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Johnson KN, Li Y, Ezell MJ, Lakey PSJ, Shiraiwa M, Finlayson-Pitts BJ. Elucidating gas-surface interactions relevant to atmospheric particle growth using combined temperature programmed desorption and temperature-dependent uptake. Phys Chem Chem Phys 2024; 26:23264-23276. [PMID: 39205494 DOI: 10.1039/d4cp02528h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Understanding growth mechanisms for particles in air is fundamental to developing a predictive capability for their impacts on human health, visibility, and climate. In the case of highly viscous semi-solid or solid particles, the likelihood of impinging gases being taken up to grow the particle will be influenced by the initial uptake coefficient and by the residence time of the adsorbed gas on the surface. Here, a new approach that combines Knudsen cell capabilities for gas uptake measurements with temperature programmed desorption (TPD) for binding energy measurements of gases is described. The application of this unique capability to the uptake of organic gases on silica demonstrates its utility and the combination of thermodynamic and kinetic data that can be obtained. Lower limits to the initial net uptake coefficients at 170 K are (3.0 ± 0.6) × 10-3, (4.9 ± 0.6) × 10-3 and (4.3 ± 0.8) × 10-3 for benzene, 1-chloropentane, and methanol, respectively, and are reported here for the first time. The uptake data demonstrated that the ideal gas lattice model was appropriate, which informed the analysis of the TPD data. From the thermal desorption measurements, desorption energies of 34.6 ± 2.5, 45.8 ± 5.5, and 40.0 ± 5.6 kJ mol-1 (errors are 1σ) are obtained for benzene, 1-chloropentane, and methanol, respectively, and show good agreement with previously reported measurements. A multiphase kinetics model was applied to quantify uptake, desorption, and diffusion through the particle multilayers and hence extract desorption kinetics. Implications for uptake of organics on silica surfaces in the atmosphere and the utility of this system for determining relationships between residence times of organic gases and particle surfaces of varying composition are discussed in the context of developing quantitative predictions for growth of aerosol particles in air.
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Affiliation(s)
- Kristen N Johnson
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
| | - Yixin Li
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
| | - Michael J Ezell
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
| | - Pascale S J Lakey
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
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2
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Xie Q, Halpern ER, Zhang J, Shrivastava M, Zelenyuk A, Zaveri RA, Laskin A. Volatility Basis Set Distributions and Viscosity of Organic Aerosol Mixtures: Insights from Chemical Characterization Using Temperature-Programmed Desorption-Direct Analysis in Real-Time High-Resolution Mass Spectrometry. Anal Chem 2024; 96:9524-9534. [PMID: 38815054 DOI: 10.1021/acs.analchem.4c01003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Quantitative assessment of gas-particle partitioning of individual components within complex atmospheric organic aerosol (OA) mixtures is critical for predicting and comprehending the formation and evolution of OA particles in the atmosphere. This investigation leverages previously documented data obtained through a temperature-programmed desorption-direct analysis in real-time, high-resolution mass spectrometry (TPD-DART-HRMS) platform. This methodology facilitates the bottom-up construction of volatility basis set (VBS) distributions for constituents found in three biogenic secondary organic aerosol (SOA) mixtures produced through the ozonolysis of α-pinene, limonene, and ocimene. The apparent enthalpies (ΔH*, kJ mol-1) and saturation mass concentrations (CT*, μg·m-3) of individual SOA components, determined as a function of temperature (T, K), facilitated an assessment of changes in VBS distributions and gas-particle partitioning with respect to T and atmospheric total organic mass loadings (tOM, μg·m-3). The VBS distributions reveal distinct differences in volatilities among monomers, dimers, and trimers, categorized into separate volatility bins. At the ambient temperature of T = 298 K, only monomers efficiently partition between gas and particle phases across a broad range of atmospherically relevant tOM values of 1-100 μg·m-3. Partitioning of dimers and trimers becomes notable only at T > 360 K and T > 420 K, respectively. The viscosity of SOA mixtures is assessed using a bottom-up calculation approach, incorporating the input of elemental formulas, ΔH*, CT*, and particle-phase mass fractions of the SOA components. Through this approach, we are able to accurately estimate the variations in SOA viscosity that result from the evaporation of its components. These variations are, in turn, influenced by atmospherically relevant changes in tOM and T. Comparison of the calculated SOA viscosity and diffusivity values with literature reported experimental results shows close agreement, thereby validating the employed calculation approach. These findings underscore the significant potential for TPD-DART-HRMS measurements in enabling the untargeted analysis of organic molecules within OA mixtures. This approach facilitates quantitative assessment of their gas-particle partitioning and allows for the estimation of their viscosity and condensed-phase diffusion, thereby contributing valuable insights to atmospheric models.
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Affiliation(s)
- Qiaorong Xie
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Emily R Halpern
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jie Zhang
- Atmospheric, Climate, and Earth Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Manish Shrivastava
- Atmospheric, Climate, and Earth Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Alla Zelenyuk
- Atmospheric, Climate, and Earth Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Rahul A Zaveri
- Atmospheric, Climate, and Earth Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Alexander Laskin
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
- Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907, United States
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3
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Dai Y, Chen Z, Qin X, Dong P, Xu J, Hu J, Gu L, Chen S. Hydrolysis reactivity reveals significant seasonal variation in the composition of organic peroxides in ambient PM 2.5. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172143. [PMID: 38569967 DOI: 10.1016/j.scitotenv.2024.172143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/24/2024] [Accepted: 03/30/2024] [Indexed: 04/05/2024]
Abstract
Atmospheric organic peroxides (POs) play a key role in the formation of O3 and secondary organic aerosol (SOA), impacting both air quality and human health. However, there still remain technical challenges in investigating the reactivity of POs in ambient aerosols due to the instability and lack of standards for POs, impeding accurate evaluation of their environmental impacts. In the present study, we conducted the first attempt to categorize and quantify POs in ambient PM2.5 through hydrolysis, which is an important transformation pathway for POs, thus revealing the reactivities of various POs. POs were generally categorized into hydrolyzable POs (HPO) and unhydrolyzable POs (UPO). HPO were further categorized into three groups: short-lifetime HPO (S-HPO), intermediate-lifetime HPO (I-HPO), and long-lifetime HPO (L-HPO). S-HPO and L-HPO are typically formed from Criegee intermediate (CI) and RO2 radical reactions, respectively. Results show that L-HPO are the most abundant HPO, indicating the dominant role of RO2 pathway in HPO formation. Despite their lower concentration compared to L-HPO, S-HPO make a major contribution to the HPO hydrolysis rate due to their faster rate constants. The hydrolysis of PM2.5 POs accounts for 19 % of the nighttime gas-phase H2O2 growth during the summer observation, constituting a noteworthy source of gas-phase H2O2 and contributing to the atmospheric oxidation capacity. Seasonal and weather conditions significantly impact the composition of POs, with HPO concentrations in summer being significantly higher than those in winter and elevated under rainy and nighttime conditions. POs are mainly composed of HPO in summer, while in winter, POs are dominated by UPO.
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Affiliation(s)
- Yishuang Dai
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zhongming Chen
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
| | - Xuan Qin
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Ping Dong
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Jiayun Xu
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Jingcheng Hu
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Linghao Gu
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Shiyi Chen
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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4
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Ye Q, Yao M, Wang W, Li Z, Li C, Wang S, Xiao H, Zhao Y. Multiphase interactions between sulfur dioxide and secondary organic aerosol from the photooxidation of toluene: Reactivity and sulfate formation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168736. [PMID: 37996034 DOI: 10.1016/j.scitotenv.2023.168736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 11/06/2023] [Accepted: 11/19/2023] [Indexed: 11/25/2023]
Abstract
There is growing evidence that the interactions between sulfur dioxide (SO2) and organic peroxides (POs) in aerosol and clouds play an important role in atmospheric sulfate formation and aerosol aging, yet the reactivity of POs arising from anthropogenic precursors toward SO2 remains unknown. In this study, we investigate the multiphase reactions of SO2 with secondary organic aerosol (SOA) formed from the photooxidation of toluene, a major type of anthropogenic SOA in the atmosphere. The reactive uptake coefficient of SO2 on toluene SOA was determined to be on the order of 10-4, depending strikingly on aerosol water content. POs contribute significantly to the multiphase reactivity of toluene SOA, but they can only explain a portion of the measured SO2 uptake, suggesting the presence of other reactive species in SOA that also contribute to the particle reactivity toward SO2. The second-order reaction rate constant (kII) between S(IV) and toluene-derived POs was estimated to be in the range of the kII values previously reported for commercially available POs (e.g., 2-butanone peroxide and 2-tert-butyl hydroperoxide) and the smallest (C1-C2) and biogenic POs. In addition, unlike commercial POs that can efficiently convert S(IV) into both inorganic sulfate and organosulfates, toluene-derived POs appear to mainly oxidize S(IV) to inorganic sulfate. Our study reveals the multiphase reactivity of typical anthropogenic SOA and POs toward SO2 and will help to develop a better understanding of the formation and evolution of atmospheric secondary aerosol.
