Quantifying the Light-Absorption Properties and Molecular Composition of Brown Carbon Aerosol from Sub-Saharan African Biomass Combustion

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: unknown

Published: Feb. 23, 2024

Sub-Saharan Africa is a hotspot for biomass burning (BB)-derived carbonaceous aerosols, including light-absorbing organic (brown) carbon (BrC). However, the chemically complex nature of BrC in BB aerosols from this region not fully understood. We generated smoke chamber through smoldering combustion common sub-Saharan African fuels (hardwoods, cow dung, savanna grass, and leaves). quantified aethalometer-based, real-time light-absorption properties BrC-containing organic-rich accounting variations wavelength, fuel type, relative humidity, photochemical aging conditions. In filter samples collected Botswana winter, we identified 182 species, classified into lignin pyrolysis products, nitroaromatics, coumarins, stilbenes, flavonoids. Using an extensive set standards, determined species-specific mass emission factors. Our analysis revealed linear relationship between combined species contribution to chamber-measured aerosol (0.4–14%) mass-absorption cross-section at 370 nm (0.2–2.2 m2 g–1). Hierarchical clustering resolved key molecular-level components matrix, with photochemically aged emissions leaf cow-dung showing fingerprints similar those found aerosols. These quantitative findings could potentially help refine climate model predictions, aid source apportionment, inform effective air quality management policies human health global climate.

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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Nitroaromatic compounds in six major Chinese cities: Influence of different formation mechanisms on light absorption properties

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 930, P. 172672 - 172672

Published: April 23, 2024

Language: Английский

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Pollutant Emissions and Oxidative Potentials of Particles from the Indoor Burning of Biomass Pellets

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(36), P. 16016 - 16027

Published: Aug. 5, 2024

Residential solid fuel combustion significantly impacts air quality and human health. Pelletized biomass fuels are promoted as a cleaner alternative, particularly for those who cannot afford the high costs of gas/electricity, but their emission characteristics potential effects remain poorly understood. The present laboratory-based study evaluated pollution emissions from pelletized burning, including CH4 (methane), NMHC (nonmethane hydrocarbon compounds), CO, SO2, NOx, PM2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm), OC (organic carbon), EC (element PAHs (polycyclic aromatic hydrocarbons), EPFRs (environmentally persistent free radicals), OP (oxidative potential) PM2.5, compared raw burning. For most targets, except SO2 mass-based factors were 62–96% lower than biomass. NOx levels negatively correlated other pollutants (p < 0.05). Based on real-world daily consumption data, this estimated that households using could achieve significant reductions (51–95%) in CH4, NMHC, OC, EC, PAHs, to biomass, while differences statistically insignificant. reduction rate benzo(a)pyrene-equivalent was only 16%, much total PAH mass (78%). This is primarily attributed more toxic potentials, such dibenz(a,h)anthracene, emissions. Consequently, health associated might be overestimated if counted. particles pellet burning also by 96%. results suggested transitional substitution option can improve mitigate exposure.

Language: Английский

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Comparison of water-soluble and water-insoluble organic compositions attributing to different light absorption efficiency between residential coal and biomass burning emissions

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(10), P. 6323 - 6337

Published: May 29, 2024

Abstract. There are growing concerns about the climate impacts of absorbing organic carbon (also known as brown carbon, BrC) in environment, yet its chemical composition and association with light absorption capabilities remain poorly understood. This study characterized water-soluble water-insoluble (WSOC WIOC) from residential solid fuel combustion at molecular level evaluated their quantitative relationship mass efficiency (MAE). The MAE values λ = 365 nm biomass burning were significantly higher than those coal (p < 0.05). Thousands peaks identified m/z range 150–800, most intense ion occurring between 200–500 for WSOC 600–800 WIOC, respectively. CHO group predominated extract emissions, while sulfur-containing compounds (SOCs) including CHOS CHONS more WIOC extract, particularly emissions. Emissions CHON positively correlated nitrogen content (r 0.936; p 0.05), explaining abundance emissions compared to biomass. SOC predominant during flaming phases, indicated by a positive correlation modified (MCE) 0.750; unique formulas aerosols lower H/C O/C regions, unsaturated van Krevelen (VK) diagram. In contained fractions condensed aromatics (32 %–59 %) only 4.3 %–9.7 % contrast, was larger aromatic compound combustion. Moreover, both 0.714; 0.05) extracts 0.929; 0.001), suggesting that these contributed variabilities across different fuels.

