1
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Mahant S, Snider JR, Petters SS, Petters MD. Effect of Aerosol Size on Glass Transition Temperature. J Phys Chem Lett 2024; 15:7509-7515. [PMID: 39018543 DOI: 10.1021/acs.jpclett.4c01415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/19/2024]
Abstract
The amorphous phase state of suspended nanoparticles affects their atmospheric lifetimes and environmental impact. Influence of relative humidity and chemical composition on the glass-to-liquid transition is well-known. However, the influence of the particle size on the phase transition remains uncertain. Here we show experimental data that probe the amorphous phase transition of suspended sucrose particles as a function of particle size. The depression in glass-transition temperature follows the Gibbs-Thomson or Keesom-Laplace predicted proportionality of ΔTg ∝ D-1 for particles 100-700 nm in diameter, but the proportionality changes to ΔTg ∝ D-1/2 for smaller sizes. Literature data for glass-transition temperature depression in thin films and nanoconfined compounds show similar and strong deviations from the expected D-1 behavior. While the observed proportionalities remain incompletely understood, the results here provide evidence that the deviation from ΔTg ∝ D-1 is not attributable to substrate effects.
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Affiliation(s)
- Sunandan Mahant
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States
- Center for Environmental Research and Technology (CE-CERT), University of California Riverside, Riverside, California 92507, United States
| | - Jefferson R Snider
- Department of Atmospheric Sciences, University of Wyoming, Laramie, Wyoming 82072, United States
| | - Sarah S Petters
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States
- Center for Environmental Research and Technology (CE-CERT), University of California Riverside, Riverside, California 92507, United States
| | - Markus D Petters
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States
- Center for Environmental Research and Technology (CE-CERT), University of California Riverside, Riverside, California 92507, United States
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2
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Wei D, Wang C, Shi G, Zhang J, Wang F, Tan P, Zhao Z, Xie Y. Enabling Self-Adaptive Water-Energy-Balance of Photothermal Water Diode Evaporator: Dynamically Maximizing Energy Utilization Under the Ever-Changing Sunlight. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2309507. [PMID: 38273713 DOI: 10.1002/adma.202309507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 01/23/2024] [Indexed: 01/27/2024]
Abstract
Maintaining a match between input solar energy and required energy by water supply management is key to achieving efficient interfacial solar-driven evaporation (ISDE). In practice, the solar radiation flux is constantly changing throughout the day, so keeping a dynamic water-energy-balance of ISDE is a big challenge. Herein, a photothermal water diode (WD) evaporator concept is proposed by an integrated hydrophilic/hydrophobic Janus absorber to overcome the issue. Due to the unique unidirectional water transport properties induced by asymmetric wettability, a self-adaptive balance between photothermal energy input and water uptake is established, thus realizing the energy matching and utilization maximization. The experimental and simulation results exhibit that with the increase of sunlight intensity, the water supply speed is significantly accelerated due to the dynamic management and self-regulation on water replenishment. Therefore, an excellent evaporation rate of up to 2.14 kg m-2 h-1 with a high efficiency of 93.7% under 1 sun illumination is achieved. This water diode engineering with Janus wettability provides a novel strategy and extends the path for designing solar evaporation systems with diverse water supply properties, which shows great potential in different environmental conditions.
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Affiliation(s)
- Dan Wei
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Chengbing Wang
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Guoliang Shi
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Jing Zhang
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Fan Wang
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Puxin Tan
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Zexiang Zhao
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Yunong Xie
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
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3
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Zhu Y, Pang S, Zhang Y. Compositional evolution for mixed aerosols containing gluconic acid and typical nitrate and the effect of multiply factors on hygroscopicity. J Environ Sci (China) 2024; 139:206-216. [PMID: 38105048 DOI: 10.1016/j.jes.2022.10.050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/31/2022] [Accepted: 10/31/2022] [Indexed: 12/19/2023]
Abstract
The aging process of atmospheric aerosols usually leads to a mixture of inorganic salts and organic compounds of anthropogenic origin. In organic compounds, polyhydroxy organic acids are important components, however, the study on composition and hygroscopic properties of the mixture containing inorganics and polyhydroxy organic acids is scanty. In this study, gluconic acid, the proxy of polyhydroxy organic acids, is mixed with the representative nitrate (Mg(NO3)2, Ca(NO3)2) to form aerosols. ATR-FTIR and optical microscopy are employed to study the component changes and hygroscopicity as a function of relative humidity. As relative humidity fluctuates, the FTIR-ATR spectra display that the internal mixed gluconic acid (CH2(CH)4(OH)5COOH) and nitrate can react to release acidic gases, forming relevant gluconate and further affecting the hygroscopicity. The specific presentation is particles cannot be recovered to their original size after the dehydration-hydration process and there will be some disparities in GF for mixed particles. For the gluconic acid-Ca(NO3)2/Mg(NO3)2 mixtures with molar ratios of 1:1, higher degree of reaction resulting in the production of large amounts of gluconate should be responsible to the lower hygroscopicity compared to ZSR model. For 1:2 gluconic acid-nitrate mixed systems (with higher nitrate content), the hygroscopicity of mixtures are higher than the ZSR prediction. A possible reason could be 'salt-promoting effect' on the organic fractions of the surplus inorganic salt in the mixture. These data can improve the chemical composition list evaluation, in turn hygroscopic properties and phase state of atmospheric aerosol, and then the climate effect.
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Affiliation(s)
- Yue Zhu
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Shufeng Pang
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Yunhong Zhang
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
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4
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Madawala C, Lee HD, Kaluarachchi CP, Tivanski AV. Quantifying the Viscosity of Individual Submicrometer Semisolid Particles Using Atomic Force Microscopy. Anal Chem 2023; 95:14566-14572. [PMID: 37740726 PMCID: PMC10551855 DOI: 10.1021/acs.analchem.3c01835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 09/08/2023] [Indexed: 09/25/2023]
Abstract
Atmospheric aerosols' viscosities can vary significantly depending on their composition, mixing states, relative humidity (RH) and temperature. The diffusion time scale of atmospheric gases into an aerosol is largely governed by its viscosity, which in turn influences heterogeneous chemistry and climate-relevant aerosol effects. Quantifying the viscosity of aerosols in the semisolid phase state is particularly important as they are prevalent in the atmosphere and have a wide range of viscosities. Currently, direct viscosity measurements of submicrometer individual atmospheric aerosols are limited, largely due to the inherent size limitations of existing experimental techniques. Herein, we present a method that utilizes atomic force microscopy (AFM) to directly quantify the viscosity of substrate-deposited individual submicrometer semisolid aerosol particles as a function of RH. The method is based on AFM force spectroscopy measurements coupled with the Kelvin-Voigt viscoelastic model. Using glucose, sucrose, and raffinose as model systems, we demonstrate the accuracy of the AFM method within the viscosity range of ∼104-107 Pa s. The method is applicable to individual particles with sizes ranging from tens of nanometers to several micrometers. Furthermore, the method does not require prior knowledge on the composition of studied particles. We anticipate future measurements utilizing the AFM method on atmospheric aerosols at various RH to aid in our understanding of the range of aerosols' viscosities, the extent of particle-to-particle viscosity variability, and how these contribute to the particle diversity observable in the atmosphere.
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Affiliation(s)
- Chamika
K. Madawala
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Hansol D. Lee
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | | | - Alexei V. Tivanski
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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5
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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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6
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Rafferty A, Vennes B, Bain A, Preston TC. Optical trapping and light scattering in atmospheric aerosol science. Phys Chem Chem Phys 2023; 25:7066-7089. [PMID: 36852581 DOI: 10.1039/d2cp05301b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Aerosol particles are ubiquitous in the atmosphere, and currently contribute a large uncertainty to climate models. Part of the endeavour to reduce this uncertainty takes the form of improving our understanding of aerosol at the microphysical level, thus enabling chemical and physical processes to be more accurately represented in larger scale models. In addition to modeling efforts, there is a need to develop new instruments and methodologies to interrogate the physicochemical properties of aerosol. This perspective presents the development, theory, and application of optical trapping, a powerful tool for single particle investigations of aerosol. After providing an overview of the role of aerosol in Earth's atmosphere and the microphysics of these particles, we present a brief history of optical trapping and a more detailed look at its application to aerosol particles. We also compare optical trapping to other single particle techniques. Understanding the interaction of light with single particles is essential for interpreting experimental measurements. In the final part of this perspective, we provide the relevant formalism for understanding both elastic and inelastic light scattering for single particles. The developments discussed here go beyond Mie theory and include both how particle and beam shape affect spectra. Throughout the entirety of this work, we highlight numerous references and examples, mostly from the last decade, of the application of optical trapping to systems that are relevant to the atmospheric aerosol.
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Affiliation(s)
| | - Benjamin Vennes
- Department of Atmospheric and Oceanic Sciences, McGill University, Montreal, Quebec, Canada.
| | - Alison Bain
- School of Chemistry, University of Bristol, Bristol, UK
| | - Thomas C Preston
- Department of Atmospheric and Oceanic Sciences, McGill University, Montreal, Quebec, Canada. .,Department of Chemistry, McGill University, Montreal, Quebec, Canada
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7
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Song M, Jeong R, Kim D, Qiu Y, Meng X, Wu Z, Zuend A, Ha Y, Kim C, Kim H, Gaikwad S, Jang KS, Lee JY, Ahn J. Comparison of Phase States of PM 2.5 over Megacities, Seoul and Beijing, and Their Implications on Particle Size Distribution. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17581-17590. [PMID: 36459099 PMCID: PMC9775198 DOI: 10.1021/acs.est.2c06377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
Although the particle phase state is an important property, there is scant information on it, especially, for real-world aerosols. To explore the phase state of fine mode aerosols (PM2.5) in two megacities, Seoul and Beijing, we collected PM2.5 filter samples daily from Dec 2020 to Jan 2021. Using optical microscopy combined with the poke-and-flow technique, the phase states of the bulk of PM2.5 as a function of relative humidity (RH) were determined and compared to the ambient RH ranges in the two cities. PM2.5 was found to be liquid to semisolid in Seoul but mostly semisolid to solid in Beijing. The liquid state was dominant on polluted days, while a semisolid state was dominant on clean days in Seoul. These findings can be explained by the aerosol liquid water content related to the chemical compositions of the aerosols at ambient RH; the water content of PM2.5 was much higher in Seoul than in Beijing. Furthermore, the overall phase states of PM2.5 observed in Seoul and Beijing were interrelated with the particle size distribution. The results of this study aid in a better understanding of the fundamental physical properties of aerosols and in examining how these are linked to PM2.5 in polluted urban atmospheres.
