Molecular insights into the composition, sources, and aging of atmospheric brown carbon

Chemical Society Reviews, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

The light-absorbing chemical components of atmospheric organic aerosols are commonly referred to as Brown Carbon (BrC), reflecting the characteristic yellowish brown appearance aerosol.

Язык: Английский

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Key toxic components and sources affecting oxidative potential of atmospheric particulate matter using interpretable machine learning: Insights from fog episodes

Journal of Hazardous Materials, Год журнала: 2023, Номер 465, С. 133175 - 133175

Опубликована: Дек. 7, 2023

Язык: Английский

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Sources, Variations, and Effects on Air Quality of Atmospheric Ammonia

Current Pollution Reports, Год журнала: 2024, Номер 10(1), С. 40 - 53

Опубликована: Янв. 19, 2024

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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Bubble Turbulent Gas-Permeable Membrane for Ammonia Recovery from Swine Wastewater: Mass Transfer Enhancement and Antifouling Mechanisms

Environmental Science & Technology, Год журнала: 2024, Номер 58(13), С. 6019 - 6029

Опубликована: Март 21, 2024

Recovering ammonium from swine wastewater employing a gas-permeable membrane (GM) has potential but suffers the limitations of unattractive mass transfer and poor-tolerance antifouling properties. Turbulence is an effective approach to enhancing release volatile ammonia while relying on interfacial disturbance interfere with contaminant adhesion. Herein, we design innovative coupled bubble turbulence (BT-GM) that enhances mitigating fouling. Bubbles act as carriers accelerate migration liquid phase, increasing concentration gradient at membrane–liquid interface. In comparison, rate BT-GM process applied real 38% higher than conventional GM (12 h). Through computational fluid dynamics simulation, kinetic energy system 3 orders magnitude GM, area nearly times GM. Seven batches tests confirmed exhibits remarkable ability, broadens its adaptability complex water quality, practically promotes development sustainable resource recycling.

Язык: Английский

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Seasonal changes in water-soluble brown carbon (BrC) at Nanling background station in South China

Frontiers in Environmental Science, Год журнала: 2024, Номер 12

Опубликована: Фев. 14, 2024

Brown carbon (BrC) is an important light-absorbing component of organic (OC), causing large uncertainty in aerosol radiative forcing evaluation and being related to health issues as well. Knowledge BrC atmospheric background station beneficial understand its role a changing climate. A year-long sampling campaign was conducted at Nanling get comprehensive knowledge WS-BrC, total seventy-two PM 2.5 samples throughout year were used. Light absorption fluorescence spectra WSOC analyzed synchronously using spectrophotometer. The low levels , OC, elemental (EC) conferred site. optical properties WS-BrC characterized excitation-emission matrix (EEM) spectroscopy. made significant contribution (365 nm, 18% ± 10%) carbonaceous absorption. mass efficiency (MAE) 0.81 0.34 m 2 gC –1 varies among seasons due the different sources or processing. Three EEM fluorescent components identified by parallel factor (PAFAFAC) analysis, including two humic-like substances (HULIS, C1, C2), one phenolic-like component. HULIS accounted for approximately 70% intensities. Primary combustion emissions showed enhanced activity during winter spring seasons, but there no influences on spring. Secondary contributed significantly winter, summer, autumn (all exceeding 50%), except Photooxidation process formation secondary autumn, may be another pathway i.e., ammonia pathway. This study contributes our understanding atmosphere.

