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Meng J, Li Z, Zhou R, Chen M, Li Y, Yi Y, Ding Z, Li H, Yan L, Hou Z, Wang G. Enhanced photochemical formation of secondary organic aerosols during the COVID-19 lockdown in Northern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 758:143709. [PMID: 33223177 PMCID: PMC7666554 DOI: 10.1016/j.scitotenv.2020.143709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/02/2020] [Accepted: 11/09/2020] [Indexed: 05/09/2023]
Abstract
To eliminate the spread of a novel coronavirus breaking out in the end of 2019 (COVID-19), the Chinese government has implemented a nationwide lockdown policy after the Chinese lunar New Year of 2020, resulting in a sharp reduction in air pollutant emissions. To investigate the impact of the lockdown on aerosol chemistry, the number fraction, size distribution and formation process of oxalic acid (C2) containing particles and its precursors were studied using a single particle aerosol mass spectrometer (SPAMS) at the urban site of Liaocheng in the North China Plain (NCP). Our results showed that five air pollutants (i.e., PM2.5, PM10, SO2, NO2, and CO) decreased by 30.0-59.8% during the lockdown compared to those before the lockdown, while O3 increased by 63.9% during the lockdown mainly due to the inefficient titration effect of O3 via NO reduction. The increased O3 concentration can boost the atmospheric oxidizing capacity and further enhance the formation of secondary organic aerosols, thereby significantly enhancing the C2 particles and its precursors as observed during the lockdown. Before the lockdown, C2 particles were significantly originated from biomass burning emissions and their subsequent aqueous-phase oxidation. The hourly variation patterns and correlation analysis before the lockdown suggested that relative humidity (RH) and aerosol liquid water content (ALWC) played a key role in the formation of C2 particles and the increased aerosol acidity can promote the conversion of precursors such as glyoxal (Gly) and methyglyoxal (mGly) into C2 particles in the aqueous phase. RH and ALWC decreased sharply but O3 concentration and solar radiation increased remarkably during the lockdown, the O3-dominated photochemical pathways played an important role in the formation of C2 particles in which aerosol acidity was ineffective. Our study indicated that air pollution treatment sponges on a joint-control and balanced strategy for controlling numerous pollutants.
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Affiliation(s)
- Jingjing Meng
- School of Environment and Planning, Liaocheng University, Liaocheng 252000, China
| | - Zheng Li
- School of Environment and Planning, Liaocheng University, Liaocheng 252000, China
| | - Ruiwen Zhou
- School of Environment and Planning, Liaocheng University, Liaocheng 252000, China
| | - Min Chen
- School of Environment and Planning, Liaocheng University, Liaocheng 252000, China
| | - Yuanyuan Li
- School of Environment and Planning, Liaocheng University, Liaocheng 252000, China
| | - Yanan Yi
- School of Environment and Planning, Liaocheng University, Liaocheng 252000, China
| | - Zhijian Ding
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200062, China
| | - Hongji Li
- College of Environmental Science and Engineering, Jilin Normal University, Siping 136000, China
| | - Li Yan
- Chinese Academy for Environmental Planning, Beijing 100012, China
| | - Zhanfang Hou
- School of Environment and Planning, Liaocheng University, Liaocheng 252000, China
| | - Gehui Wang
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200062, China.
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Cui J, Sun M, Wang L, Guo J, Xie G, Zhang J, Zhang R. Gas-particle partitioning of carbonyls and its influencing factors in the urban atmosphere of Zhengzhou, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 751:142027. [PMID: 33182009 DOI: 10.1016/j.scitotenv.2020.142027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
Despite their profound roles in atmospheric chemistry and health concerns, the gas-particle partitioning of carbonyl compounds and its influencing factors in the ambient atmosphere are poorly elucidated. In this work, a reliable method using a denuder/filter-pack system coated with the derivative reagent, O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) was developed for the simultaneous collection of gaseous and particulate carbonyls. Sampling campaigns were performed at an urban site in Zhengzhou, China. The average field-derived partitioning coefficients (Kpf) of the six most abundant carbonyls (formaldehyde, acetaldehyde, acetone, propionaldehyde, glyoxal, and methylglyoxal) were in the range of 10-5-10-4 m3·μg-1, and their effective Henry's law coefficients (eff. KH) ranged from 107 to 109 M·atm-1. Comparisons revealed that their Kpf and eff. KH were 104-106 times and 102-107 times higher than theoretically predicted, respectively. Given that the aerosol liquid water is a concentrated salt solution, these six carbonyls very clearly salted in to three atmospherically relevant aqueous salts, following the order of sulfate > ammonium > nitrate. However, even taking salting-in effects into account, the Pankow's absorptive partitioning theory and effective Henry's law both failed to explain the unexpected highly particulate carbonyls. In regard to the influencing factors, the negative correlations between Kpf and temperature indicate that lower temperature is conducive to carbonyls partitioning. As for the strong relative humidity (RH) dependence of KPf, high partitioning coefficients were observed under low and high RH conditions. Partitioning is considered to be dominated by the carbonyl-oligomer formation when RH increases from <10% to 50%, and driven by the abundant aerosol liquid water content when RH exceeds 50%. The presence of particulate inorganic components and the transition of particle phase state may also impact the partitioning process, especially in the urban atmosphere.
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Affiliation(s)
- Jia'nan Cui
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Mei Sun
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Lei Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Junyu Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Guiying Xie
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Jianbo Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
| | - Ruiqin Zhang
- Research Institute of Environmental Science, College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, China
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53
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Mahilang M, Deb MK, Pervez S. Biogenic secondary organic aerosols: A review on formation mechanism, analytical challenges and environmental impacts. CHEMOSPHERE 2021; 262:127771. [PMID: 32799139 DOI: 10.1016/j.chemosphere.2020.127771] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 07/15/2020] [Accepted: 07/19/2020] [Indexed: 06/11/2023]
Abstract
The review initiates with current state of information on the atmospheric reaction mechanism of biogenic volatile organic compounds (BVOCs) and its fate in the atmosphere. The plants release BVOCs, i.e., isoprene, monoterpenes, and sesquiterpenes, which form secondary organic aerosols (SOA) upon oxidation. These oxidation reactions are primarily influenced by solar radiations along with other meteorological parameters viz.; temperature and relative humidity, therefore, the chemistry behind SOA formation is different during day than the night time. The review throws light upon the day and nighttime formation mechanism of SOA, recent advancements in the analytical techniques available for the measurements, and its impact on the environment. Studies have revealed that day time SOA formation is dominated by OH and O3, however, NOx initiated SOA production is dominated during night. The formation mechanism addresses that the gaseous products of VOCs are firstly formed and then partitioned over the pre-existing particles. New particle formation and biomass-derived aerosols are found to be responsible for enhanced SOA formation. 2-Dimensional gas chromatography-mass spectrometer (2D-GC/MS) is observed to be best for the analysis of organic aerosols. Radiative forcing (RF) SOA is observed to be a useful parameter to evaluate the environmental impacts of SOA and reviewed studies have shown mean RF in the ranges of -0.27 to +0.20 W m-2.
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Affiliation(s)
- Mithlesh Mahilang
- School of Studies in Chemistry, Pandit Ravishankar Shukla University, Raipur, Chhattisgarh, 492010, India
| | - Manas Kanti Deb
- School of Studies in Chemistry, Pandit Ravishankar Shukla University, Raipur, Chhattisgarh, 492010, India.
| | - Shamsh Pervez
- School of Studies in Chemistry, Pandit Ravishankar Shukla University, Raipur, Chhattisgarh, 492010, India
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54
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Han S, Jang M. Simulating the impact of gas-wall partitioning on SOA formation using the explicit gas mechanism integrated with aqueous reactions containing electrolytes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 748:141360. [PMID: 32827892 DOI: 10.1016/j.scitotenv.2020.141360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/25/2020] [Accepted: 07/27/2020] [Indexed: 06/11/2023]
Abstract
The impact of the Teflon reactor wall on secondary organic aerosol (SOA) formation was explicitly simulated by using the Unified Partitioning Aerosol Phase Reaction (UNIPAR) model integrated with gas-wall partitioning (GWP). The formation of oxygenated semivolatile organic compounds (SVOCs) from the photooxidation of hydrocarbons (HC) was simulated by using an explicit gas-kinetic mechanism (MCM V3.3.1). In the model, SVOC's GWP and gas-particle partitioning onto preexisting particulate matter were kinetically treated with the absorption and desorption processes. The UNIPAR model streamlined aerosol growth via the oligomerization of reactive SVOCs in the organic phase and aqueous reactions in the inorganic phase. Two important GWP parameters, GWP coefficient (Kw, i) and the deposition rate constant (k_onw, i) of SVOCs (i) to the wall were predicted by using a quantitative structure activity relationship (QSAR) employing SVOCs' physicochemical descriptors. This GWP model was then incorporated with the UNIPAR model in the DSMACC-KPP platform and simulated SOA chamber data. The three different HCs (toluene, 1,3,5-trimethylbenzene, and α-pinene) were photochemically oxidized in the presence of NOx and inorganic seed aerosols in an outdoor photochemical smog chamber (UF-APHOR). The impact of GWP on SOA mass varied ranging from 9% to 71% with HCs, seed conditions, NOx, and temperature. Toluene SOA in the absence of inorganic aerosol was the most sensitive to GWP. However, in the presence of wet-inorganic seed, the impact of GWP on SOA was smaller than that of non-seed SOA owing to rapid reactions of organic species in the aqueous phase. SOA mass can be significantly underestimated in the absence of wet-inorganic seed when the aerosol model employs parameters derived using SOA data with GWP artifacts.
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Affiliation(s)
- Sanghee Han
- Department of Environmental Engineering Science, University of Florida, Gainesville, FL, USA
| | - Myoseon Jang
- Department of Environmental Engineering Science, University of Florida, Gainesville, FL, USA.
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Yang S, Duan F, Ma Y, Li H, Wang J, Du Z, Xu Y, Zhang T, Zhu L, Huang T, Kimoto T, Zhang L, He K. Characteristics and seasonal variations of high-molecular-weight oligomers in urban haze aerosols. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 746:141209. [PMID: 32763608 DOI: 10.1016/j.scitotenv.2020.141209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/19/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023]
Abstract
Organic aerosols (OA) undergo sophisticated physiochemical processes in the atmosphere, playing a crucial role in extreme haze formations over the Northern China Plain. However, current understandings of the detailed composition and formation pathways are limited. In this study, high-molecular weight (HMW) species were observed in samples collected year-round in urban Beijing, especially in autumn and winter, during 2016-2017. The positive-ion-mode mass spectra of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) showed that higher signal intensities were obtained in the mass-to-charge (m/z) ranges of 200-500 and 800-900, with repetitive mass difference patterns of m/z 12, 14, 16, and 18. This provided sound evidence that high-molecular-weight oligomers were generated as haze episodes became exacerbated. These oligomer signal intensities were enhanced in the presence of high relative humidity, aerosol water content, and PM2.5 (particles with an aerodynamic diameter ≤ 2.5 μm) mass, proving that the multiphase reaction processes play a fundamental role in haze formation in Beijing. Our study can form a basis for improved air pollution mitigation measures aimed at OA to improve health outcomes.
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Affiliation(s)
- Shuo Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing 100084, China
| | - Fengkui Duan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing 100084, China.
| | - Yongliang Ma
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing 100084, China
| | - Hui Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing 100084, China
| | - Jiali Wang
- Kimoto Electric Co. Ltd, Funahashi-Cho, Tennouji-Ku, Osaka 543-0024, Japan
| | - Zhenyu Du
- National Research Center for Environmental Analysis and Measurement, Beijing 100029, China
| | - Yunzhi Xu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing 100084, China
| | - Ting Zhang
- National Research Center for Environmental Analysis and Measurement, Beijing 100029, China
| | - Lidan Zhu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing 100084, China
| | - Tao Huang
- Kimoto Electric Co. Ltd, Funahashi-Cho, Tennouji-Ku, Osaka 543-0024, Japan
| | - Takashi Kimoto
- Kimoto Electric Co. Ltd, Funahashi-Cho, Tennouji-Ku, Osaka 543-0024, Japan
| | - Lifei Zhang
- National Research Center for Environmental Analysis and Measurement, Beijing 100029, China
| | - Kebin He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing 100084, China.
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56
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Qin Y, Ye J, Ohno PE, Lei Y, Wang J, Liu P, Thomson RJ, Martin ST. Synergistic Uptake by Acidic Sulfate Particles of Gaseous Mixtures of Glyoxal and Pinanediol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11762-11770. [PMID: 32838520 DOI: 10.1021/acs.est.0c02062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The uptake of gaseous organic species by atmospheric particles can be affected by the reactive interactions among multiple co-condensing species, yet the underlying mechanisms remain poorly understand. Here, the uptake of unary and binary mixtures of glyoxal and pinanediol by neutral and acidic sulfate particles is investigated. These species are important products from the oxidation of volatile organic compounds (VOCs) under atmospheric conditions. The uptake to acidic aerosol particles greatly increased for a binary mixture of glyoxal and pinanediol compared to the unary counterparts. The strength of the synergism depended on the particle acidity and water content (i.e., relative humidity). The greater uptake was up to 2.5× to 8× at 10% relative humidity (RH) for glyoxal and pinanediol, respectively. At 50% RH, it was 2× and 1.2× for the two species. Possible mechanisms of acid-catalyzed cross reactions between the species are proposed to explain the synergistic uptake. The proposed mechanisms are applicable to a broader extent across atmospheric species having carbonyl and hydroxyl functionalities. The results thus suggest that synergistic uptake reactions can be expected to significantly influence the gas-particle partitioning of VOC oxidation products under atmospheric conditions and thus greatly affect their atmospheric transport and lifetime.
