Tropospheric Multiphase Chemistry: Excited Triplet States Compete with OH Radicals and Singlet Molecular Oxygen

ACS Earth and Space Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 12, 2025

Excited triplet states of organic molecules (3C*) present in aerosols have been investigated for their ability as oxidants the aqueous phase. Aerosols were collected Grenoble (France), winter and summer times during period December 2021 through June 2022, steady-state concentrations quantum yields 3C*, 1O2, •OH determined under solar-simulated conditions using various specific chemical probes. For comparison purposes, these three at sample 10 mg C L–1. The resulting all larger samples than ones ranked follows [1O2]ss > [3C*]ss [OH]ss agreement with previous reports. However, those do exhibit different reactivities classes compounds, which can be a generic way kOH,ORG k3C*,ORG k1O2,ORG. If we combine reactivity oxidants, it appears that matter are main most compounds. This study emphasizes relevance excited compared to singlet oxygen OH radicals need additional studies conditions.

Language: Английский

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Characterization of atmospheric water-soluble brown carbon in the Athabasca oil sands region, Canada

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(4), P. 2423 - 2442

Published: Feb. 25, 2025

Abstract. Extensive industrial operations in the Athabasca oil sands region (AOSR) (Alberta, Canada) are a suspected source of water-soluble brown carbon (WS-BrC), class light-absorbing organic aerosols capable altering atmospheric solar-radiation budgets. However, current understanding WS-BrC across AOSR is limited, and primary regional sources these unknown. During summer 2021, active filter-pack samplers were deployed at five sites to collect total suspended particulate matter for purpose evaluating WS-BrC. Ultraviolet–visible spectroscopy fluorescence excitation–emission matrix (EEM) spectroscopy, complemented by parallel factor analysis (PARAFAC) modelling, employed sample characterization. Aerosol absorbance was comparable between near-industry remote field sites, suggesting that exerted limited influence on radiative forcing. The combined EEM–PARAFAC method identified three fluorescent components (fluorophores), including one humic-like substance (C1) two protein-like substances (C2 C3). Sites near facilities exposures receiving transport from local industry (as indicated back-trajectory analysis) displayed increased C1 C3 fluorescence; moreover, both fluorophores positively correlated with elements (i.e. vanadium sulfur) gaseous pollutants nitrogen dioxide reduced sulfur), indicative emissions. C2 fluorophore exhibited high emission intensity near-field during severe wildfire smoke events, while positive correlations indicator variables suggest likely reflected wildfire-generated anthropogenic These results demonstrate an accessible cost-effective tool can be applied monitor AOSR.

Language: Английский

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Impacts of meteorological parameters on the occurrence of air pollution episodes in the Sichuan basin

Journal of Environmental Sciences, Journal Year: 2022, Volume and Issue: 114, P. 308 - 321

Published: Feb. 23, 2022

Language: Английский

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Water-soluble brown carbon in PM2.5 at two typical sites in Guanzhong Basin: Optical properties, sources, and implications

Atmospheric Research, Journal Year: 2022, Volume and Issue: 281, P. 106499 - 106499

Published: Nov. 2, 2022

Brown carbon (BrC) is a light-absorbing aerosol component that has significant impact on atmospheric photochemistry and climate effects. Many studies light absorbing characteristics of BrC (such as fraction water-soluble and/or water-insoluble) have been carried out in cities over the Guanzhong Basin, including radiative forcing, optical properties sources. However, research Qinling Mountains still lacking. Therefore, PM2.5 samples were collected at northern piedmont (QL) Xi'an (XN) winter 2020, radiation effects water extracts analyzed evaluated. The mass absorption efficiency (MAE) organic (WSOC) 365 nm (MAE365) obtained QL XN 0.18 ± 0.03 m2 g−1 0.78 0.96 g−1, respectively. In ultraviolet range, relative WSOC to elemental (EC) was 6.76% 33.41% XN, respectively, simple forcing (SFE280–400) 0.71 0.43 2.82 1.71 W XN. It may important balance regional systems. chromophores are mainly composed humic-like protein-like substances, humus-like substances play dominant role two sites (52.61% 71.13%). Biomass combustion limited contribution chromophore abundance QL, which more affected by urban transmission. fluorescence index revealed had autogenous matter mostly newly generated. Furthermore, molecular weight aromatic degree higher than indicating greater capacity for absorption. This work will be instrumental assessing interaction influence between city improve capability air pollution prevention control Basin.

