Inconsistent capacity of potential HONO sources to enhance secondary pollutants: evidence from WRF-Chem modeling

Journal of Environmental Sciences, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 1, 2025

Language: Английский

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Photosensitizers Regulate Nitrate Photoproduct Yields in Bulk Aqueous Matrices

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

Published: March 17, 2025

Photolysis of nitrate (NO3-) in the presence photosensitizers is thought to promote release atmospherically important reactive nitrogen species (NOy), such as HONO, via mechanisms that are poorly understood. To address this knowledge gap, we conducted photochemistry studies on mixtures NO3-, a model photosensitizer [4-benzoylbenzoic acid (4-BBA)], and various aliphatic organic matter proxies. We found enhances production NOy superoxide (O2-) from bulk aqueous photolysis, while addition 4-BBA decreases O2- yields most cases. This effect was not observed heterogeneous systems, where enhanced photochemical when coadsorbed with NO3- silica surfaces. demonstrates act both oxidants reductants, regulating oxygen photochemistry. Given sufficient residence time phase, photoproducts can be scavenged secondary reactions photosensitizers. In aerosol systems high surface area-to-volume ratios, however, volatilization favored, less affected by chromophoric sinks phase. work intricate role moieties natural conversion (i.e., renoxification) atmosphere.

Language: Английский

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Surface Nitrate Enrichment and Enhanced HONO Production from Ionic Surfactant Aggregation at the Aqueous-Air Interface

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

Published: Dec. 5, 2024

Significant discrepancies persist between field observations and model simulations regarding the strength of marine-derived HONO sources, underscoring urgency to resolve unidentified sources. In this study, sodium dodecyl sulfate (SDS) was chosen as a proxy for marine surfactants investigate its impact on aqueous nitrate photolysis first time. Remarkable increases in NO2 production rates by factors 3.3 5.6, respectively, along with 1.9-fold rise NO2– concentration, were observed at very low SDS concentration 0.01 mM, strongly illustrating promoting effect photolysis. Furthermore, an 2 intriguingly aligned critical micelle there additional 41.7% increase rates. Vertically resolved Raman measurements indicated that anions aqueous-air interface attracted NO3– closer surfaces, increasing amount incompletely solvated surface nitrate. Importantly, anionic surfactant exhibited greater compared other typical photochemistry systems addition dissolved organic matter proxy, halogen, photosensitizer, or OH scavenger. These findings offer new insights into sources should be considered concerning budgets NOx, OH, O3.

Language: Английский

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Photoreduction of Nitrate to HONO and NO_x by Organic Matter in the Presence of Iron and Aluminum

ACS Earth and Space Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 15, 2024

Nitrogen oxides (NOy) such as NO, NO2, and HONO control the oxidative capacity of lower atmosphere. Studies have shown that photolysis nitrate on atmospheric surfaces is an efficient source nitrogen through a process termed "renoxification;" however, mechanisms responsible for this remain poorly understood, leading to difficulties in modeling composition. This work aims elucidate mechanism NOy formation from model boundary layer comprised mixtures organic matter (citrate Suwanee River fulvic acid) environmentally relevant metals (e.g., Al3+ Fe3+). Results show presence matter, photochemical yields were enhanced by factor between 5 15 compared with pure controls. Known photochemistry are unable explain enhancement, suggesting fraction directly converted strong reductants produced photochemically matter. The addition Fe (hydr)oxides catalyzed both reduction NO2 further NO via Fe2+, which formed photoreduction Fe-organic coordination complexes. In addition, study assesses contribution surface acidity visible light attenuation product yields. results support growing body evidence generated important unrecognized pathway renoxification soil airborne mineral dust aerosols).

Language: Английский

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Photooxidation of Nonanoic Acid by Molecular and Complex Environmental Photosensitizers

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: 128(45), P. 9792 - 9803

Published: Nov. 5, 2024

Photochemical aging and photooxidation of atmospheric particles play a crucial role in both the chemical physical processes occurring troposphere. In particular, presence organic chromophores within aerosols can trigger photosensitized oxidation that drives these interfaces. However, light-induced surface aerosols, especially those enriched with components, remains poorly understood. Herein, we present gravimetric vibrational spectroscopy study aimed to investigate nonanoic acid (NA), model system fatty acids complex photosensitizers molecular proxies. Specifically, this shows comparative analysis reactions thin films containing four different photosensitizers, namely marine dissolved matter (m-DOM) humic (HA) as environmental 4-imidazolecarboxaldehyde (4IC) 4-benzoylbenzoic (4BBA) All show predominant acid, important differences rate yield product formation depending on photosensitizer. Limited changes were observed photosensitizer itself. Results that, among examined, 4BBA is most effective photooxidizing acid. Overall, work underscores relevance such environment.

Language: Английский

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