Particulate nitrate photolysis in the atmosphere

Environmental Science Atmospheres, Journal Year: 2022, Volume and Issue: 2(2), P. 111 - 127

Published: Jan. 1, 2022

Particulate nitrate photolysis can lead to the formation of secondary inorganic and organic aerosols that affect climate, air quality, human health.

Language: Английский

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Aqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrate

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(1), P. 273 - 293

Published: Jan. 10, 2022

Abstract. Vanillin (VL), a phenolic aromatic carbonyl abundant in biomass burning emissions, forms triplet excited states (3VL∗) under simulated sunlight leading to aqueous secondary organic aerosol (aqSOA) formation. Nitrate and ammonium are among the main components of aerosols cloud or fog water. Under atmospherically relevant conditions, solutions composed either VL only with nitrate were subjected irradiation compare aqSOA formation via direct photosensitized oxidation absence presence nitrate. The reactions characterized by examining decay kinetics, product compositions, light absorbance changes. Both conditions generated oligomers, functionalized monomers, oxygenated ring-opening products, promoted functionalization nitration, likely due its photolysis products (⚫OH, ⚫NO2, NO2- HONO). Moreover, potential imidazole derivative observed suggested that participated reactions. majority most from both brown carbon (BrC) chromophores. effects oxygen (O2), pH, reactants concentration molar ratios on also explored. Our findings show O2 plays an essential role reactions, oligomer was enhanced at pH <4. Also, dominant low concentrations, whereas oligomerization favored high concentrations. Furthermore, oligomers hydroxylated detected guaiacol (a non-carbonyl phenol) Last, pathways proposed. This study indicates may be important source areas influenced underscores importance aqueous-phase processing carbonyls.

Language: Английский

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Sulfate Formation in Incense Burning Particles: A Single-Particle Mass Spectrometric Study

Environmental Science & Technology Letters, Journal Year: 2022, Volume and Issue: 9(9), P. 718 - 725

Published: Aug. 26, 2022

Incense burning is a common ritual in Asian communities, and it emits massive amounts of particles. These particles can undergo atmospheric aging upon exposure to sunlight other pollutants. In this work, we observed sulfate formation fresh incense SO2, using single-particle aerosol mass spectrometer (SPAMS). Analysis the positive spectra classified as K-type OC-type. both dark light experiments, SO2 uptake oxidation were found preferentially OC-type over Sulfate formation, represented by number fraction sulfate-containing (FS), under was likely due gaseous oxidants. FS increased with UV, mainly attributable photosensitization reactions. While more formed at higher relative humidity (RH) dark, independent RH. The increase photochemistry effective lower RH, where photoactive compounds concentrated generated photo-oxidants. This effect outweighed that reduced dissolution. Since contain organic photosensitizers have also been biomass particles, our findings could shed on potential trigger formation.

Language: Английский

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Single-particle Raman spectroscopy for studying physical and chemical processes of atmospheric particles

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(5), P. 3017 - 3044

Published: March 7, 2022

Abstract. Atmospheric particles experience various physical and chemical processes change their properties during lifetime. Most studies on atmospheric particles, both in laboratory field measurements, rely analyzing an ensemble of particles. Because different mixing states individual only average can be obtained from using ensembles To better understand the fate environmental impacts investigations at a single-particle level are valuable. Among wealth analytic techniques, Raman spectroscopy provides unambiguous characterization under pressure non-destructive situ manner. This paper comprehensively reviews application such technique including particle hygroscopicity, phase transition separation, solute–water interactions, pH, multiphase reactions. Investigations enhanced bioaerosols basis also reviewed. For each application, we describe principle representative examples studies. Finally, present our views future directions development further applications studying

Language: Английский

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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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Raman spectroscopy for profiling physical and chemical properties of atmospheric aerosol particles: A review

Ecotoxicology and Environmental Safety, Journal Year: 2022, Volume and Issue: 249, P. 114405 - 114405

Published: Dec. 9, 2022

Atmosphere aerosols have significant impact on human health and the environment. Aerosol particles a number of characteristics that influence their environmental effects, including size, shape, chemical composition. A great deal difficulty is associated with quantifying identifying atmospheric because these parameters are highly variable spatial temporal scale. An important component understanding aerosol fate Raman Spectroscopy (RS), which capable resolving compositions individual particles. This review presented strategic techniques, especially RS methods for characterizing aerosols. The nature properties environment were briefly described. Analytical methodologies offer insight into chemistry multidimensional discussed. In addition, perspectives practical applications using featured.

Language: Английский

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A fast and efficient method for the analysis of α-dicarbonyl compounds in aqueous solutions: Development and application

Chemosphere, Journal Year: 2023, Volume and Issue: 319, P. 137977 - 137977

Published: Feb. 1, 2023

Language: Английский

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Enhanced Sulfate Formation through Synergistic Effects of Chlorine Chemistry and Photosensitization in Atmospheric Particles

ACS ES&T Air, Journal Year: 2024, Volume and Issue: 1(2), P. 92 - 102

Published: Jan. 23, 2024

Numerous studies have demonstrated that organic photosensitizers from biomass burning can generate oxidants to effectively convert inorganic and precursors into secondary aerosols. Particulate chloride ions be internally mixed with in particles. In this study, we investigate the impact of interaction chlorine chemistry photosensitization on oxidative potential aerosols by utilizing SO2 oxidation form sulfate as an indicator. Mixed particles glyoxal its reaction products ammonia imidazole-2-carboxaldehyde (IC) were studied. Premixed NH4Cl + a 4–5 times higher formation rate than premixed NaCl glyoxal, particularly at low relative humidity, suggesting role photosensitization. Furthermore, addition IC resulted ∼73-fold increase production compared alone. No noticeable was observed presence alone, likely due high particle acidity study (i.e., pH = 2). The kinetic analysis these results yields constant triplet state IC, 3IC*, ∼3 orders magnitude previously reported values bulk solution. These findings underscore significance synergetic effect enhancing atmospheric capacity.

Language: Английский

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Simultaneous formation of sulfate and nitrate via co-uptake of SO₂ and NO₂ by aqueous NaCl droplets: combined effect of nitrate photolysis and chlorine chemistry

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(11), P. 6113 - 6126

Published: June 5, 2023

Abstract. SO2 and NO2 are the critical precursors in forming sulfate nitrate ambient particles. We studied mechanism of formation during co-uptake into NaCl droplets at different RHs under irradiation dark conditions. A significant attributable to hydrolysis was observed uptake all conditions, its rate increases with decreasing RH. The averaged coefficient, γNO2, from unary conditions is 1.6 × 10−5, 1.9 3.0 10−5 80 %, 70 60 % RH, respectively. Chloride photolysis play a crucial role co-uptake. Nitrate generates reactive species (e.g., OH radicals, NO2, N(III)) that directly react S(IV) produce sulfate. radicals generated can also chloride ions form chlorine then To parameterize sulfate, γSO2, as function rate, PNO3- (jNO3- [NO3-]), PCl- (jCl- [Cl−]), derived γSO2 = 0.41 + 0.34 PCl-. Our findings open up new perspectives on secondary aerosol combined effect chemistry.

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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