Language: Английский

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Variabilities in Primary N-Containing Aromatic Compound Emissions from Residential Solid Fuel Combustion and Implications for Source Tracers

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(19), P. 13622 - 13633

Published: Sept. 21, 2022

Nitroaromatic compounds (NACs) not only are strongly absorbing chromophores but also adversely affect human health. NACs can be emitted from incomplete combustions and derive secondarily through photochemical reactions. Here, emission experiments were conducted for 31 fuel–stove combinations to elucidate variations in, influencing factors of, NAC (EF∑NACs) explore potential tracers different combustion sources. EF∑NACs varied by 2 orders of magnitude among combinations. Differences in fuel type contributed more than the stove difference observed variation. biomass pellets was approximately 66% lower that raw biomass, although bulk organic brown carbon EFs 95% lower. 2-Nitro-1-naphthol most abundant individual compound, followed 4-nitrocatechol, while acid (salicylic benzoic acid) low abundance (<1%). Substantially profiles between coal burning emissions. Biomass had single-ring-based phenolic with combustion, two-ring products produced. This study demonstrated much ratios 2-nitro-1-naphthol/4-nitrocatechol both traditional (2.0 ± 3.5) improved stoves (3.0 2.1) coals (15 6). Coal differed compound profile, consequently leading distinct health climate impacts; moreover, ratio may used source apportionment NACs.

Language: Английский

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Optical properties and molecular composition of wintertime atmospheric water-soluble organic carbon in different coastal cities of eastern China

The Science of The Total Environment, Journal Year: 2023, Volume and Issue: 892, P. 164702 - 164702

Published: June 9, 2023

Language: Английский

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Investigating the molecular weight distribution of atmospheric water-soluble brown carbon using high-performance size exclusion chromatography coupled with diode array and fluorescence detectors

Chemosphere, Journal Year: 2023, Volume and Issue: 338, P. 139517 - 139517

Published: July 14, 2023

Language: Английский

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A Review on Brown Carbon Aerosol in China: From Molecular Composition to Climate Impact

Current Pollution Reports, Journal Year: 2024, Volume and Issue: 10(2), P. 326 - 343

Published: Feb. 29, 2024

Language: Английский

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Fluorescence characteristics, absorption properties, and radiative effects of water-soluble organic carbon in seasonal snow across northeastern China

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(21), P. 14075 - 14094

Published: Nov. 3, 2022

Abstract. Water-soluble organic carbon (WSOC) in the cryosphere can significantly influence global cycle and radiation budget. However, WSOC snowpack has received little scientific attention to date. This study reports fluorescence characteristics, absorption properties, radiative effects of based on 34 snow samples collected from sites northeastern China. A significant degree regional variability is found, with concentrations ranging 0.5±0.2 5.7±3.7 µg g−1 (average concentration: 3.6±3.2 g−1). The three principal fluorescent components are identified as (1) high-oxygenated humic-like substances (HULIS-1) terrestrial origin, (2) low-oxygenated (HULIS-2) mixed (3) protein-like (PRLIS) derived autochthonous microbial activity. In southeastern Inner Mongolia (SEIM), a region dominated by desert exposed soils, exhibits highest humification index (HIX) but lowest (FI) biological (BIX) indices; signal mainly attributed HULIS-1 thus implicates soil primary source. By contrast, HIX (FI BIX) value (highest), percentage PRLIS remote area (NEIM), suggesting primarily For south north China (SNC NNC), both which characterized intensive agriculture industrial activity, HULIS-2, HIX, FI, BIX values all moderate, indicating origins for (anthropogenic soil). We also observe that, throughout China, light HULIS-1, followed HULIS-2 PRLIS. contribution albedo reduction 3.6 g−1) ultraviolet–visible (UV–Vis) band approximately half that black (BC average 0.6 Radiative forcing 3.8 (0.8) W m−2 old (fresh) snow, equating 19 % (17 %) BC. These results indicate profound impact solar balance.

Language: Английский

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Seasonal characterization of chemical and optical properties of water-soluble organic aerosol in Beijing

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 930, P. 172508 - 172508

Published: April 18, 2024

Language: Английский

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