Characterizing optical properties of HULIS versus WSOC in cloud water of Eastern China - Insights into secondary formation in cloud processes

Atmospheric Research, Journal Year: 2025, Volume and Issue: unknown, P. 108091 - 108091

Published: March 1, 2025

Language: 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, Journal Year: 2024, Volume and Issue: 24(12), P. 6987 - 6999

Published: June 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.

Language: Английский

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Energetics of the OH radical H-abstraction reactions from simple aldehydes and their geminal diol forms

Journal of Molecular Modeling, Journal Year: 2024, Volume and Issue: 30(8)

Published: July 6, 2024

Language: Английский

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Energetics of the OH radical H-abstraction reactions from simple aldehydes and their geminal diol forms

Research Square (Research Square), Journal Year: 2024, Volume and Issue: unknown

Published: May 10, 2024

Context: Carbonyl compounds, especially aldehydes, emitted to the atmosphere, may suffer hydration in aerosols or water droplets clouds. At same time, they can react with hydroxyl radicals which add abstract hydrogen atoms from these species. The interplay between and abstraction is studied using density functional quantum composite theoretical methods, both gas phase simulated bulk water. H-abstraction aldehydic geminal diol forms of formaldehyde, acetaldehyde, glycolaldehyde, glyoxal, methylglyoxal acrolein are determine whether substituent has any noticeable effect preference for one form another. It found that H-atom adjacent carbonyl group gives a more stable radical than case acetaldehyde glycolaldehyde. presence delocalizing C_a (a glyoxal methylglyoxal, vinyl acrolein), reverts this trend now radicals. A further study was conducted abstracting other different positions species considered, forms. Only formed by –CH₂OH Abstraction atom groups equivalent addition ^•OH aldehyde. leads, some cases, decomposition into smaller neutral molecule. In interesting differences observed results gas-phase (simulated) solvent, as well respect method calculation chosen. Methods: DFT (M06-2X, B2PLYP, PW6B95), CCSD(T) (CBS-QB3, jun-ChS, SCVECV-f12) methods Dunning basis sets extrapolation CBS limit were used energetics closed shell aldehydes their keto geminal-diol forms, derived them abstraction. Both solvent calculations performed, last Polarizable Continuum Model.

Language: Английский

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Evolution of water-soluble organic aerosol composition from clean days to haze episodes in rural area of North China Plain

Journal of Environmental Sciences, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 1, 2024

Language: Английский

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