Technical note: Chemical composition and source identification of fluorescent components in atmospheric water-soluble brown carbon by excitation–emission matrix spectroscopy with parallel factor analysis – potential limitations and applications

Atmospheric chemistry and physics, Год журнала: 2023, Номер 23(4), С. 2613 - 2625

Опубликована: Фев. 24, 2023

Abstract. Three-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy is an important method for the identification of occurrence, chemical composition, and source atmospheric chromophores. However, current knowledge on interpretation fluorescent components mainly based aquatic dissolved organic matter might not be applicable to samples. Therefore, this study comprehensively investigated EEM data different types strong light-absorbing compounds, water-soluble (WSOM) in aerosol samples (combustion ambient aerosols), soil dust, purified fulvic humic acids supplemented by parallel factor (PARAFAC) modeling. The results demonstrated that compounds with high aromaticity electron-donating groups generally present spectra at longer emission wavelengths, whereas substituted electron-withdrawing have relatively weaker intensity. In particular, aromatic containing nitro (i.e., nitrophenols), which show absorption are major component brown carbon, exhibited no significant fluorescence. EEM–PARAFAC identified three C1, C2, C3) WSOM. Although EEM–PARAFAC-derived C1 (Ex/Em = 235, 270/330 nm) WSOM considered protein-like groups, our findings suggested it composed acids, phenolic their derivatives, only traces amino acids. C2 associated reaction biomass burning and/or biogenic molecules, a lower degree oxidation, more abundant Guangzhou (56 %–69 %). C3, contrast, attributed highly oxygenated molecules derived from aging processes has higher contribution Chuzhou (23 These provide new insights into analysis properties sources fluorophores using method.

Язык: Английский

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Insight into the Role of NH₃/NH₄⁺ and NO_x/NO₃^– in the Formation of Nitrogen-Containing Brown Carbon in Chinese Megacities

Environmental Science & Technology, Год журнала: 2024, Номер unknown

Опубликована: Фев. 23, 2024

Particulate brown carbon (BrC) plays a crucial role in the global radiative balance due to its ability absorb light. However, effect of molecular formation on light absorption properties BrC remains poorly understood. In this study, atmospheric samples collected from six Chinese megacities winter and summer were characterized through ultrahigh-performance liquid chromatography coupled with Orbitrap mass spectrometry (UHPLC-Orbitrap MS) measurements. The average values coefficient at wavelength 365 nm (babs365) approximately 4.0 times higher than those summer. Nitrogen-containing organic molecules (CHNO) identified as critical components light-absorbing substances both seasons, underscoring importance N-addition BrC. These nitrogen-containing chromophores more closely related nitro-containing compounds originating biomass burning nitrogen oxides (NOx)/nitrate (NO3–) reactions winter. summer, they reduced N-containing formed ammonia (NH3)/ammonium (NH4+) reactions. NH3/NH4+-mediated contributed secondary winter, particularly southern cities. Compared O/Cw, lower molecule conjugation indicator (double bond equivalent, DBE), babs365 suggest possible bleaching mechanism during oxidation process. findings strengthen connection between composition BrC, providing insights into mechanisms across northern cities different seasons.

Язык: Английский

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Measurement report: Characteristics of nitrogen-containing organics in PM_2.5 in Ürümqi, northwestern China – differential impacts of combustion of fresh and aged biomass materials

Atmospheric chemistry and physics, Год журнала: 2024, Номер 24(7), С. 4331 - 4346

Опубликована: Апрель 15, 2024

Abstract. Nitrogen-containing organic compounds (NOCs) are abundant and important aerosol components deeply involved in the global nitrogen cycle. However, sources formation processes of NOCs remain largely unknown, particularly city (Ürümqi, China) farthest from ocean worldwide. Here, PM2.5 collected Ürümqi over a 1-year period were characterized by ultra-high-resolution mass spectrometry. The abundance CHON (mainly oxygen-poor unsaturated aliphatic-like species) positive ion mode was higher warm than cold period, which attributed to contribution fresh biomass material combustion (e.g., forest fires) associated with amidation fatty acids rather oxidation processes. nitro-aromatic negative increased significantly tightly related aged dry straws) wintertime Ürümqi. For CHN compounds, alkyl nitriles aromatic species showed periods, respectively. Alkyl can be derived dehydration amides (the main period). In contrast, burning. These findings further suggested different impacts materials on NOC compositions seasons. overall results shed light mechanisms release during combustion.