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Affiliation(s)
- Mijung Song
- Department
of Environment and Energy, Jeonbuk National
University, Jeonju-si 54896, Jeollabuk-do, Republic of Korea
- Department
of Earth and Environmental Sciences, Jeonbuk
National University, Jeonju-si 54896, Jeollabuk-do, Republic of Korea
| | - Rani Jeong
- Department
of Environment and Energy, Jeonbuk National
University, Jeonju-si 54896, Jeollabuk-do, Republic of Korea
| | - Daeun Kim
- Department
of Environment and Energy, Jeonbuk National
University, Jeonju-si 54896, Jeollabuk-do, Republic of Korea
| | - Yanting Qiu
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xiangxinyue Meng
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zhijun Wu
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Andreas Zuend
- Department
of Atmospheric and Oceanic Sciences, McGill
University, Montréal, Québec H3A 0B9, Canada
| | - Yoonkyeong Ha
- School
of Civil and Environmental Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Changhyuk Kim
- School
of Civil and Environmental Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Haeri Kim
- Department
of Environment and Energy, Jeonbuk National
University, Jeonju-si 54896, Jeollabuk-do, Republic of Korea
| | - Sanjit Gaikwad
- Department
of Environment and Energy, Jeonbuk National
University, Jeonju-si 54896, Jeollabuk-do, Republic of Korea
| | - Kyoung-Soon Jang
- Bio-Chemical
Analysis Team, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
| | - Ji Yi Lee
- Department
of Environmental Science & Engineering, Ewha Womans University, 52, Ewhayeodae-gil, Seodaemun-gu, Seoul 03760, Republic
of Korea
| | - Joonyoung Ahn
- Department
of Atmospheric Environment Research, National
Institute of Environmental Research, 215, Jinheung-ro, Eunpyeong-gu, Seoul 03367, Republic of Korea
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8
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McCarthy LP, Knapp P, Walker JS, Archer J, Miles REH, Stettler MEJ, Reid JP. Dynamics and outcomes of binary collisions of equi-diameter picolitre droplets with identical viscosities. Phys Chem Chem Phys 2022; 24:21242-21249. [PMID: 36040384 DOI: 10.1039/d2cp02613a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamics of binary collisions of equi-diameter picolitre droplets with identical viscosities, varying impact speeds and impact angles have been investigated experimentally and compared to collision outcome prediction models. Collisions between pairs of pure water droplets with a viscosity of 0.89 mPa s and pairs of aqueous-sucrose (40% w/w) droplets with a viscosity of 5.17 mPa s were examined. The colliding droplets were ∼38 μm in diameter, which is around ten times smaller than those previously investigated when examining the effect of viscosity on the outcome of binary droplet collisions. Varying the impact speed and angle resulted in different collision outcomes, including coalescence, reflexive separation and stretching separation. The collision outcomes were plotted on two viscosity dependent regime maps. The regime boundaries are generally in agreement with earlier literature for both high and low viscosity cases. The agreement between experiment and theory, for both fluids, gives more confidence in the models tested here to predict collision outcomes for droplets of this size and these viscosities.
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Affiliation(s)
| | - Peter Knapp
- Department of Civil and Environmental Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Jim S Walker
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK.
| | - Justice Archer
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK.
| | | | - Marc E J Stettler
- Department of Civil and Environmental Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Jonathan P Reid
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK.
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9
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Tong YK, Liu Y, Meng X, Wang J, Zhao D, Wu Z, Ye A. The relative humidity-dependent viscosity of single quasi aerosol particles and possible implications for atmospheric aerosol chemistry. Phys Chem Chem Phys 2022; 24:10514-10523. [PMID: 35441631 DOI: 10.1039/d2cp00740a] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Viscosity is a fundamental physicochemical property of aerosol particles that influences chemical evolution, mass transfer rates, particle formation, etc. and also changes with ambient relative humidity (RH). However, the viscosity of real individual aerosol particles still remains less understood. Here, we developed a novel optical system based on dual optical tweezers to measure the viscosity of single suspending aerosol droplets under different RH conditions. In our experiment, a pair of quasi atmospheric aerosol droplets composed of organic and inorganic chemical substances were trapped and levitated by dual laser beams, respectively, and then collided and coalesced. The backscattering light signals and bright-field images of the dynamic coalescence process were recorded to infer the morphological relaxation time and the diameter of the composited droplet. Then, the viscosity of the droplet was calculated based on these measured values. The ambient RH of the aerosol droplets was controlled by varying the relative flow rates of dry and humidified nitrogen gas in a self-developed aerosol chamber. The viscosities of single aqueous droplets nebulized with solutes of sucrose, various sulfates and nitrates, and organic/inorganic mixtures were measured over the atmospheric RH range. Besides, the viscosities of the proxies of actual ambient aerosols in Beijing were investigated, which reasonably interpreted the aerosol chemistry transforming from sulfate dominating to nitrate dominating at the PM10 (particulate matter with an aerodynamic diameter of less than 10 μm) level in the last decade in Beijing. Furthermore, the hygroscopicity of droplets with a solute of organic/inorganic mixtures was researched to obtain a deep insight into the relationship between the viscosity and mass transfer process. Hence, we provide a robust approach for investigating the viscosity and hygroscopicity of the actual individual liquid PM10 aerosols.
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Affiliation(s)
- Yu-Kai Tong
- Key Laboratory for the Physics and Chemistry of Nanodevices, School of Electronics, Peking University, Beijing 100871, China.
| | - Yaoyao Liu
- Key Laboratory for the Physics and Chemistry of Nanodevices, School of Electronics, Peking University, Beijing 100871, China.
| | - Xiangxinyue Meng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Jie Wang
- Key Laboratory for the Physics and Chemistry of Nanodevices, School of Electronics, Peking University, Beijing 100871, China.
| | - Dongping Zhao
- Key Laboratory for the Physics and Chemistry of Nanodevices, School of Electronics, Peking University, Beijing 100871, China.
| | - Zhijun Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Anpei Ye
- Key Laboratory for the Physics and Chemistry of Nanodevices, School of Electronics, Peking University, Beijing 100871, China.
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10
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Zong T, Wang H, Wu Z, Lu K, Wang Y, Zhu Y, Shang D, Fang X, Huang X, He L, Ma N, Größ J, Huang S, Guo S, Zeng L, Herrmann H, Wiedensohler A, Zhang Y, Hu M. Particle hygroscopicity inhomogeneity and its impact on reactive uptake. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 811:151364. [PMID: 34740668 DOI: 10.1016/j.scitotenv.2021.151364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/10/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
Atmospheric particles are important reaction vessels for multiphase chemistry. We conducted a meta-analysis of previous field observations in various environments (includes ocean, urban and rural regions), showing that particle hygroscopicity inhomogeneity (PHI) is ubiquitous for the continental atmospheric particles, in which a considerable part of the particulate matters is hydrophobic (10%-33% on average). However, the effects of PHI in quantifying the uptake process of reactive gases are still unclear. Here, taking N2O5 uptake as an example, we showed that using a laboratory-based parameterization scheme without considering the PHI might result in a misestimation of uptake rate coefficient, especially under low ambient relative humidity (RH). Such misestimation may be caused by the differences of the uptake coefficients, as well as the proportion of surface area concentration (SA) between hydrophilic and hydrophobic particles. We suggested that the PHI should be well-considered in establishing the reactive traces gases heterogeneous uptake parameterizations.
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Affiliation(s)
- Taomou Zong
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Haichao Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhijun Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China.
| | - Keding Lu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Yu Wang
- Centre for Atmospheric Science, School of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Yishu Zhu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Dongjie Shang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xin Fang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xiaofeng Huang
- Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Lingyan He
- Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Nan Ma
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, Guangdong 511443, China
| | - Johannes Größ
- Leibniz Institute for Tropospheric Research, Permoserstraße 15, Leipzig 04318, Germany
| | - Shan Huang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, Guangdong 511443, China
| | - Song Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Limin Zeng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Hartmut Herrmann
- Leibniz Institute for Tropospheric Research, Permoserstraße 15, Leipzig 04318, Germany
| | - Alfred Wiedensohler
- Leibniz Institute for Tropospheric Research, Permoserstraße 15, Leipzig 04318, Germany
| | - Yuanhang Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
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11
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Abstract
Slow condensed phase diffusion in organic aerosol particles can impede many chemical and physical processes associated with atmospheric aerosol (e.g., gas-particle equilibrium partitioning). The characteristic times associated with these high viscosity particles are typically modelled using a concentration-dependent diffusivity within a purely Fickian framework. In that model, the medium in which diffusion is taking place is treated as being inviscid as far as mass transport is concerned. In this report, we investigate the validity of assuming that the viscosity is equal to zero by using a transport model that includes viscous pressure gradients. It is found that the effect of viscosity is negligible for particles with radii that are larger than 100 nm, but below that radius, it can delay water uptake and loss by orders of magnitude for physically realistic viscosities. However, if the Stokes–Einstein relation is obeyed, then viscosity can be ignored, even for nanosized particles. In addition to numerical calculations, a dimensionless Deborah number is defined that indicates the significance of Fickian diffusion compared with the rheological response during water transport.