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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 E Ohno
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Harvard University Center for the Environment, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Yali Lei
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Junfeng Wang
- 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
| | - Regan J Thomson
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, 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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57
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Zheng G, Su H, Wang S, Andreae MO, Pöschl U, Cheng Y. Multiphase buffer theory explains contrasts in atmospheric aerosol acidity. Science 2020; 369:1374-1377. [DOI: 10.1126/science.aba3719] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 07/21/2020] [Indexed: 01/01/2023]
Abstract
Aerosol acidity largely regulates the chemistry of atmospheric particles, and resolving the drivers of aerosol pH is key to understanding their environmental effects. We find that an individual buffering agent can adopt different buffer pH values in aerosols and that aerosol pH levels in populated continental regions are widely buffered by the conjugate acid-base pair NH4+/NH3 (ammonium/ammonia). We propose a multiphase buffer theory to explain these large shifts of buffer pH, and we show that aerosol water content and mass concentration play a more important role in determining aerosol pH in ammonia-buffered regions than variations in particle chemical composition. Our results imply that aerosol pH and atmospheric multiphase chemistry are strongly affected by the pervasive human influence on ammonia emissions and the nitrogen cycle in the Anthropocene.
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Affiliation(s)
- Guangjie Zheng
- Minerva Research Group, Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Hang Su
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Siwen Wang
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Meinrat O. Andreae
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Geology and Geophysics, King Saud University, 11451 Riyadh, Saudi Arabia
| | - Ulrich Pöschl
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Yafang Cheng
- Minerva Research Group, Max Planck Institute for Chemistry, Mainz 55128, Germany
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58
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Yang Z, Tsona NT, Li J, Wang S, Xu L, You B, Du L. Effects of NO x and SO 2 on the secondary organic aerosol formation from the photooxidation of 1,3,5-trimethylbenzene: A new source of organosulfates. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 264:114742. [PMID: 32402708 DOI: 10.1016/j.envpol.2020.114742] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/02/2020] [Accepted: 05/03/2020] [Indexed: 06/11/2023]
Abstract
1,3,5-Trimethylbeneze (TMB) is an important constituent of anthropogenic volatile organic compounds that contributes to the formation of secondary organic aerosol (SOA). A series of chamber experiments were performed to probe the effects of NOx and SO2 on SOA formation from TMB photooxidation. The molecular composition of TMB SOA was investigated by ultra-high performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS). We found that the SOA yield increases notably with elevated NOx concentrations under low-NOx condition ([TMB]0/[NOx]0 > 10 ppbC ppb-1), while an opposite trend is observed in high-NOx experiments ([TMB]0/[NOx]0 < 10 ppbC ppb-1). The increase in SOA yield in low-NOx regime is attributed to the increase of NOx-induced OH concentrations. The formation of low-volatility species might be suppressed, thereby leading to a lower SOA yield in high-NOx conditions. Moreover, SOA formation was promoted in experiment with SO2 addition. Multifunctional products containing carbonyl, acid, alcohol, and nitrate functional groups were characterized in TMB/NOx photooxidation, whereas several organosulfates (OSs) and nitrooxy organosulfates were identified in TMB/NOx/SO2 photooxidation based on HR-Q-TOFMS analysis. The formation mechanism relevant to the detected compounds in SOA were proposed. Based on our measurements, the photooxidation of TMB in the presence of SO2 may be a new source of OSs in the atmosphere. The results presented here also deepen the understanding of SOA formation under relatively complex polluted environments.
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Affiliation(s)
- Zhaomin Yang
- Environment Research Institute, Shandong University, Qingdao, 266237, China
| | - Narcisse T Tsona
- School of Life Science, Shandong University, Qingdao, 266237, China
| | - Jianlong Li
- Environment Research Institute, Shandong University, Qingdao, 266237, China
| | - Shuyan Wang
- Environment Research Institute, Shandong University, Qingdao, 266237, China
| | - Li Xu
- Environment Research Institute, Shandong University, Qingdao, 266237, China
| | - Bo You
- Environment Research Institute, Shandong University, Qingdao, 266237, China
| | - Lin Du
- Environment Research Institute, Shandong University, Qingdao, 266237, China.
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59
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Gas-Phase Reaction of trans-2-Methyl-2-butenal with Cl: Kinetics, Gaseous Products, and SOA Formation. ATMOSPHERE 2020; 11:715. [PMID: 33154821 PMCID: PMC7116312 DOI: 10.3390/atmos11070715] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The gas-phase reaction between trans-2-methyl-2-butenal and chlorine (Cl) atoms has been studied in a simulation chamber at 298 ± 2 K and 760 ± 5 Torr of air under free-NOx conditions. The rate coefficient of this reaction was determined as k = (2.45 ± 0.32) × 10-10 cm3 molecule−1 s−1 by using a relative method and Fourier transform infrared spectroscopy. In addition to this technique, gas chromatography coupled to mass spectrometry and proton transfer time-of-flight mass spectrometry were used to detect and monitor the time evolution of the gas-phase reaction products. The major primary reaction product from the addition of Cl to the C-3 of trans-2-methyl-2-butenal was 3-chloro-2-butanone, with a molar yield (YProd) of (52.5 ± 7.3)%. Acetaldehyde (Y = (40.8 ± 0.6)%) and HCl were also identified, indicating that the H-abstraction by Cl from the aldehyde group is a reaction pathway as well. Secondary organic aerosol (SOA) formation was investigated by using a fast mobility particle sizer spectrometer. The SOA yield in the Cl + trans-2-methyl-2-butenal reaction is reported to be lower than 2.4%, thus its impact can be considered negligible. The atmospheric importance of the titled reaction is similar to the corresponding OH reaction in areas with high Cl concentration.
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60
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Wang R, Huang Y, Cao G. Heterogeneous oxidation of isoprene SOA and toluene SOA tracers by ozone. CHEMOSPHERE 2020; 249:126258. [PMID: 32213391 DOI: 10.1016/j.chemosphere.2020.126258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/20/2020] [Accepted: 02/15/2020] [Indexed: 06/10/2023]
Abstract
Secondary Organic aerosols (SOA) are important components of PM 2.5. In order to control the heavy haze pollution, it is essential to find out the contributions of main SOA precursors. Nowadays, the tracer-based method has been widely used in analyzing the contributions of the precursors to SOA. However, it is not well known that whether the SOA tracers can be oxidized or how the instability of the SOA tracers would influence the accuracy of the tracer-based method for source apportionment. In this paper, the heterogeneous oxidation experiments of SOA tracers produced from isoprene and toluene as well as their mixtures under different conditions were conducted in a 2 m3 indoor chamber. The relative rate constants approach was used to determine the effective rate constants of the ozone reactions of the tracers. Concentrations of 2-Methyl Erythritol, a tracer of isoprene SOA, and 2, 3-Dihydroxy-4-oxopentanoic Acid, a tracer of toluene SOA, were analyzed using GC-MS. The effects of different seed aerosols and initial VOC0/NO on the heterogeneous oxidation of the tracers were investigated. The effects of co-existing components in the SOA produced from the mixture of isoprene and toluene on the heterogeneous oxidation of the tracers by ozone were also studied.
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Affiliation(s)
- Runhua Wang
- Harbin Institute of Technology (Shenzhen), Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Shenzhen, 518055, PR China
| | - Yajuan Huang
- Harbin Institute of Technology (Shenzhen), Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Shenzhen, 518055, PR China
| | - Gang Cao
- Harbin Institute of Technology (Shenzhen), Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Shenzhen, 518055, PR China.
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61
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Yee LD, Isaacman-VanWertz G, Wernis RA, Kreisberg NM, Glasius M, Riva M, Surratt JD, de Sá SS, Martin ST, Alexander ML, Palm BB, Hu W, Campuzano-Jost P, Day DA, Jimenez JL, Liu Y, Misztal PK, Artaxo P, Viegas J, Manzi A, de Souza RAF, Edgerton ES, Baumann K, Goldstein AH. Natural and Anthropogenically Influenced Isoprene Oxidation in Southeastern United States and Central Amazon. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:5980-5991. [PMID: 32271021 DOI: 10.1021/acs.est.0c00805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Anthropogenic emissions alter secondary organic aerosol (SOA) formation chemistry from naturally emitted isoprene. We use correlations of tracers and tracer ratios to provide new perspectives on sulfate, NOx, and particle acidity influencing isoprene-derived SOA in two isoprene-rich forested environments representing clean to polluted conditions-wet and dry seasons in central Amazonia and Southeastern U.S. summer. We used a semivolatile thermal desorption aerosol gas chromatograph (SV-TAG) and filter samplers to measure SOA tracers indicative of isoprene/HO2 (2-methyltetrols, C5-alkene triols, 2-methyltetrol organosulfates) and isoprene/NOx (2-methylglyceric acid, 2-methylglyceric acid organosulfate) pathways. Summed concentrations of these tracers correlated with particulate sulfate spanning three orders of magnitude, suggesting that 1 μg m-3 reduction in sulfate corresponds with at least ∼0.5 μg m-3 reduction in isoprene-derived SOA. We also find that isoprene/NOx pathway SOA mass primarily comprises organosulfates, ∼97% in the Amazon and ∼55% in Southeastern United States. We infer under natural conditions in high isoprene emission regions that preindustrial aerosol sulfate was almost exclusively isoprene-derived organosulfates, which are traditionally thought of as representative of an anthropogenic influence. We further report the first field observations showing that particle acidity correlates positively with 2-methylglyceric acid partitioning to the gas phase and negatively with the ratio of 2-methyltetrols to C5-alkene triols.
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Affiliation(s)
- Lindsay D Yee
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States
| | - Gabriel Isaacman-VanWertz
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States
| | - Rebecca A Wernis
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
| | | | - Marianne Glasius
- Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
| | - Matthieu Riva
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Jason D Surratt
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Suzane S de Sá
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 01451, United States
| | - Scot T Martin
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 01451, United States
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 01451, United States
| | - M Lizabeth Alexander
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Brett B Palm
- Department of Chemistry & Biochemistry and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado 80309, United States
| | - Weiwei Hu
- Department of Chemistry & Biochemistry and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado 80309, United States
| | - Pedro Campuzano-Jost
- Department of Chemistry & Biochemistry and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado 80309, United States
| | - Douglas A Day
- Department of Chemistry & Biochemistry and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado 80309, United States
| | - Jose L Jimenez
- Department of Chemistry & Biochemistry and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado 80309, United States
| | - Yingjun Liu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 01451, United States
| | - Pawel K Misztal
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States
| | - Paulo Artaxo
- Universidade de São Paulo, São Paulo, Brazil 05508-020
| | - Juarez Viegas
- Instituto Nacional de Pesquisas da Amazonia, Manaus, Amazonas, Brazil 69060-001
| | - Antonio Manzi
- Instituto Nacional de Pesquisas da Amazonia, Manaus, Amazonas, Brazil 69060-001
| | | | - Eric S Edgerton
- Atmospheric Research & Analysis, Inc., Cary, North Carolina 27513, United States
| | - Karsten Baumann
- Atmospheric Research & Analysis, Inc., Cary, North Carolina 27513, United States
| | - Allen H Goldstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
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62
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Source Apportionment of PM2.5 in Florence (Italy) by PMF Analysis of Aerosol Composition Records. ATMOSPHERE 2020. [DOI: 10.3390/atmos11050484] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
An extensive field campaign was carried out in Florence (Tuscany) to investigate the PM2.5 composition and to identify its sources. The scientific objective of this study is providing a reliable source apportionment, which is mandatory for the application of effective mitigation actions. Particulate matter (PM) was collected for one year, simultaneously in a traffic site, in an urban background, and in a regional background site. While the use of two filter types (quartz and Teflon) allowed obtaining a comprehensive chemical characterization (elemental and organic carbon, ions, elements) by the application of different analytical techniques, the location of the three sampling sites allowed getting a better separation among local, urban, regional and transboundary sources. During shorter periods, the aerosol was also collected by means of a streaker sampler and PIXE (Particle Induced X-ray Emission) analysis of these samples allowed the assessment of hourly resolution elemental time trends. Positive matrix factorisation (PMF) identified seven main sources: traffic, biomass burning, secondary sulphate, secondary nitrates, urban dust, Saharan dust and marine aerosol. Traffic mass concentration contributions were found to be strong only at the traffic site (~8 μg·m−3, 33% of PM2.5). Biomass burning turned out to be an important PM2.5 source in Florence (~4 μg·m−3), with very similar weights in both city sites while at the regional background site its weight was negligible. Secondary sulphate is an important PM2.5 source on a regional scale, with comparable values in all three sites (~3.5 μg·m−3). On average, the contribution of the “natural” components (e.g., mineral dust and marine aerosols) to PM2.5 is moderate (~1 μg·m−3) except during Saharan dust intrusions where this contribution is higher (detected simultaneously in all three sites). High-time resolution data confirmed and reinforced these results.
