Comparison of aqueous secondary organic aerosol (aqSOA) product distributions from guaiacol oxidation by non-phenolic and phenolic methoxybenzaldehydes as photosensitizers in the absence and presence of ammonium nitrate

Atmospheric chemistry and physics, Год журнала: 2023, Номер 23(4), С. 2859 - 2875

Опубликована: Март 2, 2023

Abstract. Aromatic carbonyls (e.g., methoxybenzaldehydes), an important class of photosensitizers, are abundant in the atmosphere. Photosensitization and nitrate-mediated photo-oxidation can occur simultaneously, yet studies about their interactions, particularly for aqueous secondary organic aerosol (aqSOA) formation, remain limited. This study compared non-phenolic (3,4-dimethoxybenzaldehyde, DMB) phenolic (vanillin, VL) methoxybenzaldehydes as photosensitizers aqSOA formation via guaiacol (GUA) oxidation absence presence ammonium nitrate (AN) under atmospherically relevant cloud fog conditions. GUA by triplet excited states DMB (3DMB∗) (GUA + was ∼ 4 times faster exhibited greater light absorption than 3VL∗ VL). Both VL formed composed oligomers, functionalized monomers, oxygenated ring-opening species, N-containing products AN. The observation N-heterocycles such imidazoles indicates participation reactions. majority generated comprises potential brown carbon (BrC) chromophores. Oligomerization functionalization dominated VL, but appeared to be more due contributions from itself. AN did not significantly affect kinetics, it had distinct effects on product distributions, likely differences photosensitizing abilities structural features VL. In particular, extensive fragmentation AN, increased oligomers may VL-derived phenoxy radicals induced ⚫OH or ⚫NO2 photolysis. Furthermore, nitrated observed both alone imply that photosensitized reactions promote nitration. work demonstrates how non-carbonyl phenol oxidation. Potential interactions between photosensitization photolysis were also elucidated. These findings facilitate a better understanding highlight importance these

Язык: Английский

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Secondary Organic Aerosol Generated from Biomass Burning Emitted Phenolic Compounds: Oxidative Potential, Reactive Oxygen Species, and Cytotoxicity

Environmental Science & Technology, Год журнала: 2024, Номер 58(19), С. 8194 - 8206

Опубликована: Апрель 29, 2024

Phenolic compounds are largely emitted from biomass burning (BB) and have a significant potential to form SOA (Phc-SOA). However, the toxicological properties of Phc-SOA remain unclear. In this study, phenol guaiacol were chosen as two representative phenolic gases in BB plumes, water-soluble components their generated under different photochemical ages NOx levels investigated. contribute greatly oxidative (OP) biomass-burning SOA. OH-adducts (e.g., 2-methoxyhydroquinone) identified (GSOA) with high OP. The addition nitro groups 2,5-dimethyl-1,4-benzoquinone, surrogate quinone compound Phc-SOA, increased its toxicity both (PSOA) GSOA vitro human alveolar epithelial cells decreased aging terms cell death cellular reactive oxygen species (ROS), possibly due more ring-opening products relatively low toxicity. influence was consistent between ROS for but not PSOA, indicating that production does necessarily represent all processes contributing caused by PSOA. Combining acellular assays can provide comprehensive understanding aerosol properties.

Язык: Английский

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Aqueous-phase chemistry of atmospheric phenolic compounds: A critical review of laboratory studies

The Science of The Total Environment, Год журнала: 2022, Номер 856, С. 158895 - 158895

Опубликована: Сен. 18, 2022

Язык: Английский

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Aqueous-Phase Photoreactions of Mixed Aromatic Carbonyl Photosensitizers Yield More Oxygenated, Oxidized, and less Light-Absorbing Secondary Organic Aerosol (SOA) than Single Systems

Environmental Science & Technology, Год журнала: 2024, Номер 58(18), С. 7924 - 7936

Опубликована: Апрель 23, 2024

Aromatic carbonyls have been mainly probed as photosensitizers for aqueous secondary organic aerosol (aqSOA) and light-absorbing (i.e., brown carbon or BrC) formation, but due to their nature, they can also undergo oxidation form aqSOA BrC. However, photochemical transformations of aromatic carbonyl photosensitizers, particularly in multicomponent systems, are understudied. This study explored formation from the irradiation mixed single systems under cloud/fog conditions. Mixed consisting phenolic only (VL + ActSyr SyrAld: vanillin [VL] acetosyringone [ActSyr] syringaldehyde [SyrAld]) another composed both nonphenolic (DMB 3,4-dimethoxybenzaldehyde [DMB], a carbonyl, SyrAld) were compared VL (VL*) DMB (DMB*), respectively. In shorter lifetimes indicate diminished capacity trigger other compounds (e.g., guaiacol [GUA], noncarbonyl phenol). contrast slow decay minimal photoenhancement DMB*, rapid photodegradation significant VL* efficient direct photosensitized self-photosensitization). Relative increased oxidant availability promoted functionalization SyrAld accelerated conversion early generation SyrAld. Moreover, oxidizable substrates countered by stronger oxidative limited contribution light absorption. suggests weaker radiative effect BrC photosensitizer than systems. Furthermore, more oxygenated oxidized was observed with increasing complexity reaction < GUA). work offers new insights into emphasizing dual role sources substrates.