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Affiliation(s)
- Thomas C. Preston
- Department of Atmospheric and Oceanic Sciences and Department of Chemistry, McGill University, 805 Sherbrooke Street West, Montreal, QC H3A 0B9, Canada
- Department of Atmospheric and Oceanic Sciences and Department of Chemistry, McGill University, 805 Sherbrooke Street West, Montreal, QC H3A 0B9, Canada
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12
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Lu Y, Yang L, Kuang Y, Song Y, Zhao J, Sum AK. Molecular simulations on the stability and dynamics of bulk nanobubbles in aqueous environments. Phys Chem Chem Phys 2021; 23:27533-27542. [PMID: 34874384 DOI: 10.1039/d1cp03325e] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Nanobubbles have attracted significant attention due to their unexpectedly long lifetimes and stabilities in liquid solutions. However, explanations for the unique properties of nanobubbles at the molecular scale are somewhat controversial. Of special interest is the validity of the Young-Laplace equation in predicting the inner pressure of such bubbles. In this work, large-scale molecular dynamics simulations were performed to study the stability and diffusion of nanobubbles of methane in water. Two types of force field, atomistic and coarse-grained, were used to compare the calculated results. In accordance with predictions from the Young-Laplace equation, it was found that the inner pressure of the nanobubbles increased with decreasing nanobubble size. Consequently, a large pressure difference between the nanobubble and its surroundings resulted in the high solubility of methane molecules in water. The solubility was considered to enable nanobubble stability at exceptionally high pressures. Smaller bubbles were observed to be more mobile via Brownian motion. The calculated diffusion coefficient also showed a strong dependence on the nanobubble size. However, this active mobility of small nanobubbles also triggered a mutable nanobubble shape over time. Nanobubbles were also found to coalesce when they were sufficiently close. A critical distance between two nanobubbles was thus identified to avoid coalescence. These results provide insight into the behavior of nanobubbles in solution and the mechanism of their unique stability while withstanding high inner pressures.
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Affiliation(s)
- Yi Lu
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology, Dalian 116024, China.
| | - Lei Yang
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology, Dalian 116024, China.
| | - Yangmin Kuang
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology, Dalian 116024, China.
| | - Yongchen Song
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology, Dalian 116024, China.
| | - Jiafei Zhao
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology, Dalian 116024, China.
| | - Amadeu K Sum
- Phases to Flow Laboratory, Chemical & Biological Engineering Department, Colorado School of Mines, Golden, Colorado 80401, USA.
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13
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Ambroxol Hydrochloride Loaded Gastro-Retentive Nanosuspension Gels Potentiate Anticancer Activity in Lung Cancer (A549) Cells. Gels 2021; 7:gels7040243. [PMID: 34940303 PMCID: PMC8700943 DOI: 10.3390/gels7040243] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/18/2021] [Accepted: 11/25/2021] [Indexed: 12/19/2022] Open
Abstract
This study aimed to develop gastro-retentive sustained-release ambroxol (ABX) nanosuspensions utilizing ambroxol-kappa-carrageenan (ABX-CRGK) complexation formulations. The complex was characterized by differential scanning calorimetry, powder x-ray diffractometer, and scanning electron microscopy. The prepared co-precipitate complex was used for the development of the sustained-release formulation to overcome the high metabolic and poor solubility problems associated with ABX. Furthermore, the co-precipitate complex was formulated as a suspension in an aqueous floating gel-forming vehicle of sodium alginate with chitosan, which might be beneficial for targeting the stomach as a good absorption site for ABX. The suspension exhibited rapid floating gel behaviour for more than 8 h, thus confirming the gastro-retentive effects. Particle size analysis revealed that the optimum nanosuspension (ABX-NS) had a mean particle size of 332.3 nm. Afterward, the ABX released by the nanoparticles would be distributed to the pulmonary tissue as previously described. Based on extensive pulmonary distribution, the developed nanosuspension-released ABX nanoparticles showed significant cytotoxic enhancement compared to free ABX in A549 lung cancer cells. However, a significant loss of mitochondrial membrane potential (MMP) also occurred. The level of caspase-3 was the highest in the ABX-NS-released particle-treated samples, with a value of 416.6 ± 9.11 pg/mL. Meanwhile, the levels of nuclear factor kappa beta, interleukins 6 and 1 beta, and tumour necrosis alpha (NF-kB, IL-6, IL-1β, and TNF-α, respectively) were lower for ABX-NS compared to free ABX (p < 0.05). In caspase-3, Bax, and p53, levels significantly increased in the presence of ABX-NS compared to free ABX. Overall, ABX-NS produced an enhancement of the anticancer effects of ABX on the A549 cells, and the developed sustained-release gel was successful in providing a gastro-retentive effect.
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14
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Dalton AB, Nizkorodov SA. Photochemical Degradation of 4-Nitrocatechol and 2,4-Dinitrophenol in a Sugar-Glass Secondary Organic Aerosol Surrogate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:14586-14594. [PMID: 34669384 DOI: 10.1021/acs.est.1c04975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The roles that chemical environment and viscosity play in the photochemical fate of molecules trapped in atmospheric particles are poorly understood. The goal of this work was to characterize the photolysis of 4-nitrocatechol (4NC) and 2,4-dinitrophenol (24DNP) in semisolid isomalt as a new type of surrogate for glassy organic aerosols and compare it to photolysis in liquid water, isopropanol, and octanol. UV/vis spectroscopy was used to monitor the absorbance decay to determine the rates of photochemical loss of 4NC and 24DNP. The quantum yield of 4NC photolysis was found to be smaller in an isomalt glass (2.6 × 10-6) than in liquid isopropanol (1.1 × 10-5). Both 4NC and 24NDP had much lower photolysis rates in water than in organic matrices, suggesting that they would photolyze more efficiently in organic aerosol particles than in cloud or fog droplets. Liquid chromatography in tandem with mass spectrometry was used to examine the photolysis products of 4NC. In isopropanol solution, most products appeared to result from the oxidation of 4NC, in stark contrast to photoreduction and dimerization products that were observed in solid isomalt. Therefore, the photochemical fate of 4NC, and presumably of other nitrophenols, should depend on whether they undergo photodegradation in a liquid or semisolid organic particle.
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Affiliation(s)
- Avery B Dalton
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Sergey A Nizkorodov
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
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15
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Ma S, Pang S, Li J, Zhang Y. A review of efflorescence kinetics studies on atmospherically relevant particles. CHEMOSPHERE 2021; 277:130320. [PMID: 33773310 DOI: 10.1016/j.chemosphere.2021.130320] [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: 01/14/2021] [Revised: 03/11/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
The efflorescence transitions of aerosol particles have been intensively investigated due to their critical impacts on global climate and atmospheric chemistry. In the present study, we present a critical review of efflorescence kinetics focusing on three key issues: the efflorescence relative humidity (ERH) and the influence factors for aerosol ERH (e.g. particle sizes, and temperature); efflorescence processes of mixed aerosols, concerning the effect of coexisting inorganic and organic components on the efflorescence of inorganic salts; homogeneous and heterogeneous nucleation rates of pure and mixed aerosols. Among the previous studies, there are significant discrepancies for measured aerosol ERH under even the same conditions. Moreover, the interactions between organic and inorganic components remain largely unclear, causing efflorescence transition behaviours and chemical composition evolutions of certain mixed systems to be debatable. Thus, it is important to better understand efflorescence to gain insights into the physicochemical properties and characterize observed efflorescence characteristics of atmospheric particles, as well as guide further studies on aerosol hygroscopicity and reactivity.
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Affiliation(s)
- Shuaishuai Ma
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
| | - Shufeng Pang
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
| | - Jing Li
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, People's Republic of China.
| | - Yunhong Zhang
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, People's Republic of China.
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16
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Chang YP, Devi Y, Chen CH. Micro-droplet Trapping and Manipulation: Understanding Aerosol Better for a Healthier Environment. Chem Asian J 2021; 16:1644-1660. [PMID: 33999498 DOI: 10.1002/asia.202100516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Indexed: 11/09/2022]
Abstract
Understanding the physicochemical properties and heterogeneous processes of aerosols is key not only to elucidate the impacts of aerosols on the atmosphere and humans but also to exploit their further applications, especially for a healthier environment. Experiments that allow for spatially control of single aerosol particles and investigations on the fundamental properties and heterogeneous chemistry at the single-particle level have flourished during the last few decades, and significant breakthroughs in recent years promise better control and novel applications aimed at resolving key issues in aerosol science. Here we propose graphene oxide (GO) aerosols as prototype aerosols containing polycyclic aromatic hydrocarbons, and GO can behave as two-dimensional surfactants which could modify the interfacial properties of aerosols. We describe the techniques of trapping single particles and furthermore the current status of the optical spectroscopy and chemistry of GO. The current applications of these single-particle trapping techniques are summarized and interesting future applications of GO aerosols are discussed.
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Affiliation(s)
- Yuan-Pin Chang
- Department of Chemistry, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan.,Aerosol Science Research Center, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan
| | - Yanita Devi
- Department of Chemistry, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan
| | - Chun-Hu Chen
- Department of Chemistry, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan
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17
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Liang Z, Zhang R, Gen M, Chu Y, Chan CK. Nitrate Photolysis in Mixed Sucrose-Nitrate-Sulfate Particles at Different Relative Humidities. J Phys Chem A 2021; 125:3739-3747. [PMID: 33899478 DOI: 10.1021/acs.jpca.1c00669] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atmospheric particles can be viscous. The limitation in diffusion impedes the mass transfer of oxidants from the gas phase to the particle phase and hinders multiphase oxidation processes. On the other hand, nitrate photolysis has been found to be effective in producing oxidants such as OH radicals within the particles. Whether nitrate photolysis can effectively proceed in viscous particles and how it may affect the physicochemical properties of the particle have not been much explored. In this study, we investigated particulate nitrate photolysis in mixed sucrose-nitrate-sulfate particles as surrogates of atmospheric viscous particles containing organic and inorganic components as a function of relative humidity (RH) and the molar fraction of sucrose to the total solute (FSU) with an in situ micro-Raman system. Sucrose suppressed nitrate crystallization, and high photolysis rate constants (∼10-5 s-1) were found, irrespective of the RH. For FSU = 0.5 and 0.33 particles under irradiation at 30% RH, we observed morphological changes from droplets to the formation of inclusions and then likely "hollow" semisolid particles, which did not show Raman signal at central locations. Together with the phase states of inorganics indicated by the full width at half-maxima (FWHM), images with bulged surfaces, and size increase of the particles in optical microscopic imaging, we inferred that the hindered diffusion of gaseous products (i.e., NOx, NOy) from nitrate photolysis is a likely reason for the morphological changes. Atmospheric implications of these results are also presented.
