assessing particle volatility.
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Affiliation(s)
| | | | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, United States
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11
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Mai H, Shiraiwa M, Flagan RC, Seinfeld JH. Under What Conditions Can Equilibrium Gas-Particle Partitioning Be Expected to Hold in the Atmosphere? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:11485-11491. [PMID: 26339802 DOI: 10.1021/acs.est.5b02587] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The prevailing treatment of secondary organic aerosol formation in atmospheric models is based on the assumption of instantaneous gas-particle equilibrium for the condensing species, yet compelling experimental evidence indicates that organic aerosols can exhibit the properties of highly viscous, semisolid particles, for which gas-particle equilibrium may be achieved slowly. The approach to gas-particle equilibrium partitioning is controlled by gas-phase diffusion, interfacial transport, and particle-phase diffusion. Here we evaluate the controlling processes and the time scale to achieve gas-particle equilibrium as a function of the volatility of the condensing species, its surface accommodation coefficient, and its particle-phase diffusivity. For particles in the size range of typical atmospheric organic aerosols (∼50-500 nm), the time scale to establish gas-particle equilibrium is generally governed either by interfacial accommodation or particle-phase diffusion. The rate of approach to equilibrium varies, depending on whether the bulk vapor concentration is constant, typical of an open system, or decreasing as a result of condensation into the particles, typical of a closed system.
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Affiliation(s)
| | - Manabu Shiraiwa
- Multiphase Chemistry Department, Max Planck Institute for Chemistry , 55128 Mainz, Germany
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12
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Robinson ES, Saleh R, Donahue NM. Probing the Evaporation Dynamics of Mixed SOA/Squalane Particles Using Size-Resolved Composition and Single-Particle Measurements. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:9724-32. [PMID: 26158746 DOI: 10.1021/acs.est.5b01692] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An analysis of the formation and evaporation of mixed-particles containing squalane (a surrogate for hydrophobic primary organic aerosol, POA) and secondary organic aerosol (SOA) is presented. In these experiments, one material (D62-squalane or SOA from α-pinene + O3) was prepared first to serve as surface area for condensation of the other, forming the mixed-particles. The mixed-particles were then subjected to a heating-ramp from 22 to 44 °C. We were able to determine that (1) almost all of the SOA mass is comprised of material less volatile than D62-squalane; (2) AMS collection efficiency in these mixed-particle systems can be parametrized as a function of the relative mass fraction of the components; and (3) the vast majority of D62-squalane is able to evaporate from the mixed particles, and does so on the same time scale regardless of the order of preparation. We also performed two-population mixing experiments to directly test whether D62-squalane and SOA from α-pinene + O3 form a single solution or two separate phases. We find that these two OA types are immiscible, which informs our inference of the morphology of the mixed-particles. If the morphology is core-shell and dictated by the order of preparation, these data indicate that squalane is able to diffuse relatively quickly through the SOA shell, implying that there are no major diffusion limitations.
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Affiliation(s)
- Ellis Shipley Robinson
- Center for Atmospheric Particle Studies, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Rawad Saleh
- Center for Atmospheric Particle Studies, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Neil M Donahue
- Center for Atmospheric Particle Studies, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
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13
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Price HC, Mattsson J, Zhang Y, Bertram AK, Davies JF, Grayson JW, Martin ST, O'Sullivan D, Reid JP, Rickards AMJ, Murray BJ. Water diffusion in atmospherically relevant α-pinene secondary organic material. Chem Sci 2015; 6:4876-4883. [PMID: 28717493 PMCID: PMC5502394 DOI: 10.1039/c5sc00685f] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/04/2015] [Indexed: 12/11/2022] Open
Abstract
We report the first direct measurements of water diffusion coefficients in secondary organic aerosol.