Язык: Английский

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Nitroaromatic compounds in six major Chinese cities: Influence of different formation mechanisms on light absorption properties

The Science of The Total Environment, Год журнала: 2024, Номер 930, С. 172672 - 172672

Опубликована: Апрель 23, 2024

Язык: Английский

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Oxidative potential of atmospheric brown carbon in six Chinese megacities: Seasonal variation and source apportionment

Atmospheric Environment, Год журнала: 2023, Номер 309, С. 119909 - 119909

Опубликована: Июнь 15, 2023

Язык: Английский

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Molecular compositions and optical properties of water-soluble brown carbon during the autumn and winter in Guangzhou, China

Atmospheric Environment, Год журнала: 2022, Номер 296, С. 119573 - 119573

Опубликована: Дек. 30, 2022

Язык: Английский

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Impact of fossil and non-fossil fuel sources on the molecular compositions of water-soluble humic-like substances in PM_2.5 at a suburban site of Yangtze River Delta, China

Atmospheric chemistry and physics, Год журнала: 2023, Номер 23(14), С. 8305 - 8324

Опубликована: Июль 25, 2023

Abstract. Atmospheric humic-like substances (HULIS) affect the global radiation balance due to their strong light absorption at ultraviolet wavelength. The potential sources and molecular compositions of water-soluble HULIS a suburban site in Yangtze River Delta from 2017 2018 were discussed, based on results radiocarbon (14C) analysis combining Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) technique this study. 14C showed that averaged non-fossil-fuel source contributions 39 ± 8 % 36 6 summer winter, respectively, indicating significant fossil fuel HULIS. Van Krevelen diagrams obtained FT-ICR-MS proportions tannin-like carbohydrate-like groups higher summer, suggesting contribution biogenic secondary organic aerosols (SOAs). condensed aromatic structures winter suggested increasing anthropogenic emissions. Molecular composition CHO, CHON, CHOS, CHONS subgroups relatively intensities high O-containing macromolecular oligomers CHO compounds further stronger SOA formation summer. High-intensity phenolic flavonoids, which related biomass burning polycyclic hydrocarbon (PAH) derivatives combustion emissions, found compounds. Besides, two high-intensity containing ring (C9H6O7 C10H5O8) identified samples similar those off-road engine samples, traffic emissions one important study site. CHON mainly composed nitro or organonitrates with significantly associated addition enhanced NOx winter. However, formulas referring N-heterocyclic compounds, produced atmospheric processes involving reduced N species (e.g., ammonium). S-containing organosulfates (OSs) derived precursors, namely long-chain alkane hydrocarbon, illustrate mixed Generally, different policies need be considered for each season seasonal (i.e., sources, both seasons, additional coal winter). Measures control motor vehicles industrial Additional measures power plants should applied These findings add our understanding interaction between

Язык: Английский

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Characterization and sources of water-soluble organic species in PM2.5 in a remote mountain environment in Southeastern China

Atmospheric Environment, Год журнала: 2023, Номер 313, С. 120057 - 120057

Опубликована: Авг. 30, 2023

Язык: Английский

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Characterization of fine particulate matter water-soluble inorganic ions and estimation of aerosol acidity at three COALESCE network sites — Mysuru, Bhopal, and Mesra — in India

Environmental Science and Pollution Research, Год журнала: 2023, Номер 30(26), С. 69241 - 69257

Опубликована: Май 3, 2023

Язык: Английский

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Optical source apportionment of aqueous brown carbon (BrC) on a daytime and nighttime basis in the eastern Indo-Gangetic Plain (IGP) and insights from 13C and 15N isotopic signatures

The Science of The Total Environment, Год журнала: 2023, Номер 894, С. 164872 - 164872

Опубликована: Июнь 19, 2023

Язык: Английский

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