Язык: Английский

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Phototransformation of Vanillin in Artificial Snow by Direct Photolysis and Mediated by Nitrite

Environmental Science & Technology, Год журнала: 2023, Номер 57(23), С. 8785 - 8795

Опубликована: Июнь 3, 2023

The photodegradation of vanillin, as a proxy methoxyphenols emitted by biomass burning, was investigated in artificial snow at 243 K and liquid water room temperature. Nitrite (NO2–) used photosensitizer reactive oxygen nitrogen species under UVA light, because its key photochemical role snowpacks atmospheric ice/waters. In the absence NO2–, slow direct photolysis vanillin observed due to back-reactions taking place quasi-liquid layer ice-grain surface. addition NO2– made faster, important contribution photoproduced phototransformation. These triggered both nitration oligomerization irradiated snow, identified by-products showed. Conversely, water, main pathway even presence which had negligible effects on photodegradation. results outline different iced fate environmental compartments.

Язык: Английский

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Formation and emission characteristics of intermediate volatile organic compounds (IVOCs) from the combustion of biomass and their cellulose, hemicellulose, and lignin

Atmospheric Environment, Год журнала: 2022, Номер 286, С. 119217 - 119217

Опубликована: Июнь 9, 2022

Язык: Английский

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Optical Variation and Molecular Transformation of Brown Carbon During Oxidation by NO₃^• in the Aqueous Phase

Environmental Science & Technology, Год журнала: 2024, Номер unknown

Опубликована: Фев. 6, 2024

The NO3•-driven nighttime aging of brown carbon (BrC) is known to greatly impact its atmospheric radiative forcing. However, the oxidation by NO3• on optical properties BrC in waters as well associated reaction mechanism remain unclear. In this work, we found that variation proxies under environmentally relevant exposure depends strongly their sources, with enhanced light absorptivity for biomass-burning but bleaching urban aerosols and humic substances. High-resolution mass spectrometry using FT-ICR MS shows leads formation light-absorbing species (e.g., nitrated organics) while destroying electron donors phenols) within charge transfer complexes substances, evidenced transient absorption spectroscopy NaBH4 reduction experiments well. Moreover, measured rate constants between real BrCs (k = (1.8 ± 0.6) × 107 MC–1s–1, expressed moles carbon) are much higher than those individual model organic (OC), suggesting OCs may be a previously ill-quantified important sink waters. This work provides insights into kinetics molecular transformation during NO3•, facilitating further evaluation BrC's climatic effects levels.

Язык: Английский

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Heterogeneous Reactions of Phenol on Different Components of Mineral Dust Aerosol: Formation of Oxidized Organic and Nitro-Phenolic Compounds

ACS ES&T Air, Год журнала: 2024, Номер 1(4), С. 259 - 272

Опубликована: Фев. 23, 2024

Phenol, a common semi-volatile compound associated with different emissions including from plants and biomass burning, as well anthropogenic its derivatives, are important components of secondary organic aerosols (SOAs). Gas aqueous phase reactions phenol, in the presence photochemical drivers, fairly understood. However, despite observations showing aromatic content within SOA size mass increases during dust episodes, heterogeneous phenol mineral dusts poorly In current study, surface at gas/solid interface SiO2, α-Fe2O3, TiO2 have been investigated. Whereas reversible adsorption occurs on SiO2 surfaces, for both α-Fe2O3 reacts to form wide range OH substituted products. For surfaces that nitrated by gas-phase nitric acid prior exposure unique compounds nitro-phenolic compounds. Moreover, additional chemistry was observed when adsorbed products were exposed SO2 result formation nitrite nitrate redox SO2. Overall, this study reveals extensive complexity prevalent leading surfaces.

Язык: Английский

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Molecular-Scale Investigation on the Formation of Brown Carbon Aerosol via Iron-Phenolic Compound Reactions in the Dark

Environmental Science & Technology, Год журнала: 2023, Номер 57(30), С. 11173 - 11184

Опубликована: Июль 18, 2023

Brown carbon (BrC) is one of the most mysterious aerosol components responsible for global warming and air pollution. Iron (Fe)-induced catalytic oxidation ubiquitous phenolic compounds has been considered as a potential pathway BrC formation in dark. However, reaction mechanism product composition are still poorly understood. Herein, 13 precursors were employed to react with Fe under environmentally relevant conditions. Using Fourier transform ion cyclotron resonance mass spectrometry, total 764 unique molecular formulas identified, over 85% them can be found atmospheric aerosols. In particular, products derived from catechol-, guaiacol-, syringol-like-based structures distinguished by their optical characteristics, indicating structure-dependent precursors. Multiple pieces evidence indicate that acidic conditions, contribution either autoxidation or oxygen-induced free radical extremely limited. Ligand-to-Fe charge transfer subsequent phenoxy coupling reactions main polymerization high diversity, efficiency generation was linearly correlated ionization The present study uncovered how chemically diverse formed Fe-phenolic compound at level also provide new paradigm mechanism.

Язык: Английский

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Diurnal variations of biogenic volatile organic compounds and their role in secondary pollutant formation in the Huai Hong Khrai subtropical forest, Thailand

Environmental Pollution, Год журнала: 2025, Номер 372, С. 126044 - 126044

Опубликована: Март 11, 2025

Язык: Английский

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