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Affiliation(s)
- Zhancong Liang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue 83, Kowloon, Hong Kong, China
| | - Ruifeng Zhang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue 83, Kowloon, Hong Kong, China
| | - Masao Gen
- Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Yangxi Chu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Chak K Chan
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue 83, Kowloon, Hong Kong, China
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18
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Lee HD, Tivanski AV. Atomic Force Microscopy: An Emerging Tool in Measuring the Phase State and Surface Tension of Individual Aerosol Particles. Annu Rev Phys Chem 2021; 72:235-252. [PMID: 33428467 DOI: 10.1146/annurev-physchem-090419-110133] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Atmospheric aerosols are suspended particulate matter of varying composition, size, and mixing state. Challenges remain in understanding the impact of aerosols on the climate, atmosphere, and human health. The effect of aerosols depends on their physicochemical properties, such as their hygroscopicity, phase state, and surface tension. These properties are dynamic with respect to the highly variable relative humidity and temperature of the atmosphere. Thus, experimental approaches that permit the measurement of these dynamic properties are required. Such measurements also need to be performed on individual, submicrometer-, and supermicrometer-sized aerosol particles, as individual atmospheric particles from the same source can exhibit great variability in their form and function. In this context, this review focuses on the recent emergence of atomic force microscopy as an experimental tool in physical, analytical, and atmospheric chemistry that enables such measurements. Remaining challenges are noted and suggestions for future studies are offered.
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Affiliation(s)
- Hansol D Lee
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA; ,
| | - Alexei V Tivanski
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA; ,
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19
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Walker JS, Archer J, Gregson FKA, Michel SES, Bzdek BR, Reid JP. Accurate Representations of the Microphysical Processes Occurring during the Transport of Exhaled Aerosols and Droplets. ACS CENTRAL SCIENCE 2021; 7:200-209. [PMID: 33532579 PMCID: PMC7845015 DOI: 10.1021/acscentsci.0c01522] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Indexed: 05/19/2023]
Abstract
Aerosols and droplets from expiratory events play an integral role in transmitting pathogens such as SARS-CoV-2 from an infected individual to a susceptible host. However, there remain significant uncertainties in our understanding of the aerosol droplet microphysics occurring during drying and sedimentation and the effect on the sedimentation outcomes. Here, we apply a new treatment for the microphysical behavior of respiratory fluid droplets to a droplet evaporation/sedimentation model and assess the impact on sedimentation distance, time scale, and particle phase. Above a 100 μm initial diameter, the sedimentation outcome for a respiratory droplet is insensitive to composition and ambient conditions. Below 100 μm, and particularly below 80 μm, the increased settling time allows the exact nature of the evaporation process to play a significant role in influencing the sedimentation outcome. For this size range, an incorrect treatment of the droplet composition, or imprecise use of RH or temperature, can lead to large discrepancies in sedimentation distance (with representative values >1 m, >2 m, and >2 m, respectively). Additionally, a respiratory droplet is likely to undergo a phase change prior to sedimenting if initially <100 μm in diameter, provided that the RH is below the measured phase change RH. Calculations of the potential exposure versus distance from the infected source show that the volume fraction of the initial respiratory droplet distribution, in this size range, which remains elevated above 1 m decreases from 1 at 1 m to 0.125 at 2 m.
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Affiliation(s)
- Jim S. Walker
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Justice Archer
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | | | - Sarah E. S. Michel
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Bryan R. Bzdek
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Jonathan P. Reid
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
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20
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Otero Fernandez M, Thomas RJ, Oswin H, Haddrell AE, Reid JP. Transformative Approach To Investigate the Microphysical Factors Influencing Airborne Transmission of Pathogens. Appl Environ Microbiol 2020; 86:e01543-20. [PMID: 32978136 PMCID: PMC7657628 DOI: 10.1128/aem.01543-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/17/2020] [Indexed: 01/06/2023] Open
Abstract
Emerging outbreaks of airborne pathogenic infections worldwide, such as the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, have raised the need to understand parameters affecting the airborne survival of microbes in order to develop measures for effective infection control. We report a novel experimental strategy, TAMBAS (tandem approach for microphysical and biological assessment of airborne microorganism survival), to explore the synergistic interactions between the physicochemical and biological processes that impact airborne microbe survival in aerosol droplets. This innovative approach provides a unique and detailed understanding of the processes taking place from aerosol droplet generation through to equilibration and viability decay in the local environment, elucidating decay mechanisms not previously described. The impact of evaporation kinetics, solute hygroscopicity and concentration, particle morphology, and equilibrium particle size on airborne survival are reported, using Escherichia coli MRE162 as a benchmark system. For this system, we report that (i) particle crystallization does not directly impact microbe longevity, (ii) bacteria act as crystallization nuclei during droplet drying and equilibration, and (iii) the kinetics of size and compositional change appear to have a larger effect on microbe longevity than the equilibrium solute concentration.IMPORTANCE A transformative approach to identify the physicochemical processes that impact the biological decay rates of bacteria in aerosol droplets is described. It is shown that the evaporation process and changes in the phase and morphology of the aerosol particle during evaporation impact microorganism viability. The equilibrium droplet size was found to affect airborne bacterial viability. Furthermore, the presence of Escherichia coli MRE162 in a droplet does not affect aerosol growth/evaporation but influences the dynamic behavior of the aerosol by processing the culture medium prior to aerosolization, affecting the hygroscopicity of the culture medium; this highlights the importance of the inorganic and organic chemical composition within the aerosolized droplets that impact hygroscopicity. Bacteria also act as crystallization nuclei. The novel approach and data have implications for increased mechanistic understanding of aerosol survival and infectivity in bioaerosol studies spanning the medical, veterinary, farming, and agricultural fields, including the role of microorganisms in atmospheric processing and cloud formation.
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Affiliation(s)
| | - Richard J Thomas
- Defence Science Technology Laboratory (DSTL), Porton Down, Salisbury, United Kingdom
| | - Henry Oswin
- School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Allen E Haddrell
- School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Jonathan P Reid
- School of Chemistry, University of Bristol, Bristol, United Kingdom
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21
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Richards DS, Trobaugh KL, Hajek-Herrera J, Price CL, Sheldon CS, Davies JF, Davis RD. Ion-molecule interactions enable unexpected phase transitions in organic-inorganic aerosol. SCIENCE ADVANCES 2020; 6:6/47/eabb5643. [PMID: 33208357 PMCID: PMC7673807 DOI: 10.1126/sciadv.abb5643] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 10/07/2020] [Indexed: 05/17/2023]
Abstract
Atmospheric aerosol particles are commonly complex, aqueous organic-inorganic mixtures, and accurately predicting the properties of these particles is essential for air quality and climate projections. The prevailing assumption is that aqueous organic-inorganic aerosols exist predominately with liquid properties and that the hygroscopic inorganic fraction lowers aerosol viscosity relative to the organic fraction alone. Here, in contrast to those assumptions, we demonstrate that increasing inorganic fraction can increase aerosol viscosity (relative to predictions) and enable a humidity-dependent gel phase transition through cooperative ion-molecule interactions that give rise to long-range networks of atmospherically relevant low-mass oxygenated organic molecules (180 to 310 Da) and divalent inorganic ions. This supramolecular, ion-molecule effect can drastically influence the phase and physical properties of organic-inorganic aerosol and suggests that aerosol may be (semi)solid under more conditions than currently predicted. These observations, thus, have implications for air quality and climate that are not fully represented in atmospheric models.
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Affiliation(s)
- David S Richards
- Department of Chemistry, Trinity University, 1 Trinity Place, San Antonio, TX 78212, USA
| | - Kristin L Trobaugh
- Department of Chemistry, Trinity University, 1 Trinity Place, San Antonio, TX 78212, USA
| | - Josefina Hajek-Herrera
- Department of Chemistry, Trinity University, 1 Trinity Place, San Antonio, TX 78212, USA
| | - Chelsea L Price
- Department of Chemistry, University of California-Riverside, Riverside, CA 92521, USA
| | - Craig S Sheldon
- Department of Chemistry, University of California-Riverside, Riverside, CA 92521, USA
| | - James F Davies
- Department of Chemistry, University of California-Riverside, Riverside, CA 92521, USA
| | - Ryan D Davis
- Department of Chemistry, Trinity University, 1 Trinity Place, San Antonio, TX 78212, USA.
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22
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Petters M, Kasparoglu S. Predicting the influence of particle size on the glass transition temperature and viscosity of secondary organic material. Sci Rep 2020; 10:15170. [PMID: 32938963 PMCID: PMC7495436 DOI: 10.1038/s41598-020-71490-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 08/10/2020] [Indexed: 11/15/2022] Open
Abstract
Atmospheric aerosols can assume liquid, amorphous semi-solid or glassy, and crystalline phase states. Particle phase state plays a critical role in understanding and predicting aerosol impacts on human health, visibility, cloud formation, and climate. Melting point depression increases with decreasing particle diameter and is predicted by the Gibbs-Thompson relationship. This work reviews existing data on the melting point depression to constrain a simple parameterization of the process. The parameter [Formula: see text] describes the degree to which particle size lowers the melting point and is found to vary between 300 and 1800 K nm for a wide range of particle compositions. The parameterization is used together with existing frameworks for modeling the temperature and RH dependence of viscosity to predict the influence of particle size on the glass transition temperature and viscosity of secondary organic aerosol formed from the oxidation of [Formula: see text]-pinene. Literature data are broadly consistent with the predictions. The model predicts a sharp decrease in viscosity for particles less than 100 nm in diameter. It is computationally efficient and suitable for inclusion in models to evaluate the potential influence of the phase change on atmospheric processes. New experimental data of the size-dependence of particle viscosity for atmospheric aerosol mimics are needed to thoroughly validate the predictions.