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Affiliation(s)
- Qing Ye
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Min Yao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; School of Environmental & Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - Wei Wang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ziyue Li
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chenxi Li
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shunyao Wang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Huayun Xiao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yue Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
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5
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Qiu Y, Liu Y, Wu Z, Wang F, Meng X, Zhang Z, Man R, Huang D, Wang H, Gao Y, Huang C, Hu M. Predicting Atmospheric Particle Phase State Using an Explainable Machine Learning Approach Based on Particle Rebound Measurements. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15055-15064. [PMID: 37774013 DOI: 10.1021/acs.est.3c05284] [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: 10/01/2023]
Abstract
The particle phase state plays a vital role in the gas-particle partitioning, multiphase reactions, ice nucleation activity, and particle growth in the atmosphere. However, the characterization of the atmospheric phase state remains challenging. Herein, based on measured aerosol chemical composition and ambient relative humidity (RH), a machine learning (ML) model with high accuracy (R2 = 0.952) and robustness (RMSE = 0.078) was developed to predict the particle rebound fraction, f, which is an indicator of the particle phase state. Using this ML model, the f of particles in the urban atmosphere was predicted based on seasonal average aerosol chemical composition and RH. Regardless of seasons, aerosols remain in the liquid state of mid-high latitude cities in the northern hemisphere and in the semisolid state over semiarid regions. In the East Asian megacities, the particles remain in the liquid state in spring and summer and in the semisolid state in other seasons. The effects of nitrate, which is becoming dominant in fine particles in several urban areas, on the particle phase state were evaluated. More nitrate led the particles to remain in the liquid state at an even lower RH. This study proposed a new approach to predict the particle phase state in the atmosphere based on RH and aerosol chemical composition.
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Affiliation(s)
- Yanting Qiu
- State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yuechen Liu
- State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zhijun Wu
- State Joint Key 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
| | - Fuzhou Wang
- Department of Computer Science, City University of Hong Kong, Hong Kong, SAR 999077, China
| | - Xiangxinyue Meng
- State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zirui Zhang
- State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Ruiqi Man
- State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Dandan Huang
- State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Hongli Wang
- State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Yaqin Gao
- State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Cheng Huang
- State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Min Hu
- State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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6
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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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7
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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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8
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Yu Z, Jang M, Madhu A. Prediction of Phase State of Secondary Organic Aerosol Internally Mixed with Aqueous Inorganic Salts. J Phys Chem A 2021; 125:10198-10206. [PMID: 34797662 DOI: 10.1021/acs.jpca.1c06773] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the presence of inorganic salts, secondary organic aerosol (SOA) undergoes liquid-liquid phase separation (LLPS), liquid-solid phase separation, or a homogeneous phase in ambient air. In this study, a regression model was derived to predict aerosol phase separation relative humidity (SRH) for various organic and inorganic mixes. The model implemented organic physicochemical parameters (i.e., oxygen to carbon ratio, molecular weight, and hydrogen-bonding ability) and the parameters related to inorganic compositions (i.e., ammonium, sulfate, nitrate, and water). The aerosol phase data were observed using an optical microscope and also collected from the literature. The crystallization of aerosols at the effloresce RH (ERH) was semiempirically predicted with a neural network model. Overall, the greater SRH appeared for the organic compounds with the lower oxygen to carbon ratios or the greater molecular weight and the higher aerosol acidity or the larger fraction of inorganic nitrate led to the lower SRH. The resulting model has been demonstrated for three different chamber-generated SOA (originated from β-pinene, toluene, and 1,3,5-trimethylbenzene), which were internally mixed with the inorganic aqueous system of ammonium-sulfate-water. For all three SOA systems, both observations and model predictions showed LLPS at RH <80%. In the urban atmosphere, LLPS is likely a frequent occurrence for the typical anthropogenic SOA, which originates from aromatic and alkane hydrocarbon.
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Affiliation(s)
- Zechen Yu
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611, United States
| | - Myoseon Jang
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611, United States
| | - Azad Madhu
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611, United States
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9
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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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10
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Qin Y, Ye J, Ohno P, Zhai J, Han Y, Liu P, Wang J, Zaveri RA, Martin ST. Humidity Dependence of the Condensational Growth of α-Pinene Secondary Organic Aerosol Particles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:14360-14369. [PMID: 34404213 DOI: 10.1021/acs.est.1c01738] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The influence of relative humidity (RH) on the condensational growth of organic aerosol particles remains incompletely understood. Herein, the RH dependence was investigated via a series of experiments for α-pinene ozonolysis in a continuously mixed flow chamber in which recurring cycles of particle growth occurred every 7 to 8 h at a given RH. In 5 h, the mean increase in the particle mode diameter was 15 nm at 0% RH and 110 nm at 75% RH. The corresponding particle growth coefficients, representing a combination of the thermodynamic driving force and the kinetic resistance to mass transfer, increased from 0.35 to 2.3 nm2 s-1. The chemical composition, characterized by O:C and H:C atomic ratios of 0.52 and 1.48, respectively, and determined by mass spectrometry, did not depend on RH. The Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) was applied to reproduce the observed size- and RH-dependent particle growth by optimizing the diffusivities Db within the particles of the condensing molecules. The Db values increased from 5 α-1 × 10-16 at 0% RH to 2 α-1 × 10-12 cm-2 s-1 at 75% RH for mass accommodation coefficients α of 0.1 to 1.0, highlighting the importance of particle-phase properties in modeling the growth of atmospheric aerosol particles.
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Affiliation(s)
- Yiming Qin
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Jianhuai Ye
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Paul Ohno
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Jinghao Zhai
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Yuemei Han
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Pengfei Liu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Junfeng Wang
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Rahul A Zaveri
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Scot T Martin
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
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11
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Liu Y, Meng X, Wu Z, Huang D, Wang H, Chen J, Chen J, Zong T, Fang X, Tan T, Zhao G, Chen S, Zeng L, Guo S, Huang X, He L, Zeng L, Hu M. The particle phase state during the biomass burning events. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 792:148035. [PMID: 34153758 DOI: 10.1016/j.scitotenv.2021.148035] [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: 11/30/2020] [Revised: 05/14/2021] [Accepted: 05/21/2021] [Indexed: 06/13/2023]
Abstract
The phase state of biomass burning aerosols (BBA) remains largely unclear, impeding our understanding of their effects on air quality, climate and human health, due to its profound roles in mass transfer between gaseous and particulate phase. In this study, the phase state of BBA was investigated by measuring the particle rebound fraction ƒ combining field observations and laboratory experiments. We found that both ambient and laboratory-generated BBA had unexpectedly lower rebound fraction ƒ (<0.6) under the dry conditions (RH = 20-50%), indicating that BBA were in non-solid state at such low RH. This was obviously different from the secondary organic aerosols (SOA) derived from the oxidation of both anthropogenic and biogenic volatile organic compounds, typically with a rebound fraction ƒ larger than 0.8 at RH below 50%. Therefore, we proposed that the diffusion coefficient of gaseous molecular in the bulk of BBA might be much higher than SOA under the dry conditions.