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63
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Lei Z, Bliesner SE, Mattson CN, Cooke ME, Olson NE, Chibwe K, Albert JNL, Ault AP. Aerosol Acidity Sensing via Polymer Degradation. Anal Chem 2020; 92:6502-6511. [PMID: 32227877 DOI: 10.1021/acs.analchem.9b05766] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The acidity of atmospheric aerosols is a critical property that affects the chemistry and composition of the atmosphere. Many key multiphase chemical reactions are pH-dependent, impacting processes like secondary organic aerosol formation, and need to be understood at a single particle level due to differences in particle-to-particle composition that impact both climate and health. However, the analytical challenge of measuring aerosol acidity in individual particles has limited pH measurements for fine (<2.5 μm) and coarse (2.5-10 μm) particles. This has led to a reliance on indirect methods or thermodynamic modeling, which focus on average, not individual, particle pH. Thus, new approaches are needed to probe single particle pH. In this study, a novel method for pH measurement was explored using degradation of a pH-sensitive polymer, poly(ε-caprolactone), to determine the acidity of individual submicron particles. Submicron particles of known pH (0 or 6) were deposited on a polymer film (21-25 nm thick) and allowed to react. Particles were then rinsed off, and the degradation of the polymer was characterized using atomic force microscopy and Raman microspectroscopy. After degradation, holes in the PCL films exposed to pH 0 were observed, and the loss of the carbonyl stretch was monitored at 1723 cm-1. As particle size decreased, polymer degradation increased, indicating an increase in aerosol acidity at smaller particle diameters. This study describes a new approach to determine individual particle acidity and is a step toward addressing a key measurement gap related to our understanding of atmospheric aerosol impacts on climate and health.
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Affiliation(s)
- Ziying Lei
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Samuel E Bliesner
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - Claire N Mattson
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Madeline E Cooke
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Nicole E Olson
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kaseba Chibwe
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - Julie N L Albert
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - Andrew P Ault
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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64
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Zhao P, Du X, Su J, Ding J, Dong Q. Aerosol hygroscopicity based on size-resolved chemical compositions in Beijing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 716:137074. [PMID: 32036147 DOI: 10.1016/j.scitotenv.2020.137074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/23/2020] [Accepted: 01/31/2020] [Indexed: 05/21/2023]
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65
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Gladich I, Carignano MA, Francisco JS. Adsorption and isomerization of glyoxal and methylglyoxal at the air/hydroxylated silica surface. J Chem Phys 2020; 152:164702. [PMID: 32357765 DOI: 10.1063/1.5143402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present results from molecular dynamics simulations coupled with enhanced sampling techniques on the adsorption and isomerization of glyoxal (GL) and methylglyoxal (MG) at the air/hydroxylated silica (α-Quartz) interface. GL and MG are two organic compounds present in the atmosphere as oxidation products of both biogenic and anthropogenic precursors. By adsorption and hydration on liquid droplets or wetted dust particles, they can enable aerosol growth in the atmosphere. Moreover, thanks to the different polar characters of their trans and cis conformers, GL and MG have been suggested as possible molecular switches capable of responding to changes in solvent polarity. Here, we show that the hydroxylated silica surface does not significantly catalyze the trans-to-cis isomerization, but it stabilizes the cis-isomers, indicating a higher interfacial cis/trans relative concentration compared to the gas phase. Moreover, adsorbed GL prefers to lie parallel on the silica surface, while adsorbed MG shows a tilted orientation. In particular, we report the aldehyde group pointing upward (downward) to the gas phase (to the silica surface) in trans-MG (cis-MG). These results will help in the rationalization of upcoming experimental and modeling work on the adsorption of ketonic compounds on dust aerosols, while it clarifies the catalytic role of the solid substrate surface in promoting conformational changes.
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Affiliation(s)
- Ivan Gladich
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 34110, Doha, Qatar
| | - Marcelo A Carignano
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 34110, Doha, Qatar
| | - Joseph S Francisco
- Department of Earth and Environmental Science and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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66
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Pye HOT, Nenes A, Alexander B, Ault AP, Barth MC, Clegg SL, Collett JL, Fahey KM, Hennigan CJ, Herrmann H, Kanakidou M, Kelly JT, Ku IT, McNeill VF, Riemer N, Schaefer T, Shi G, Tilgner A, Walker JT, Wang T, Weber R, Xing J, Zaveri RA, Zuend A. The Acidity of Atmospheric Particles and Clouds. ATMOSPHERIC CHEMISTRY AND PHYSICS 2020; 20:4809-4888. [PMID: 33424953 PMCID: PMC7791434 DOI: 10.5194/acp-20-4809-2020] [Citation(s) in RCA: 155] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Acidity, defined as pH, is a central component of aqueous chemistry. In the atmosphere, the acidity of condensed phases (aerosol particles, cloud water, and fog droplets) governs the phase partitioning of semi-volatile gases such as HNO3, NH3, HCl, and organic acids and bases as well as chemical reaction rates. It has implications for the atmospheric lifetime of pollutants, deposition, and human health. Despite its fundamental role in atmospheric processes, only recently has this field seen a growth in the number of studies on particle acidity. Even with this growth, many fine particle pH estimates must be based on thermodynamic model calculations since no operational techniques exist for direct measurements. Current information indicates acidic fine particles are ubiquitous, but observationally-constrained pH estimates are limited in spatial and temporal coverage. Clouds and fogs are also generally acidic, but to a lesser degree than particles, and have a range of pH that is quite sensitive to anthropogenic emissions of sulfur and nitrogen oxides, as well as ambient ammonia. Historical measurements indicate that cloud and fog droplet pH has changed in recent decades in response to controls on anthropogenic emissions, while the limited trend data for aerosol particles indicates acidity may be relatively constant due to the semi-volatile nature of the key acids and bases and buffering in particles. This paper reviews and synthesizes the current state of knowledge on the acidity of atmospheric condensed phases, specifically particles and cloud droplets. It includes recommendations for estimating acidity and pH, standard nomenclature, a synthesis of current pH estimates based on observations, and new model calculations on the local and global scale.
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Affiliation(s)
- Havala O. T. Pye
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Athanasios Nenes
- School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
- Institute for Chemical Engineering Sciences, Foundation for Research and Technology Hellas, Patras, GR-26504, Greece
| | - Becky Alexander
- Department of Atmospheric Science, University of Washington, Seattle, WA, 98195, USA
| | - Andrew P. Ault
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - Mary C. Barth
- National Center for Atmospheric Research, Boulder, CO, 80307, USA
| | - Simon L. Clegg
- School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Jeffrey L. Collett
- Department of Atmospheric Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Kathleen M. Fahey
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Christopher J. Hennigan
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, 21250, USA
| | - Hartmut Herrmann
- Leibniz Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), Leipzig, 04318, Germany
| | - Maria Kanakidou
- Department of Chemistry, University of Crete, Voutes, Heraklion Crete, 71003, Greece
| | - James T. Kelly
- Office of Air Quality Planning & Standards, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - I-Ting Ku
- Department of Atmospheric Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - V. Faye McNeill
- Department of Chemical Engineering, Columbia University, New York, NY, 10027, USA
| | - Nicole Riemer
- Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois, 61801, USA
| | - Thomas Schaefer
- Leibniz Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), Leipzig, 04318, Germany
| | - Guoliang Shi
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, Nankai University, Tianjin, 300071, China
| | - Andreas Tilgner
- Leibniz Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), Leipzig, 04318, Germany
| | - John T. Walker
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Tao Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Rodney Weber
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Jia Xing
- School of Environment, Tsinghua University, Beijing, 100084, China
| | - Rahul A. Zaveri
- Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Andreas Zuend
- Department of Atmospheric and Oceanic Sciences, McGill University, Montreal, Quebec, H3A 0B9, Canada
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67
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Aswini AR, Hegde P, Aryasree S, Girach IA, Nair PR. Continental outflow of anthropogenic aerosols over Arabian Sea and Indian Ocean during wintertime: ICARB-2018 campaign. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 712:135214. [PMID: 31836221 DOI: 10.1016/j.scitotenv.2019.135214] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 06/10/2023]
Abstract
Chemical characterisation of atmospheric aerosols over Arabian Sea (AS) and Indian Ocean (IO) have been carried out during the winter period (January to February 2018) as part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB-2018). Mass concentrations of organic carbon (OC), elemental carbon (EC), water soluble and insoluble OC (WSOC, WIOC), primary and secondary OC (POC, SOC), water-soluble inorganic ions and trace metals have been estimated with a view to identify and quantify the major anthropogenic pollutants affecting the oceanic environments. Aerosol mass loading was found to exhibit strong spatial heterogeneity (varying from 13 to 84 μg m-3), significantly modulated by the origin of air-mass trajectories. Chemical analysis of aerosols revealed the presence of an intense pollution plume over south-eastern coastal Arabian Sea, near to south-west Indian peninsula (extending from ~ 12°N to 0° at 75°E) with a strong latitudinal gradient (~3 μg m-3/deg. from north to south) dominated by anthropogenic species contributing as high as 73% (38% nss-SO42-, 24.2% carbonaceous aerosols (21% Organic Matter, 3.2% EC) and 10% NH4+). Anthropogenic signature over oceanic environment was also evident from the dominance and high enrichment of elements like Zn, Cu, Mn and Pb in trace metals. Long-range transport of air-masses originating from Indo Gangetic Plains and its outflow regions in Bay of Bengal, has been seen over Arabian Sea during winter, that imparted such strong anthropogenic signatures over this oceanic environment. Comparison with previous cruise studies conducted nearly two decades ago shows a more than two-fold increase in the concentration of nss-SO42-, over the continental outflow region in Arabian Sea.
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Affiliation(s)
- A R Aswini
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, India; Cochin University of Science and Technology, Cochin, India
| | - Prashant Hegde
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, India.
| | - S Aryasree
- Institute for applied Geosciences, Technical University Darmstadt, Darmstadt, Germany
| | - Imran A Girach
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, India
| | - Prabha R Nair
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, India
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68
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XU J, HUANG MQ. Influence of Inorganic Gases on Formation and Chemical Composition of Monoaromatic Hydrocarbons Secondary Organic Aerosol. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2020. [DOI: 10.1016/s1872-2040(20)60008-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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69
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Zhu C, Zeng XC, Francisco JS, Gladich I. Hydration, Solvation, and Isomerization of Methylglyoxal at the Air/Water Interface: New Mechanistic Pathways. J Am Chem Soc 2020; 142:5574-5582. [PMID: 32091211 DOI: 10.1021/jacs.9b09870] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aqueous-phase processing of methylglyoxal (MG) has been suggested to play a key role in the formation of secondary organic aerosols and catalyze particle growth in the atmosphere. However, the details of these processes remain speculative owing to the lack of a complete description of the physicochemical behavior of MG on atmospheric aerosols. Here, the solvation and hydrolysis of MG at the air/liquid water interface is studied via classical and first-principles molecular dynamics simulations combined with free-energy methods. Our results reveal that the polarity of the water solvent catalyzed the trans-to-cis isomerization of MG at the air/liquid water interface relative to the gas phase. Despite the presence of a hydrophobic group, MG often solvates with both the ketone and methyl groups parallel to the water interface. Analysis of the instantaneous water surface reveals that when MG is in the trans state, the methyl group repels interfacial water to maintain the planarity of the molecule, indicating that lateral and temporal inhomogeneities of interfacial environments are important for fully characterizing the solvation of MG. The counterintuitive behavior of the hydrophobic group is ascribed to a tendency to maximize the number of hydrogen bonds between MG and interfacial water while minimizing the torsional free energy. This drives MG hydration, and our simulations indicate that the formation of MG diol is catalyzed at the air/liquid water interface compared to the gas phase and occurs through nucleophilic attack of water on the carbonyl carbon.
