Molecular Dynamics and Light Absorption Properties of Atmospheric Dissolved Organic Matter

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(15), P. 10268 - 10279

Published: July 21, 2021

The light-absorbing organic aerosol referred to as brown carbon (BrC) affects the global radiative balance. linkages between its molecular composition and light absorption properties how environmental factors influence BrC are not well understood. In this study, atmospheric dissolved matter (ADOM) in 55 samples from Guangzhou was characterized using Fourier transform ion cyclotron resonance mass spectrometry measurements. abundant components ADOM were aliphatics peptide-likes (in structure), or nitrogen- sulfur-containing compounds elemental composition). of positively correlated with levels unsaturated aromatic structures. Particularly, 17 nitrogen-containing species, which identified by a random forest, variation well. Aggregated boosted tree model nonmetric multidimensional scaling analysis show that largely driven meteorological conditions anthropogenic activities, among biomass burning (BB) OH radical two important factors. often accumulate elevated BB emissions related secondary processes, whereas photolysis/photooxidation usually occurs under high solar radiance/•OH concentration. This study first illuminated at level provided clues for molecular-level research future.

Language: Английский

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Substantial brown carbon emissions from wintertime residential wood burning over France

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 743, P. 140752 - 140752

Published: July 6, 2020

Language: Английский

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Molecular Characterization of Nitrogen-Containing Compounds in Humic-like Substances Emitted from Biomass Burning and Coal Combustion

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 56(1), P. 119 - 130

Published: Dec. 9, 2021

N-containing organic compounds (NOCs) in humic-like substances (HULIS) emitted from biomass burning (BB) and coal combustion (CC) were characterized by ultrahigh-resolution mass spectrometry the positive electrospray ionization mode. Our results indicate that NOCs include CHON+ CHN+ groups, which are detected as a substantial fraction both BB- CC-derived HULIS, suggest not only BB but also CC is potential important source of atmosphere. The mainly consist reduced nitrogen with other oxygenated functional straw- coal-smoke HULIS exhibit lower degree oxidation than pine-smoke HULIS. In addition, higher N atoms (N2 and/or N3) generally bear modified aromaticity index (AImod) values contained especially straw-smoke whereas atom (N1) always have relatively AImod dominant These findings imply primary emission may be significant N1 compounds, high number (e.g., N2–3) could associated materials. Further study warranted to distinguish more sources.

Language: Английский

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Chemical Fingerprinting of HULIS in Particulate Matters Emitted from Residential Coal and Biomass Combustion

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(6), P. 3593 - 3603

Published: March 3, 2021

Identification of humic-like substances (HULIS) structures and components is still a major challenge owing to their chemical complexity. This study first employed complementary method with the combination two-dimensional gas chromatography-time-of-flight mass spectrometry liquid chromatography-quadrupole-time-of-flight address low-polarity polar HULIS in PM2.5 (particulate matter an aerodynamic diameter less than 2.5 μm), respectively. The showed significant correlation identifying overlapping species performed well uncovering complexity HULIS. A total 1246 compound (65.6-81.0% for each sample), approximately 1 order magnitude more compounds that reported previous studies, were addressed collected real-world household biomass coal combustion. Aromatics most abundant (37.4-64.1% 34.5-70.0% samples) all samples according carbon skeleton determination, while included phenols (2.6-21.1%), ketones (6.0-17.1%), aldehydes (1.1-6.8%), esters (2.9-20.0%), amines/amides (3.2-8.5%), alcohols (3.8-17.0%), acids (4.7-15.1%). Among identified species, 11-36% 11-41% chromophores, another 22-35 23-29% chromophore precursors, shows promise fingerprinting.

Language: Английский

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Biomass burning organic aerosols significantly influence the light absorption properties of polarity-dependent organic compounds in the Pearl River Delta Region, China

Environment International, Journal Year: 2020, Volume and Issue: 144, P. 106079 - 106079

Published: Aug. 28, 2020

Atmospheric brown carbon (BrC) is an important constituent of light-absorbing organic aerosols with many unclear issues. Here, the light-absorption properties BrC different polarity characteristics at a regional site Pearl River Delta Region during 2016–2017, influenced by sources and molecular compositions, were revealed using radiocarbon analysis Fourier transform ion cyclotron resonance mass spectrometry. Humic-like substance (HULIS), middle polar (MP), low (LP) fractions constitute 46 ± 17%, 30 7%, 7 3% total absorption coefficient from bulk extracts, respectively. Our results show that proportions HULIS MP to are higher than their mass, indicating main components in water-soluble water-insoluble fractions, With decreases non-fossil HULIS, MP, LP (66 2%, 52 36 3%, respectively), abundances unsaturated compounds efficiency 365 nm three decreased synchronously. Increases both levoglucosan winter imply enhanced could be attributed elevated levels biomass burning (BBOA), which increases number nitrogen-containing compounds. Moreover, major type potential oxidized BBOA, but chromophores mainly associated primary BBOA. This study reveals has adverse effects on radiative forcing air quality, probably indicates significant influences atmospheric oxidation reactions forms chromophores.

