Molecular compositions and optical properties of dissolved brown carbon in biomass burning, coal combustion, and vehicle emission aerosols illuminated by excitation–emission matrix spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry analysis

Atmospheric chemistry and physics, Год журнала: 2020, Номер 20(4), С. 2513 - 2532

Опубликована: Март 2, 2020

Abstract. Brown carbon (BrC) plays an essential impact on radiative forcing due to its ability absorb sunlight. In this study, the optical properties and molecular characteristics of water-soluble methanol-soluble organic (OC; MSOC) emitted from simulated combustion biomass coal fuels vehicle emissions were investigated using ultraviolet–visible (UV–vis) spectroscopy, excitation–emission matrix (EEM) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) coupled with electrospray ionization (ESI). The results showed that these smoke aerosol samples burning (BB) (CC) had a higher absorption efficiency at 365 nm (MAE365) than emission samples. A stronger MAE365 value was also found in MSOC (WSOC), indicating low polar compounds would possess light capacity. Parallel factor (PARAFAC) analysis identified six types fluorophores (P1–6) WSOC including two humic-like substances (HULIS-1) (P1 P6), three protein-like (PLOM) (P2, P3, P5), one undefined substance (P4). HULIS-1 mainly aging exhaust particles; P2 only abundant BB aerosols; P3 ubiquitous all tested P4 fossil P5 more intense fresh particles. chromophores (six components; C1–6) exhibited consistent WSOC, suggesting method could be used indicate origins chromophores. FT-ICR spectra CHO CHON most components but S-containing appeared abundance CC aerosols aerosols, while considerably fewer largely detected MSOC. unique formulas different sources van Krevelen (VK) diagram presented distributions. To specific, medium H ∕ C O ratio, opposite ratio. Moreover, capacity positively associated unsaturation degree weight source aerosols. above are potentially applicable further studies EEM-based or molecular-characteristic-based apportionment atmospheric

Язык: Английский

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Shortwave absorption by wildfire smoke dominated by dark brown carbon

Nature Geoscience, Год журнала: 2023, Номер 16(8), С. 683 - 688

Опубликована: Авг. 1, 2023

Wildfires emit large amounts of black carbon and light-absorbing organic carbon, known as brown into the atmosphere. These particles perturb Earth's radiation budget through absorption incoming shortwave radiation. It is generally thought that loses its absorptivity after emission in atmosphere due to sunlight-driven photochemical bleaching. Consequently, atmospheric warming effect exerted by remains highly variable poorly represented climate models compared with relatively nonreactive carbon. Given wildfires are predicted increase globally coming decades, it increasingly important quantify these radiative impacts. Here we present measurements ensemble-scale particle-scale smoke plumes from western United States. We find a type dark contributes three-quarters short visible light half long absorption. This strongly absorbing aerosol species water insoluble, resists daytime photobleaching increases night-time processing. Our findings suggest parameterizations need be revised improve estimation forcing associated warming.

Язык: Английский

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Molecular Characterization of Water- and Methanol-Soluble Organic Compounds Emitted from Residential Coal Combustion Using Ultrahigh-Resolution Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Environmental Science & Technology, Год журнала: 2019, Номер 53(23), С. 13607 - 13617

Опубликована: Ноя. 4, 2019

Water-soluble organic compounds (WSOC) and methanol-soluble (MSOC) in smoke particles emitted from residential coal combustion were characterized by ultrahigh-resolution mass spectrometry. The results showed that the molecular compositions of WSOC MSOC are different. S-containing (CHOS CHONS) found to be dominant components (65-87%) WSOC, whereas CHO CHON make a great contribution (79-96%) samples. It is worth noting greater abundance was produced compared biomass burning atmospheric also varied significantly depending on maturity coal. derived low-maturity contained higher proportion oxidized functional groups but with lower degree aromaticity than high-maturity Our findings suggest molecules high modified index, low O/C ratio, polarity stronger light absorption. This study suggests contributed absorption may stronger.

Язык: Английский

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Long-term brown carbon spectral characteristics in a Mediterranean city (Athens)

The Science of The Total Environment, Год журнала: 2019, Номер 708, С. 135019 - 135019

Опубликована: Ноя. 20, 2019

Язык: Английский

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Brown Carbon in Primary and Aged Coal Combustion Emission

Environmental Science & Technology, Год журнала: 2021, Номер 55(9), С. 5701 - 5710

Опубликована: Апрель 7, 2021

Smog chamber experiments were conducted to characterize the light absorption of brown carbon (BrC) from primary and photochemically aged coal combustion emissions. Light was measured by UV–visible spectrophotometric analysis water methanol extracts filter samples. The single-scattering albedo at 450 nm 0.73 ± 0.10 for emissions 0.75 0.13 coefficient 365 higher than that a factor 10 7 This suggests majority BrC is water-insoluble even after aging. mass efficiency this (MAE365) OA (POA) dependent on conditions, with an average 0.84 0.54 m2 g–1, which significantly (0.24 0.18 g–1). Secondary (SOA) dominated decreased MAE365 aging indicates SOA less absorbing POA and/or bleached (oxidized) estimated (0.14 0.08 g–1) much lower POA. A comparison residential other anthropogenic sources are among strongest organics.

Язык: Английский

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Brown carbon in atmospheric fine particles in Yangzhou, China: Light absorption properties and source apportionment

Atmospheric Research, Год журнала: 2020, Номер 244, С. 105028 - 105028

Опубликована: Май 16, 2020

Язык: 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, Год журнала: 2021, Номер 789, С. 147971 - 147971

Опубликована: Май 24, 2021

Язык: Английский

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Rate of atmospheric brown carbon whitening governed by environmental conditions

Proceedings of the National Academy of Sciences, Год журнала: 2022, Номер 119(38)

Опубликована: Сен. 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.

Язык: 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, Год журнала: 2022, Номер 22(10), С. 6449 - 6470

Опубликована: Май 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.

Язык: Английский

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Large contribution of fossil-derived components to aqueous secondary organic aerosols in China

Nature Communications, Год журнала: 2022, Номер 13(1)

Опубликована: Авг. 31, 2022

Incomplete understanding of the sources secondary organic aerosol (SOA) leads to large uncertainty in both air quality management and climate change assessment. Chemical reactions occurring atmospheric aqueous phase represent an important source SOA mass, yet, effects anthropogenic emissions on (aqSOA) are not well constrained. Here we use compound-specific dual-carbon isotopic fingerprints (δ13C Δ14C) dominant aqSOA molecules, such as oxalic acid, track precursor formation mechanisms aqSOA. Substantial stable carbon isotope fractionation molecules provides robust evidence for extensive aqueous-phase processing. Contrary paradigm that these compounds largely biogenic, radiocarbon-based apportionments show fossil precursors produced over one-half molecules. Large fractions fossil-derived contribute substantially total water-soluble load hence impact projections radiative forcing. Our findings reveal importance with quality.

Язык: Английский

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