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Affiliation(s)
- Chongqin Zhu
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States.,Department of Earth and Environmental Science and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Xiao Cheng Zeng
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Joseph S Francisco
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States.,Department of Earth and Environmental Science and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Ivan Gladich
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825, Doha, Qatar.,European Centre for Living Technology (ECLT), Ca' Bottacin, Dorsoduro 3911, Calle Crosera, 30124 Venice, Italy
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70
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Chang P, Chen Z, Zhang Y, Liu Y. Direct measurement of aerosol pH in individual malonic acid and citric acid droplets under different relative humidity conditions via Raman spectroscopy. CHEMOSPHERE 2020; 241:124960. [PMID: 31590017 DOI: 10.1016/j.chemosphere.2019.124960] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/14/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
Acidity of aerosol particles plays important roles in atmospheric chemistry, in turn, impacting climate system and public health. Current knowledge of acidity in atmosphere aerosols remains fairly scarce largely because of difficulty in direct measurement. On the other hand, indirect methods for estimating aerosol pH are often inconsistent with pH values predicted by thermodynamic models. Recently, a direct Raman spectroscopy method has been reported to determine pH values of acid-conjugate base equilibria systems based on Raman intensity of distinct characteristic peaks of conjugate acid-base pair. Nevertheless, for pure carboxylic acid aerosol particles, such as malonic acid (MA), characteristic peak of its conjugate base cannot be clearly observed in Raman spectra owing to small Ka value (weak acid dissociation constant), which leads to little dissociation of weak acid and low concentration of its conjugated base. As a result, pH of carboxylic acid particles cannot be directly determined by calibrating concentrations of acid and its conjugated base using the above-mentioned method. To address such an issue, we demonstrate a new approach for determining pH values of malonic acid (MA) and citric acid (CA) droplets under different relative humidity (RH) based on calibration curves. We measure Raman intensity ratios of acid solutions at different concentrations and their pH values to establish a calibration curve, and then using the intensity ratio of MA and CA droplets under different RH to determine aerosol particle pH based on calibration curves. Results have shown that aerosol pH of MA droplet decreases with a decreasing RH and pH values ranges from 1.03 to -0.12, when RH value is reduced from 90% to 26%, in good agreement with model prediction values. In addition, we also, for the first time, report pH values of CA droplets under different RH conditions and its pH values range from 1.13 to -0.74 when RH is reduced from 91% to 28%.
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Affiliation(s)
- Pianpian Chang
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, PR China
| | - Zhe Chen
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, PR China
| | - Yunhong Zhang
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, PR China.
| | - Yong Liu
- Department of Chemistry, University of Colorado Denver, Denver, CO, 80217, USA.
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71
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Zhao Z, Tolentino R, Lee J, Vuong A, Yang X, Zhang H. Interfacial Dimerization by Organic Radical Reactions during Heterogeneous Oxidative Aging of Oxygenated Organic Aerosols. J Phys Chem A 2019; 123:10782-10792. [PMID: 31765152 DOI: 10.1021/acs.jpca.9b10779] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oxidative aging of atmospheric organic aerosols (OA) substantially modifies their chemical compositions, physical properties, and hence the various environmental impacts. Here, we report observations of a previously unrecognized process leading to dimer formation during heterogeneous •OH-initiated oxidative aging of oxygenated OA. Isomer-resolved ion mobility mass spectrometry measurements and reaction-diffusion kinetic simulations are in good agreement, elucidating new mechanisms of dimerization by organic radical (i.e., peroxy and alkoxy radicals) cross reactions using glutaric acid as a surrogate oxygenated OA. These radical reactions are predicted to occur more prominently near the gas-particle interface following oxidation, especially in diffusion-limited viscous OA particles. Chemical structure analysis shows that esters dominate the detected dimers, followed by organic peroxides and ethers, highlighting the importance of acyl peroxy and acyloxy radicals. Simulations suggest that the reported dimer formation through the new interfacial mechanism could be appreciable under both laboratory and ambient conditions. Therefore, the dimers that are formed and enriched at the gas-particle interface are expected to play a crucial role in the effective reactivity, volatility, viscosity, and hygroscopicity of aged OA particles.
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Affiliation(s)
- Zixu Zhao
- Department of Chemistry , University of California at Riverside , Riverside , California 92521 , United States
| | - Ricardo Tolentino
- Department of Chemistry , University of California at Riverside , Riverside , California 92521 , United States
| | - Jennifer Lee
- Department of Chemistry , University of California at Riverside , Riverside , California 92521 , United States
| | - Austin Vuong
- Department of Molecular, Cell, and Systems Biology , University of California at Riverside , Riverside , California 92521 , United States
| | - Xiaoyan Yang
- Department of Environmental Sciences , University of California at Riverside , Riverside , California 92521 , United States
| | - Haofei Zhang
- Department of Chemistry , University of California at Riverside , Riverside , California 92521 , United States
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72
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Gordon BP, Moore FG, Scatena LF, Richmond GL. On the Rise: Experimental and Computational Vibrational Sum Frequency Spectroscopy Studies of Pyruvic Acid and Its Surface-Active Oligomer Species at the Air–Water Interface. J Phys Chem A 2019; 123:10609-10619. [DOI: 10.1021/acs.jpca.9b08854] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Brittany P. Gordon
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, United States
| | - Frederick G. Moore
- Department of Physics, Whitman College, Walla Walla, Washington 99362, United States
| | - Lawrence F. Scatena
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, United States
| | - Geraldine L. Richmond
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, United States
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73
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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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74
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Riva M, Chen Y, Zhang Y, Lei Z, Olson NE, Boyer HC, Narayan S, Yee LD, Green HS, Cui T, Zhang Z, Baumann K, Fort M, Edgerton E, Budisulistiorini SH, Rose CA, Ribeiro IO, e Oliveira RL, dos Santos EO, Machado CMD, Szopa S, Zhao Y, Alves EG, de Sá SS, Hu W, Knipping EM, Shaw SL, Duvoisin S, de Souza RAF, Palm BB, Jimenez JL, Glasius M, Goldstein AH, Pye HOT, Gold A, Turpin BJ, Vizuete W, Martin ST, Thornton JA, Dutcher CS, Ault AP, Surratt JD. Increasing Isoprene Epoxydiol-to-Inorganic Sulfate Aerosol Ratio Results in Extensive Conversion of Inorganic Sulfate to Organosulfur Forms: Implications for Aerosol Physicochemical Properties. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:8682-8694. [PMID: 31335134 PMCID: PMC6823602 DOI: 10.1021/acs.est.9b01019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Acid-driven multiphase chemistry of isoprene epoxydiols (IEPOX), key isoprene oxidation products, with inorganic sulfate aerosol yields substantial amounts of secondary organic aerosol (SOA) through the formation of organosulfur compounds. The extent and implications of inorganic-to-organic sulfate conversion, however, are unknown. In this article, we demonstrate that extensive consumption of inorganic sulfate occurs, which increases with the IEPOX-to-inorganic sulfate concentration ratio (IEPOX/Sulfinorg), as determined by laboratory measurements. Characterization of the total sulfur aerosol observed at Look Rock, Tennessee, from 2007 to 2016 shows that organosulfur mass fractions will likely continue to increase with ongoing declines in anthropogenic Sulfinorg, consistent with our laboratory findings. We further demonstrate that organosulfur compounds greatly modify critical aerosol properties, such as acidity, morphology, viscosity, and phase state. These new mechanistic insights demonstrate that changes in SO2 emissions, especially in isoprene-dominated environments, will significantly alter biogenic SOA physicochemical properties. Consequently, IEPOX/Sulfinorg will play an important role in understanding the historical climate and determining future impacts of biogenic SOA on the global climate and air quality.
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Affiliation(s)
- Matthieu Riva
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Yuzhi Chen
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Yue Zhang
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Aerodyne Research Inc., Billerica, MA 01821, USA
| | - Ziying Lei
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicole E. Olson
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Hallie C. Boyer
- Department of Mechanical Engineering, University of Minnesota-Twin Cities, Minneapolis, MN 55455, USA
| | - Shweta Narayan
- Department of Mechanical Engineering, University of Minnesota-Twin Cities, Minneapolis, MN 55455, USA
| | - Lindsay D. Yee
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA
| | - Hilary S. Green
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Tianqu Cui
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Zhenfa Zhang
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | - Mike Fort
- Atmospheric Research & Analysis, Inc., Cary, NC 27513, USA
| | - Eric Edgerton
- Atmospheric Research & Analysis, Inc., Cary, NC 27513, USA
| | - Sri H. Budisulistiorini
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Caitlin A. Rose
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Igor O. Ribeiro
- Escola Superior de Tecnologia, Universidade do Estado do Amazonas, Manaus, Amazonas, 69050, Brasil
| | - Rafael L. e Oliveira
- Escola Superior de Tecnologia, Universidade do Estado do Amazonas, Manaus, Amazonas, 69050, Brasil
| | - Erickson O. dos Santos
- Department of Chemistry, Federal University of Amazonas, Manaus, Amazonas, 69067, Brazil
| | - Cristine M. D. Machado
- Department of Chemistry, Federal University of Amazonas, Manaus, Amazonas, 69067, Brazil
| | - Sophie Szopa
- Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ-IPSL, 91190, Gif-sur-Yvette, France
| | - Yue Zhao
- Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195, USA
| | - Eliane G. Alves
- Environment Dynamics Department, National Institute of Amazonian Research (INPA), Manaus, 69067, Brazil
| | - Suzane S. de Sá
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Weiwei Hu
- Department of Chemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
| | | | | | - Sergio Duvoisin
- Escola Superior de Tecnologia, Universidade do Estado do Amazonas, Manaus, Amazonas, 69050, Brasil
| | - Rodrigo A. F. de Souza
- Escola Superior de Tecnologia, Universidade do Estado do Amazonas, Manaus, Amazonas, 69050, Brasil
| | - Brett B. Palm
- Department of Chemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
| | - Jose-Luis Jimenez
- Department of Chemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
| | | | - Allen H. Goldstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA
| | - Havala O. T. Pye
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Avram Gold
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Barbara J. Turpin
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - William Vizuete
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Scot T. Martin
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Joel A. Thornton
- Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195, USA
| | - Cari S. Dutcher
- Department of Mechanical Engineering, University of Minnesota-Twin Cities, Minneapolis, MN 55455, USA
| | - Andrew P. Ault
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jason D. Surratt
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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75
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Coddens EM, Angle KJ, Grassian VH. Titration of Aerosol pH through Droplet Coalescence. J Phys Chem Lett 2019; 10:4476-4483. [PMID: 31298863 DOI: 10.1021/acs.jpclett.9b00757] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The pH of aqueous aerosols, as well as cloud and fog droplets, has an important influence on the chemistry that takes place within these unique microenvironments. Utilizing conjugate acid/base pairs to infer pH changes, we investigate, for the first time, changes in aerosol pH upon coalescence. In particular, we show that the pH within individual aqueous aerosols that are ∼8 μm in diameter can be titrated via droplet coalescence in an aerosol optical tweezer. Using sulfate/bisulfate and carbonate/bicarbonate as model systems, the pH of trapped aerosols is determined before and after introduction of smaller aerosols containing a strong acid. The pH change upon coalescence with the smaller, acidic aerosol is calculated using specific ion interaction theory. Furthermore, we show that the pH of an individual aerosol can be altered along a fairly wide range of pH values, paving the way for future studies requiring rigorous pH control of an aqueous aerosol.
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Affiliation(s)
- Ellen M Coddens
- Department of Chemistry and Biochemistry , University of California San Diego , La Jolla , California 92093 , United States
| | - Kyle J Angle
- Department of Chemistry and Biochemistry , University of California San Diego , La Jolla , California 92093 , United States
| | - Vicki H Grassian
- Department of Chemistry and Biochemistry , University of California San Diego , La Jolla , California 92093 , United States
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76
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Abstract
Environmental chambers have proven to be essential for atmospheric photochemistry research. This historical perspective summarizes chamber research characterizing smog. Experiments with volatile organic compounds (VOCs)-nitrogen oxides (NOx) have characterized O3 and aerosol chemistry. These led to the creation and evaluation of complex reaction mechanisms adopted for various applications. Gas-phase photochemistry was initiated and developed using chamber studies. Post-1950s study of photochemical aerosols began using smog chambers. Much of the knowledge about the chemistry of secondary organic aerosols (SOA) derives from chamber studies complemented with specially designed atmospheric studies. Two major findings emerge from post-1990s SOA experiments: (1) photochemical SOAs hypothetically involve hydrocarbons and oxygenates with carbon numbers of 2, and (2) SOA evolves via more than one generation of reactions as condensed material exchanges with the vapor phase during “aging”. These elements combine with multiphase chemistry to yield mechanisms for aerosols. Smog chambers, like all simulators, are limited representations of the atmosphere. Translation to the atmosphere is complicated by constraints in reaction times, container interactions, influence of precursor injections, and background species. Interpretation of kinetics requires integration into atmospheric models addressing the combined effects of precursor emissions, surface exchange, hydrometeor interactions, air motion and sunlight.
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77
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Duell AK, McWhirter KJ, Korzun T, Strongin RM, Peyton DH. Sucralose-Enhanced Degradation of Electronic Cigarette Liquids during Vaping. Chem Res Toxicol 2019; 32:1241-1249. [PMID: 31079450 PMCID: PMC9831380 DOI: 10.1021/acs.chemrestox.9b00047] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Electronic cigarette liquids (e-liquids) with sweetener additives such as sucralose, a synthetic chlorinated disaccharide, are popular among some e-cigarette consumers; sucralose can be added either by the manufacturer or by the consumer. The prevalence of sucralose in commercial e-liquids is not known, nor is the typical concentration of sucralose when present; labels are not required to disclose ingredient information. Here, we report the effects of sucralose on e-liquid degradation upon e-cigarette vaping as studied using 1H NMR spectroscopy, ion chromatography, and gas chromatography coupled with detection by mass spectrometry or flame ionization detector. Sucralose was found to be subject to degradation when included in propylene glycol + glycerol based e-liquids and vaped; the presence of sucralose in the e-liquids also resulted in altered and enhanced solvent degradation. In particular, production of aldehydes (carbonyls) and hemiacetals (which have implications for health) was enhanced, as demonstrated by 1H NMR. The presence of sucralose at 0.03 mol % (0.14 wt %) in an e-liquid also resulted in production of potentially harmful organochlorine compounds and catalyzed the cyclization of aldehydes with solvents to acetals upon vaping; the presence of chloride in e-liquid aerosols was confirmed by ion chromatography. Quantities of sucralose as low as 0.05 mol % (0.24 wt %) in e-liquids lead to significant production of solvent degradation products.