Language: Английский

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Revealing Molecular Structures of Nitrogen-Containing Compounds in Dissolved Black Carbon Using Ultrahigh-Resolution Mass Spectrometry Combined with Thermodynamic Calculations

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(27), P. 11998 - 12007

Published: June 27, 2024

Landscape wildfires generate a substantial amount of dissolved black carbon (DBC) annually, yet the molecular nitrogen (N) structures in DBC are poorly understood. Here, we systematically compared chemodiversity N-containing molecules among three different samples from rice straw biochar pyrolyzed at 300, 400, and 500 °C, one leached organic (LDOC) sample composted straw, fire-affected soil matter (SDOMFire) using Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). N-Containing contributed 20.0%, 36.1%, 43.7% total compounds Combined (pooling together DBC), LDOC, SDOMFire, respectively, with fewer N atoms had higher proportions (i.e., N1 > N2 N3). The were dominated by polycyclic aromatic (62.2%) (14.4%) components, while those LDOC lignin-like (50.4%) (30.1%) components. composition SDOMFire more similar to than LDOC. As temperature rose, proportion nitrogenous component significantly increased concurrent enhanced oxidation unsaturation N. indicated density functional theory (DFT)-based thermodynamic calculations, aliphatic amide decreased 23.2% 7.9%, whereas that nitroaromatic 10.0% 39.5% as 300 °C; alternatively, 5/6 membered ring remained relatively stable (∼31%) peaked 400 °C (32.7%). Our work first provides comprehensive thorough description DBC, which helps better understand predict their fate biogeochemical behavior.

Language: Английский

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Characteristics of PM2.5 bounded carbonaceous aerosols, carbon dioxide and its stable carbon isotopes (δ13C) in rural households in northwest China: Effect of different fuel combustion

Journal of Environmental Management, Journal Year: 2024, Volume and Issue: 359, P. 121004 - 121004

Published: May 1, 2024

Language: Английский

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Enhanced sulfate formation in mixed biomass burning and sea-salt interactions mediated by photosensitization: effects of chloride, nitrogen-containing compounds, and atmospheric aging

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(1), P. 425 - 439

Published: Jan. 13, 2025

Abstract. Discrepancies persist between modeled simulations and measured sulfate concentrations in the marine boundary layer, especially when air is influenced by biomass burning plumes. However, there has been a notable dearth of research conducted on interactions sea-salt aerosol plumes, impeding comprehensive understanding formation. This work studied formation mixing real (BB) extracts NaCl, mimicking internal mixtures BB particles. BB–NaCl particles had significantly higher rate than incense (IS)–NaCl For fresh particles, followed trend corn straw (CS)–NaCl > rice (RS)–NaCl wheat (WS)–NaCl IS–NaCl. The filter sample aging was achieved exposure to OH• generated from UV irradiation. After aging, RS–NaCl exhibited highest enhancement rates among all due RS NaCl. Bulk aqueous experiments spiked with NaCl using model photosensitizers (PSs) nitrogen-containing organic compounds (NOCs), pyrazine (CHN), 4-nitrocatechol (CHON) revealed positive effects chloride PS–CHON system negative PS–CHN Our suggests that reaching or near coastal areas can affect via photosensitizer-mediated reactions, potentially exacerbating pollution.

Language: Английский

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Environmentally Persistent Free Radical Emissions from Indoor Burning of Pelletized Biofuels

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: March 12, 2025

Pelletization of biomass fuels has been promoted as an effective alternative to mitigate particulate matter (PM) emissions from the residential burning raw materials; however, environmentally persistent free radicals (EPFRs), a class harmful components in PM, pellet have rarely studied yet. Here, laboratory-based combustion experiments were conducted characterize EPFRs for different pellets burned cooking and heating stoves compared with those corresponding uncompressed biofuels. Emission factors (EFs) ranged 2.97 × 1017 2.33 1019 spins/kg, following log-normal distribution, geometric mean 4.21 1018 spins/kg. These carbon-centered adjacent oxygen atoms. Emissions varied largely across fuel–stove combinations, efficiency temperature key influencing explaining 49% variations EFPR EFs. Compared fuels, pelletized showed 50–80% lower EPFR EFs 40–70% per PM but more types, there was no significant change degree oxidation EPFRs. The made crop residues clean cookstove can reduce nearly 90% EFPRs burning, which is reduction mass. This study provides valuable data promoting understanding formation deployment protection air quality human health.

Language: Английский

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Particulate nitrated aromatic compounds from corn straw burning: Compositions, optical properties and potential health risks

Environmental Pollution, Journal Year: 2023, Volume and Issue: 323, P. 121332 - 121332

Published: Feb. 21, 2023

Language: Английский

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