Unveiling the Molecular Characteristics, Origins, and Formation Mechanism of Reduced Nitrogen Organic Compounds in the Urban Atmosphere of Shanghai Using a Versatile Aerosol Concentration Enrichment System

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(16), P. 7099 - 7112

Published: March 27, 2024

Reduced nitrogen-containing organic compounds (NOCs) in aerosols play a crucial role altering their light-absorption properties, thereby impacting regional haze and climate. Due to the low concentration levels of individual NOCs air, utilization accurate detection quantification technologies becomes essential. For first time, this study investigated diurnal variation, chemical characteristics, potential formation pathways urban ambient Shanghai using versatile aerosol enrichment system (VACES) coupled with HPLC-Q-TOF-MS. The results showed that accounted over 60% identified components aerosols, O/N < 3 being major contributors (>70%). predominance positive ionization mode suggested prevalence reduced NOCs. Higher relative intensities number fractions were observed during nighttime, while CHO an opposite trend. Notably, correlation between intensity ammonium nighttime was observed, suggesting reaction form imines may be pathway for nighttime. Seven prevalent types autumn winter characterized by CH2 long-chain homologues. These included alkyl, cyclic, aromatic amides CHON compounds, as well heterocyclic or cyclic amines aniline homologue series CHN which associated anthropogenic activities capable forming light-absorbing chromophores posing harm human health. findings highlight significant contributions both primary emissions chemistry, particularly amination processes, pollution Shanghai's atmosphere.

Language: Английский

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Nitroaromatic Compounds from Secondary Nitrate Formation and Biomass Burning Are Major Proinflammatory Components in Organic Aerosols in Guangzhou: A Bioassay Combining High-Resolution Mass Spectrometry Analysis

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(51), P. 21570 - 21580

Published: Nov. 21, 2023

The limited characterization and detection capacity of unknown compounds hinder our understanding the molecular composition toxic in PM2.5. present study applied Fourier transform ion cyclotron resonance mass spectrometry coupled with negative positive electrospray ionization sources (ESI–/ESI+ FT-ICR-MS) to probe characteristics dynamic formation processes effective proinflammatory components organic aerosols (OAs) PM2.5 Guangzhou for one year. We detected abundant molecules OAs, mainly classified as CHON (compounds composed C, H, O, N atoms) elemental nitroaromatic (NACs) structures. From perspective process, we discovered that these molecules, especially NACs, were largely driven by secondary nitrate biomass burning (in emission source), well SO2 atmospheric evolution). In addition, results indicated had replaced primary main contributing source OAs. This highlights importance community measures control production derived from urban areas.

Language: Английский

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Aqueous-Phase Reactions of Anthropogenic Emissions Lead to the High Chemodiversity of Atmospheric Nitrogen-Containing Compounds during the Haze Event

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(43), P. 16500 - 16511

Published: Oct. 16, 2023

Nitrogen-containing organic compounds (NOCs), a type of important reactive-nitrogen species, are abundant in aerosols haze events observed Northern China. However, due to the complex nature NOCs, sources, formation, and influencing factors still ambiguous. Here, molecular composition matters (OMs) hourly PM2.5 samples collected during event China was characterized using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). We found that CHON (formulas containing C, H, O, N atoms) dominated OM fractions showed high chemodiversity transformability. Relying on newly developed revised-workflow oxidation-hydrolyzation knowledge for compounds, 64% major aromatic (>80%) could be derived from oxidization or hydrolyzation processes. Results FT-ICR MS data analysis further aerosol liquid water (ALW)-involved aqueous-phase reactions distribution aromatic-CHON besides coal combustion, ALW-involved compound formation daytime nighttime different. Our results improve understanding composition, potential which can help advance evolution, control haze.

Language: 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, Journal Year: 2024, Volume and Issue: 24(7), P. 4331 - 4346

Published: April 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.