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Affiliation(s)
- Anna K. Duell
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States
| | - Kevin J. McWhirter
- Department of Civil and Environmental Engineering, Portland State University, Portland, Oregon 97207-0751, United States
| | - Tetiana Korzun
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States
| | - Robert M. Strongin
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States
| | - David H. Peyton
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States,Corresponding Author
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78
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Liu Y, Li X, Tang G, Wang L, Lv B, Guo X, Wang Y. Secondary organic aerosols in Jinan, an urban site in North China: Significant anthropogenic contributions to heavy pollution. J Environ Sci (China) 2019; 80:107-115. [PMID: 30952328 DOI: 10.1016/j.jes.2018.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 06/09/2023]
Abstract
Secondary organic aerosols (SOAs) are an important component of particulates, but whether biogenic SOAs (BSOAs) or anthropogenic SOAs (ASOAs) are the dominant contributors to haze pollution remains poorly characterized. In this study, particulate samples were collected from September 2014 to August 2015 at an urban site in Jinan, which is the capital of Shandong Province and a typical city in the North China Plain. The PM2.5 samples were analyzed for BSOA (isoprene (SOAI) and monoterpenes (SOAM)) and ASOA (aromatic (SOAA)) tracers. The concentrations of the SOAA tracer (1.1 ± 1.0 ng/m3) were lowest, and those of SOAI tracers (41.8 ± 86.2 ng/m3) were highest, with the concentrations of SOAM tracers (19.4 ± 9.9 ng/m3) being intermediate. The SOAI tracers were more abundant in the summer and less abundant in the winter. Both SOAI and SOAM increased with increasing ozone level but decreased with increasing NOx level. Correlation analysis revealed a good correlation between 2,3-dihydroxy-4-oxopentanoic acid and levoglucosan levels in three seasons. These results suggested that biomass burning activities occurring in the NCP can enhance the emissions of aromatics and should be controlled, especially in the autumn and winter. SOA tracers were classified according to pollution degree, and the results showed that as pollution increases, the contributions of SOAA increase. These results indicate that reducing anthropogenic emissions is necessary to prevent SOA pollution, especially during heavy pollution episodes.
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Affiliation(s)
- Yusi Liu
- Department of Chemistry, Analytical and Testing Center, Capital Normal University, Beijing 100048, China; State Key Laboratory of Severe Weather & Key Laboratory for Atmospheric Chemistry of China Meteorology Administration, Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Xingru Li
- Department of Chemistry, Analytical and Testing Center, Capital Normal University, Beijing 100048, China.
| | - Guiqian Tang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; State Key Laboratory of Severe Weather & Key Laboratory for Atmospheric Chemistry of China Meteorology Administration, Chinese Academy of Meteorological Sciences, Beijing 100081, China; Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Lili Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Bo Lv
- Jinan Environmental Monitoring Center, Jinan 250014, China
| | - Xueqing Guo
- Department of Chemistry, Analytical and Testing Center, Capital Normal University, Beijing 100048, China
| | - Yuesi Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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79
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Theoretical study on the atmospheric oxidation reaction of 2-furanaldehyde initiated by NO3 radicals. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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80
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Song SK, Shon ZH, Kang YH, Kim KH, Han SB, Kang M, Bang JH, Oh I. Source apportionment of VOCs and their impact on air quality and health in the megacity of Seoul. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 247:763-774. [PMID: 30721867 DOI: 10.1016/j.envpol.2019.01.102] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 01/02/2019] [Accepted: 01/25/2019] [Indexed: 06/09/2023]
Abstract
The source apportionment of volatile organic compounds (VOCs) was examined using receptor models (positive matrix factorization and chemical mass balance) and a chemical transport model (CTM). The receptor model-based analysis was performed using the datasets collected from four different sites from the megacity of Seoul during the years 2013-2015. The contributions of VOC emission sources to ozone (O3) and PM2.5 concentrations and the subsequent health effects in the study area were also assessed during a photochemically active period (June 2015) using a three-dimensional CTM, Community Multi-scale Air Quality (CMAQ), and the Environmental Benefits Mapping and Analysis Program (BenMAP). The solvent use and the on-road mobile emission sources were found to exert dominant controls on the VOC levels observed in the target city. VOCs transported from regions outside of Seoul accounted for a significant proportion (up to approximately 35%) of ambient VOC levels during the study period. The solvent use accounted for 3.4% of the ambient O3 concentrations during the day (daily mean of 2.6%) and made insignificant contributions to PM2.5 (<1%) during the simulation period. Biogenic VOC made insignificant contributions to O3 (<1%) and a small contribution to PM2.5 during the day (5.6% with a daily mean of 2.4%). The number of premature deaths attributed indirectly (O3 and PM2.5 formations via the oxidation of VOCs) to solvent use is expected to be significant.
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Affiliation(s)
- Sang-Keun Song
- Department of Earth and Marine Sciences, Jeju National University, Jeju, 63243, Republic of Korea
| | - Zang-Ho Shon
- Department of Environmental Engineering, Dong-Eui University, Busan, 47340, Republic of Korea.
| | - Yoon-Hee Kang
- The Institute of Environmental Studies, Pusan National University, Busan, 46241, Republic of Korea
| | - Ki-Hyun Kim
- Department of Civil & Environmental Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Seung-Beom Han
- Department of Earth and Marine Sciences, Jeju National University, Jeju, 63243, Republic of Korea
| | - Minsung Kang
- Department of Environmental Engineering, Dong-Eui University, Busan, 47340, Republic of Korea
| | - Jin-Hee Bang
- Environmental Health Center, University of Ulsan College of Medicine, Ulsan, 44033, Republic of Korea
| | - Inbo Oh
- Environmental Health Center, University of Ulsan College of Medicine, Ulsan, 44033, Republic of Korea
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81
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Ultrasensitive detection of volatile aldehydes with chemi-ionization-coupled time-of-flight mass spectrometry. Talanta 2019; 194:888-894. [PMID: 30609620 DOI: 10.1016/j.talanta.2018.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 10/25/2018] [Accepted: 11/04/2018] [Indexed: 12/20/2022]
Abstract
The chemi-ionization reaction is a high-efficiency pathway to produce molecular ions in plasma, however, it has rarely been applied in mass spectrometry to directly produce analyte ions. In this study, a novel chemi-ionization technique for mass spectrometry was applied for the direct and ultrasensitive detection of gaseous aldehydes. The ionization technique was enacted by a recently observed chemi-ionization reaction: the efficient proton transfer from H2O to oxygenated compounds was stimulated by vacuum ultraviolet (VUV)-excited CH2Cl2. By analyzing a series of aliphatic aldehydes (C2-C5) and benzaldehyde with different proton affinities (PAs) and polarities, the ionization features of the new ionization method were investigated for the first time. The chemi-ionization of aldehydes presented soft ionization characteristics with fragmentation patterns analogous to that of VUV photoionization. The method showed ultrahigh sensitivities toward aldehydes (up to 1108 ± 6 counts pptv-1 for benzaldehyde in 10 s acquisition time). The corresponding 3σ limits of detection (LODs) achieved 0.30-0.69 pptv, which are equivalent of 1.35-1.92 ng m-3, for the compounds investigated. The humidity experiments revealed that the moisture in the sample gas had an evident impact on the detection efficiency of the analyte and the influence was PA dependent. In addition, the applicability of this ionization mode was further tested by analysis of aldehydes in cigarette smoke. This study provides a promising ionization method for greatly improving the current on-line detection sensitivity of volatile aldehydes.
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82
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Hong Z, Zhang H, Zhang Y, Xu L, Liu T, Xiao H, Hong Y, Chen J, Li M, Deng J, Wu X, Hu B, Chen X. Secondary organic aerosol of PM 2.5 in a mountainous forest area in southeastern China: Molecular compositions and tracers implication. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 653:496-503. [PMID: 30414579 DOI: 10.1016/j.scitotenv.2018.10.370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/27/2018] [Accepted: 10/27/2018] [Indexed: 06/09/2023]
Abstract
Secondary organic aerosol (SOA) plays an important role in global climate change and air quality. PM2.5 (particles with aerodynamic diameters ≤2.5 μm) samples were collected at a mountainous forest site (Mt. Wuyi) in southeastern China between November 2015 and July 2016. Fourteen PM2.5-bound SOA tracers, including isoprene, α/β‑pinene, β‑caryophyllene, and toluene, were measured using the gas-chromatography-mass-spectrometry method. The total concentrations of the isoprene, α/β‑pinene, β‑caryophyllene, and toluene SOA tracers were 45.28 ± 65.52, 30.66 ± 24.44, 5.99 ± 7.25, and 0.62 ± 0.72 ng m-3, respectively. The isoprene SOA tracers exhibited the highest concentration (145.97 ± 53.78 ng m-3) and accounted for 76 ± 9% of the total concentration of SOA tracers in summer. In fall-winter, the mass fraction of 2‑methylglyceric acid was significantly enhanced because of the lower temperature and higher NOx level. As later-generation products of α/β‑pinene tracers, high proportions of 3‑hydroxyglutaric acid and 3‑methyl‑1,2,3 butanetricarboxylic acid were observed on Mt. Wuyi, suggesting that the aerosols were highly oxidized. Biomass burning events affected by local and regional sources were identified by analyzing typical SOA tracers. Significant positive correlation (R2 = 0.74) was found between the β‑caryophyllene tracer and levoglucosan. The average concentration of secondary organic carbon (SOC) as estimated from SOA tracers was 1.46 μgC m-3. The isoprene SOC accounted for 70% of the total SOC in summer, whereas the β‑caryophyllene SOC was the predominant component in winter. Meanwhile, the estimated toluene SOC accounted for 11.6% of the total SOC during the study period. The study helps understanding the characteristics and the formation of SOA in a mountainous forest area of southeastern China.
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Affiliation(s)
- Zhenyu Hong
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100086, China
| | - Han Zhang
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Yanru Zhang
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100086, China
| | - Lingling Xu
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Taotao Liu
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100086, China
| | - Hang Xiao
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Youwei Hong
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Jinsheng Chen
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Mengren Li
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Junjun Deng
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Xin Wu
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100086, China
| | - Baoye Hu
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100086, China
| | - Xiaoqiu Chen
- Environmental Monitoring Center of Fujian, Fuzhou 350003, China
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83
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Khan MF, Hamid AH, Bari MA, Tajudin ABA, Latif MT, Nadzir MSM, Sahani M, Wahab MIA, Yusup Y, Maulud KNA, Yusoff MF, Amin N, Akhtaruzzaman M, Kindzierski W, Kumar P. Airborne particles in the city center of Kuala Lumpur: Origin, potential driving factors, and deposition flux in human respiratory airways. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 650:1195-1206. [PMID: 30308807 DOI: 10.1016/j.scitotenv.2018.09.072] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 08/21/2018] [Accepted: 09/05/2018] [Indexed: 05/28/2023]
Abstract
Equatorial warming conditions in urban areas can influence the particle number concentrations (PNCs), but studies assessing such factors are limited. The aim of this study was to evaluate the level of size-resolved PNCs, their potential deposition rate in the human respiratory system, and probable local and transboundary inputs of PNCs in Kuala Lumpur. Particle size distributions of a 0.34 to 9.02 μm optical-equivalent size range were monitored at a frequency of 60 s between December 2016 and January 2017 using an optical-based compact scanning mobility particle sizer (SMPS). Diurnal and correlation analysis showed that traffic emissions and meteorological confounding factors were potential driving factors for changes in the PNCs (Dp ≤1 μm) at the modeling site. Trajectory modeling showed that a PNC <100/cm3 was influenced mainly by Indo-China region air masses. On the other hand, a PNC >100/cm3 was influenced by air masses originating from the Indian Ocean and Indochina regions. Receptor models extracted five potential sources of PNCs: industrial emissions, transportation, aged traffic emissions, miscellaneous sources, and a source of secondary origin coupled with meteorological factors. A respiratory deposition model for male and female receptors predicted that the deposition flux of PM1 (particle mass ≤1 μm) into the alveolar (AL) region was higher (0.30 and 0.25 μg/h, respectively) than the upper airway (UA) (0.29 and 0.24 μg/h, respectively) and tracheobronchial (TB) regions (0.02 μg/h for each). However, the PM2.5 deposition flux was higher in the UA (2.02 and 1.68 μg/h, respectively) than in the TB (0.18 and 0.15 μg/h, respectively) and the AL regions (1.09 and 0.91 μg/h, respectively); a similar pattern was also observed for PM10.