Secondary organic material (SOM) constitutes a large mass fraction of atmospheric aerosol particles. Understanding its impact on climate and air quality relies on accurate models of interactions with water vapour. Recent research shows that SOM can be highly viscous and can even behave mechanically like a solid, leading to suggestions that particles exist out of equilibrium with water vapour in the atmosphere. In order to quantify any kinetic limitation we need to know water diffusion coefficients for SOM, but this quantity has, until now, only been estimated and has not yet been measured. We have directly measured water diffusion coefficients in the water soluble fraction of α-pinene SOM between 240 and 280 K. Here we show that, although this material can behave mechanically like a solid, at 280 K water diffusion is not kinetically limited on timescales of 1 s for atmospheric-sized particles. However, diffusion slows as temperature decreases. We use our measured data to constrain a Vignes-type parameterisation, which we extend to lower temperatures to show that SOM can take hours to equilibrate with water vapour under very cold conditions. Our modelling for 100 nm particles predicts that under mid- to upper-tropospheric conditions radial inhomogeneities in water content produce a low viscosity surface region and more solid interior, with implications for heterogeneous chemistry and ice nucleation.
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Affiliation(s)
- Hannah C Price
- School of Earth and Environment , University of Leeds , Leeds , LS2 9JT , UK . ; ; Tel: +44-(0)113-343-9085 ; Tel: +44(0)-0113-343-2887
| | - Johan Mattsson
- School of Physics and Astronomy , University of Leeds , Leeds , LS2 9JT , UK
| | - Yue Zhang
- School of Engineering and Applied Sciences , Harvard University , Cambridge , MA 02138 , USA
| | - Allan K Bertram
- Department of Chemistry , University of British Columbia , Vancouver , BC , Canada V6T 1Z1
| | - James F Davies
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK
| | - James W Grayson
- Department of Chemistry , University of British Columbia , Vancouver , BC , Canada V6T 1Z1
| | - Scot T Martin
- School of Engineering and Applied Sciences , Harvard University , Cambridge , MA 02138 , USA.,Department of Earth and Planetary Sciences , Harvard University , Cambridge , MA 02138 , USA
| | - Daniel O'Sullivan
- School of Earth and Environment , University of Leeds , Leeds , LS2 9JT , UK . ; ; Tel: +44-(0)113-343-9085 ; Tel: +44(0)-0113-343-2887
| | - Jonathan P Reid
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK
| | | | - Benjamin J Murray
- School of Earth and Environment , University of Leeds , Leeds , LS2 9JT , UK . ; ; Tel: +44-(0)113-343-9085 ; Tel: +44(0)-0113-343-2887
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14
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Wilson J, Imre D, Beránek J, Shrivastava M, Zelenyuk A. Evaporation kinetics of laboratory-generated secondary organic aerosols at elevated relative humidity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:243-249. [PMID: 25494490 DOI: 10.1021/es505331d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Secondary organic aerosols (SOA) dominate atmospheric organic aerosols that affect climate, air quality, and health. Recent studies indicate that, contrary to previously held assumptions, at low relative humidity (RH) these particles are semisolid and evaporate orders of magnitude slower than expected. Elevated relative humidity has the potential to affect significantly formation, properties, and atmospheric evolution of SOA particles. Here we present a study of the effect of RH on the room-temperature evaporation kinetics of SOA particles formed by ozonolysis of α-pinene and limonene. Experiments were carried out on α-pinene SOA particles generated, evaporated, and aged at <5%, 50 and 90% RH, and on limonene SOA particles at <5% and 90% RH. We find that in all cases evaporation begins with a relatively fast phase, during which 30-70% of the particle mass evaporates in 2 h, followed by a much slower evaporation rate. Evaporation kinetics at <5% and 50% RH are nearly the same, while at 90% RH a slightly larger fraction evaporates. In all cases, aging the particles prior to inducing evaporation reduces the evaporative losses; with aging at elevated RH leading to a more significant effect. In all cases, the observed SOA evaporation is nearly size-independent.
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Affiliation(s)
- Jacqueline Wilson
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
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15
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Wang B, O’Brien RE, Kelly ST, Shilling JE, Moffet RC, Gilles MK, Laskin A. Reactivity of Liquid and Semisolid Secondary Organic Carbon with Chloride and Nitrate in Atmospheric Aerosols. J Phys Chem A 2014; 119:4498-508. [DOI: 10.1021/jp510336q] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Bingbing Wang
- Environmental
Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354 United States
| | - Rachel E. O’Brien
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Stephen T. Kelly
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - John E. Shilling
- Atmospheric
Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Ryan C. Moffet
- Department
of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Mary K. Gilles
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Alexander Laskin
- Environmental
Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354 United States
| |
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