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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
| | - 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; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China.
| | - Dandan Huang
- State Environmental Protection Key Laboratory of Formation and Prevention of the Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Hongli Wang
- State Environmental Protection Key Laboratory of Formation and Prevention of the Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Jie Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Jingchuan Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Taomou Zong
- 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
| | - Tianyi Tan
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Gang Zhao
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Shiyi Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Liwu Zeng
- State Environmental Protection Key Laboratory of Formation and Prevention of the Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Song Guo
- 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, China
| | - Lingyan He
- Shenzhen Graduate School, Peking University, Shenzhen 518055, China
| | - Limin Zeng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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12
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Cheng Z, Sharma N, Tseng KP, Kovarik L, China S. Direct observation and assessment of phase states of ambient and lab-generated sub-micron particles upon humidification. RSC Adv 2021; 11:15264-15272. [PMID: 35424057 PMCID: PMC8698329 DOI: 10.1039/d1ra02530a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 04/15/2021] [Indexed: 12/11/2022] Open
Abstract
We present a new analytical platform that uses a tilted stage (60°) integrated to the Peltier cooling stage interfaced with an Environmental Scanning Electron Microscope (ESEM) to directly observe and assess the phase state of particles as a function of RH at a controlled temperature. Three types of organic particles have been studied: (a) Suwannee River Fulvic Acid (SRFA) particles, (b) lab generated soil organic particles, and (c) field-collected ambient particles. The chemical composition, morphology, and functional groups of individual particles were probed using computer-controlled scanning electron microscopy with energy-dispersive X-ray spectroscopy (CCSEM/EDX) and scanning transmission X-ray microscopy with near-edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Results show that all three types of particles are organic-rich, but soil organic particles and ambient particles contain a considerable amount of inorganic species. The phase state can be determined based on the particle's aspect ratio (particle width/height), which we proposed for solid, semisolid, and liquid particles are 1.00–1.30, 1.30–1.85, and >1.85, respectively. We found that solid SRFA particles transition to a semisolid state at ∼90% RH and to the liquid state at ∼97% RH, in agreement with the literature. The solid soil organic particles transition to a semisolid state at ∼85% RH and to the liquid state at ∼97% RH. The solid ambient organic particles transition to a semisolid state at ∼65% RH and the liquid state at ∼97% RH. Our results indicate that this new platform can directly observe and quantitatively indicate the phase transition of field-collected particles under different ambient conditions. We present a new analytical platform that uses a tilted and Peltier cooling stage interfaced with an environmental scanning electron microscope to directly observe and assess the phase state of individual particles as a function of relative humidity.![]()
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Affiliation(s)
- Zezhen Cheng
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory Richland Washington USA
| | - Noopur Sharma
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory Richland Washington USA
| | - Kuo-Pin Tseng
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory Richland Washington USA
| | - Libor Kovarik
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory Richland Washington USA
| | - Swarup China
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory Richland Washington USA
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13
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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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14
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He Y, Akherati A, Nah T, Ng NL, Garofalo LA, Farmer DK, Shiraiwa M, Zaveri RA, Cappa CD, Pierce JR, Jathar SH. Particle Size Distribution Dynamics Can Help Constrain the Phase State of Secondary Organic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:1466-1476. [PMID: 33417446 DOI: 10.1021/acs.est.0c05796] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Particle phase state is a property of atmospheric aerosols that has important implications for the formation, evolution, and gas/particle partitioning of secondary organic aerosol (SOA). In this work, we use a size-resolved chemistry and microphysics model (Statistical Oxidation Model coupled to the TwO Moment Aerosol Sectional (SOM-TOMAS)), updated to include an explicit treatment of particle phase state, to constrain the bulk diffusion coefficient (Db) of SOA produced from α-pinene ozonolysis. By leveraging data from laboratory experiments performed in the absence of a seed and under dry conditions, we find that the Db for SOA can be constrained ((1-7) × 10-15 cm2 s-1 in these experiments) by simultaneously reproducing the time-varying SOA mass concentrations and the evolution of the particle size distribution. Another version of our model that used the predicted SOA composition to calculate the glass-transition temperature, viscosity, and, ultimately, Db (∼10-15 cm2 s-1) of the SOA was able to reproduce the mass and size distribution measurements when we included oligomer formation (oligomers accounted for about a fifth of the SOA mass). Our work highlights the potential of a size-resolved SOA model to constrain the particle phase state of SOA using historical measurements of the evolution of the particle size distribution.
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Affiliation(s)
- Yicong He
- Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Ali Akherati
- Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Theodora Nah
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China
| | - Nga L Ng
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Lauren A Garofalo
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Delphine K Farmer
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Rahul A Zaveri
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Christopher D Cappa
- Department of Civil and Environmental Engineering, University of California Davis, Davis, California 95616, United States
| | - Jeffrey R Pierce
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Shantanu H Jathar
- Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
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15
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Meng X, Wu Z, Guo S, Wang H, Liu K, Zong T, Liu Y, Zhang W, Zhang Z, Chen S, Zeng L, Hallquist M, Shuai S, Hu M. Humidity-Dependent Phase State of Gasoline Vehicle Emission-Related Aerosols. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:832-841. [PMID: 33377762 DOI: 10.1021/acs.est.0c05478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The phase states of primarily emitted and secondarily formed aerosols from gasoline vehicle exhausts were investigated by quantifying the particle rebound fraction (f). The rebound behaviors of gasoline vehicle emission-related aerosols varied with engines, fuel types, and photochemical aging time, showing distinguished differences from biogenic secondary organic aerosols. The nonliquid-to-liquid phase transition of primary aerosols emitted from port fuel injection (PFI) and gasoline direct injection (GDI) vehicles started at a relative humidity (RH) = 50 and 60%, and liquefaction was accomplished at 60 and 70%, respectively. The RH at which f declined to 0.5 decreased from 70 to 65% for the PFI case with 92# fuel, corresponding to the photochemical aging time from 0.37 to 4.62 days. For the GDI case, such RH enhanced from 60 to 65%. Our results can be used to imply the phase state of traffic-related aerosols and further understand their roles in urban atmospheric chemistry. Taking Beijing, China, as an example, traffic-related aerosols were mainly nonliquid during winter with the majority ambient RH below 50%, whereas they were mostly liquid during the morning rush hour of summer, and traffic-related secondary aerosols fluctuated between nonliquid and liquid during the daytime and tended to be liquid at night with increased ambient RH.
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Affiliation(s)
- Xiangxinyue Meng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional 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, International Joint Laboratory for Regional 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
| | - Song Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional 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
| | - Hui Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Kefan Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Taomou Zong
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yuechen Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Wenbin Zhang
- State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China
| | - Zhou Zhang
- State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China
| | - Shiyi Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Limin Zeng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional 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
| | - Mattias Hallquist
- Department of Chemistry and Molecular Biology, Atmospheric Science, University of Gothenburg, Gothenburg SE-412 96, Sweden
| | - Shijin Shuai
- State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional 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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16
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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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17
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Schmedding R, Rasool QZ, Zhang Y, Pye HOT, Zhang H, Chen Y, Surratt JD, Lopez-Hilfiker FD, Thornton JA, Goldstein AH, Vizuete W. Predicting secondary organic aerosol phase state and viscosity and its effect on multiphase chemistry in a regional-scale air quality model. ATMOSPHERIC CHEMISTRY AND PHYSICS 2020; 20:8201-8225. [PMID: 32983235 PMCID: PMC7510956 DOI: 10.5194/acp-20-8201-2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Atmospheric aerosols are a significant public health hazard and have substantial impacts on the climate. Secondary organic aerosols (SOAs) have been shown to phase separate into a highly viscous organic outer layer surrounding an aqueous core. This phase separation can decrease the partitioning of semi-volatile and low-volatile species to the organic phase and alter the extent of acid-catalyzed reactions in the aqueous core. A new algorithm that can determine SOA phase separation based on their glass transition temperature (T g), oxygen to carbon (O : C) ratio and organic mass to sulfate ratio, and meteorological conditions was implemented into the Community Multiscale Air Quality Modeling (CMAQ) system version 5.2.1 and was used to simulate the conditions in the continental United States for the summer of 2013. SOA formed at the ground/surface level was predicted to be phase separated with core-shell morphology, i.e., aqueous inorganic core surrounded by organic coating 65.4 % of the time during the 2013 Southern Oxidant and Aerosol Study (SOAS) on average in the isoprene-rich southeastern United States. Our estimate is in proximity to the previously reported ~ 70 % in literature. The phase states of organic coatings switched between semi-solid and liquid states, depending on the environmental conditions. The semi-solid shell occurring with lower aerosol liquid water content (western United States and at higher altitudes) has a viscosity that was predicted to be 102-1012 Pa s, which resulted in organic mass being decreased due to diffusion limitation. Organic aerosol was primarily liquid where aerosol liquid water was dominant (eastern United States and at the surface), with a viscosity < 102 Pa s. Phase separation while in a liquid phase state, i.e., liquid-liquid phase separation (LLPS), also reduces reactive uptake rates relative to homogeneous internally mixed liquid morphology but was lower than aerosols with a thick viscous organic shell. The sensitivity cases performed with different phase-separation parameterization and dissolution rate of isoprene epoxydiol (IEPOX) into the particle phase in CMAQ can have varying impact on fine particulate matter (PM2.5) organic mass, in terms of bias and error compared to field data collected during the 2013 SOAS. This highlights the need to better constrain the parameters that govern phase state and morphology of SOA, as well as expand mechanistic representation of multiphase chemistry for non-IEPOX SOA formation in models aided by novel experimental insights.
