scholarly journals Chemical composition, optical properties, and oxidative potential of water- and methanol-soluble organic compounds emitted from the combustion of biomass materials and coal

2021 ◽  
Vol 21 (17) ◽  
pp. 13187-13205
Author(s):  
Tao Cao ◽  
Meiju Li ◽  
Chunlin Zou ◽  
Xingjun Fan ◽  
Jianzhong Song ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Organic Compounds ◽  
1H Nmr ◽  
Water Soluble ◽  
Proton Nuclear Magnetic Resonance ◽  
Oxidative Potential ◽  
Strong Light ◽  
Soluble Organic Carbon ◽  
Biomass Materials

Abstract. Biomass burning (BB) and coal combustion (CC) are important sources of brown carbon (BrC) in ambient aerosols. In this study, six biomass materials and five types of coal were combusted to generate fine smoke particles. The BrC fractions, including water-soluble organic carbon (WSOC), humic-like substance carbon (HULIS-C), and methanol-soluble organic carbon (MSOC), were subsequently fractionated, and their optical properties and chemical structures were then comprehensively investigated using UV–visible spectroscopy, proton nuclear magnetic resonance spectroscopy (1H NMR), and fluorescence excitation–emission matrix (EEM) spectroscopy combined with parallel factor (PARAFAC) analysis. In addition, the oxidative potential (OP) of BB and CC BrC was measured with the dithiothreitol (DTT) method. The results showed that WSOC, HULIS-C, and MSOC accounted for 2.3 %–22 %, 0.5 %–10 %, and 6.4 %–73 % of the total mass of combustion-derived smoke PM2.5, respectively, with MSOC extracting the highest concentrations of organic compounds. The MSOC fractions had the highest light absorption capacity (mass absorption efficiency at 365 nm (MAE365): 1.0–2.7 m2/gC) for both BB and CC smoke, indicating that MSOC contained more of the strong light-absorbing components. Therefore, MSOC may represent the total BrC better than the water-soluble fractions. Some significant differences were observed between the BrC fractions emitted from BB and CC with more water-soluble BrC fractions with higher MAE365 and lower absorption Ångström exponent values detected in smoke emitted from BB than from CC. EEM-PARAFAC identified four fluorophores: two protein-like, one humic-like, and one polyphenol-like fluorophores. The protein-like substances were the dominant components of WSOC (47 %–80 %), HULIS-C (44 %–87 %), and MSOC (42 %–70 %). The 1H-NMR results suggested that BB BrC contained more oxygenated aliphatic functional groups (H-C-O), whereas CC BrC contained more unsaturated fractions (H-C-C= and Ar−H). The DTT assays indicated that BB BrC generally had a stronger oxidative potential (DTTm, 2.6–85 pmol/min/µg) than CC BrC (DTTm, 0.4–11 pmol/min/µg), with MSOC having a stronger OP than WSOC and HULIS-C. In addition, HULIS-C contributed more than half of the DTT activity of WSOC (63.1 % ± 15.5 %), highlighting that HULIS was a major contributor of reactive oxygen species (ROS) production in WSOC. Furthermore, the principal component analysis and Pearson correlation coefficients indicated that highly oxygenated humic-like fluorophore C4 may be the important DTT active substances in BrC.

scholarly journals Chemical composition, optical properties, and oxidative potential of water- and methanol-soluble organic compounds emitted from the combustion of biomass materials and coal

2021 ◽  
Author(s):  
Tao Cao ◽  
Meiju Li ◽  
Chunlin Zou ◽  
Xingjun Fan ◽  
Jianzhong Song ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Compounds ◽  
1H Nmr ◽  
Water Soluble ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Oxidative Potential ◽  
Strong Light ◽  
Chemical Structures ◽  
Biomass Materials

Abstract. Biomass burning (BB) and coal combustion (CC) are important sources of brown carbon (BrC) in ambient aerosols. In this study, six biomass materials and five types of coal were combusted to generate fine smoke particles. The BrC fractions, including water-soluble organic compounds (WSOC), humic-like substances (HULIS), and methanol-soluble organic compounds (MSOC), were subsequently fractionated and their optical properties and chemical structures were then comprehensively investigated using UV-visible spectroscopy, proton nuclear magnetic resonance spectroscopy (1H-NMR), and fluorescence extraction-emission matrix spectroscopy (EEM) combined with parallel factor analysis (PARAFAC). In addition, the oxidative potential (OP) of BB and CC BrC was measured with the dithiothreitol (DTT) method. The results showed that WSOC, HULIS, and MSOC accounted for 2.3 %–22 %, 0.5 %–10 %, and 6.4 %–73 % of the total mass of combustion-derived PM2.5, respectively, with MSOC extracting the highest concentrations of organic compounds. The MSOC fractions had the highest light absorption capacity (mass absorption efficiency at 365 nm (MAE365): 1.0–2.7 m2/gC) for both BB and CC smoke, indicating that MSOC contained more of the strong light-absorbing components. Therefore, MSOC may better represent the total BrC than the water-soluble fractions. Some significant differences were observed between the BrC fractions emitted from BB and CC, with more water-soluble BrC fractions with higher MAE365 and lower absorption Ångström exponent values detected in smoke emitted from BB than from CC. The EEM-PARAFAC analysis identified four fluorophores: two protein-like, one humic-like, and one polyphenol-like. The protein-like substance was the dominant component of WSOC (47 %–80 %), HULIS (44 %–87 %), and MSOC (42 %–70 %). The 1H-NMR results suggested that BB BrC contained more oxygenated aliphatic functional groups (H-C-O), whereas CC BrC contained more unsaturated fractions (H-C-C = and Ar-H). The DTT assays indicated that BB BrC generally had a stronger OP (DTTmass, 2.6–85 pmol/min/μg) than CC BrC (DTTmass, 0.4–11 pmol/min/μg), with MSOC having a stronger OP than WSOC and HULIS. Therefore, the BrC fractions from BB had higher OP values than those from CC.