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Affiliation(s)
- Md Firoz Khan
- Center for Tropical Climate Change System, Institute of Climate Change, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.
| | - Ahmad Hazuwan Hamid
- Center for Tropical Climate Change System, Institute of Climate Change, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Md Aynul Bari
- School of Public Health, University of Alberta, 3-57 South Academic Building, 11405-87 Avenue, Edmonton, Alberta T6G 1C9, Canada; Department of Environmental & Sustainable Engineering, College of Engineering and Applied Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Abdul Basit Ahmad Tajudin
- Environmental Health and Industrial Safety Program, Centre for Health and Applied Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50586 Kuala Lumpur, Malaysia
| | - Mohd Talib Latif
- School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 4300 Bangi, Selangor, Malaysia
| | - Mohd Shahrul Mohd Nadzir
- Center for Tropical Climate Change System, Institute of Climate Change, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia; School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 4300 Bangi, Selangor, Malaysia
| | - Mazrura Sahani
- Environmental Health and Industrial Safety Program, Centre for Health and Applied Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50586 Kuala Lumpur, Malaysia.
| | - Muhammad Ikram A Wahab
- Environmental Health and Industrial Safety Program, Centre for Health and Applied Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50586 Kuala Lumpur, Malaysia
| | - Yusri Yusup
- Environmental Technology, School of Industrial Technology, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia
| | - Khairul Nizam Abdul Maulud
- Earth Observation Center, Institute of Climate Change, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia; Smart & Sustainable Township Research Centre, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Mohd Famey Yusoff
- School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 4300 Bangi, Selangor, Malaysia
| | - Nowshad Amin
- Institute of Sustainable Energy, Universiti Tenaga Nasional (The National Energy University), Jalan IKRAM-UNITEN, 43000 Kajang, Selangor, Malaysia
| | - Md Akhtaruzzaman
- Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Warren Kindzierski
- School of Public Health, University of Alberta, 3-57 South Academic Building, 11405-87 Avenue, Edmonton, Alberta T6G 1C9, Canada
| | - Prashant Kumar
- Global Center for Clean Air Research (GCARE), Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, Surrey, United Kingdom
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84
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Freedman MA, Ott EJE, Marak KE. Role of pH in Aerosol Processes and Measurement Challenges. J Phys Chem A 2019; 123:1275-1284. [PMID: 30586311 DOI: 10.1021/acs.jpca.8b10676] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
pH is one of the most basic chemical properties of aqueous solution, but its measurement in nanoscale aerosol particles presents many challenges. The pH of aerosol particles is of growing interest in the atmospheric chemistry community because of its demonstrated effects on heterogeneous chemistry and human health, as well as potential effects on climate. The authors have shown that phase transitions of aerosol particles are sensitive to pH, focusing on systems that undergo liquid-liquid phase separation. Currently, aerosol pH is calculated indirectly from knowledge of species present in the gas and aerosol phases through the use of thermodynamic models. From these models, ambient aerosol is expected to be highly acidic (pH ∼ 0-3). Direct measurements have focused on model systems due to the difficulty of this measurement. This area is one in which physical chemists should be encouraged to contribute because of the potential consequences for aerosol processes in the environment.
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Affiliation(s)
- Miriam Arak Freedman
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Emily-Jean E Ott
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Katherine E Marak
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
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85
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Marrero-Ortiz W, Hu M, Du Z, Ji Y, Wang Y, Guo S, Lin Y, Gomez-Hermandez M, Peng J, Li Y, Secrest J, Zamora ML, Wang Y, An T, Zhang R. Formation and Optical Properties of Brown Carbon from Small α-Dicarbonyls and Amines. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:117-126. [PMID: 30499298 DOI: 10.1021/acs.est.8b03995] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Brown Carbon (BrC) aerosols scatter and absorb solar radiation, directly affecting the Earth's radiative budget. However, considerable uncertainty exists concerning the chemical mechanism leading to BrC formation and their optical properties. In this work, BrC particles were prepared from mixtures of small α-dicarbonyls (glyoxal and methylglyoxal) and amines (methylamine, dimethylamine, and trimethylamine). The absorption and scattering of BrC particles were measured using a photoacoustic extinctometer (405 and 532 nm), and the chemical composition of the α-dicarbonyl-amine mixtures was analyzed using orbitrap-mass spectrometry and thermal desorption-ion drift-chemical ionization mass spectrometry. The single scattering albedo for methylglyoxal-amine mixtures is smaller than that of glyoxal-amine mixtures and increases with the methyl substitution of amines. The mass absorption cross-section for methylglyoxal-amine mixtures is two times higher at 405 nm wavelength than that at 532 nm wavelength. The derived refractive indexes at the 405 nm wavelength are 1.40-1.64 for the real part and 0.002-0.195 for the imaginary part. Composition analysis in the α-dicarbonyl-amine mixtures reveals N-heterocycles as the dominant products, which are formed via multiple steps involving nucleophilic attack, steric hindrance, and dipole-dipole interaction between α-dicarbonyls and amines. BrC aerosols, if formed from the particle-phase reaction of methylglyoxal with methylamine, likely contribute to atmospheric warming.
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Affiliation(s)
- Wilmarie Marrero-Ortiz
- Department of Chemistry , Texas A&M University , College Station , Texas 77840 , United States
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
| | - Zhuofei Du
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
| | - Yuemeng Ji
- Center for Urban Transport Emission Research & State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering , Nankai University , Tianjin , 300071 , China
- Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control , Guangdong University of Technology , Guangzhou 510006 , China
| | - Yujue Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
| | - Song Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
| | - Yun Lin
- Department of Atmospheric Sciences , Texas A&M University , College Station , Texas 77843 , United States
| | - Mario Gomez-Hermandez
- Department of Chemistry , Texas A&M University , College Station , Texas 77840 , United States
- Department of Chemistry and Biochemistry , Florida International University , Miami , Florida 33199 , United States
| | - Jianfei Peng
- Department of Atmospheric Sciences , Texas A&M University , College Station , Texas 77843 , United States
| | - Yixin Li
- Department of Chemistry , Texas A&M University , College Station , Texas 77840 , United States
| | - Jeremiah Secrest
- Department of Chemistry , Texas A&M University , College Station , Texas 77840 , United States
| | - Misti L Zamora
- Department of Atmospheric Sciences , Texas A&M University , College Station , Texas 77843 , United States
- Environmental Health & Engineering, Johns Hopkins School of Public Health , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Yuan Wang
- Division of Geological and Planetary Sciences , California Institute of Technology , Pasadena , California 91125 , United States
| | - Taicheng An
- Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control , Guangdong University of Technology , Guangzhou 510006 , China
| | - Renyi Zhang
- Department of Chemistry , Texas A&M University , College Station , Texas 77840 , United States
- Department of Atmospheric Sciences , Texas A&M University , College Station , Texas 77843 , United States
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86
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Wu P, Huang X, Zhang J, Luo B, Luo J, Song H, Zhang W, Rao Z, Feng Y, Zhang J. Characteristics and formation mechanisms of autumn haze pollution in Chengdu based on high time-resolved water-soluble ion analysis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:2649-2661. [PMID: 30478772 DOI: 10.1007/s11356-018-3630-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/29/2018] [Indexed: 06/09/2023]
Abstract
To investigate the characteristics and formation mechanisms of haze pollution in the autumn season in the Sichuan Basin, hourly concentrations of water-soluble inorganic ions in PM2.5 (Na+, K +, NH4+, Mg2+, Ca2+, Cl-, NO3-, and SO42-) and major gaseous precursors (HCl, NH3, SO2, HONO, and HNO3) were measured by a gas and aerosol collector combined with ion chromatography (GAC-IC) from September to November 2017 at an urban site in Chengdu. The average mass concentration of total water-soluble ions was 36.9 ± 29.4 μg m-3, accounting for 62.8% of PM2.5 mass. Nitrate was the most abundant ion, comprising 41.2% of the total ions, followed by sulfate (27.1%) and ammonium (18.1%), indicating the important contribution of motor vehicle emissions to PM2.5 in Chengdu. Secondary formation of inorganic ions and biomass burning emissions played a vital role in the haze pollution processes. The formation of nitrate aerosol was particularly dominant and exhibited the most substantial increase during haze processes. It was likely to be produced primarily through homogeneous reactions, whereas heterogeneous reactions dominated sulfate formation. Additionally, distinct differences in diurnal patterns of secondary inorganic ions between clean days and polluted days were observed, reflecting different formation characteristics under polluted conditions. Due to a large increase of acidic aerosols, most particles collected on polluted days were acidic, and ammonium in most samples existed mainly as NH4HSO4 and NH4NO3. Furthermore, backward-trajectory cluster analysis revealed that air masses originating from the northeast of Chengdu prevailed in the autumn season, and haze pollution was dominated mainly by short-distance transport within the Sichuan Basin.
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Affiliation(s)
- Pan Wu
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China
| | - Xiaojuan Huang
- Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, 610225, China
| | - Junke Zhang
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China.
| | - Bin Luo
- Sichuan Environmental Monitoring Center, Chengdu, 610074, China
| | - Jinqi Luo
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China
| | - Hongyi Song
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China
| | - Wei Zhang
- Sichuan Environmental Monitoring Center, Chengdu, 610074, China
| | - Zhihan Rao
- Sichuan Environmental Monitoring Center, Chengdu, 610074, China
| | - Yanpeng Feng
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China
| | - Jianqiang Zhang
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China
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87
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Ma X, Sun Y, Huang Z, Zhang Q, Wang W. A density functional theory study of the molecular interactions between a series of amides and sulfuric acid. CHEMOSPHERE 2019; 214:781-790. [PMID: 30296766 DOI: 10.1016/j.chemosphere.2018.08.152] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/27/2018] [Accepted: 08/29/2018] [Indexed: 06/08/2023]
Abstract
Amides, a class of nitrogen-containing organic pollutants in the atmosphere, may affect the formation of atmospheric aerosols by the interactions with sulfuric acid. Here, the molecular interactions of sulfuric acid with formamide, methylformamide, dimethylformamide, acetamide, methylacetamide and dimethylacetamide was investigated by density functional theory. Geometry optimization and Gibbs free energy calculation were carried out at M06-2X/6-311++G(3df,3pd) level. The results indicate that the addition of amides to H2SO4 might have a promoting effect on atmospheric new particle formation at 298.15 K and 1 atm. In the initial stage of new particle formation, the binding capacity of amides and sulfuric acid is stronger than ammonia, but weaker than methylamine. It is worth noting that the trans-methylacetamide could have similar capabilities of stabilizing sulfuric acid as dimethylamine. In the presence of water, amides are found to only have a weak enhancement capability on new particle formation. In addition, we can infer from evaporation rate that the small molecule clusters of formamide and sulfuric acid may be more energetically favorable than macromolecule clusters.
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Affiliation(s)
- Xiaohui Ma
- Environment Research Institute, Shandong University, Jinan 250100, PR China
| | - Yanhui Sun
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Zixiao Huang
- Environment Research Institute, Shandong University, Jinan 250100, PR China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Jinan 250100, PR China.
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Jinan 250100, PR China
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88
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Nestorowicz K, Jaoui M, Rudzinski KJ, Lewandowski M, Kleindienst TE, Spólnik G, Danikiewicz W, Szmigielski R. Chemical composition of isoprene SOA under acidic and non-acidic conditions: effect of relative humidity. ATMOSPHERIC CHEMISTRY AND PHYSICS 2018; 18:18101-18121. [PMID: 32158471 PMCID: PMC7063744 DOI: 10.5194/acp-18-18101-2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The effect of acidity and relative humidity on bulk isoprene aerosol parameters has been investigated in several studies; however, few measurements have been conducted on individual aerosol compounds. The focus of this study has been the examination of the effect of acidity and relative humidity on secondary organic aerosol (SOA) chemical composition from isoprene photooxidation in the presence of nitrogen oxide (NO x ). A detailed characterization of SOA at the molecular level was also investigated. Experiments were conducted in a 14.5 m3 smog chamber operated in flow mode. Based on a detailed analysis of mass spectra obtained from gas chromatography-mass spectrometry of silylated derivatives in electron impact and chemical ionization modes, ultra-high performance liquid chromatography/electrospray ionization/time-of-flight high-resolution mass spectrometry, and collision-induced dissociation in the negative ionization modes, we characterized not only typical isoprene products but also new oxygenated compounds. A series of nitroxy-organosulfates (NOSs) were tentatively identified on the basis of high-resolution mass spectra. Under acidic conditions, the major identified compounds include 2-methyltetrols (2MT), 2-methylglyceric acid (2mGA), and 2MT-OS. Other products identified include epoxydiols, mono- and dicarboxylic acids, other organic sulfates, and nitroxy- and nitrosoxy-OS. The contribution of SOA products from isoprene oxidation to PM2.5 was investigated by analyzing ambient aerosol collected at rural sites in Poland. Methyltetrols, 2mGA, and several organosulfates and nitroxy-OS were detected in both the field and laboratory samples. The influence of relative humidity on SOA formation was modest in non-acidic-seed experiments and stronger under acidic seed aerosol. Total secondary organic carbon decreased with increasing relative humidity under both acidic and non-acidic conditions. While the yields of some of the specific organic compounds decreased with increasing relative humidity, others varied in an indeterminate manner from changes in the relative humidity.