Язык: Английский

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Molecular signatures and formation mechanisms of water-soluble chromophores in particulate matter from Karachi in Pakistan

The Science of The Total Environment, Год журнала: 2024, Номер 914, С. 169890 - 169890

Опубликована: Янв. 6, 2024

Язык: Английский

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Atmospheric Brown Carbon: Sources, Optical Properties, and Chromophore Composition

Aerosol and Air Quality Research, Год журнала: 2024, Номер 24(9), С. 240035 - 240035

Опубликована: Янв. 1, 2024

Brown carbon (BrC) constitutes a significant portion of organic (OC) and exerts substantial influence on air quality, atmospheric chemical processes, the impact climate dynamics. The intricate chemistry BrC arises from multiple mechanisms source types, yielding wide spectrum spectral properties. Consequently, identifying representative chromophore species to develop reference material is crucial capture full diversity found in atmosphere ensure its precise monitoring. This also emphasizes need for more comprehensive measurement method link BrC's optical traits with composition. One objectives this review evaluate existing level understanding concerning molecular compositions compounds by analyzing recent field laboratory data. paper revises expands part prior database containing critical assessments primary secondary sources, photochemistry multi-phase reactions involving BrC, potential candidate chromophores, studies properties cryosphere, draw lessons advances that lead improved representation atmosphere.

Язык: Английский

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Non-negligible secondary contribution to brown carbon in autumn and winter: inspiration from particulate nitrated and oxygenated aromatic compounds in urban Beijing

Atmospheric chemistry and physics, Год журнала: 2024, Номер 24(11), С. 6525 - 6538

Опубликована: Июнь 4, 2024

Abstract. Nitrated aromatic compounds (NACs) and oxygenated derivatives of polycyclic hydrocarbons (OPAHs) play vital roles within brown carbon (BrC), influencing both climate dynamics human health to a certain degree. The concentrations these drug classes were analyzed in PM2.5 from an urban area Beijing during the autumn winter 2017 2018. There four heavy haze episodes campaign, two which happened prior heating other heating. During entire course sampling, mean total nine NACs eight OPAHs 1.2–263 2.1–234 ng m−3, respectively. approximately 2–3 times higher period than before For NACs, relative molecular composition did not change significantly heating, with 4-nitrocatechol 4-nitrophenol demonstrating highest abundance. OPAHs, 1-naphthaldehyde was most abundant species while proportion anthraquinone increased by more twice, 13 % 31 In Beijing's winter, significant sources have been traced back automobile emissions biomass burning activities. Interestingly, it observed that contribution coal combustion notably It is worth noting secondary generation BrC important throughout whole sampling period, manifested photochemical reaction aqueous further found nitrate-driven organic (SOC)-driven formation pollution events, particularly

Язык: Английский

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Different formation pathways of nitrogen-containing organic compounds in aerosols and fog water in northern China

Atmospheric chemistry and physics, Год журнала: 2024, Номер 24(12), С. 6987 - 6999

Опубликована: Июнь 18, 2024

Abstract. While aqueous-phase processing is known to contribute the formation of nitrogen-containing organic compounds (NOCs), specific pathways involved remain poorly understood. In this study, we aimed characterize NOCs present in both pre-fog aerosols and fog water collected at a suburban site northern China. Fourier-transform ion cyclotron resonance mass spectrometry was utilized analyze molecular composition negative positive modes electrospray ionization (ESI− ESI+). samples, constituted significant portion, accounting for over 60 % all assigned formulas ESI− more than 80 ESI+. By comparing originating from biomass burning, coal combustion, vehicle emissions, identified that 72.3 were attributed primary anthropogenic sources (pNOCs), while remaining categorized as secondary formed within (saNOCs). Unique found classified (sfNOCs). Through comprehensive “precursor–product pair” screening involving 39 reaction pathways, observed nitration reaction, amine pathway, intramolecular N-heterocycle pathway NH3 addition reactions contributed 43.6 %, 22.1 11.6 saNOCs, respectively. contrast, these 26.8 28.4 29.7 sfNOCs, This disparity likely influenced by diverse precursors, aqueous acidity, gas-phase species partitioning. Correspondingly, saNOCs contain higher abundance carbohydrate-like highly oxygenated with two nitrogen atoms compared pNOCs. Conversely, sfNOCs exhibited content lipid-like fewer oxygen atoms. These results underscore distinct processes contributing diversity water, which may lead their different climate effects.

Язык: Английский

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