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Affiliation(s)
- Markus Petters
- Department of Marine, Earth, and Atmospheric Sciences, NC State University, Raleigh, 27695-8208, USA.
| | - Sabin Kasparoglu
- Department of Marine, Earth, and Atmospheric Sciences, NC State University, Raleigh, 27695-8208, USA
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23
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Gregson FKA, Robinson JF, Miles REH, Royall CP, Reid JP. Drying and Crystallization of Evaporating Sodium Nitrate Aerosol Droplets. J Phys Chem B 2020; 124:6024-6036. [DOI: 10.1021/acs.jpcb.0c04079] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- F. K. A. Gregson
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | - J. F. Robinson
- School of Physics, University of Bristol, Bristol BS8 1TS, U.K
| | - R. E. H. Miles
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | - C. P. Royall
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
- School of Physics, University of Bristol, Bristol BS8 1TS, U.K
| | - J. P. Reid
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
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24
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Kaur Kohli R, Davies JF. Paper spray mass spectrometry for the analysis of picoliter droplets. Analyst 2020; 145:2639-2648. [PMID: 32064475 DOI: 10.1039/c9an02534k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent experimental efforts have shown that single particle levitation methods may be effectively coupled with mass spectrometry (MS) using paper spray (PS) ionization for compositional analysis of picoliter droplets. In this work, we characterize the response of PS-MS to analytes delivered in the form of picoliter droplets and explore its potential for identification and quantification of these samples. Using a microdroplet dispenser to generate droplets, we demonstrate sensitivity to a range of oxygenated organic molecules typical of compounds found in atmospheric secondary organic aerosol. We assess experimental factors that influence the reproducibility and sensitivity of the method and explore the linearity of the system response to increasing analyte mass in droplets containing single or multicomponent analytes. We show that the ratio of analyte signal from multicomponent samples may be used to characterize the relative composition of the system. These measurements demonstrate that the droplet PS-MS method is an effective tool for qualitative and quantitative analysis of single picoliter droplets containing picogram levels of analyte. The potential applications of this technique for characterizing the composition of levitated particles will be discussed.
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Affiliation(s)
- Ravleen Kaur Kohli
- Department of Chemistry, University of California, Riverside, California 92521, USA.
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25
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Abstract
Atmospheric aerosol particles cool Earth’s climate by serving as cloud droplet seeds. This cooling effect represents both the single most uncertain and the largest negative radiative forcing. Cloud droplet activation is strongly influenced by aerosol particle surface tension, which in climate models is assumed equivalent to that of pure water. We directly measure the surface tensions of surfactant-coated, high surface-to-volume ratio droplets, demonstrating that their surface tensions are significantly lower than pure water but do not match the surface tension of the solution from which they were produced and depend on finite droplet size. These results suggest surfactants could potentially significantly modify radiative forcing and highlight the need for a better understanding of atmospheric surfactant concentrations and properties. Surface tension influences the fraction of atmospheric particles that become cloud droplets. Although surfactants are an important component of aerosol mass, the surface tension of activating aerosol particles is still unresolved, with most climate models assuming activating particles have a surface tension equal to that of water. By studying picoliter droplet coalescence, we demonstrate that surfactants can significantly reduce the surface tension of finite-sized droplets below the value for water, consistent with recent field measurements. Significantly, this surface tension reduction is droplet size-dependent and does not correspond exactly to the macroscopic solution value. A fully independent monolayer partitioning model confirms the observed finite-size-dependent surface tension arises from the high surface-to-volume ratio in finite-sized droplets and enables predictions of aerosol hygroscopic growth. This model, constrained by the laboratory measurements, is consistent with a reduction in critical supersaturation for activation, potentially substantially increasing cloud droplet number concentration and modifying radiative cooling relative to current estimates assuming a water surface tension. The results highlight the need for improved constraints on the identities, properties, and concentrations of atmospheric aerosol surfactants in multiple environments and are broadly applicable to any discipline where finite volume effects are operative, such as studies of the competition between reaction rates within the bulk and at the surface of confined volumes and explorations of the influence of surfactants on dried particle morphology from spray driers.
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26
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Price CL, Bain A, Wallace BJ, Preston TC, Davies JF. Simultaneous Retrieval of the Size and Refractive Index of Suspended Droplets in a Linear Quadrupole Electrodynamic Balance. J Phys Chem A 2020; 124:1811-1820. [PMID: 32013433 DOI: 10.1021/acs.jpca.9b10748] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Single-particle trapping is an effective strategy to explore the physical and optical properties of aerosol with high precision. Laser-based methods are commonly used to probe the size, optical properties, and composition of nonlight-absorbing droplets in optical and electrodynamic traps. However, these methods cannot be applied to droplets containing photoactive chromophores, and thus, single-particle methods have been restricted to only a subset of atmospherically relevant particle compositions. In this work, we explore the application of a broadband light scattering approach, Mie resonance spectroscopy, to simultaneously probe the size and the refractive index (RI) of droplets in a linear quadrupole electrodynamic balance. We examine the evaporation of poly(ethylene glycol)s and compare the calculated vapor pressures with literature values to benchmark the size accuracy without prior constraint on the RI. We then explore the hygroscopic growth and deliquescence of sodium chloride droplets, measuring RI at the deliquescence relative humidity and demonstrating agreement to literature values. These data allow the wavelength dependence of the RI of aqueous NaCl to be determined using a first-order Cauchy equation, and we effectively reproduce literature data from multiple techniques. We finally discuss measurements from a light-absorbing aqueous droplet containing humic acid and interpret the spectra via the imaginary component of the RI. The approach described here allows the radius of nonabsorbing droplets to be determined within 0.1%, the refractive index within 0.2%, and the first-order term in the Cauchy dispersion equation within ∼5%.
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Affiliation(s)
- Chelsea L Price
- Department of Chemistry, University of California Riverside, Riverside, California 92420, United States
| | - Alison Bain
- Department of Atmospheric and Oceanic Sciences and Department of Chemistry, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - Brandon J Wallace
- Department of Atmospheric and Oceanic Sciences and Department of Chemistry, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - Thomas C Preston
- Department of Atmospheric and Oceanic Sciences and Department of Chemistry, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - James F Davies
- Department of Chemistry, University of California Riverside, Riverside, California 92420, United States
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27
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Fernandez MO, Thomas RJ, Garton NJ, Hudson A, Haddrell A, Reid JP. Assessing the airborne survival of bacteria in populations of aerosol droplets with a novel technology. J R Soc Interface 2020; 16:20180779. [PMID: 30958165 DOI: 10.1098/rsif.2018.0779] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The airborne transmission of infection relies on the ability of pathogens to survive aerosol transport as they transit between hosts. Understanding the parameters that determine the survival of airborne microorganisms is critical to mitigating the impact of disease outbreaks. Conventional techniques for investigating bioaerosol longevity in vitro have systemic limitations that prevent the accurate representation of conditions that these particles would experience in the natural environment. Here, we report a new approach that enables the robust study of bioaerosol survival as a function of relevant environmental conditions. The methodology uses droplet-on-demand technology for the generation of bioaerosol droplets (1 to greater than 100 per trial) with tailored chemical and biological composition. These arrays of droplets are captured in an electrodynamic trap and levitated within a controlled environmental chamber. Droplets are then deposited on a substrate after a desired levitation period (less than 5 s to greater than 24 h). The response of bacteria to aerosolization can subsequently be determined by counting colony forming units, 24 h after deposition. In a first study, droplets formed from a suspension of Escherichia coli MRE162 cells (108 ml-1) with initial radii of 27.8 ± 0.08 µm were created and levitated for extended periods of time at 30% relative humidity. The time-dependence of the survival rate was measured over a time period extending to 1 h. We demonstrate that this approach can enable direct studies at the interface between aerobiology, atmospheric chemistry and aerosol physics to identify the factors that may affect the survival of airborne pathogens with the aim of developing infection control strategies for public health and biodefence applications.
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Affiliation(s)
| | - Richard J Thomas
- 2 Defence Science Technology Laboratory (DSTL) , Porton Down, Salisbury SP4 0JQ , UK
| | - Natalie J Garton
- 3 Department of Infection, Immunity and Inflammation, University of Leicester , Leicester LE1 7RH , UK
| | - Andrew Hudson
- 4 Department of Chemistry, Leicester Institute of Structural and Chemical Biology, University of Leicester , Leicester LE1 7RH , UK
| | - Allen Haddrell
- 1 School of Chemistry, University of Bristol , Bristol BS8 1TS , UK
| | - Jonathan P Reid
- 1 School of Chemistry, University of Bristol , Bristol BS8 1TS , UK
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28
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Robinson JF, Gregson FKA, Miles REH, Reid JP, Royall CP. Drying kinetics and nucleation in evaporating sodium nitrate aerosols. J Chem Phys 2020; 152:074503. [PMID: 32087631 DOI: 10.1063/1.5139106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Joshua F. Robinson
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Florence K. A. Gregson
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Rachael E. H. Miles
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Jonathan P. Reid
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - C. Patrick Royall
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
- Centre for Nanoscience and Quantum Information, University of Bristol, Bristol BS8 1FD, United Kingdom
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29
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Richards DS, Trobaugh KL, Hajek-Herrera J, Davis RD. Dual-Balance Electrodynamic Trap as a Microanalytical Tool for Identifying Gel Transitions and Viscous Properties of Levitated Aerosol Particles. Anal Chem 2020; 92:3086-3094. [PMID: 31941272 DOI: 10.1021/acs.analchem.9b04487] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The formation of gelatinous networks within an aerosol particle significantly alters the physicochemical properties of the aerosol material. Existing techniques for studying gel transitions rely on bulk rheometry, which is limited by contact with the sample, or microrheological techniques such as holographic optical tweezers, which rely on expensive equipment and high-powered lasers that can degrade light-absorbing aerosol. Here, we present a new technique to probe the microrheological characteristics of aerosol particles and explore gel formation under atmospheric conditions in a contactless environment without the need for high-power light sources. In a dual-balance quadrupole electrodynamic balance, levitated droplets of opposite polarity are trapped and equilibrated at fixed relative humidity (RH) and then subsequently merged, and the physical characteristics of the merged droplets are monitored as a function of time and RH using imaging techniques. By comparing the RH-dependent characteristics of MgSO4 (known to undergo a gel transition) to glucose and sucrose (known to remain as viscous Newtonian fluids) under fixed equilibration time scales, we demonstrate that gel phase transitions can be identified in aerosol particles, with MgSO4 abruptly transitioning to a rigid microgel at 30% RH. Further, we demonstrate this technique can be used to also measure aerosol viscosity and identify non-Newtonian fluid dynamics in model sea spray aerosol composed of NaCl, CaCl2, and sorbitol. Thus, using this experimental technique, it is possible to distinguish between aerosol compositions that form viscous Newtonian fluids and those that undergo a gel transition or form non-Newtonian fluids. This technique offers a simple and cost-effective analytical tool for probing gel transitions outside of bulk solubility limits, with relevant applications ranging from atmospheric science to microengineering of soft matter materials.
