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, Journal Year: 2023, Volume and Issue: 23(4), P. 2859 - 2875

Published: March 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

Language: Английский

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Reactive Oxygen Species Formation and Peroxide and Carbonyl Decomposition in Aqueous Photolysis of Secondary Organic Aerosols

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(10), P. 4716 - 4726

Published: Feb. 27, 2024

The mechanism and kinetics of reactive oxygen species (ROS) formation when atmospheric secondary organic aerosol (SOA) is exposed to solar radiation are poorly understood. In this study, we combined an in situ UV–vis irradiation system with electron paramagnetic resonance (EPR) spectroscopy characterize the photolytic ROS aqueous extracts SOA formed by oxidation isoprene, α-pinene, α-terpineol, toluene. We observed substantial free radicals, including •OH, superoxide (HO2•), radicals (R•/RO•) upon irradiation. Compared dark conditions, radical yield was enhanced a factor ∼30 for •OH 2–10 emergence radicals. Total peroxide measurements showed decreases contents after photoirradiation, indicating that peroxides can be important source A liquid chromatography interfaced high-resolution mass spectrometry used detect number form adducts spin trap, BMPO. types detected photolysis model compounds indicated carbonyls Norrish type I mechanisms plays role formation. serves as driving force cloud fog processing SOA.

Language: Английский

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Pollution characteristics, source appointment and environmental effect of oxygenated volatile organic compounds in Guangdong-Hong Kong-Macao Greater Bay Area: Implication for air quality management

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 919, P. 170836 - 170836

Published: Feb. 10, 2024

Language: Английский

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Important yet Overlooked HONO Source from Aqueous-phase Photochemical Oxidation of Nitrophenols

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(35), P. 15722 - 15731

Published: Aug. 23, 2024

Nitrites (NO

Language: Английский

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Photoenhanced Radical Formation in Aqueous Mixtures of Levoglucosan and Benzoquinone: Implications to Photochemical Aging of Biomass-Burning Organic Aerosols

The Journal of Physical Chemistry A, Journal Year: 2023, Volume and Issue: 127(24), P. 5209 - 5221

Published: June 7, 2023

The photochemical aging of biomass-burning organic aerosols (BBOAs) by exposure to sunlight changes the chemical composition over its atmospheric lifetime, affecting toxicological and climate-relevant properties BBOA particles. This study used electron paramagnetic resonance (EPR) spectroscopy with a spin-trapping agent, 5-tert-butoxycarbonyl-5-methyl-1-pyrroline-N-oxide (BMPO), high-resolution mass spectrometry, kinetic modeling photosensitized formation reactive oxygen species (ROS) free radicals in mixtures benzoquinone levoglucosan, known tracer molecules. EPR analysis irradiated solutions showed dominant hydroxyl (•OH), which are products reaction triplet-state water, also yielding semiquinone radicals. In addition, hydrogen (H•) were observed, not detected previous studies. They most likely generated decomposition irradiation levoglucosan led substantial carbon- oxygen-centered radicals, became prominent higher fraction levoglucosan. High-resolution spectrometry permitted direct observation BMPO-radical adducts demonstrated •OH, derived from oxidation Mass superoxide radical (BMPO-OOH) that did appear spectra. Kinetic processes successfully reproduced time evolution observed BMPO •OH H• EPR. model was then applied describe would occur absence BMPO, predicting generation HO2• due dissolved oxygen. These results imply photoirradiation containing photosensitizers induces ROS secondary chemistry drive atmosphere.

Language: Английский

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Sulfate Formation by Photosensitization in Mixed Incense Burning–Sodium Chloride Particles: Effects of RH, Light Intensity, and Aerosol Aging

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(28), P. 10295 - 10307

Published: July 7, 2023

Elevated particulate sulfate concentrations have been frequently observed in coastal areas when air masses are influenced by continental emissions, especially combustion sources like biomass burning. We studied the SO2 uptake laboratory-generated droplets containing incense smoke extracts and sodium chloride (IS–NaCl) under irradiation found enhanced production over pure NaCl droplets, attributable to photosensitization induced constituents IS. Low relative humidity high light intensity facilitated formation increased coefficient IS–NaCl particles. Aging of IS particles further production, secondary oxidant promoted proportions nitrogen-containing CHN oxygen- CHON species air. Experiments using model compounds syringaldehyde, pyrazine, 4-nitroguaiacol verified enhancements formation. This work provides experimental evidence via triggered multiphase oxidation processes Our results can shed on possible interactions between sea salt burning aerosols enhancing production.

Language: Английский

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Formation of Artifacts from Simple Phenolic Compounds in SFC-UV-(HR)MS

Analytical Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 19, 2025

In this study, we present the formation of artifacts from simple phenolic compounds and derivatives in SFC-UV-MS analysis. These ions were detected only when UV detector was turned on, demonstrating that light is necessary for their formation. Based on high-resolution mass spectrometry (HRMS) analysis 21 standards negative electrospray ionization mode, annotated as where CO2 or NO2 had been added to molecular ion an lost a functional group. approximately half cases, MS signal artifact higher than ion. Although can complicate nontarget does not match with analyzed standard, demonstrated phenomenon aid structural identification isomers due specific ions. addition, overall increased which help detection low-abundance compounds, one compound─ anisole─ thanks artifact. Thus, aim article make researchers aware effect together advantages disadvantages

Language: Английский

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Spectroscopic characterization of phenol in frozen aqueous solution and on the ice surface

Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, Journal Year: 2025, Volume and Issue: 335, P. 125948 - 125948

Published: Feb. 22, 2025

Language: Английский

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Study on the kinetics and product characteristics of aqueous-phase oxidation of Eugenol and acetosyringone upon 254 nm/313 nm irradiation

Air Quality Atmosphere & Health, Journal Year: 2025, Volume and Issue: unknown

Published: March 1, 2025

Language: Английский

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The Photochemistry of Quinones and Combustion-derived Particles in Forming Hydroxyl Radicals and Singlet Oxygen in the Atmosphere

Atmospheric Environment, Journal Year: 2025, Volume and Issue: unknown, P. 121189 - 121189

Published: March 1, 2025

Language: Английский

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