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Affiliation(s)
- Klara Nestorowicz
- Environmental Chemistry Group, Institute of Physical Chemistry Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Mohammed Jaoui
- US Environmental Protection Agency, 109 T.W. Alexander Drive, RTP, NC 27711, USA
| | - Krzysztof Jan Rudzinski
- Environmental Chemistry Group, Institute of Physical Chemistry Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Michael Lewandowski
- US Environmental Protection Agency, 109 T.W. Alexander Drive, RTP, NC 27711, USA
| | | | - Grzegorz Spólnik
- Mass Spectrometry Group, Institute of Organic Chemistry, Polish Academy of Science, 01-224 Warsaw, Poland
| | - Witold Danikiewicz
- Mass Spectrometry Group, Institute of Organic Chemistry, Polish Academy of Science, 01-224 Warsaw, Poland
| | - Rafal Szmigielski
- Environmental Chemistry Group, Institute of Physical Chemistry Polish Academy of Sciences, 01-224 Warsaw, Poland
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89
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Ren Y, Grosselin B, Daële V, Mellouki A. Investigation of the reaction of ozone with isoprene, methacrolein and methyl vinyl ketone using the HELIOS chamber. Faraday Discuss 2018; 200:289-311. [PMID: 28581006 DOI: 10.1039/c7fd00014f] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The rate constants for the ozonolysis of isoprene (ISO), methacrolein (MACR) and methyl vinyl ketone (MVK) have been measured using the newly built large volume atmospheric simulation chamber at CNRS-Orleans (France), HELIOS (Chambre de simulation atmosphérique à irradiation naturelle d'Orléans). The OH radical yields from the ozonolysis of isoprene, MACR and MVK have also been determined, as well as the gas phase stable products and their yields. The secondary organic aerosol yield for the ozonolysis of isoprene has been tentatively measured in the presence and absence of an OH radical scavenger. The measurements were performed under different experimental conditions with and without adding cyclohexane (cHX) as an OH radical scavenger. All experiments have been conducted at 760 torr of purified dry air (RH < 1%) and ambient temperature (T = 281-295 K). The data obtained are discussed and compared with those from the literature. The use of the HELIOS facility and its associated analytical equipment enables the derivation of kinetic parameters as well as mechanistic information under near realistic atmospheric conditions.
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Affiliation(s)
- Yangang Ren
- Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), CNRS (UPR 3021), 1C Avenue de la Recherche Scientifique, 45071 Orléans Cedex 2, France.
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90
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Zhang J, Tong L, Huang Z, Zhang H, He M, Dai X, Zheng J, Xiao H. Seasonal variation and size distributions of water-soluble inorganic ions and carbonaceous aerosols at a coastal site in Ningbo, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 639:793-803. [PMID: 29803050 DOI: 10.1016/j.scitotenv.2018.05.183] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 05/13/2018] [Accepted: 05/15/2018] [Indexed: 06/08/2023]
Abstract
Size-fractioned aerosol samples were collected by an eight-stage Anderson sampler for four seasons from November 2014 to August 2015 at a coastal and suburban site in Ningbo, China, with a total of 270 samples were obtained. The seasonal variations and size distributions of water-soluble inorganic ions (WSIIs), carbonaceous aerosols (OC and EC), which consist of four organic carbon (OC1-OC4), pyrolyzed carbon (OP) and three elemental carbon fraction (EC1-EC3), were investigated. For the sampling periods, the average total concentration of WSIIs, OC and EC in PM1.1, PM1.1-2.1 and PM2.1-9.0 were 21.3 ± 7 μg/m3, 6.7 ± 2.7 μg/m3 and 12.8 ± 1.9 μg/m3, constituting 75.5%, 62.7% and 43.2% of the different size particle mass, respectively. The predominant chemical species were SO42-, NO3-, and OC. WSIIs, OC and EC all exhibited significant difference between PM2.1 and PM2.1-9.0, reflecting their different sources. Ion balance calculations showed that the acidity of aerosols increased with a decrease in size, with the maximum of 1.07 in 1.1-2.1 μm and the minimum of 0.47 in 2.1-9 μm. It showed that size distributions of high-temperature carbon fraction such as OC4, OP and EC1 were almost unimodal during all seasons as well as SO42- and NH4+, in contrast, that of lower temperature carbon fraction (OC1-OC3), Mg2+, and Ca2+ appear like bimodal. Furthermore, the high consistency between the size distribution of OC4, OP and SO42-, NH4+ in all seasons suggests that the similar or related generation process for the secondary organic and inorganic/ionic species, which contribute the most significant component of the particulate matter. Besides the secondary aerosols, primary carbonaceous aerosols (PC), which may originate in emissions from mixed combustion or natural source, also contributed a significant fraction of haze pollution, especially in autumn, spring and summer.
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Affiliation(s)
- Jingjing Zhang
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lei Tong
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Zhongwen Huang
- School of Chemistry and Environmental Engineering, Hanshan Normal University, Chaozhou 521041, China
| | - Huiling Zhang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mengmeng He
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Xiaorong Dai
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Jie Zheng
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Hang Xiao
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
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91
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Shen H, Chen Z, Li H, Qian X, Qin X, Shi W. Gas-Particle Partitioning of Carbonyl Compounds in the Ambient Atmosphere. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10997-11006. [PMID: 30153412 DOI: 10.1021/acs.est.8b01882] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite their crucial roles in health and climate concerns, the gas-particle partitioning of carbonyl compounds is poorly characterized in the ambient atmosphere. In this study, we investigate their partitioning by simultaneously measuring six carbonyl compounds (formaldehyde, acetaldehyde, acetone, propionaldehyde, glyoxal, and methylglyoxal) in the gas and particle phase at an urban site in Beijing. The field-derived partitioning coefficients ( Kpf) are in the range of 10-5-10-3 m3 μg-1, and the corresponding effective Henry's law coefficients ( KHf) should be 107-109 M atm-1. The Pankow's absorptive partitioning theory and Henry's law both significantly underestimate concentrations of particle-phase carbonyl compounds (105-106 times and >103 times, respectively). The observed "salting-in" effects only partially explain the enhanced partitioning to particles, which is approximately 1 order of magnitude. The measured Kpf values are higher at low relative humidity, and the overall effective vapor pressure of these carbonyl species are lower than their hydrates, indicating that carbonyl oligomers potentially formed in highly concentrated particle phase. The reaction kinetics of oligomer formation should be included if applying Henry's law to low-to-moderate relative humidity, and the high partitioning coefficients observed need to be proved by further field and laboratory studies. These findings provide deeper insights into the formation of carbonyl secondary organic aerosols in the ambient atmosphere.
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Affiliation(s)
- Hengqing Shen
- 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
| | - Huan Li
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
| | - Xi Qian
- 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
| | - Wenxiao Shi
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering , Peking University , Beijing 100871 , China
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92
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Zhang C, Lu X, Zhai J, Chen H, Yang X, Zhang Q, Zhao Q, Fu Q, Sha F, Jin J. Insights into the formation of secondary organic carbon in the summertime in urban Shanghai. J Environ Sci (China) 2018; 72:118-132. [PMID: 30244738 DOI: 10.1016/j.jes.2017.12.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/14/2017] [Accepted: 12/20/2017] [Indexed: 06/08/2023]
Abstract
To investigate formation mechanisms of secondary organic carbon (SOC) in Eastern China, measurements were conducted in an urban site in Shanghai in the summer of 2015. A period of high O3 concentrations (daily peak > 120 ppb) was observed, during which daily maximum SOC concentrations exceeding 9.0 μg/(C·m3). Diurnal variations of SOC concentration and SOC/organic carbon (OC) ratio exhibited both daytime and nighttime peaks. The SOC concentrations correlated well with Ox (= O3 + NO2) and relative humidity in the daytime and nighttime, respectively, suggesting that secondary organic aerosol formation in Shanghai is driven by both photochemical production and aqueous phase reactions. Single particle mass spectrometry was used to examine the formation pathways of SOC. Along with the daytime increase of SOC, the number fraction of elemental carbon (EC) particles coated with OC quickly increased from 38.1% to 61.9% in the size range of 250-2000 nm, which was likely due to gas-to-particle partitioning of photochemically generated semi-volatile organic compounds onto EC particles. In the nighttime, particles rich in OC components were highly hygroscopic, and number fraction of these particles correlated well with relative humidity and SOC/OC nocturnal peaks. Meanwhile, as an aqueous-phase SOC tracer, particles that contained oxalate-Fe(III) complex also peaked at night. These observations suggested that aqueous-phase processes had an important contribution to the SOC nighttime formation. The influence of aerosol acidity on SOC formation was studied by both bulk and single particle level measurements, suggesting that the aqueous-phase formation of SOC was enhanced by particle acidity.
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Affiliation(s)
- Ci Zhang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Xiaohui Lu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Jinghao Zhai
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Hong Chen
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Xin Yang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Qi Zhang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Department of Environmental Toxicology, University of California, Davis, CA 95616, United States
| | - Qianbiao Zhao
- Shanghai Environmental Monitoring Center, Shanghai 200235, China
| | - Qingyan Fu
- Shanghai Environmental Monitoring Center, Shanghai 200235, China
| | - Fei Sha
- Environment Management Bureau of Shanghai Pudong New Area, Shanghai 200125, China
| | - Jing Jin
- Environment Management Bureau of Shanghai Pudong New Area, Shanghai 200125, China
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93
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Shen R, Liu Z, Liu Y, Wang L, Li D, Wang Y, Wang G, Bai Y, Li X. Typical polar organic aerosol tracers in PM 2.5 over the North China Plain: Spatial distribution, seasonal variations, contribution and sources. CHEMOSPHERE 2018; 209:758-766. [PMID: 29960943 DOI: 10.1016/j.chemosphere.2018.06.133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 06/11/2018] [Accepted: 06/19/2018] [Indexed: 05/26/2023]
Abstract
PM2.5 samples were collected simultaneously at three urban sites including Beijing (BJ), Tianjin (TJ), Shijiazhuang (SJZ) and one background site Xinglong (XL) from June 2014 till April 2015. Typical polar organic aerosol tracers including 2-methylglyceric acid, 2-methyltetrols, 3-hydroxyglutaric acid, anhydrous saccharides and phthalic acid were analyzed by gas chromatography-mass spectrometry. Both Isoprene secondary organic aerosol (SOA) tracers and pinene SOA tracers had higher mass concentrations at background site than those at urban sites. But they showed different seasonal variations. The former had the highest mass concentration in summer while the latter had the highest mass concentration in spring. Anhydrous saccharides and phthalic acids at urban sites had higher mass concentrations than those at background site and showed higher mass concentration in autumn and winter, respectively. Corresponding estimated secondary organic carbons (SOCs) showed similar variation trends with tracers. In general, biogenic sources had more influence on background site while urban sites were more affected by anthropogenic sources.
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Affiliation(s)
- Rongrong Shen
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Zirui Liu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Yusi Liu
- Department of Chemistry, Analytical and Testing Center, Capital Normal University, Beijing 100048, China
| | - Lili Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Dong Li
- Department of Chemistry, Analytical and Testing Center, Capital Normal University, Beijing 100048, China
| | - Yuesi Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Science, Xiamen 361021, China; University of Chinese Academy of Science, Beijing 100049, China.
| | - Guo'an Wang
- Department of Chemistry, Analytical and Testing Center, Capital Normal University, Beijing 100048, China
| | - Yu Bai
- Department of Chemistry, Analytical and Testing Center, Capital Normal University, Beijing 100048, China
| | - Xingru Li
- Department of Chemistry, Analytical and Testing Center, Capital Normal University, Beijing 100048, China.
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94
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Werner J, Persson I, Björneholm O, Kawecki D, Saak CM, Walz MM, Ekholm V, Unger I, Valtl C, Caleman C, Öhrwall G, Prisle NL. Shifted equilibria of organic acids and bases in the aqueous surface region. Phys Chem Chem Phys 2018; 20:23281-23293. [PMID: 30191936 PMCID: PMC6146375 DOI: 10.1039/c8cp01898g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acid-base equilibria of carboxylic acids and alkyl amines in the aqueous surface region were studied using surface-sensitive X-ray photoelectron spectroscopy and molecular dynamics simulations. Solutions of these organic compounds were examined as a function of pH, concentration and chain length to investigate the distribution of acid and base form in the surface region as compared to the aqueous bulk. Results from these experiments show that the neutral forms of the studied acid-base pairs are strongly enriched in the aqueous surface region. Moreover, we show that for species with at least four carbon atoms in their alkyl-chain, their charged forms are also found to be abundant in the surface region. Using a combination of XPS and MD results, a model is proposed that effectively describes the surface composition. Resulting absolute surface concentration estimations show clearly that the total organic mole fractions in the surface region change drastically as a function of solution pH. The origin of the observed surface phenomena, hydronium/hydroxide concentrations in the aqueous surface region and why standard chemical equations, used to describe equilibria in dilute bulk solution are not valid in the aqueous surface region, are discussed in detail. The reported results are of considerable importance especially for the detailed understanding of properties of small aqueous droplets that can be found in the atmosphere.
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Affiliation(s)
- Josephina Werner
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.