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Affiliation(s)
- David S Richards
- Department of Chemistry , Trinity University , 1 Trinity Place , San Antonio , Texas 78212 , United States
| | - Kristin L Trobaugh
- Department of Chemistry , Trinity University , 1 Trinity Place , San Antonio , Texas 78212 , United States
| | - Josefina Hajek-Herrera
- Department of Chemistry , Trinity University , 1 Trinity Place , San Antonio , Texas 78212 , United States
| | - Ryan D Davis
- Department of Chemistry , Trinity University , 1 Trinity Place , San Antonio , Texas 78212 , United States
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30
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Song YC, Ingram S, Arbon RE, Topping DO, Glowacki DR, Reid JP. Transient cavity dynamics and divergence from the Stokes-Einstein equation in organic aerosol. Chem Sci 2020; 11:2999-3006. [PMID: 34122802 PMCID: PMC8157714 DOI: 10.1039/c9sc06228a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/15/2020] [Indexed: 12/26/2022] Open
Abstract
The diffusion of small molecules through viscous matrices formed by large organic molecules is important across a range of domains, including pharmaceutical science, materials chemistry, and atmospheric science, impacting on, for example, the formation of amorphous and crystalline phases. Here we report significant breakdowns in the Stokes-Einstein (SE) equation from measurements of the diffusion of water (spanning 5 decades) and viscosity (spanning 12 decades) in saccharide aerosol droplets. Molecular dynamics simulations show water diffusion is not continuous, but proceeds by discrete hops between transient cavities that arise and dissipate as a result of dynamical fluctuations within the saccharide lattice. The ratio of transient cavity volume to solvent volume increases with size of molecules making up the lattice, increasing divergence from SE predictions. This improved mechanistic understanding of diffusion in viscous matrices explains, for example, why organic compounds equilibrate according to SE predictions and water equilibrates more rapidly in aerosols.
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Affiliation(s)
- Young-Chul Song
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Stephen Ingram
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
- Centre for Computational Chemistry, University of Bristol Cantock's Close BS8 1TS UK
| | - Robert E Arbon
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
- Centre for Computational Chemistry, University of Bristol Cantock's Close BS8 1TS UK
| | - David O Topping
- School of Earth and Environmental Science, University of Manchester Manchester M13 9PL UK
| | - David R Glowacki
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
- Centre for Computational Chemistry, University of Bristol Cantock's Close BS8 1TS UK
- Department of Computer Science, University of Bristol UK
| | - Jonathan P Reid
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
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31
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Gorkowski K, Donahue NM, Sullivan RC. Aerosol Optical Tweezers Constrain the Morphology Evolution of Liquid-Liquid Phase-Separated Atmospheric Particles. Chem 2020. [DOI: 10.1016/j.chempr.2019.10.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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32
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Effect of Bulk Composition on the Heterogeneous Oxidation of Semi-Solid Atmospheric Aerosols. ATMOSPHERE 2019. [DOI: 10.3390/atmos10120791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The OH-initiated heterogeneous oxidation of semi-solid saccharide particles with varying bulk compositions was investigated in an atmospheric pressure flow tube at 30% relative humidity. Reactive uptake coefficients were determined from the rate loss of the saccharide reactants measured by mass spectrometry at different monosaccharide (methyl-β-d-glucopyranoside, C7H14O6) and disaccharide (lactose, C12H22O11) molar ratios. The reactive uptake for the monosaccharide was found to decrease from 0.53 ± 0.10 to 0.05 ± 0.06 as the mono-to-disaccharide molar ratio changed from 8:1 to 1:1. A reaction–diffusion model was developed in order to determine the effect of chemical composition on the reactive uptake. The observed decays can be reproduced using a Vignes relationship to predict the composition dependence of the reactant diffusion coefficients. The experimental data and model results suggest that the addition of the disaccharide significantly increases the particle viscosity leading to slower mass transport phenomena from the bulk to the particle surface and to a decreased reactivity. These findings illustrate the impact of bulk composition on reactant bulk diffusivity which determines the rate-limiting step during the chemical transformation of semi-solid particles in the atmosphere.
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33
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Moreno C, Baeza-Romero MT. A kinetic model for ozone uptake by solutions and aqueous particles containing I - and Br -, including seawater and sea-salt aerosol. Phys Chem Chem Phys 2019; 21:19835-19856. [PMID: 31497813 DOI: 10.1039/c9cp03430g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The heterogeneous interactions of gaseous ozone (O3) with seawater and with sea-salt aerosols are known to generate volatile halogen species, which, in turn, lead to further destruction of O3. Here, a kinetic model for the interaction of ozone (O3) with Br- and I- solutions and aqueous particles has been proposed that satisfactorily explains previous literature studies about this process. Apart from the aqueous-phase reactions X- + O3 (X = I, Br), the interaction also involves the surface reactions X- + O3 that occur via O3 adsorption on the aqueous surface. In single salt solutions and aerosols, the partial order in ozone and the total order of the surface reactions are one, but the apparent total order is second order because the number of ozone sites where reaction can occur is equal to the surficial concentration of X- ([X-]surf). In the presence of Cl-, the surface reactions are enhanced by a factor equal to , where and . Therefore, we have inferred that Cl- acts as a catalyst in the surface reactions X- + O3. The model has been applied to estimate ozone uptake by the reaction with these halides in/on seawater and in/on sea-salt aerosol, where it has been concluded that the Cl--catalyzed surface reaction is important relative to total ozone uptake and should therefore be considered to model Y/YO (Y = I, Br, Cl) levels in the troposphere.
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Affiliation(s)
- Carolina Moreno
- Escuela de Ingeniería Industrial y Aeroespacial, Universidad de Castilla-La Mancha, 45071, Toledo, Spain.
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34
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Dou J, Luo B, Peter T, Alpert PA, Corral Arroyo P, Ammann M, Krieger UK. Carbon Dioxide Diffusivity in Single, Levitated Organic Aerosol Particles. J Phys Chem Lett 2019; 10:4484-4489. [PMID: 31295402 DOI: 10.1021/acs.jpclett.9b01389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The diffusivity of molecules relevant to condensed-phase chemistry within viscous secondary organic aerosol (SOA) remains highly uncertain. Whereas there has been an effort to characterize water diffusivity as well as the diffusivity of larger compounds, data are lacking almost entirely for small molecules, such as carbon dioxide (CO2). Here we use photochemically generated CO2 in single particles of aqueous citric acid as a SOA proxy, levitated in an electrodynamic balance, to deduce CO2 diffusivity in the particle with unprecedented accuracy. For medium viscosities at intermediate relative humidities (∼25-40% RH), we find CO2 diffusivities DCO2 ≈ 10-14 m2 s-1, agreeing with the Stokes-Einstein relationship based on current viscosity data but 10 times lower than that for water. Conversely, under dry high-viscosity conditions, we find that DCO2 ≈ 10-16 m2 s-1, which is 10 times higher than for water. We infer that the chemical degradation of atmospheric SOA particles will likely not be limited by CO2 diffusivity.
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Affiliation(s)
- Jing Dou
- Institute for Atmospheric and Climate Science , ETH Zürich , 8092 Zürich , Switzerland
| | - Beiping Luo
- Institute for Atmospheric and Climate Science , ETH Zürich , 8092 Zürich , Switzerland
| | - Thomas Peter
- Institute for Atmospheric and Climate Science , ETH Zürich , 8092 Zürich , Switzerland
| | - Peter A Alpert
- Paul Scherrer Institute , Laboratory of Environmental Chemistry , 5232 Villigen PSI , Switzerland
| | - Pablo Corral Arroyo
- Paul Scherrer Institute , Laboratory of Environmental Chemistry , 5232 Villigen PSI , Switzerland
| | - Markus Ammann
- Paul Scherrer Institute , Laboratory of Environmental Chemistry , 5232 Villigen PSI , Switzerland
| | - Ulrich K Krieger
- Institute for Atmospheric and Climate Science , ETH Zürich , 8092 Zürich , Switzerland
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35
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Liu Y, Wu Z, Huang X, Shen H, Bai Y, Qiao K, Meng X, Hu W, Tang M, He L. Aerosol Phase State and Its Link to Chemical Composition and Liquid Water Content in a Subtropical Coastal Megacity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:5027-5033. [PMID: 30933482 DOI: 10.1021/acs.est.9b01196] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Particle phase state plays a key role in gas-particle partitioning, heterogeneous and multiphase reactions, and secondary aerosol formation. In this work, the rebound fraction and chemical composition of submicron particles were simultaneously measured to investigate the particle phase state and its link to chemical composition in a subtropical coastal urban city (Shenzhen, China). Submicron particles were found to be in the liquid state for most of the measurement period in spring. During the sampling time, both high relative humidity (RH, ranged from 40% to 93%) and inorganic mass fraction in particles (62.6 ± 12.4% of dry particles, on average) resulted in abundant aerosol liquid water (43 ± 6% in the wet PM1, on average), which may liquefy the particles. Considering the high frequency of ambient RH > 60% and large inorganic mass fraction in aerosol particles, we deduced that particles were in the liquid state throughout the year in coastal urban areas, where this study was performed. The liquid phase particles may accelerate the mass transfer of reactive trace gases and multiphase reactions, thereby enhanced secondary aerosol formation, further resulting in a rapid growth in aerosol mass. Our work suggested that in regions heavily impacted by SO2 and NO x emissions, especially in developing countries, the presence of inorganics could significantly impact the phase state of ambient aerosol particles, and thus the mixing state of inorganic and organic matter should be taken into account for the investigation of the aerosol phase state in urban environments.