scholarly journals Functional characterization of the water-soluble organic carbon of size-fractionated aerosol in the southern Mississippi Valley

2014 ◽  
Vol 14 (12) ◽  
pp. 6075-6088 ◽  
Author(s):  
M.-C. G. Chalbot ◽  
J. Brown ◽  
P. Chitranshi ◽  
G. Gamboa da Costa ◽  
E. D. Pollock ◽  
...  
Keyword(s):  
Organic Carbon ◽  
1H Nmr ◽  
Biomass Burning ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Particle Mass ◽  
Proton Nuclear Magnetic Resonance ◽  
Relative Distribution ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Abstract. The chemical content of water-soluble organic carbon (WSOC) as a function of particle size was characterized in Little Rock, Arkansas in winter and spring 2013. The objectives of this study were to (i) compare the functional characteristics of coarse, fine and ultrafine WSOC and (ii) reconcile the sources of WSOC for periods when carbonaceous aerosol was the most abundant particulate component. The WSOC accounted for 5% of particle mass for particles with dp > 0.96 μm and 10% of particle mass for particles with dp < 0.96 μm. Non-exchangeable aliphatic (H–C), unsaturated aliphatic (H–C–C=), oxygenated saturated aliphatic (H–C–O), acetalic (O–CH–O) and aromatic (Ar–H) protons were determined by proton nuclear magnetic resonance (1H-NMR). The total non-exchangeable organic hydrogen concentrations varied from 4.1 ± 0.1 nmol m−3 for particles with 1.5 < dp < 3.0 μm to 73.9 ± 12.3 nmol m−3 for particles with dp < 0.49 μm. The molar H / C ratios varied from 0.48 ± 0.05 to 0.92 ± 0.09, which were comparable to those observed for combustion-related organic aerosol. The R–H was the most abundant group, representing about 45% of measured total non-exchangeable organic hydrogen concentrations, followed by H–C–O (27%) and H–C–C= (26%). Levoglucosan, amines, ammonium and methanesulfonate were identified in NMR fingerprints of fine particles. Sucrose, fructose, glucose, formate and acetate were associated with coarse particles. These qualitative differences of 1H-NMR profiles for different particle sizes indicated the possible contribution of biological aerosols and a mixture of aliphatic and oxygenated compounds from biomass burning and traffic exhausts. The concurrent presence of ammonium and amines also suggested the presence of ammonium/aminium nitrate and sulfate secondary aerosol. The size-dependent origin of WSOC was further corroborated by the increasing δ13C abundance from −26.81 ± 0.18‰ for the smallest particles to −25.93 ± 0.31‰ for the largest particles and the relative distribution of the functional groups as compared to those previously observed for marine, biomass burning and secondary organic aerosol. The latter also allowed for the differentiation of urban combustion-related aerosol and biological particles. The five types of organic hydrogen accounted for the majority of WSOC for particles with dp > 3.0 μm and dp < 0.96 μm.

scholarly journals Water-soluble organic carbon aerosols during a full New Delhi winter: Isotope-based source apportionment and optical properties

2014 ◽  
Vol 119 (6) ◽  
pp. 3476-3485 ◽  
Author(s):  
Elena N. Kirillova ◽  
August Andersson ◽  
Suresh Tiwari ◽  
Atul Kumar Srivastava ◽  
Deewan Singh Bisht ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Source Apportionment ◽  
Water Soluble ◽  
New Delhi ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
Carbon Aerosols

scholarly journals Measurements of Oxidative Potential of Particulate Matter at Belgrade Tunnel; Comparison of BPEAnit, DTT and DCFH Assays

2019 ◽  
Vol 16 (24) ◽  
pp. 4906 ◽  
Author(s):  
Maja V. Jovanovic ◽  
Jasmina Z. Savic ◽  
Farhad Salimi ◽  
Svetlana Stevanovic ◽  
Reece A. Brown ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Organic Carbon ◽  
Oxidative Capacity ◽  
Organic Content ◽  
Molecular Probes ◽  
Water Soluble ◽  
Oxidative Potential ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
Pm2.5 And Pm10