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Affiliation(s)
- Ryan Schmedding
- Department of Environmental Science and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27516, USA
| | - Quazi Z. Rasool
- Department of Environmental Science and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27516, USA
| | - Yue Zhang
- Department of Environmental Science and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27516, USA
- Aerodyne Research, Inc., Billerica, MA 01821, USA
| | - Havala O. T. Pye
- Department of Environmental Science and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27516, USA
- Office of Research and Development, Environmental Protection Agency, Research Triangle Park, Durham, NC 27709, USA
| | - Haofei Zhang
- Department of Chemistry, University of California at Riverside, Riverside, CA 92521, USA
| | - Yuzhi Chen
- Department of Environmental Science and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27516, USA
| | - Jason D. Surratt
- Department of Environmental Science and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27516, USA
| | | | - Joel A. Thornton
- Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195, USA
| | - Allen H. Goldstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USA
| | - William Vizuete
- Department of Environmental Science and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27516, USA
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18
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Zawadowicz MA, Lee BH, Shrivastava M, Zelenyuk A, Zaveri RA, Flynn C, Thornton JA, Shilling JE. Photolysis Controls Atmospheric Budgets of Biogenic Secondary Organic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:3861-3870. [PMID: 32154714 DOI: 10.1021/acs.est.9b07051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Secondary organic aerosol (SOA) accounts for a large fraction of the tropospheric particulate matter. Although SOA production rates and mechanisms have been extensively investigated, loss pathways remain uncertain. Most large-scale chemistry and transport models account for mechanical deposition of SOA but not chemical losses such as photolysis. There is also a paucity of laboratory measurements of SOA photolysis, which limits how well photolytic losses can be modeled. Here, we show, through a combined experimental and modeling approach, that photolytic loss of SOA mass significantly alters SOA budget predictions. Using environmental chamber experiments at variable relative humidity between 0 and 60%, we find that SOA produced from several biogenic volatile organic compounds undergoes photolysis-induced mass loss at rates between 0 and 2.2 ± 0.4% of nitrogen dioxide (NO2) photolysis, equivalent to average atmospheric lifetimes as short as 10 h. We incorporate our photolysis rates into a regional chemical transport model to test the sensitivity of predicted SOA mass concentrations to photolytic losses. The addition of photolysis causes a ∼50% reduction in biogenic SOA loadings over the Amazon, indicating that photolysis exerts a substantial control over the atmospheric SOA lifetime, with a likely dependence upon the SOA molecular composition and thus production mechanisms.
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Affiliation(s)
- Maria A Zawadowicz
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Ben H Lee
- Department of Atmospheric Science, University of Washington, Seattle, Washington 98195, United States
| | - Manish Shrivastava
- Atmospheric Sciences and Global Change Division, 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
| | - Rahul A Zaveri
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Connor Flynn
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Joel A Thornton
- Department of Atmospheric Science, University of Washington, Seattle, Washington 98195, United States
| | - John E Shilling
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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19
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Zaveri RA, Shilling JE, Zelenyuk A, Zawadowicz MA, Suski K, China S, Bell DM, Veghte D, Laskin A. Particle-Phase Diffusion Modulates Partitioning of Semivolatile Organic Compounds to Aged Secondary Organic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:2595-2605. [PMID: 31994876 DOI: 10.1021/acs.est.9b05514] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The diffusivity of semivolatile organic compounds (SVOCs) in the bulk particle phase of a viscous atmospheric secondary organic aerosol (SOA) can have a profound impact on aerosol growth and size distribution dynamics. Here, we investigate the bulk diffusivity of SVOCs formed from photo-oxidation of isoprene as they partition to a bimodal aerosol consisting of an Aitken (potassium sulfate) and accumulation mode (aged α-pinene SOA) particles as a function of relative humidity (RH). The model analysis of the observed size distribution evolution shows that liquid-like diffusion coefficient values of Db > 10-10 cm2 s-1 fail to explain the growth of the Aitken mode. Instead, much lower values of Db between 2.5 × 10-15 cm2 s-1 at 32% RH and 8 × 10-15 cm2 s-1 at 82% RH were needed to successfully reproduce the growth of both modes. The diffusivity within the aged α-pinene SOA remains appreciably slow even at 80% RH, resulting in hindered partitioning of SVOCs to large viscous particles and allowing smaller and relatively less viscous particles to effectively absorb the available SVOCs and grow much faster than would be possible otherwise. These results have important implications for modeling SOA formation and growth in the ambient atmosphere.
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Affiliation(s)
- Rahul A Zaveri
- 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
| | - Alla Zelenyuk
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Maria A Zawadowicz
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Kaitlyn Suski
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Swarup China
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - David M Bell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Daniel Veghte
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Alexander Laskin
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
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20
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Vander Wall AC, Perraud V, Wingen LM, Finlayson-Pitts BJ. Evidence for a kinetically controlled burying mechanism for growth of high viscosity secondary organic aerosol. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:66-83. [PMID: 31670732 DOI: 10.1039/c9em00379g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Secondary organic aerosol (SOA) particles are ubiquitous in air and understanding the mechanism by which they grow is critical for predicting their effects on visibility and climate. The uptake of three organic nitrates into semi-solid SOA particles formed by α-pinene ozonolysis either with or without an OH scavenger was investigated. Four types of experiments are presented here. In Series A, uptake of the selected organic nitrates (2-ethylhexyl nitrate (2EHN); β-hydroxypropyl nitrate (HPN); β-hydroxyhexyl nitrate (HHN)) into impacted SOA particles was interrogated by attenuated total reflectance (ATR)-FTIR. In this case, equilibrium was reached and partition coefficients (KSOA = [-ONO2]SOA/[-ONO2]air) were measured to be K2EHN = (3.2-11) × 104, KHPN = (4.4-5.4) × 105, and KHHN = (4.9-9.0) × 106. In Series B, SOA particles were exposed on-the-fly to gas phase organic nitrates for comparison to Series A, and uptake of organic nitrates was quantified by HR-ToF-AMS analysis, which yielded similar results. In Series C (AMS) and D (ATR-FTIR), each organic nitrate was incorporated into the SOA as the particles formed and grew. The incorporation of the RONO2 was much larger in Series C and D (during growth), exceeding equilibrium values determined in Series A and B (after growth). This suggests that enhanced uptake of organic nitrates during SOA formation and growth is due to a kinetically controlled "burying" mechanism, rather than equilibrium partitioning. This has important implications for understanding SOA formation and growth under conditions where the particles are semi-solid, which is central to accurately predicting properties for such SOA.