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95
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Craig RL, Peterson PK, Nandy L, Lei Z, Hossain MA, Camarena S, Dodson RA, Cook RD, Dutcher CS, Ault AP. Direct Determination of Aerosol pH: Size-Resolved Measurements of Submicrometer and Supermicrometer Aqueous Particles. Anal Chem 2018; 90:11232-11239. [DOI: 10.1021/acs.analchem.8b00586] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
| | | | - Lucy Nandy
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | | | | | | | | | | | - Cari S. Dutcher
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
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96
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Wu C, Wang G, Wang J, Li J, Ren Y, Zhang L, Cao C, Li J, Ge S, Xie Y, Wang X, Xue G. Chemical characteristics of haze particles in Xi'an during Chinese Spring Festival: Impact of fireworks burning. J Environ Sci (China) 2018; 71:179-187. [PMID: 30195676 DOI: 10.1016/j.jes.2018.04.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 04/07/2018] [Accepted: 04/09/2018] [Indexed: 06/08/2023]
Abstract
Fireworks burning releases massive fine particles and gaseous pollutants, significantly deteriorating air quality during Chinese Lunar New Year (LNY) period. To investigate the impact of the fireworks burning on the atmospheric aerosol chemistry, 1-hr time resolution of PM2.5 samples in Xi'an during the winter of 2016 including the LNY were collected and detected for inorganic ions, acidity and liquid water content (LWC) of the fine aerosols. PM2.5 during the LNY was 167±87μg/m3, two times higher than the China National Ambient Air Quality Standard (75μg/m3). K+ (28wt.% of the total ion mass) was the most abundant ion in the LNY period, followed by SO42- (25wt.%) and Cl- (18wt.%). In contrast, NO3- (34wt.%) was the most abundant species in the haze periods (hourly PM2.5>75μg/m3), followed by SO42- (29.2wt.%) and NH4+ (16.3wt.%), while SO42 - (35wt.%) was the most abundant species in the clean periods (hourly PM2.5<75μg/m3), followed by NO3- (23.1wt.%) and NH4+ (11wt.%). Being different from the acidic nature in the non-LNY periods, aerosol in the LNY period presented an alkaline nature with a pH value of 7.8±1.3. LWC during the LNY period showed a robust linear correlation with K2SO4 and KCl, suggesting that aerosol hygroscopicity was dominated by inorganic salts derived from fireworks burning. Analysis of correlations between the ratios of NO3-/SO42- and NH4+/SO42- indicated that heterogeneous reaction of HNO3 with NH3 was an important formation pathway of particulate nitrate and ammonium during the LNY period.
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Affiliation(s)
- Can Wu
- State Key Laboratory of Loess and Quaternary Geology, Key Lab of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Gehui Wang
- State Key Laboratory of Loess and Quaternary Geology, Key Lab of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 210062, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Jiayuan Wang
- State Key Laboratory of Loess and Quaternary Geology, Key Lab of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Jianjun Li
- State Key Laboratory of Loess and Quaternary Geology, Key Lab of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Yanqin Ren
- State Key Laboratory of Loess and Quaternary Geology, Key Lab of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Lu Zhang
- State Key Laboratory of Loess and Quaternary Geology, Key Lab of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Cong Cao
- State Key Laboratory of Loess and Quaternary Geology, Key Lab of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin Li
- State Key Laboratory of Loess and Quaternary Geology, Key Lab of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuagshuang Ge
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 210062, China
| | - Yuning Xie
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 210062, China
| | - Xinpei Wang
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 210062, China
| | - Guoyan Xue
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 210062, China
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97
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Lovett C, Baasiri M, Atwi K, Sowlat MH, Shirmohammadi F, Shihadeh AL, Sioutas C. Comparison of the oxidative potential of primary (POA) and secondary (SOA) organic aerosols derived from α-pinene and gasoline engine exhaust precursors. F1000Res 2018; 7:1031. [PMID: 30828421 PMCID: PMC6392154 DOI: 10.12688/f1000research.15445.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/08/2019] [Indexed: 12/02/2022] Open
Abstract
Background: Primary (POA) and secondary (SOA) organic aerosols, deriving from both anthropogenic and biogenic sources, represent a major fraction of ambient particulate matter (PM) and play an important role in the etiology of respiratory and cardiovascular diseases, largely through systemic inflammation and cellular oxidative stress. The relative contributions of these species to the inhalation burden, however, are rather poorly characterized. In this study, we measured the in vitro oxidative stress response of alveolar macrophages exposed to primary and secondary PM derived from both anthropogenic and biogenic sources. Methods: POA and SOA were generated within an oxidation flow reactor (OFR) fed by pure, aerosolized α-pinene or gasoline engine exhaust, as representative emissions of biogenic and anthropogenic sources, respectively. The OFR utilized an ultraviolet (UV) lamp to achieve an equivalent atmospheric aging process of several days. Results: Anthropogenic SOA produced the greatest oxidative response (1900 ± 255 µg-Zymosan/mg-PM), followed by biogenic (α-pinene) SOA (1321 ± 542 µg-Zymosan/mg-PM), while anthropogenic POA produced the smallest response (51.4 ± 64.3 µg-Zymosan/mg-PM). Conclusions: These findings emphasize the importance of monitoring and controlling anthropogenic emissions in the urban atmosphere, while also taking into consideration spatial and seasonal differences in SOA composition. Local concentrations of biogenic and anthropogenic species contributing to the oxidative potential of ambient PM may vary widely, depending on the given region and time of year, due to factors such as surrounding vegetation, proximity to urban areas, and hours of daylight.
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Affiliation(s)
- Christopher Lovett
- Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Mohamad Baasiri
- Department of Mechanical Engineering, American University of Beirut, Riad El Solh, Beirut, 1107 2020, Lebanon
| | - Khairallah Atwi
- Department of Mechanical Engineering, American University of Beirut, Riad El Solh, Beirut, 1107 2020, Lebanon
| | - Mohammad H. Sowlat
- Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Farimah Shirmohammadi
- Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Alan L. Shihadeh
- Department of Mechanical Engineering, American University of Beirut, Riad El Solh, Beirut, 1107 2020, Lebanon
| | - Constantinos Sioutas
- Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, 90089, USA
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98
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Jia S, Sarkar S, Zhang Q, Wang X, Wu L, Chen W, Huang M, Zhou S, Zhang J, Yuan L, Yang L. Characterization of diurnal variations of PM 2.5 acidity using an open thermodynamic system: A case study of Guangzhou, China. CHEMOSPHERE 2018; 202:677-685. [PMID: 29602100 DOI: 10.1016/j.chemosphere.2018.03.127] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 03/16/2018] [Accepted: 03/19/2018] [Indexed: 06/08/2023]
Abstract
Aerosol acidity has significant implications for atmospheric processing, and high time-resolution measurements can provide critical insights into those processes. This paper reports diurnal variations of aerosol acidity characterized using an open thermodynamic system in Guangzhou, China. Hourly measurements of PM2.5-associated ionic species and related parameters were carried out during June-September 2013 followed by application of the Extended Aerosol Inorganic Model in open mode to estimate aerosol pH. The model-estimated aerosol pH was 2.4 ± 0.3, and the pH diurnal profile exhibited peaks in the early morning (6 a.m.) and troughs in the afternoon (2 p.m.) that appeared to be constrained by liquid water content (LWC) and free H+. A linear regression model was developed to predict aerosol pH, which performed strongly with 4 variables during daytime (NH4+, Na+, SO42- and RH; R2 = 0.95) and 3 during nighttime (NH4+, SO42- and RH; R2 = 0.91). The effect of aerosol acidity on the partitioning of HNO3, HCl and NH3 was studied based on theoretical considerations and measurement data. The fractions in particulate phase for acidic compounds correlated strongly with pH (R2 = 0.64-0.69) while that for NH3, interestingly, was weak (R2 = 0.17). Analytical expressions were developed to explain these observations and it was concluded that the partitioning of HCl and HNO3 was more sensitive to pH compared to that of NH3. These results are significant in terms of potential atmospheric depletion rates of HCl and HNO3 in the region and stress the need for future studies in this direction.
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Affiliation(s)
- Shiguo Jia
- School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China; Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Sayantan Sarkar
- Department of Earth Sciences, and Centre for Climate and Environmental Studies, Indian Institute of Science Education and Research, Kolkata, Nadia 741246, West Bengal, India
| | - Qi Zhang
- School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China
| | - Xuemei Wang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 510632, PR China.
| | - Luolin Wu
- School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China
| | - Weihua Chen
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, PR China
| | - Minjuan Huang
- School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China; Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Shengzhen Zhou
- School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China; Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Jinpu Zhang
- Guangzhou Environmental Monitoring Center, Guangzhou, 510030, PR China
| | - Luan Yuan
- Guangdong Environmental Monitoring Center, Guangzhou 510308, PR China
| | - Liming Yang
- Department of Chemical and Bimolecular Engineering, National University of Singapore, 117576, Singapore.
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99
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Gordon BP, Moore FG, Scatena LF, Valley NA, Wren SN, Richmond GL. Model Behavior: Characterization of Hydroxyacetone at the Air-Water Interface Using Experimental and Computational Vibrational Sum Frequency Spectroscopy. J Phys Chem A 2018; 122:3837-3849. [PMID: 29608301 DOI: 10.1021/acs.jpca.8b01193] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Small atmospheric aldehydes and ketones are known to play a significant role in the formation of secondary organic aerosols (SOA). However, many of them are difficult to experimentally isolate, as they tend to form hydration and oligomer species. Hydroxyacetone (HA) is unusual in this class as it contributes to SOA while existing predominantly in its unhydrated monomeric form. This allows HA to serve as a valuable model system for similar secondary organic carbonyls. In this paper the surface behavior of HA at the air-water interface has been investigated using vibrational sum frequency (VSF) spectroscopy and Wilhelmy plate surface tensiometry in combination with computational molecular dynamics simulations and density functional theory calculations. The experimental results demonstrate that HA has a high degree of surface activity and is ordered at the interface. Furthermore, oriented water is observed at the interface, even at high HA concentrations. Spectral features also reveal the presence of both cis and trans HA conformers at the interface, in differing orientations. Molecular dynamics results indicate conformer dependent shifts in HA orientation between the subsurface (∼5 Å deep) and surface. Together, these results provide a picture of a highly dynamic, but statistically ordered, interface composed of multiple HA conformers with solvated water. These results have implications for HA's behavior in aqueous particles, which may affect its role in the atmosphere and SOA formation.
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Affiliation(s)
- Brittany P Gordon
- Department of Chemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
| | - Frederick G Moore
- Department of Physics , Whitman College , Walla Walla , Washington 99362 , United States
| | - Lawrence F Scatena
- Department of Chemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
| | - Nicholas A Valley
- Department of Chemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States.,Department of Science and Mathematics , California Northstate University College of Health Sciences , Rancho Cordova , California 95670 , United States
| | - Sumi N Wren
- Department of Chemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States.,Department of Air Quality Process Research , Environment and Climate Change Canada (ECCC) , Toronto , Ontario M3H 5T4 , Canada
| | - Geraldine L Richmond
- Department of Chemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
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100
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Tan T, Hu M, Li M, Guo Q, Wu Y, Fang X, Gu F, Wang Y, Wu Z. New insight into PM 2.5 pollution patterns in Beijing based on one-year measurement of chemical compositions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 621:734-743. [PMID: 29197792 DOI: 10.1016/j.scitotenv.2017.11.208] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/16/2017] [Accepted: 11/18/2017] [Indexed: 06/07/2023]
Abstract
In recent years, air pollution has become a major concern in China, especially in the capital city of Beijing. Haze events occur in Beijing over all four seasons, exhibiting distinct characteristics. In this study, the typical evolution patterns of atmospheric particulate matter with a diameter of less than 2.5μm (PM2.5) in each season were illustrated by episode-based analysis. In addition, a novel method was developed to elucidate the driving species of pollution, which is the largest contributor to the incremental PM2.5 (ΔPM2.5), not PM2.5. This method revealed a temporal variation of the driving species throughout the year: nitrate-driven spring, sulfate-driven summer, nitrate-driven early fall, and organic matters (OM)-driven late fall and winter. These results suggested that primary organic particles or volatile organic compounds emissions were dominant in the heating season due to residential heating, while NOx and SO2 emissions dominated in the other seasons. Besides, nitrate formation seemed more significant than sulfate formation during severe pollution episodes. It was also found that the pollution formation mechanism in the winter showed some unique features in comparison with the other seasons: aqueous reactions were more important in the winter, while multiple pathways coexisted in the other seasons. Furthermore, this study confirmed that the PM2.5 in Beijing was moderately acidic despite a fully neutralized system. In addition, the acidity variation during pollution episodes displayed different patterns between seasons and was driven by both the variation of aerosol water and chemical compositions. These results provide a new perspective to understand the characteristics and mechanisms of aerosol pollution in Beijing. However, more accurate measurements are necessary for effective air pollution control that depends on the seasonal variation of fine particle formation in Beijing and the surrounding areas.
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Affiliation(s)
- Tianyi Tan
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China; Beijing Innovation Center for Engineering Sciences and Advanced Technology, Peking University, Beijing, China.
| | - Mengren Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Qingfeng Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Yusheng Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Xin Fang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Fangting Gu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Yu Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Zhijun Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
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