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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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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Seasonal and diurnal variation of PM2.5 HULIS over Xi'an in Northwest China: Optical properties, chemical functional group, and relationship with reactive oxygen species (ROS)

Atmospheric Environment, Journal Year: 2021, Volume and Issue: 268, P. 118782 - 118782

Published: Oct. 12, 2021

Language: Английский

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Significant coal combustion contribution to water-soluble brown carbon during winter in Xingtai, China: Optical properties and sources

Journal of Environmental Sciences, Journal Year: 2022, Volume and Issue: 124, P. 892 - 900

Published: Feb. 26, 2022

Language: Английский

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Optical properties, chemical functional group, and oxidative activity of different polarity levels of water-soluble organic matter in PM2.5 from biomass and coal combustion in rural areas in Northwest China

Atmospheric Environment, Journal Year: 2022, Volume and Issue: 283, P. 119179 - 119179

Published: May 17, 2022

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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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, Journal Year: 2024, Volume and Issue: unknown

Published: Feb. 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.

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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Unraveling the Light‐Absorbing Properties of Brown Carbon at a Molecular Level

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(10)

Published: May 15, 2024

Abstract Brown carbon (BrC) exhibits a highly complex chemical composition with diverse light‐absorbing properties, which complicates our understanding of its climate impacts. This study examined the impact molecular characteristics (including mass, unsaturation, oxidation state, and polarity) heteroatoms on properties (absorptivity wavelength dependence) BrC from perspective, based ultraviolet‐visible spectra over 40,000 substances in aerosol different sources ambience. Our findings reveal that light‐absorptivity molecules increases decreasing polarity O/C ratio, while it rises higher mass unsaturation. We developed predictive models for absorptivity double bond equivalent ratio. In addition, we observed an inverse correlation between dependence at level, as determined through mathematical analysis. molecular‐level provides valuable insights into absorbing mechanisms, facilitating more accurate characterization atmospheric models.

Language: Английский

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Molecular Characterization of Water-Soluble Aerosol Particle Extracts by Ultrahigh-Resolution Mass Spectrometry: Observation of Industrial Emissions and an Atmospherically Aged Wildfire Plume at Lake Baikal

ACS Earth and Space Chemistry, Journal Year: 2022, Volume and Issue: 6(4), P. 1095 - 1107

Published: March 29, 2022

Air pollution over Lake Baikal originating from anthropogenic emissions as well wildfire events and secondary organic aerosol (SOA) formation poses a threat to this world heritage ecosystem. During ship expedition in 2018, ambient particles were sampled on filters at different locations of extracted obtain the fraction water-soluble (WSOA). Subsequent analysis by Fourier transform ion cyclotron resonance (FTICR) mass spectrometry with direct-infusion electrospray ionization (ESI) both modes provides insights into molecular composition polar high-molecular-weight species WSOA. Light absorption spectral dependence determined Ångstrom exponent (AAE) is correlated summed compound class abundancies identify light-absorbing compounds. Most detected are heavily oxidized, associated intense atmospheric aging, contain significant amounts nitrogen or sulfur, most abundant classes being CHO, CHON, CHOS. Nitrogen-containing more frequently found positive ESI correlate AAE. Oxygen-to-nitrogen ratios (O/N) larger than 3 indicate nitrates, also less oxidized can be linked brown carbon (BrC). complementary information with, one hand, sensitive detection high average oxidation state (OSC) low-volatility negative mode, other lower OSC (OSC < 0) oligomers potential biomass burning mode. Additionally, great overlap sum formulae was all sampling sites along route, regardless primary emission sources, indicating strong aging mixing, leading similar (OOA) sources.

Language: Английский

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