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Affiliation(s)
| | - Véronique Perraud
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
| | - Lisa M Wingen
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
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21
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Han Y, Gong Z, Ye J, Liu P, McKinney KA, Martin ST. Quantifying the Role of the Relative Humidity-Dependent Physical State of Organic Particulate Matter in the Uptake of Semivolatile Organic Molecules. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:13209-13218. [PMID: 31593442 DOI: 10.1021/acs.est.9b05354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The uptake of gas-phase dicarboxylic acids to organic particulate matter (PM) was investigated to probe the role of the PM physical state in exchange processes between gas-phase semivolatile organic molecules and organic PM. A homologous series of probe molecules, specifically isotopically labeled 13C-dicarboxylic acids, was used in conjunction with aerosol mass spectrometry to obtain a quantitative characterization of the uptake to organic PM for different relative humidities (RHs). The PM was produced by the dark ozonolysis of unlabeled α-pinene. The uptake of 13C-labeled oxalic, malonic, and α-ketoglutaric acids increased stepwise by 5 to 15 times with increases in RH from 15 to 80%. The enhanced uptake with increasing RH was explained primarily by the higher molecular diffusivity in the particle phase, as associated with changes in the physical state of the organic PM from a nonliquid state to a progressively less-viscous liquid state. At high RH, the partitioning of the probe molecules to the particle phase was more associated with physicochemical interactions with the organic PM than that with the co-absorbed liquid water. Uptake of the probe molecules also increased with a decrease in volatility along the homologous series. This study quantitatively shows the key roles of the particle physical state in governing the interactions of organic PM with semivolatile organic molecules.
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Affiliation(s)
- Yuemei Han
- Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment , Chinese Academy of Sciences , Xi'an , Shaanxi 710061 , China
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22
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Liu S, Tsona NT, Zhang Q, Jia L, Xu Y, Du L. Influence of relative humidity on cyclohexene SOA formation from OH photooxidation. CHEMOSPHERE 2019; 231:478-486. [PMID: 31151007 DOI: 10.1016/j.chemosphere.2019.05.131] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 05/06/2019] [Accepted: 05/14/2019] [Indexed: 06/09/2023]
Abstract
Secondary organic aerosol (SOA) is a complex mixture consisting of a variety of oxidation products. In this study, the role of relative humidity (RH) on SOA formation with different [H2O2]0/[cyclohexene]0 was investigated in a smog chamber. It was found that the cyclohexene SOA yield increases with increasing initial OH concentration at both high and low RH conditions. The increased rate of SOA formation was lower at wet conditions than that at dry conditions. For [H2O2]0/[cyclohexene]0 = 0.4 and 0.8, the SOA yield increased from 1.5% to 8% at dry condition to 7% and 12% at wet condition, respectively. In contrast, at high RH the SOA yield fell from 54% to 52% for [H2O2]0/[cyclohexene]0 = 1.3. The SOA mass loss was higher at high RH at the same OH exposure. The chemical composition of SOA was characterized using hybrid quadrupole-orbitrap mass spectrometer equipped with electrospray ionization (ESI-Q-Orbitrap-HRMS). Oligomers, which were responsible for the increase of the SOA yield, were detected in the SOA formed at high RH conditions. The esterification reaction between dicarboxylic acids and HOC6H10-O-O-C6H10OH was the pathway of oligomers formation. All the oligomers have cyclic molecular structures. For [H2O2]0/[cyclohexene]0 = 1.3, the relative intensity of both low and high molecular weight substances reduced more at wet conditions. This indicates that at sufficient OH level, the inhibition of oligomers formation and the further reaction of SOA with OH result in a slightly lower SOA yield at wet condition.
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Affiliation(s)
- Shijie Liu
- Environment Research Institute, Shandong University, Qingdao, 266237, China
| | - Narcisse T Tsona
- School of Life Science, Shandong University, Qingdao, 266237, China
| | - Qun Zhang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Long Jia
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Yongfu Xu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Lin Du
- Environment Research Institute, Shandong University, Qingdao, 266237, China.
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23
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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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24
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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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25
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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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26
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Resolving the mechanisms of hygroscopic growth and cloud condensation nuclei activity for organic particulate matter. Nat Commun 2018; 9:4076. [PMID: 30287821 PMCID: PMC6172236 DOI: 10.1038/s41467-018-06622-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 09/14/2018] [Indexed: 12/02/2022] Open
Abstract
Hygroscopic growth and cloud condensation nuclei activation are key processes for accurately modeling the climate impacts of organic particulate matter. Nevertheless, the microphysical mechanisms of these processes remain unresolved. Here we report complex thermodynamic behaviors, including humidity-dependent hygroscopicity, diameter-dependent cloud condensation nuclei activity, and liquid–liquid phase separation in the laboratory for biogenically derived secondary organic material representative of similar atmospheric organic particulate matter. These behaviors can be explained by the non-ideal mixing of water with hydrophobic and hydrophilic organic components. The non-ideality-driven liquid–liquid phase separation further enhances water uptake and induces lowered surface tension at high relative humidity, which result in a lower barrier to cloud condensation nuclei activation. By comparison, secondary organic material representing anthropogenic sources does not exhibit complex thermodynamic behavior. The combined results highlight the importance of detailed thermodynamic representations of the hygroscopicity and cloud condensation nuclei activity in models of the Earth’s climate system. The interactions between organic particulate matter and water vapour affect climate predictions, yet the mechanisms of these interactions remain unresolved. Here, the authors propose a phase separation mechanism that reconciles the observed hygroscopicity and cloud condensation nuclei activity.
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27
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Wang Y, Liu P, Li YJ, Bateman AP, Martin ST, Hung HM. The Reactivity of Toluene-Derived Secondary Organic Material with Ammonia and the Influence of Water Vapor. J Phys Chem A 2018; 122:7739-7747. [DOI: 10.1021/acs.jpca.8b06685] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yan Wang
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts United States
| | | | - Yong Jie Li
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau, China
| | | | | | - Hui-Ming Hung
- Department of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan
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28
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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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29
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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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30
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Zaveri RA, Shilling JE, Zelenyuk A, Liu J, Bell DM, D'Ambro EL, Gaston CJ, Thornton JA, Laskin A, Lin P, Wilson J, Easter RC, Wang J, Bertram AK, Martin ST, Seinfeld JH, Worsnop DR. Growth Kinetics and Size Distribution Dynamics of Viscous Secondary Organic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:1191-1199. [PMID: 29244949 DOI: 10.1021/acs.est.7b04623] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Low bulk diffusivity inside viscous semisolid atmospheric secondary organic aerosol (SOA) can prolong equilibration time scale, but its broader impacts on aerosol growth and size distribution dynamics are poorly understood. Here, we present quantitative insights into the effects of bulk diffusivity on the growth and evaporation kinetics of SOA formed under dry conditions from photooxidation of isoprene in the presence of a bimodal aerosol consisting of Aitken (ammonium sulfate) and accumulation (isoprene or α-pinene SOA) mode particles. Aerosol composition measurements and evaporation kinetics indicate that isoprene SOA is composed of several semivolatile organic compounds (SVOCs), with some reversibly reacting to form oligomers. Model analysis shows that liquid-like bulk diffusivities can be used to fit the observed evaporation kinetics of accumulation mode particles but fail to explain the growth kinetics of bimodal aerosol by significantly under-predicting the evolution of the Aitken mode. In contrast, the semisolid scenario successfully reproduces both evaporation and growth kinetics, with the interpretation that hindered partitioning of SVOCs into large viscous particles effectively promotes the growth of smaller particles that have shorter diffusion time scales. This effect has important implications for the growth of atmospheric ultrafine particles to climatically active sizes.