To estimate the oxidative potential (OP) of particulate matter (PM), two commonly used cell-free, molecular probes were applied: dithiothreitol (DTT) and dichloro-dihydro-fluorescein diacetate (DCFH-DA), and their performance was compared with 9,10-bis (phenylethynyl) anthracene-nitroxide (BPEAnit). To the best of our knowledge, this is the first study in which the performance of the DTT and DCFH has been compared with the BPEAnit probe. The average concentrations of PM, organic carbon (OC) and elemental carbon (EC) for fine (PM2.5) and coarse (PM10) particles were determined. The results were 44.8 ± 13.7, 9.8 ± 5.1 and 9.3 ± 4.8 µg·m−3 for PM2.5 and 75.5 ± 25.1, 16.3 ± 8.7 and 11.8 ± 5.3 µg·m−3 for PM10, respectively, for PM, OC and EC. The water-soluble organic carbon (WSOC) fraction accounted for 42 ± 14% and 28 ± 9% of organic carbon in PM2.5 and PM10, respectively. The average volume normalized OP values for the three assays depended on both the sampling periods and the PM fractions. The OPBPEAnit had its peak at 2 p.m.; in the afternoon, it was three times higher compared to the morning and late afternoon values. The DCFH and BPEAnit results were correlated (r = 0.64), while there was no good agreement between the BPEAnit and the DTT (r = 0.14). The total organic content of PM does not necessarily represent oxidative capacity and it shows varying correlation with the OP. With respect to the two PM fractions studied, the OP was mostly associated with smaller particles.

scholarly journals Significant Seasonal Change in Optical Properties by atmospheric humic-like substances (HULIS) in Water-Soluble Organic Carbon Aerosols

2017 ◽  
Author(s):  
Heejun Han ◽  
Guebuem Kim
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Uv Radiation ◽  
Dominant Role ◽  
Critical Role ◽  
Organic Aerosols ◽  
Water Soluble ◽  
Photochemical Degradation ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Abstract. Atmospheric humic-like substance (HULIS) is an important fraction of water-soluble organic carbon (WSOC) accounting for the light-absorbing properties of organic aerosols. HULIS is responsible for light-absorbing properties of organic aerosols in the atmosphere. Although various sources of HULIS have been studied extensively, its sinks are poorly constrained. In this study, we found seasonal changes in the optical and chemical characteristics of HULIS and WSOC, which are decreased by approximately 80 % and 30 %, respectively, from the cold season (Oct–Jan) to the warm season (Jun–Sep) due to enhanced solar ultraviolet (UV) radiation. The dominant role of photochemical degradation on light-absorbing organic aerosols, as a sink of HULIS, was further confirmed based on a laboratory experiment by evaluating impact of UV radiation on the optical properties of HULIS and WSOC contents. Our results suggest that seasonal variation of HULIS in WSOC is resulted mainly by photo-induced degradation in the atmosphere. Thus, photochemical degradation of HULIS seems to play a critical role on seasonal variations in the light-absorbing properties of organic aerosols as well as the biogeochemical impact of WSOC on Earth’s surface.

scholarly journals Estimation of Source-Based Aerosol Optical Properties for Polydisperse Aerosols from Receptor Models

2019 ◽  
Vol 9 (7) ◽  
pp. 1443 ◽  
Author(s):  
Chang Jung ◽  
Ji Lee ◽  
Junshik Um ◽  
Seoung Lee ◽  
Young Yoon ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Mass Concentration ◽  
Water Soluble ◽  
Aerosol Size Distribution ◽  
Receptor Model ◽  
Aerosol Optical Properties ◽  
Extinction Coefficients ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

We estimated source-based aerosol optical properties for polydisperse aerosols according to a chemical-species-resolved mass contribution method based on source apportionment. We investigated the sensitivity of aerosol optical properties based on PM2.5 (particulate matter that have a diameter of less than 2.5 micrometers) monitoring results. These aerosols were composed of ions, metals, elemental carbon, and water-soluble organic carbon which includes humic-like carbon substances and water-soluble organic carbon. We calculated aerosols’ extinction coefficients based on the PM2.5 composition data and the results of a multivariate receptor model (Solver for Mixture Problem model, SMP). Based on the mass concentration of chemical composition and nine sources calculated with the SMP receptor model, we estimated the size-resolved mass extinction efficiencies for each aerosol source using a multilinear regression model. Consequently, this study quantitatively determined the size resolved sources contributing to the apportionment-based aerosol optical properties and calculated their respective contributions. The results show that source-resolved mass concentrations and extinction coefficients had varying contributions. This discrepancy between the source-based mass concentration and extinction coefficient was mainly due to differences between the source-dependent aerosol size distribution and the aerosol optical properties from different sources.

scholarly journals Investigating the evolution of water-soluble organic carbon in evaporating cloud water

2021 ◽  
Author(s):  
Vikram Pratap ◽  
Amy E. Christiansen ◽  
Annmarie G. Carlton ◽  
Sara Lance ◽  
Paul Casson ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Cloud Water ◽  
Atmospheric Particles ◽  
Water Soluble ◽  
Secondary Aerosol ◽  
Aerosol Mass ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Cloud cycling plays a key role in the evolution of atmospheric particles and gases, producing secondary aerosol mass and transforming the optical properties and impacts of aerosols globally.

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