Language: Английский

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Source and formation process impact the chemodiversity of rainwater dissolved organic matter along the Yangtze River Basin in summer

Water Research, Journal Year: 2021, Volume and Issue: 211, P. 118024 - 118024

Published: Dec. 30, 2021

Language: Английский

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Atmospheric Brown Carbon on the Tibetan Plateau: Regional Differences in Chemical Composition and Light Absorption Properties

Environmental Science & Technology Letters, Journal Year: 2022, Volume and Issue: 9(3), P. 219 - 225

Published: Feb. 9, 2022

Fine particulate matter (PM2.5) filter samples were collected from two high-altitude remote sites located in the southern (QOMS) and northern (WLG) regions of Tibetan Plateau (TP) to explore regional differences brown carbon (BrC) properties. Chemical BrC composition representative these areas inferred molecular-level analysis PM2.5 using high-performance liquid chromatography coupled with photodiode array high-resolution mass spectrometry detectors. The results show that more polar chromophores abundant QOMS samples, while contributions less comparable WLG samples. A higher absorption coefficient was observed at than WLG. Strong identified as oxygenated aromatics nitrophenol compounds, organosulfate compounds found sample. this study indicate provide insights into their sources chemical processes, which should be considered for predictive understanding modeling radiative forcing aerosol TP area.

Language: Английский

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pH-Dependent Chemical Transformations of Humic-Like Substances and Further Cognitions Revealed by Optical Methods

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(12), P. 7578 - 7587

Published: June 1, 2022

Humic-like substances (HULIS) are macromolecular complex groups in water-soluble organic compounds (WSOC). pH is a crucial factor that influences the chemical transformations of HULIS atmospheric particles, but this has been rarely investigated, especially under varying conditions. This study attempted to unveil transformation mechanisms range conditions using optical methods. The pH-dependent light absorption and fluorescence properties were comprehensively analyzed; acidity coefficient (pKa) relation structures was determined, hypothetical with increasing analyzed by characterizations. results suggested greatly impacted efficiencies both winter summer seasons, pKa an important inflection point. ranged from 3.5 8.0 6.4 10.0 summer. acidic/basic identified as −OH or −NH2 substituted quinolines, carboxylic aromatics, pyridines. pH-sensitive species accounted for about 6% 21% HULIS-C (carbon concentrations HULIS) summer, respectively. spectra might result charge transfer reactions deprotonation.

Language: Английский

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Light absorption and source apportionment of water soluble humic-like substances (HULIS) in PM2.5 at Nanjing, China

Environmental Research, Journal Year: 2021, Volume and Issue: 206, P. 112554 - 112554

Published: Dec. 21, 2021

Language: Английский

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Measurement report: Changes in light absorption and molecular composition of water-soluble humic-like substances during a winter haze bloom-decay process in Guangzhou, China

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(2), P. 963 - 979

Published: Jan. 20, 2023

Abstract. Water-soluble humic-like substances (HULIS) absorb light in near-UV and visible wavelengths exert significant influence on the atmospheric environment climate. However, knowledge HULIS evolution during haze bloom-decay process is limited. Herein, PM2.5 samples were obtained a winter event Guangzhou, China, absorption molecular composition of investigated by UV–Vis spectrophotometry ultrahigh-resolution mass spectrometry. Compared with clean days, coefficients (Abs365) days significantly higher but efficiencies (MAE365) relatively low, suggesting diverse dynamic properties episodes. The CHO CHON compounds most abundant components HULIS, followed CHOS, CHONS, CHN. Haze presented comparatively high weight; lower aromaticity index (AImod); O/Cw, O/Nw, O/Sw ratios, indicating that fractions undergo oxidation compared to days. Moreover, AImod major potential chromophores contributed absorption. It worth noting proportions these decreased events, mainly owing their Besides, accumulated contribution organic emitted from vehicles formed reactions biogenic volatile (bio-VOCs) also diluted light-absorbing HULIS. These findings help us understand processes subtropic region China.

Language: Английский

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