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Affiliation(s)
- Rahul A Zaveri
- 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
| | - Alla Zelenyuk
- Physical Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Jiumeng Liu
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - David M Bell
- Physical Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Emma L D'Ambro
- Department of Atmospheric Sciences, University of Washington , Seattle, Washington 98195, United States
- Department of Chemistry, University of Washington , Seattle, Washington 98195, United States
| | - Cassandra J Gaston
- Department of Atmospheric Sciences, University of Washington , Seattle, Washington 98195, United States
| | - Joel A Thornton
- Department of Atmospheric Sciences, University of Washington , Seattle, Washington 98195, United States
- Department of Chemistry, University of Washington , Seattle, Washington 98195, United States
| | - Alexander Laskin
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Peng Lin
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Jacqueline Wilson
- Physical Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Richard C Easter
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Jian Wang
- Environmental and Climate Sciences Department, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - Allan K Bertram
- Department of Chemistry, University of British Columbia , Vancouver, British Columbia V6T 1Z1, Canada
| | - Scot T Martin
- John A. Paulson School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
- Department of Earth and Planetary Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
| | - John H Seinfeld
- Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
- Division of Engineering and Applied Science, California Institute of Technology , Pasadena, California 91125, United States
| | - Douglas R Worsnop
- Center for Aerosol and Cloud Chemistry, Aerodyne Research , Billerica, Massachusetts 01821, United States
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31
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Following Particle-Particle Mixing in Atmospheric Secondary Organic Aerosols by Using Isotopically Labeled Terpenes. Chem 2018. [DOI: 10.1016/j.chempr.2017.12.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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32
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Ji ZR, Zhang Y, Pang SF, Zhang YH. Crystal Nucleation and Crystal Growth and Mass Transfer in Internally Mixed Sucrose/NaNO3 Particles. J Phys Chem A 2017; 121:7968-7975. [DOI: 10.1021/acs.jpca.7b08004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhi-Ru Ji
- The Institute of Chemical
Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
| | - Yun Zhang
- The Institute of Chemical
Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
| | - Shu-Feng Pang
- The Institute of Chemical
Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
| | - Yun-Hong 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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33
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Rothfuss NE, Petters MD. Characterization of the temperature and humidity-dependent phase diagram of amorphous nanoscale organic aerosols. Phys Chem Chem Phys 2017; 19:6532-6545. [PMID: 28197614 DOI: 10.1039/c6cp08593h] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Atmospheric aerosols can exist in amorphous semi-solid or glassy phase states. These states are determined by the temperature (T) and relative humidity (RH). New measurements of viscosity for amorphous semi-solid nanometer size sucrose particles as a function of T and RH are reported. Viscosity is measured by inducing coagulation between two particles and probing the thermodynamic states that induce the particle to relax into a sphere. It is shown that the glass transition temperature can be obtained by extrapolation to 1012 Pa s from the measured temperature-dependent viscosity in the 106 to 107 Pa s range. The experimental methodology was refined to allow isothermal probing of RH dependence and to increase the range of temperatures over which the dry temperature dependence can be studied. Several experiments where one monomer was sodium dodecyl sulfate (SDS), which remains solid at high RH, are also reported. These sucrose-SDS dimers were observed to relax into a sphere at T and RH similar to those observed in sucrose-sucrose dimers, suggesting that amorphous sucrose will flow over an insoluble particle at a viscosity similar to that characteristic of coalescence between two sucrose particles. Possible physical and analytical implications of this observation are considered. The data reported here suggest that semi-solid viscosity between 104 and 1012 Pa s can be modelled over a wide range of T and RH using an adapted Vogel-Fulcher-Tammann equation and the Gordon-Taylor mixing rule. Sensitivity of modelled viscosity to variations in dry glass transition temperature, Gordon-Taylor constant, and aerosol hygroscopicity are explored, along with implications for atmospheric processes such as ice nucleation of glassy organic aerosols in the upper free troposphere. The reported measurement and modelling framework provides a template for characterizing the phase diagram of other amorphous aerosol systems, including secondary organic aerosols.
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Affiliation(s)
- Nicholas E Rothfuss
- Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 26795, USA.
| | - Markus D Petters
- Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 26795, USA.
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34
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Global long-range transport and lung cancer risk from polycyclic aromatic hydrocarbons shielded by coatings of organic aerosol. Proc Natl Acad Sci U S A 2017; 114:1246-1251. [PMID: 28115713 DOI: 10.1073/pnas.1618475114] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) have toxic impacts on humans and ecosystems. One of the most carcinogenic PAHs, benzo(a)pyrene (BaP), is efficiently bound to and transported with atmospheric particles. Laboratory measurements show that particle-bound BaP degrades in a few hours by heterogeneous reaction with ozone, yet field observations indicate BaP persists much longer in the atmosphere, and some previous chemical transport modeling studies have ignored heterogeneous oxidation of BaP to bring model predictions into better agreement with field observations. We attribute this unexplained discrepancy to the shielding of BaP from oxidation by coatings of viscous organic aerosol (OA). Accounting for this OA viscosity-dependent shielding, which varies with temperature and humidity, in a global climate/chemistry model brings model predictions into much better agreement with BaP measurements, and demonstrates stronger long-range transport, greater deposition fluxes, and substantially elevated lung cancer risk from PAHs. Model results indicate that the OA coating is more effective in shielding BaP in the middle/high latitudes compared with the tropics because of differences in OA properties (semisolid when cool/dry vs. liquid-like when warm/humid). Faster chemical degradation of BaP in the tropics leads to higher concentrations of BaP oxidation products over the tropics compared with higher latitudes. This study has profound implications demonstrating that OA strongly modulates the atmospheric persistence of PAHs and their cancer risks.
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35
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Rothfuss NE, Petters MD. Influence of Functional Groups on the Viscosity of Organic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:271-279. [PMID: 27990815 DOI: 10.1021/acs.est.6b04478] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Organic aerosols can exist in highly viscous or glassy phase states. A viscosity database for organic compounds with atmospherically relevant functional groups is compiled and analyzed to quantify the influence of number and location of functional groups on viscosity. For weakly functionalized compounds the trend in viscosity sensitivity to functional group addition is carboxylic acid (COOH) ≈ hydroxyl (OH) > nitrate (ONO2) > carbonyl (CO) ≈ ester (COO) > methylene (CH2). Sensitivities to group addition increase with greater levels of prior functionalization and decreasing temperature. For carboxylic acids a sharp increase in sensitivity is likely present already at the second addition at room temperature. Ring structures increase viscosity relative to linear structures. Sensitivities are correlated with analogously derived sensitivities of vapor pressure reduction. This may be exploited in the future to predict viscosity in numerical models by piggybacking on schemes that track the evolution of organic aerosol volatility with age.
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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
| | - Markus D Petters
- Department of Marine Earth and Atmospheric Sciences, North Carolina State University , Raleigh, North Carolina 27695, United States
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36
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Ingram S, Cai C, Song YC, Glowacki DR, Topping DO, O’Meara S, Reid JP. Characterising the evaporation kinetics of water and semi-volatile organic compounds from viscous multicomponent organic aerosol particles. Phys Chem Chem Phys 2017; 19:31634-31646. [DOI: 10.1039/c7cp05172g] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we present methods to simultaneously investigate diffusivities and volatilities in studies of evolving single aerosol particle size and composition.
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Affiliation(s)
- Stephen Ingram
- School of Chemistry
- University of Bristol
- Bristol BS8 1TS
- UK
| | - Chen Cai
- Department of Atmospheric and Oceanic Sciences
- School of Physics
- Peking University
- Beijing 100871
- China
| | | | - David R. Glowacki
- School of Chemistry
- University of Bristol
- Bristol BS8 1TS
- UK
- Department of Computer Science
| | - David O. Topping
- School of Earth and Atmospheric Sciences
- University of Manchester
- Manchester M13 9PL
- UK
| | - Simon O’Meara
- School of Earth and Atmospheric Sciences
- University of Manchester
- Manchester M13 9PL
- UK
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37
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Abstract
Atmospheric aerosols exert a substantial influence on climate, ecosystems, visibility, and human health. Although secondary organic aerosols (SOA) dominate fine-particle mass, they comprise myriad compounds with uncertain sources, chemistry, and interactions. SOA formation involves absorption of vapors into particles, either because gas-phase chemistry produces low-volatility or semivolatile products that partition into particles or because more-volatile organics enter particles and react to form lower-volatility products. Thus, SOA formation involves both production of low-volatility compounds and their diffusion into particles. Most chemical transport models assume a single well-mixed phase of condensing organics and an instantaneous equilibrium between bulk gas and particle phases; however, direct observations constraining diffusion of semivolatile organics into particles containing SOA are scarce. Here we perform unique mixing experiments between SOA populations including semivolatile constituents using quantitative, single-particle mass spectrometry to probe any mass-transfer limitations in particles containing SOA. We show that, for several hours, particles containing SOA from toluene oxidation resist exchange of semivolatile constituents at low relative humidity (RH) but start to lose that resistance above 20% RH. Above 40% RH, the exchange of material remains constant up to 90% RH. We also show that dry particles containing SOA from α-pinene ozonolysis do not appear to resist exchange of semivolatile compounds. Our interpretation is that in-particle diffusion is not rate-limiting to mass transfer in these systems above 40% RH. To the extent that these systems are representative of ambient SOA, we conclude that diffusion limitations are likely not common under typical ambient boundary layer conditions.
