Chemical Composition and Molecular-Specific Optical Properties of Atmospheric Brown Carbon Associated with Biomass Burning

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(4), P. 2511 - 2521

Published: Jan. 27, 2021

This study provides molecular insights into the light absorption properties of biomass burning (BB) brown carbon (BrC) through chemical characterization tar condensates generated from heated wood pellets at oxidative and pyrolysis conditions. Both liquid separated "darker oily" "lighter aqueous" immiscible phases. The composition these samples was investigated using reversed-phase chromatography coupled with a photodiode array detector high-resolution mass spectrometer. results revealed two sets BrC chromophores: (1) common to all four (2) specific "oily" fractions. chromophores consist polar, monoaromatic species. oil-specific include less-polar nonpolar polyaromatic compounds. most-light-absorbing oily phase (PO) aerosolized size-separated cascade impactor compare optical bulk versus BrC. coefficient (MAC300-500 nm) PO increased compared that bulk, due gas-phase partitioning more volatile less absorbing chromophores. were consistent previously reported ambient BB measurements. These suggest darkening atmospheric following non-reactive evaporation transforms aged aerosols.

Language: Английский

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

Chemical Society Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 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.

Language: Английский

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Fluorescence characteristics of water-soluble organic carbon in atmospheric aerosol☆

Environmental Pollution, Journal Year: 2020, Volume and Issue: 268, P. 115906 - 115906

Published: Oct. 20, 2020

Language: Английский

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Understanding the removal of an anionic dye in textile wastewaters by adsorption on ZnCl2 activated carbons from rice and coffee husk wastes: A combined experimental and theoretical study

Journal of environmental chemical engineering, Journal Year: 2021, Volume and Issue: 9(4), P. 105685 - 105685

Published: May 14, 2021

Language: Английский

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Water-soluble brown carbon in atmospheric aerosols along the transport pathway of Asian dust: Optical properties, chemical compositions, and potential sources

The Science of The Total Environment, Journal Year: 2021, Volume and Issue: 789, P. 147971 - 147971

Published: May 24, 2021

Language: Английский

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Rate of atmospheric brown carbon whitening governed by environmental conditions

Proceedings of the National Academy of Sciences, Journal Year: 2022, Volume and Issue: 119(38)

Published: Sept. 12, 2022

Biomass burning organic aerosol (BBOA) in the atmosphere contains many compounds that absorb solar radiation, called brown carbon (BrC). While BBOA is atmosphere, BrC can undergo reactions with oxidants such as ozone which decrease absorbance, or whiten. The effect of temperature and relative humidity (RH) on whitening has not been well constrained, leading to uncertainties when predicting direct radiative climate. Using an flow-tube reactor, we show by oxidation strongly dependent RH temperature. a poke-flow technique, viscosity also depends these conditions. measured rate described data, assuming due occurring bulk BBOA, within thin shell beneath surface. our combined datasets, developed kinetic model this process, lifetime 1 d less below ∼1 km altitude but often much longer than above altitude. Including dependence chemical transport causes large change predicted warming Overall, results illustrate need be considered understand role atmosphere.

Language: Английский

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Measurement report: Optical properties and sources of water-soluble brown carbon in Tianjin, North China – insights from organic molecular compositions

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(10), P. 6449 - 6470

Published: May 19, 2022

Abstract. Brown carbon (BrC) aerosols exert vital impacts on climate change and atmospheric photochemistry due to their light absorption in the wavelength range from near-ultraviolet (UV) visible light. However, optical properties formation mechanisms of ambient BrC remain poorly understood, limiting estimation radiative forcing. In present study, fine particles (PM2.5) were collected during 2016–2017 a day/night basis over urban Tianjin, megacity northern China. Light fluorescence water extracts PM2.5 investigated obtain seasonal diurnal patterns water-soluble BrC. There obvious seasonal, but no evident diurnal, variations winter, showed much stronger light-absorbing ability, with mass efficiency at 365 nm (MAE365) winter (1.54±0.33 m2 gC−1) that was 1.8 times larger than MAE365 summer (0.84±0.22 gC−1). Direct effects by relative black UV 54.3±16.9 % 44.6±13.9 summer, respectively. addition, five fluorescent components BrC, including three humic-like fluorophores two protein-like identified excitation–emission matrix spectrometry parallel factor (PARAFAC) analysis. The less oxygenated contributed more nighttime samples, while increased daytime samples. higher humification index (HIX), together lower biological (BIX) (FI), suggests chemical compositions associated high aromaticity degree photobleaching. Fluorescent indicate wintertime predominantly affected primary emissions fresh secondary organic aerosol (SOA), ones influenced aging processes. Results source apportionments using molecular same set reveal fossil fuel combustion processes, bioaerosol emission, biomass burning, biogenic anthropogenic SOA main sources Biomass burning nighttime, daytime. particular, our study highlights emission is an important Tianjin summer.