Language: Английский

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Molecular Signatures and Sources of Fluorescent Components in Atmospheric Organic Matter in South China

Environmental Science & Technology Letters, Journal Year: 2022, Volume and Issue: 9(11), P. 913 - 920

Published: Oct. 18, 2022

Excitation emission matrix (EEM) spectra coupled with parallel factor analysis (PARAFAC) have been used to characterize brown carbon (BrC). The molecular composition of PARAFAC components is not well understood in atmospheric science, which has impeded the accurate interpretation chemical changes and source apportionment BrC using EEM-PARAFAC methods. We assigned numerous formulas identified by Fourier transform ion cyclotron resonance mass spectrometry (both negative positive electrospray ionization modes) each PARAFAC-derived fluorescent component (FC) PM2.5 samples. Obvious differences characteristics sources were observed between hydrospheric FCs, indicating need for caution explaining FC based on FC. Previously protein-like (C4) less-oxidized humic-like (C1) associated mainly highly saturated photoresistant species less-polar anthropogenic emissions. Highly oxidized FCs aromatic unsaturated/phenolic compounds (high oxygen), potentially influenced biomass burning related secondary processes. seasonal variations light absorption similar those fluorescence intensity degree humification, oxygen). These linkages indicated potential investigating absorption, composition, BrC.

Language: 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, Journal Year: 2022, Volume and Issue: 296, P. 119573 - 119573

Published: Dec. 30, 2022

Language: Английский

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More water-soluble brown carbon after the residential “coal-to-gas” conversion measure in urban Beijing

npj Climate and Atmospheric Science, Journal Year: 2023, Volume and Issue: 6(1)

Published: March 23, 2023

Abstract The implementation of air pollution reduction measures has significantly reduced the concentration atmospheric fine particles (PM 2.5 ) in Beijing, among which “coal-to-gas” conversion may play a crucial role. However, effect this measure on brown carbon (BrC) is not well known. Here, chemical composition BrC humic-like fraction (HULIS-BrC) and water-insoluble (WI-BrC) were characterized for ambient PM samples collected Beijing before after measure. After measure, number HULIS-BrC compounds increased by ~14%, while WI-BrC decreased ~8%. intensity over 90% also correspondingly O/C ratios CHO CHON generally with increase after/before indicating that there more water-soluble highly oxygenated On contrary, than 80% decrease low decreased. This work sheds light differences between suggests future studies residential coal combustion secondary deserve further exploration.

Language: Английский

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Organosulfur Compounds: A Non‐Negligible Component Affecting the Light Absorption of Brown Carbon During North China Haze Events

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(1)

Published: Jan. 4, 2025

Abstract The roles of organosulfur compounds (OSCs), an important component in organic matter, brown carbon (BrC) aerosol absorption is often overlooked. Here, the molecular composition OSCs and its associations with methanol‐soluble BrC (MS‐BrC) during a haze event North China were revealed using Fourier transform ion cyclotron resonance mass spectrometry analysis. By combining aggregated boosted tree model partial least squares regression estimation, our results suggested that mainly composed potential aromatic structures, MS‐BrC was closely related to OSCs. Specifically, contribute notable 26% total number upper limit 10.4% absorption. Furthermore, we found influenced by coal combustion, desulfurization reactions showed variations Since residential combustion (an primary source OSs) major energy China, research underscores as tracers for assessing impact fossil fuel on highlights atmospheric influences (e.g., light health), which need more works uncover origins, fates, environmental effects

Language: Английский

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Evolution of atmospheric high-molecular-weight Organonitrates (HMW ONs) in urban Yangtze River Delta (YRD), China

npj Climate and Atmospheric Science, Journal Year: 2025, Volume and Issue: 8(1)

Published: Feb. 14, 2025

Language: Английский

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The critical role of aqueous-phase processes in aromatic-derived nitrogen-containing organic aerosol formation in cities with different energy consumption patterns

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(5), P. 2763 - 2780

Published: March 4, 2025

Abstract. Nitrogen-containing organic compounds (NOCs) impact air quality and human health. Here, the abundance, potential precursors, main formation mechanisms of NOCs in PM2.5 during winter were compared for first time among Haerbin (dependent on coal heating), Beijing (natural gas as heating energy), Hangzhou (no centralized policy). The total signal intensity CHON+, CHN+, CHON− was highest lowest Hangzhou. Anthropogenic aromatics accounted 73 %–93 % all identified precursors Haerbin. Although abundance aromatic-derived lower than Haerbin, also contributors to NOC Beijing. exhibited levels aromatic precursors. Furthermore, non-metric multidimensional scaling analysis indicated an overall reduction fossil fuel combustion pollution along route from We found that aqueous-phase processes (mainly condensation, hydrolysis, or dehydration reduced mainly oxidization hydrolysis oxidized NOCs) can promote transformation produce NOCs, leading most significant increase (particularly haze days). Reduced precursor emissions (the lowest) constrained NOCs. results suggest aerosol coal-dependent cities is controlled by anthropogenic processes. Thus, without effective emission controls, through may still pose a large threat quality.

Language: Английский

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