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38
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Abstract
The energy flows in Earth's natural and modified climate systems are strongly influenced by the concentrations of atmospheric particulate matter (PM). For predictions of concentration, equilibrium partitioning of semivolatile organic compounds (SVOCs) between organic PM and the surrounding vapor has widely been assumed, yet recent observations show that organic PM can be semisolid or solid for some atmospheric conditions, possibly suggesting that SVOC uptake and release can be slow enough that equilibrium does not prevail on timescales relevant to atmospheric processes. Herein, in a series of laboratory experiments, the mass labilities of films of secondary organic material representative of similar atmospheric organic PM were directly determined by quartz crystal microbalance measurements of evaporation rates and vapor mass concentrations. There were strong differences between films representative of anthropogenic compared with biogenic sources. For films representing anthropogenic PM, evaporation rates and vapor mass concentrations increased above a threshold relative humidity (RH) between 20% and 30%, indicating rapid partitioning above a transition RH but not below. Below the threshold, the characteristic time for equilibration is estimated as up to 1 wk for a typically sized particle. In contrast, for films representing biogenic PM, no RH threshold was observed, suggesting equilibrium partitioning is rapidly obtained for all RHs. The effective diffusion rate Dorg for the biogenic case is at least 103 times greater than that of the anthropogenic case. These differences should be accounted for in the interpretation of laboratory data as well as in modeling of organic PM in Earth's atmosphere.
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39
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Song YC, Haddrell AE, Bzdek BR, Reid JP, Bannan T, Topping DO, Percival C, Cai C. Measurements and Predictions of Binary Component Aerosol Particle Viscosity. J Phys Chem A 2016; 120:8123-8137. [DOI: 10.1021/acs.jpca.6b07835] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Young Chul Song
- School
of Chemistry, University of Bristol, Bristol, BS8 1TS, United Kingdom
| | - Allen E. Haddrell
- 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
| | - Thomas Bannan
- School
of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - David O. Topping
- School
of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester, M13 9PL, United Kingdom
- National
Centre for Atmospheric Science, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Carl Percival
- School
of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Chen Cai
- The
Institute of Chemical Physics, Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
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40
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Price HC, Mattsson J, Murray BJ. Sucrose diffusion in aqueous solution. Phys Chem Chem Phys 2016; 18:19207-16. [PMID: 27364512 PMCID: PMC5044753 DOI: 10.1039/c6cp03238a] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 06/21/2016] [Indexed: 12/02/2022]
Abstract
The diffusion of sugar in aqueous solution is important both in nature and in technological applications, yet measurements of diffusion coefficients at low water content are scarce. We report directly measured sucrose diffusion coefficients in aqueous solution. Our technique utilises a Raman isotope tracer method to monitor the diffusion of non-deuterated and deuterated sucrose across a boundary between the two aqueous solutions. At a water activity of 0.4 (equivalent to 90 wt% sucrose) at room temperature, the diffusion coefficient of sucrose was determined to be approximately four orders of magnitude smaller than that of water in the same material. Using literature viscosity data, we show that, although inappropriate for the prediction of water diffusion, the Stokes-Einstein equation works well for predicting sucrose diffusion under the conditions studied. As well as providing information of importance to the fundamental understanding of diffusion in binary solutions, these data have technological, pharmaceutical and medical implications, for example in cryopreservation. Moreover, in the atmosphere, slow organic diffusion may have important implications for aerosol growth, chemistry and evaporation, where processes may be limited by the inability of a molecule to diffuse between the bulk and the surface of a particle.
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Affiliation(s)
- Hannah C. Price
- School of Earth and Environment , University of Leeds , Leeds , UK .
| | - Johan Mattsson
- School of Physics and Astronomy , University of Leeds , Leeds , UK .
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41
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Harvey RM, Bateman AP, Jain S, Li YJ, Martin S, Petrucci GA. Optical Properties of Secondary Organic Aerosol from cis-3-Hexenol and cis-3-Hexenyl Acetate: Effect of Chemical Composition, Humidity, and Phase. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:4997-5006. [PMID: 27074496 DOI: 10.1021/acs.est.6b00625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Atmospheric aerosols play an important role in Earth's radiative balance directly, by scattering and absorbing radiation, and indirectly, by acting as cloud condensation nuclei (CCN). Atmospheric aerosol is dominated by secondary organic aerosol (SOA) formed by the oxidation of biogenic volatile organic compounds (BVOCs). Green leaf volatiles (GLVs) are a class of BVOCs that contribute to SOA, yet their role in the Earth's radiative budget is poorly understood. In this work we measured the scattering efficiency (at 450, 525, and 635 nm), absorption efficiency (between 190 and 900 nm), particle phase, bulk chemical properties (O:C, H:C), and molecular-level composition of SOA formed from the ozonolysis of two GLVs: cis-3-hexenol (HXL) and cis-3-hexenyl acetate (CHA). Both HXL and CHA produced SOA that was weakly absorbing, yet CHA-SOA was a more efficient absorber than HXL-SOA. The scatter efficiency of SOA from both systems was wavelength-dependent, with the stronger dependence exhibited by HXL-SOA, likely due to differences in particle size. HXL-SOA formed under both dry (10% RH) and wet (70% RH) conditions had the same bulk chemical properties (O:C), yet significantly different optical properties, which was attributed to differences in molecular-level composition. We have found that SOA derived from green leaf volatiles has the potential to affect the Earth's radiative budget, and also that bulk chemical properties can be insufficient to predict SOA optical properties.
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Affiliation(s)
- Rebecca M Harvey
- Department of Chemistry, University of Vermont , Burlington, Vermont 05405, United States
| | - Adam P Bateman
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Shashank Jain
- Department of Chemistry, University of Vermont , Burlington, Vermont 05405, United States
| | - Yong Jie Li
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Scot Martin
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
- Department of Earth and Planetary Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Giuseppe A Petrucci
- Department of Chemistry, University of Vermont , Burlington, Vermont 05405, United States
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42
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Marais EA, Jacob DJ, Jimenez JL, Campuzano-Jost P, Day DA, Hu W, Krechmer J, Zhu L, Kim PS, Miller CC, Fisher JA, Travis K, Yu K, Hanisco TF, Wolfe GM, Arkinson HL, Pye HOT, Froyd KD, Liao J, McNeill VF. Aqueous-phase mechanism for secondary organic aerosol formation from isoprene: application to the Southeast United States and co-benefit of SO 2 emission controls. ATMOSPHERIC CHEMISTRY AND PHYSICS 2016; 16:1603-1618. [PMID: 32742280 PMCID: PMC7394309 DOI: 10.5194/acp-16-1603-2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA), but the mechanism and yields are uncertain. Aerosol is prevailingly aqueous under the humid conditions typical of isoprene-emitting regions. Here we develop an aqueous-phase mechanism for isoprene SOA formation coupled to a detailed gas-phase isoprene oxidation scheme. The mechanism is based on aerosol reactive uptake coefficients (γ) for water-soluble isoprene oxidation products, including sensitivity to aerosol acidity and nucleophile concentrations. We apply this mechanism to simulation of aircraft (SEAC4RS) and ground-based (SOAS) observations over the Southeast US in summer 2013 using the GEOS-Chem chemical transport model. Emissions of nitrogen oxides (NOx ≡ NO + NO2) over the Southeast US are such that the peroxy radicals produced from isoprene oxidation (ISOPO2) react significantly with both NO (high-NOx pathway) and HO2 (low-NOx pathway), leading to different suites of isoprene SOA precursors. We find a mean SOA mass yield of 3.3 % from isoprene oxidation, consistent with the observed relationship of total fine organic aerosol (OA) and formaldehyde (a product of isoprene oxidation). Isoprene SOA production is mainly contributed by two immediate gas-phase precursors, isoprene epoxydiols (IEPOX, 58% of isoprene SOA) from the low-NOx pathway and glyoxal (28%) from both low- and high-NOx pathways. This speciation is consistent with observations of IEPOX SOA from SOAS and SEAC4RS. Observations show a strong relationship between IEPOX SOA and sulfate aerosol that we explain as due to the effect of sulfate on aerosol acidity and volume. Isoprene SOA concentrations increase as NOx emissions decrease (favoring the low-NOx pathway for isoprene oxidation), but decrease more strongly as SO2 emissions decrease (due to the effect of sulfate on aerosol acidity and volume). The US EPA projects 2013-2025 decreases in anthropogenic emissions of 34% for NOx (leading to 7% increase in isoprene SOA) and 48% for SO2 (35% decrease in isoprene SOA). Reducing SO2 emissions decreases sulfate and isoprene SOA by a similar magnitude, representing a factor of 2 co-benefit for PM2.5 from SO2 emission controls.