Language: Английский

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Chemical composition, optical properties, and oxidative potential of water- and methanol-soluble organic compounds emitted from the combustion of biomass materials and coal

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(17), P. 13187 - 13205

Published: Sept. 6, 2021

Abstract. Biomass burning (BB) and coal combustion (CC) are important sources of brown carbon (BrC) in ambient aerosols. In this study, six biomass materials five types were combusted to generate fine smoke particles. The BrC fractions, including water-soluble organic (WSOC), humic-like substance (HULIS-C), methanol-soluble (MSOC), subsequently fractionated, their optical properties chemical structures then comprehensively investigated using UV–visible spectroscopy, proton nuclear magnetic resonance spectroscopy (1H NMR), fluorescence excitation–emission matrix (EEM) combined with parallel factor (PARAFAC) analysis. addition, the oxidative potential (OP) BB CC was measured dithiothreitol (DTT) method. results showed that WSOC, HULIS-C, MSOC accounted for 2.3 %–22 %, 0.5 %–10 6.4 %–73 % total mass combustion-derived PM2.5, respectively, extracting highest concentrations compounds. fractions had light absorption capacity (mass efficiency at 365 nm (MAE365): 1.0–2.7 m2/gC) both smoke, indicating contained more strong light-absorbing components. Therefore, may represent better than fractions. Some significant differences observed between emitted from higher MAE365 lower Ångström exponent values detected CC. EEM-PARAFAC identified four fluorophores: two protein-like, one humic-like, polyphenol-like fluorophores. protein-like substances dominant components WSOC (47 %–80 %), HULIS-C (44 %–87 (42 %–70 %). 1H-NMR suggested oxygenated aliphatic functional groups (H-C-O), whereas unsaturated (H-C-C= Ar−H). DTT assays indicated generally a stronger (DTTm, 2.6–85 pmol/min/µg) 0.4–11 pmol/min/µg), having OP HULIS-C. contributed half activity (63.1 ± 15.5 highlighting HULIS major contributor reactive oxygen species (ROS) production WSOC. Furthermore, principal component analysis Pearson correlation coefficients highly fluorophore C4 be active BrC.

Language: Английский

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Characteristics and evolution of brown carbon in western United States wildfires

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(12), P. 8009 - 8036

Published: June 21, 2022

Abstract. Brown carbon (BrC) associated with aerosol particles in western United States wildfires was measured between July and August 2019 aboard the NASA DC-8 research aircraft during Fire Influence on Regional to Global Environments Air Quality (FIREX-AQ) study. Two BrC measurement methods are investigated, highly spectrally resolved light absorption solvent (water methanol) extracts of collected filters situ bulk particle at three wavelengths (405, 532 664 nm) a photoacoustic spectrometer (PAS). A light-absorption closure analysis for 300 700 nm performed. The combined pure black material, including enhancements due internally mixed materials, plus soluble Mie-predicted factor conversion BrC, compared spectra from power law fit PAS wavelengths. For various parameters used, wavelength roughly 400 they agreed, lower individual component-predicted significantly exceeded higher consistently but more variable. Limitations extrapolation data below 405 missing species low solubility that strongly absorb may account differences. Based measurements closest fires, emission ratio PAS-measured relative monoxide (CO) average 0.13 Mm−1 ppbv−1; ratios also provided. As smoke moved away burning regions, evolution over time observed be complex; enhancement, depletion or constant levels age were all first 8 h after different plumes. Within following emissions, 4-nitrocatechol, well-characterized chromophore commonly found particles, largely depleted BrC. In descending plume where temperature increased by 15 K, 4-nitrocatechol dropped, possibly temperature-driven evaporation, remained unchanged. Evidence reactions ozone, related species, as pathway secondary formation under both high oxides nitrogen (NOx) conditions, while bleached regions ozone NOx, consistent complex behaviors laboratory studies. Although hours is variable, limited number aged (15 30 h) indicate net loss It yet determined how near-field affects characteristics longer timescales spatial scales, its environmental impacts likely greater.

Language: Английский

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The Influence of Heterogeneous Processes on the Physicochemical Properties of Atmospheric Aerosols

Advances in Atmospheric Sciences, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 22, 2025

Language: Английский

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