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Affiliation(s)
- Yuechen Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
| | - Zhijun Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
| | - Xiaofeng Huang
- Shenzhen Graduate School , Peking University , Shenzhen 518055 , PR China
| | - Hangyin Shen
- Shenzhen Graduate School , Peking University , Shenzhen 518055 , PR China
| | - Yao Bai
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
| | - Kai Qiao
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
| | - Xiangxinyue Meng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
| | - Weiwei Hu
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization , Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640 , China
| | - Mingjin Tang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization , Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640 , China
| | - Lingyan He
- Shenzhen Graduate School , Peking University , Shenzhen 518055 , PR China
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36
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Rovelli G, Song YC, Maclean AM, Topping DO, Bertram AK, Reid JP. Comparison of Approaches for Measuring and Predicting the Viscosity of Ternary Component Aerosol Particles. Anal Chem 2019; 91:5074-5082. [PMID: 30921513 DOI: 10.1021/acs.analchem.8b05353] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Measurements of the water activity-dependent viscosity of aerosol particles from two techniques are compared, specifically from the coalescence of two droplets in holographic optical tweezers (HOT) and poke-and-flow experiments on particles deposited onto a glass substrate. These new data are also compared with the fitting of dimer coagulation, isolation, and coalescence (DCIC) measurements. The aerosol system considered in this work are ternary mixtures of sucrose-citric acid-water and sucrose-NaNO3-water, at varying solute mass ratios. Results from HOT and poke-and-flow are in excellent agreement over their overlapping range of applicability (∼103-107 Pa s); fitted curves from DCIC data show variable agreement with the other two techniques because of the sensitivity of the applied modeling framework to the representation of water content in the particles. Further, two modeling approaches for the predictions of the water activity-dependent viscosity of these ternary systems are evaluated. We show that it is possible to represent their viscosity with relatively simple mixing rules applied to the subcooled viscosity values of each component or to the viscosity of the corresponding binary mixtures.
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Affiliation(s)
- Grazia Rovelli
- School of Chemistry , University of Bristol , Bristol BS8 1TS , U.K
| | - Young-Chul Song
- School of Chemistry , University of Bristol , Bristol BS8 1TS , U.K
| | - Adrian M Maclean
- Department of Chemistry , University of British Columbia , Vancouver , BC V6T 1Z1 , Canada
| | - David O Topping
- School of Earth, Atmospheric and Environmental Science , University of Manchester , Manchester M13 9PL , U.K
| | - Allan K Bertram
- Department of Chemistry , University of British Columbia , Vancouver , BC V6T 1Z1 , Canada
| | - Jonathan P Reid
- School of Chemistry , University of Bristol , Bristol BS8 1TS , U.K
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37
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Miles REH, Glerum MWJ, Boyer HC, Walker JS, Dutcher CS, Bzdek BR. Surface Tensions of Picoliter Droplets with Sub-Millisecond Surface Age. J Phys Chem A 2019; 123:3021-3029. [PMID: 30864798 DOI: 10.1021/acs.jpca.9b00903] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Aerosols are key components of the atmosphere and play important roles in many industrial processes. Because aerosol particles have high surface-to-volume ratios, their surface properties are especially important. However, direct measurement of the surface properties of aerosol particles is challenging. In this work, we describe an approach to measure the surface tension of picoliter volume droplets with surface age <1 ms by resolving their dynamic oscillations in shape immediately after ejection from a microdroplet dispenser. Droplet shape oscillations are monitored by highly time-resolved (500 ns) stroboscopic imaging, and droplet surface tension is accurately retrieved across a wide range of droplet sizes (10-25 μm radius) and surface ages (down to ∼100 μs). The approach is validated for droplets containing sodium chloride, glutaric acid, and water, which all show no variation in surface tension with surface age. Experimental results from the microdroplet dispenser approach are compared to complementary surface tension measurements of 5-10 μm radius droplets with aged surfaces using a holographic optical tweezers approach and predictions of surface tension using a statistical thermodynamic model. These approaches combined will allow investigation of droplet surface tension across a wide range of droplet sizes, compositions, and surface ages.
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Affiliation(s)
- Rachael E H Miles
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , United Kingdom
| | - Michael W J Glerum
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , United Kingdom
| | - Hallie C Boyer
- Department of Mechanical Engineering , University of Minnesota, Twin Cities , Minneapolis , Minnesota 55455 , United States
| | - Jim S Walker
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , United Kingdom
| | - Cari S Dutcher
- Department of Mechanical Engineering , University of Minnesota, Twin Cities , Minneapolis , Minnesota 55455 , United States
| | - Bryan R Bzdek
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , United Kingdom
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38
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Edebeli J, Ammann M, Bartels-Rausch T. Microphysics of the aqueous bulk counters the water activity driven rate acceleration of bromide oxidation by ozone from 289-245 K. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:63-73. [PMID: 30534711 DOI: 10.1039/c8em00417j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The reaction of ozone with bromide is an initiation process in bromine activation resulting in the formation of reactive bromine species with impacts on the fate of compounds in the lower atmosphere. Environmental halide sources often contain organics, which are known to influence aqueous bulk reactivity. Here, we present a study investigating the temperature dependence of bromide oxidation by ozone using a coated wall flow tube reactor coated with an aqueous mixture of citric acid, as a proxy for oxidized secondary organic matter, and sodium bromide. Using the resistor model formulation, we quantify changes in the properties of the aqueous bulk relevant for the observed reactivity. The reactive uptake coefficient decreased from 2 × 10-6 at 289 K to 0.5 × 10-6 at 245 K. Our analysis indicates that the humidity-driven increase in concentration with a corresponding increase in the pseudo-first order reaction rate was countered by the colligative change in ozone solubility and the effect of the organic fraction via increased viscosity and decreased diffusivity of ozone as the temperature decreased. From our parameterization, we provide an extension of the temperature dependence of the reaction rate coefficients driving the oxidation of bromide, and assess the temperature-dependent salting effects of citric acid on ozone solubility. This study shows the effects of the organic species at relatively mild temperatures, between the freezing point and eutectic temperature of sea as is typical for the Earth's cryosphere. Thus, this study may be relevant for atmospheric models at different scales describing halogen activation in the marine boundary layer or free troposphere including matrices such as sea-spray aerosol and brine in sea ice, snow, and around mid-latitude salt lakes.
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Affiliation(s)
- Jacinta Edebeli
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, Villigen PSI, Switzerland.
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39
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Nadler KA, Kim P, Huang DL, Xiong W, Continetti RE. Water diffusion measurements of single charged aerosols using H2O/D2O isotope exchange and Raman spectroscopy in an electrodynamic balance. Phys Chem Chem Phys 2019; 21:15062-15071. [DOI: 10.1039/c8cp07052k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report water diffusion measurements on single charged aerosols using isotope exchange in an electrodynamic balance.
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Affiliation(s)
- Katherine A. Nadler
- Department of Chemistry and Biochemistry
- University of California San Diego
- La Jolla
- USA
| | - Pyeongeun Kim
- Department of Chemistry and Biochemistry
- University of California San Diego
- La Jolla
- USA
| | - Dao-Ling Huang
- Department of Chemistry and Biochemistry
- University of California San Diego
- La Jolla
- USA
| | - Wei Xiong
- Department of Chemistry and Biochemistry
- University of California San Diego
- La Jolla
- USA
| | - Robert E. Continetti
- Department of Chemistry and Biochemistry
- University of California San Diego
- La Jolla
- USA
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40
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Gregson FKA, Robinson JF, Miles REH, Royall CP, Reid JP. Drying Kinetics of Salt Solution Droplets: Water Evaporation Rates and Crystallization. J Phys Chem B 2018; 123:266-276. [DOI: 10.1021/acs.jpcb.8b09584] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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41
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Marsh A, Rovelli G, Song YC, Pereira KL, Willoughby RE, Bzdek BR, Hamilton JF, Orr-Ewing AJ, Topping DO, Reid JP. Accurate representations of the physicochemical properties of atmospheric aerosols: when are laboratory measurements of value? Faraday Discuss 2018; 200:639-661. [PMID: 28574570 DOI: 10.1039/c7fd00008a] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Laboratory studies can provide important insights into the processes that occur at the scale of individual particles in ambient aerosol. We examine the accuracies of measurements of core physicochemical properties of aerosols that can be made in single particle studies and explore the impact of these properties on the microscopic processes that occur in ambient aerosol. Presenting new measurements, we examine here the refinements in our understanding of aerosol hygroscopicity, surface tension, viscosity and optical properties that can be gained from detailed laboratory measurements for complex mixtures through to surrogates for secondary organic atmospheric aerosols.
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Rothfuss NE, Marsh A, Rovelli G, Petters MD, Reid JP. Condensation Kinetics of Water on Amorphous Aerosol Particles. J Phys Chem Lett 2018; 9:3708-3713. [PMID: 29924626 DOI: 10.1021/acs.jpclett.8b01365] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Responding to changes in the surrounding environment, aerosol particles can grow by water condensation changing rapidly in composition and changing dramatically in viscosity. The timescale for growth is important to establish for particles undergoing hydration processes in the atmosphere or during inhalation. Using an electrodynamic balance, we report direct measurements at -7.5, 0, and 20 °C of timescales for hygroscopic condensational growth on a range of model hygroscopic aerosol systems. These extend from viscous aerosol particles containing a single saccharide solute (sucrose, glucose, raffinose, or trehalose) and a starting viscosity equivalent to a glass of ∼1012 Pa·s, to nonviscous (∼10-2 Pa·s) tetraethylene glycol particles. The condensation timescales observed in this work indicate that water condensation occurs rapidly at all temperatures examined (<10 s) and for particles of all initial viscosities spanning 10-2 to 1012 Pa·s. Only a marginal delay (<1 order of magnitude) is observed for particles starting as a glass.