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Affiliation(s)
- E A Marais
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - D J Jacob
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - J L Jimenez
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - P Campuzano-Jost
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - D A Day
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - W Hu
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - J Krechmer
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - L Zhu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - P S Kim
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - C C Miller
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - J A Fisher
- School of Chemistry and School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - K Travis
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - K Yu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - T F Hanisco
- Atmospheric Chemistry and Dynamics Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - G M Wolfe
- Atmospheric Chemistry and Dynamics Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - H L Arkinson
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD, USA
| | - H O T Pye
- National Exposure Research Laboratory, US EPA, Research Triangle Park, NC, USA
| | - K D Froyd
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
| | - J Liao
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
| | - V F McNeill
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
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43
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Marais EA, Jacob DJ, Jimenez JL, Campuzano-Jost P, Day DA, Hu W, Krechmer J, Zhu L, Kim PS, Miller CC, Fisher JA, Travis K, Yu K, Hanisco TF, Wolfe GM, Arkinson HL, Pye HOT, Froyd KD, Liao J, McNeill VF. Aqueous-phase mechanism for secondary organic aerosol formation from isoprene: application to the Southeast United States and co-benefit of SO 2 emission controls. ATMOSPHERIC CHEMISTRY AND PHYSICS 2016. [PMID: 32742280 DOI: 10.5194/acp16-1603-2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA), but the mechanism and yields are uncertain. Aerosol is prevailingly aqueous under the humid conditions typical of isoprene-emitting regions. Here we develop an aqueous-phase mechanism for isoprene SOA formation coupled to a detailed gas-phase isoprene oxidation scheme. The mechanism is based on aerosol reactive uptake coefficients (γ) for water-soluble isoprene oxidation products, including sensitivity to aerosol acidity and nucleophile concentrations. We apply this mechanism to simulation of aircraft (SEAC4RS) and ground-based (SOAS) observations over the Southeast US in summer 2013 using the GEOS-Chem chemical transport model. Emissions of nitrogen oxides (NOx ≡ NO + NO2) over the Southeast US are such that the peroxy radicals produced from isoprene oxidation (ISOPO2) react significantly with both NO (high-NOx pathway) and HO2 (low-NOx pathway), leading to different suites of isoprene SOA precursors. We find a mean SOA mass yield of 3.3 % from isoprene oxidation, consistent with the observed relationship of total fine organic aerosol (OA) and formaldehyde (a product of isoprene oxidation). Isoprene SOA production is mainly contributed by two immediate gas-phase precursors, isoprene epoxydiols (IEPOX, 58% of isoprene SOA) from the low-NOx pathway and glyoxal (28%) from both low- and high-NOx pathways. This speciation is consistent with observations of IEPOX SOA from SOAS and SEAC4RS. Observations show a strong relationship between IEPOX SOA and sulfate aerosol that we explain as due to the effect of sulfate on aerosol acidity and volume. Isoprene SOA concentrations increase as NOx emissions decrease (favoring the low-NOx pathway for isoprene oxidation), but decrease more strongly as SO2 emissions decrease (due to the effect of sulfate on aerosol acidity and volume). The US EPA projects 2013-2025 decreases in anthropogenic emissions of 34% for NOx (leading to 7% increase in isoprene SOA) and 48% for SO2 (35% decrease in isoprene SOA). Reducing SO2 emissions decreases sulfate and isoprene SOA by a similar magnitude, representing a factor of 2 co-benefit for PM2.5 from SO2 emission controls.
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Affiliation(s)
- E A Marais
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - D J Jacob
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - J L Jimenez
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - P Campuzano-Jost
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - D A Day
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - W Hu
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - J Krechmer
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - L Zhu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - P S Kim
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - C C Miller
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - J A Fisher
- School of Chemistry and School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - K Travis
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - K Yu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - T F Hanisco
- Atmospheric Chemistry and Dynamics Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - G M Wolfe
- Atmospheric Chemistry and Dynamics Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - H L Arkinson
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD, USA
| | - H O T Pye
- National Exposure Research Laboratory, US EPA, Research Triangle Park, NC, USA
| | - K D Froyd
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
| | - J Liao
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
| | - V F McNeill
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
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44
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Hinks ML, Brady MV, Lignell H, Song M, Grayson JW, Bertram AK, Lin P, Laskin A, Laskin J, Nizkorodov SA. Effect of viscosity on photodegradation rates in complex secondary organic aerosol materials. Phys Chem Chem Phys 2016; 18:8785-93. [DOI: 10.1039/c5cp05226b] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
This work explores the effect of environmental conditions on the photodegradation rates of atmospherically relevant, photolabile, organic molecules embedded in a film of viscous secondary organic material (SOM).
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Affiliation(s)
| | | | - Hanna Lignell
- Department of Chemistry
- University of California
- Irvine
- USA
| | - Mijung Song
- Department of Chemistry
- University of British Columbia
- Vancouver
- Canada
| | - James W. Grayson
- Department of Chemistry
- University of British Columbia
- Vancouver
- Canada
| | - Allan K. Bertram
- Department of Chemistry
- University of British Columbia
- Vancouver
- Canada
| | - Peng Lin
- Environmental Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
| | - Alexander Laskin
- Environmental Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
| | - Julia Laskin
- Physical Sciences Division
- Pacific Northwest National Laboratory
- Richland
- USA
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45
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Li YJ, Liu P, Gong Z, Wang Y, Bateman AP, Bergoend C, Bertram AK, Martin ST. Chemical Reactivity and Liquid/Nonliquid States of Secondary Organic Material. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:13264-74. [PMID: 26465059 DOI: 10.1021/acs.est.5b03392] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The reactivity of secondary organic material (SOM) of variable viscosity, ranging from nonliquid to liquid physical states, was studied. The SOM, produced in aerosol form from terpenoid and aromatic precursor species, was reacted with ammonia at variable relative humidity (RH). The ammonium-to-organic mass ratio (MNH4+/MOrg) increased monotonically from <5% RH to a limiting value at a threshold RH, implicating a transition from particle reactivity limited by diffusion at low RH to one limited by other factors at higher RH. For the studied size distributions and reaction times, the transition corresponded to a diffusivity above 10-17.5 ± 0.5 m2 s-1. The threshold RH values for the transition were <5% RH for isoprene-derived SOM, 35-45% RH for SOM derived from α-pinene, toluene, m-xylene, and 1,3,5-trimethylbenzene, and >90% for β-caryophyllene-derived SOM. The transition RH for reactivity differed in all cases from the transition RH of a nonliquid to a liquid state. For instance, for α-pinene-derived SOM the transition for chemical reactivity of 35-45% RH can be compared to the nonliquid to liquid transition of 65-90% RH. These differences imply that chemical transport models of atmospheric chemistry should not use the SOM liquid to nonliquid phase transition as one-to-one surrogates of SOM reactivity.
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Affiliation(s)
- Yong Jie Li
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau , Avenida da Universidade, Taipa, Macau, China
| | - Pengfei Liu
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Zhaoheng Gong
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Yan Wang
- Department of Environmental Health, Harvard T.H. Chan School of Public Health , Boston, Massachusetts 02115, United States
| | - Adam P Bateman
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Clara Bergoend
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
- Department of Energy and Environment, National Institute of Applied Science of Lyon , Villeurbanne 69100, France
| | - Allan K Bertram
- Department of Chemistry, University of British Columbia , Vancouver, British Columbia V6T 1Z1, Canada
| | - Scot T Martin
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
- Department of Earth and Planetary Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
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