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Affiliation(s)
- Nicholas E Rothfuss
- Department of Marine, Earth, and Atmospheric Sciences , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Aleksandra Marsh
- School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
| | - Grazia Rovelli
- School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
| | - Markus D Petters
- Department of Marine, Earth, and Atmospheric Sciences , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Jonathan P Reid
- School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
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43
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Abstract
Aerosols are dynamic systems, responding to variations in the surrounding environmental conditions by changing in size, composition and phase. Although, widely used in inhalation therapies, details of the processes occurring on aerosol generation and during inhalation have received little attention. Instead, research has focused on improvements to the formulation of the drug prior to aerosolization and the resulting clinical efficacy of the treatment. Here, we highlight the processes that occur during aerosol generation and inhalation, affecting aerosol disposition when deposited and, potentially, impacting total and regional doses. In particular, we examine the response of aerosol particles to the humid environment of the respiratory tract, considering both the capacity of particles to grow by absorbing moisture and the timescale for condensation to occur. [Formula: see text].
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44
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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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45
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Reid JP, Bertram AK, Topping DO, Laskin A, Martin ST, Petters MD, Pope FD, Rovelli G. The viscosity of atmospherically relevant organic particles. Nat Commun 2018; 9:956. [PMID: 29511168 PMCID: PMC5840428 DOI: 10.1038/s41467-018-03027-z] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 01/12/2018] [Indexed: 11/13/2022] Open
Abstract
The importance of organic aerosol particles in the environment has been long established, influencing cloud formation and lifetime, absorbing and scattering sunlight, affecting atmospheric composition and impacting on human health. Conventionally, ambient organic particles were considered to exist as liquids. Recent observations in field measurements and studies in the laboratory suggest that they may instead exist as highly viscous semi-solids or amorphous glassy solids under certain conditions, with important implications for atmospheric chemistry, climate and air quality. This review explores our understanding of aerosol particle phase, particularly as identified by measurements of the viscosity of organic particles, and the atmospheric implications of phase state.
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Affiliation(s)
- Jonathan P Reid
- School of Chemistry, University of Bristol, Manchester, BS8 1TS, UK.
| | - Allan K Bertram
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
| | - David O Topping
- School of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester, M13 9PL, UK
| | - Alexander Laskin
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - 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
| | - Markus D Petters
- Department of Marine Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | - Francis D Pope
- School of Geography, Earth and Environmental Sciences, University of Birmingham Edgbaston, Birmingham, B15 2TT, UK
| | - Grazia Rovelli
- School of Chemistry, University of Bristol, Manchester, BS8 1TS, UK
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46
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Liu P, Li YJ, Wang Y, Bateman AP, Zhang Y, Gong Z, Bertram AK, Martin ST. Highly Viscous States Affect the Browning of Atmospheric Organic Particulate Matter. ACS CENTRAL SCIENCE 2018; 4. [PMID: 29532020 PMCID: PMC5832997 DOI: 10.1021/acscentsci.7b00452] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Initially transparent organic particulate matter (PM) can become shades of light-absorbing brown via atmospheric particle-phase chemical reactions. The production of nitrogen-containing compounds is one important pathway for browning. Semisolid or solid physical states of organic PM might, however, have sufficiently slow diffusion of reactant molecules to inhibit browning reactions. Herein, organic PM of secondary organic material (SOM) derived from toluene, a common SOM precursor in anthropogenically affected environments, was exposed to ammonia at different values of relative humidity (RH). The production of light-absorbing organonitrogen imines from ammonia exposure, detected by mass spectrometry and ultraviolet-visible spectrophotometry, was kinetically inhibited for RH < 20% for exposure times of 6 min to 24 h. By comparison, from 20% to 60% RH organonitrogen production took place, implying ammonia uptake and reaction. Correspondingly, the absorption index k across 280 to 320 nm increased from 0.012 to 0.02, indicative of PM browning. The k value across 380 to 420 nm increased from 0.001 to 0.004. The observed RH-dependent behavior of ammonia uptake and browning was well captured by a model that considered the diffusivities of both the large organic molecules that made up the PM and the small reactant molecules taken up from the gas phase into the PM. Within the model, large-molecule diffusivity was calculated based on observed SOM viscosity and evaporation. Small-molecule diffusivity was represented by the water diffusivity measured by a quartz-crystal microbalance. The model showed that the browning reaction rates at RH < 60% could be controlled by the low diffusivity of the large organic molecules from the interior region of the particle to the reactive surface region. The results of this study have implications for accurate modeling of atmospheric brown carbon production and associated influences on energy balance.
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Affiliation(s)
- Pengfei Liu
- John A. Paulson School of Engineering and Applied
Sciences and Department
of Earth and
Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Yong Jie Li
- John A. Paulson School of Engineering and Applied
Sciences and Department
of Earth and
Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Department
of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau, China
| | - Yan Wang
- John A. Paulson School of Engineering and Applied
Sciences and Department
of Earth and
Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- T. H.
Chan School of Public Health, Harvard University, Boston, Massachusetts 02115, United States
| | - Adam P. Bateman
- John A. Paulson School of Engineering and Applied
Sciences and Department
of Earth and
Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Yue Zhang
- John A. Paulson School of Engineering and Applied
Sciences and Department
of Earth and
Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Aerodyne
Research Inc., Billerica, Massachusetts 01821, United States
| | - Zhaoheng Gong
- John A. Paulson School of Engineering and Applied
Sciences and Department
of Earth and
Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Allan K. Bertram
- Department
of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Scot T. Martin
- John A. Paulson School of Engineering and Applied
Sciences and Department
of Earth and
Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- E-mail:
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47
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Wiegel AA, Liu MJ, Hinsberg WD, Wilson KR, Houle FA. Diffusive confinement of free radical intermediates in the OH radical oxidation of semisolid aerosols. Phys Chem Chem Phys 2018; 19:6814-6830. [PMID: 28218326 DOI: 10.1039/c7cp00696a] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multiphase chemical reactions (gas + solid/liquid) involve a complex interplay between bulk and interface chemistry, diffusion, evaporation, and condensation. Reactions of atmospheric aerosols are an important example of this type of chemistry: the rich array of particle phase states and multiphase transformation pathways produce diverse but poorly understood interactions between chemistry and transport. Their chemistry is of intrinsic interest because of their role in controlling climate. Their characteristics also make them useful models for the study of principles of reactivity of condensed materials under confined conditions. In previous work, we have reported a computational study of the oxidation chemistry of a liquid aliphatic aerosol. In this study, we extend the calculations to investigate nearly the same reactions at a semisolid gas-aerosol interface. A reaction-diffusion model for heterogeneous oxidation of triacontane by hydroxyl radicals (OH) is described, and its predictions are compared to measurements of aerosol size and composition, which evolve continuously during oxidation. These results are also explicitly compared to those obtained for the corresponding liquid system, squalane, to pinpoint salient elements controlling reactivity. The diffusive confinement of the free radical intermediates at the interface results in enhanced importance of a few specific chemical processes such as the involvement of aldehydes in fragmentation and evaporation, and a significant role of radical-radical reactions in product formation. The simulations show that under typical laboratory conditions semisolid aerosols have highly oxidized nanometer-scale interfaces that encapsulate an unreacted core and may confer distinct optical properties and enhanced hygroscopicity. This highly oxidized layer dynamically evolves with reaction, which we propose to result in plasticization. The validated model is used to predict chemistry under atmospheric conditions, where the OH radical concentration is much lower. The oxidation reactions are more strongly influenced by diffusion in the particle, resulting in a more liquid-like character.
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Affiliation(s)
- Aaron A Wiegel
- Lawrence Berkeley National Laboratory, Chemical Sciences Division, Berkeley, CA 94702, USA.
| | - Matthew J Liu
- Lawrence Berkeley National Laboratory, Chemical Sciences Division, Berkeley, CA 94702, USA. and University of California, Berkeley, Department of Chemical and Biomolecular Engineering, Berkeley, CA 94702, USA
| | | | - Kevin R Wilson
- Lawrence Berkeley National Laboratory, Chemical Sciences Division, Berkeley, CA 94702, USA.
| | - Frances A Houle
- Lawrence Berkeley National Laboratory, Chemical Sciences Division, Berkeley, CA 94702, USA.
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48
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Marsh A, Petters SS, Rothfuss NE, Rovelli G, Song YC, Reid JP, Petters MD. Amorphous phase state diagrams and viscosity of ternary aqueous organic/organic and inorganic/organic mixtures. Phys Chem Chem Phys 2018; 20:15086-15097. [PMID: 29796502 DOI: 10.1039/c8cp00760h] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A Dimer Coagulation, Isolation and Coalescence (DCIC) technique is used to probe the phase behaviour and glass transition temperatures of ternary aerosol mixtures.
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Affiliation(s)
| | - Sarah Suda Petters
- Department of Atmospheric Science
- Colorado State University
- Fort Collins
- USA
| | | | | | | | | | - Markus Dirk Petters
- Department of Marine
- Earth, and Atmospheric Sciences
- North Carolina State University
- Raleigh
- USA
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49
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Marshall FH, Berkemeier T, Shiraiwa M, Nandy L, Ohm PB, Dutcher CS, Reid JP. Influence of particle viscosity on mass transfer and heterogeneous ozonolysis kinetics in aqueous–sucrose–maleic acid aerosol. Phys Chem Chem Phys 2018; 20:15560-15573. [DOI: 10.1039/c8cp01666f] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ozonolysis kinetics of viscous aerosol particles containing maleic acid are studied. Kinetic fits are constrained by measured particle viscosities.
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Affiliation(s)
| | - Thomas Berkemeier
- School of Chemical & Biomolecular Engineering
- Georgia Institute of Technology
- Atlanta
- USA
| | | | - Lucy Nandy
- Department of Mechanical Engineering
- University of Minnesota
- Minneapolis
- USA
| | - Peter B. Ohm
- Department of Mechanical Engineering
- University of Minnesota
- Minneapolis
- USA
| | - Cari S. Dutcher
- Department of Mechanical Engineering
- University of Minnesota
- Minneapolis
- USA
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50
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Bzdek BR, Reid JP. Perspective: Aerosol microphysics: From molecules to the chemical physics of aerosols. J Chem Phys 2017; 147:220901. [DOI: 10.1063/1.5002641] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Bryan R. Bzdek
- School of Chemistry, University of Bristol, Bristol BS8 1TS,
United Kingdom
| | - Jonathan P. Reid
- School of Chemistry, University of Bristol, Bristol BS8 1TS,
United Kingdom
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