Organic Peroxides in Aerosol: Key Reactive Intermediates for Multiphase Processes in the Atmosphere

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(4), P. 1635 - 1679

Published: Jan. 11, 2023

Organic peroxides (POs) are organic molecules with one or more peroxide (−O–O−) functional groups. POs commonly regarded as chemically labile termination products from gas-phase radical chemistry and therefore serve temporary reservoirs for oxidative radicals (HOx ROx) in the atmosphere. Owing to their ubiquity, active gas-particle partitioning behavior, reactivity, key reactive intermediates atmospheric multiphase processes determining life cycle (formation, growth, aging), climate, health impacts of aerosol. However, there remain substantial gaps origin, molecular diversity, fate due complex nature dynamic behavior. Here, we summarize current understanding on POs, a focus identification quantification, state-of-the-art analytical developments, molecular-level formation mechanisms, chemical transformation pathways, well environmental impacts. We find that interactions SO2 transition metal ions generally fast PO pathways liquid water, lifetimes estimated be minutes hours, while hydrolysis is particularly important α-substituted hydroperoxides. Meanwhile, photolysis thermolysis likely minor sinks POs. These distinctly different fates, such reaction OH radicals, which highlights need understand By summarizing advances remaining challenges investigation propose future research priorities regarding fate,

Language: Английский

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pH-Dependent Aqueous-Phase Brown Carbon Formation: Rate Constants and Implications for Solar Absorption and Atmospheric Photochemistry

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(2), P. 1236 - 1243

Published: Jan. 3, 2024

Aqueous-phase reactions of α-dicarbonyls with amines or ammonium have been identified as important sources secondary brown carbon (BrC). However, the kinetics BrC formation and effects pH are still not very clear. In this study, by aqueous (glyoxal methylglyoxal) ammonium, amino acids, alkylamines in bulk solution at different values investigated. Our results reveal pH-parameterized production rate constants, kBrCII (m–1 [M]−2 s–1), based on light absorption between 300 500 nm: log10(kBrCII) = (1.0 ± 0.1) × – (7.4 1.0) for glyoxal (6.3 0.9) methylglyoxal. The linear slopes closing to 1.0 indicate that is governed nitrogen nucleophilic addition pathway. Consequently, absorptivities produced increase exponentially pH. from methylglyoxal higher (≥6.5) exhibits optical properties comparable biomass burning coal combustion, categorized "weakly" absorbing BrC, while lower (<6.0) (pH 5.0–7.0) falls into "very weakly" BrC. pH-dependent feature significantly affects solar ability thus atmospheric photochemical processes, e.g., 7.0 absorbs 14–16 times more power compared 5.0, which turn could lead a decrease 1 order magnitude photolysis constants O3 NO2.

Language: Английский

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A review of atmospheric aging of sea spray aerosols: Potential factors affecting chloride depletion

Atmospheric Environment, Journal Year: 2022, Volume and Issue: 290, P. 119365 - 119365

Published: Sept. 2, 2022

Language: Английский

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A critical review of sulfate aerosol formation mechanisms during winter polluted periods

Journal of Environmental Sciences, Journal Year: 2022, Volume and Issue: 123, P. 387 - 399

Published: July 16, 2022

Language: Английский

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Sulfate Formation Apportionment during Winter Haze Events in North China

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(12), P. 7771 - 7778

Published: May 24, 2022

There is a large gap between the simulated and observed sulfate concentrations during winter haze events in North China. Although multiphase formation mechanisms have been proposed, they not evaluated using chemical transport models. In this study, Weather Research Forecasting model coupled with Chemistry (WRF-Chem) was used to apportion formation. It found that Mn-catalyzed oxidation on aerosol surfaces dominant pathway, accounting for 92.3 ± 3.5% of events. Gas-phase contributed 3.1 0.5% due low OH levels. The H2O2 water accounted 4.2 3.6% formation, caused by rapid consumption H2O2. contributions O3, NO2 oxidation, transition metal ion-catalyzed reactions could be negligible owing content, pH, high ionic strength. from in-cloud were barrier provided stable stratification

Language: Английский

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Effects of Acidity on Reactive Oxygen Species Formation from Secondary Organic Aerosols

ACS Environmental Au, Journal Year: 2022, Volume and Issue: 2(4), P. 336 - 345

Published: April 29, 2022

Reactive oxygen species (ROS) play a critical role in the chemical transformation of atmospheric secondary organic aerosols (SOA) and aerosol health effects by causing oxidative stress vivo. Acidity is an important physicochemical property aerosols, but its on ROS formation from SOA have been poorly characterized. By applying electron paramagnetic resonance spin-trapping technique Diogenes chemiluminescence assay, we find highly distinct radical yields composition at different pH values range 1–7.4 generated oxidation isoprene, α-terpineol, α-pinene, β-pinene, toluene, naphthalene. We observe that isoprene has substantial hydroxyl (•OH) neutral pH, which are 1.5–2 times higher compared to acidic conditions total yields. Superoxide (O2•–) found be dominant all types SOAs lower pH. At α-terpineol exhibits yield carbon-centered radicals, while no observed aromatic SOA. Further experiments with model compounds show decomposition peroxide leading may suppressed due acid-catalyzed rearrangement peroxides. also 1.5–3 molar hydrogen (H2O2) biogenic SOA, likely enhanced α-hydroxyhydroperoxides quinone redox cycling, respectively. These findings bridge gap understanding mechanisms kinetics physiological environments.

Language: Английский

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Differences in airborne stability of SARS-CoV-2 variants of concern is impacted by alkalinity of surrogates of respiratory aerosol

Journal of The Royal Society Interface, Journal Year: 2023, Volume and Issue: 20(203)

Published: June 1, 2023

The mechanistic factors hypothesized to be key drivers for the loss of infectivity viruses in aerosol phase often remain speculative. Using a next-generation bioaerosol technology, we report measurements aero-stability several SARS-CoV-2 variants concern droplets well-defined size and composition at high (90%) low (40%) relative humidity (RH) upwards 40 min. When compared with ancestral virus, Delta variant displayed different decay profiles. At RH, viral approximately 55% was observed over initial 5 s both variants. Regardless RH variant, greater than 95% lost after min being aerosolized. Aero-stability correlate their sensitivities alkaline pH. Removal all acidic vapours dramatically increased rate decay, 90% 2 min, while addition nitric acid vapour improved aero-stability. Similar artificial saliva growth medium observed. A model predict is proposed: pH exhaled drives loss; salt content limits infectivity.

Language: Английский

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New Insights into the Brown Carbon Chromophores and Formation Pathways for Aqueous Reactions of α-Dicarbonyls with Amines and Ammonium

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(33), P. 12351 - 12361

Published: Aug. 5, 2023

Aqueous-phase reactions of α-dicarbonyls with ammonium or amines have been identified as important sources secondary brown carbon (BrC). However, the identities most chromophores in these and effects pH remain largely unknown. In this study, chemical structures, formation pathways, optical properties individual BrC formed through aqueous (glyoxal methylglyoxal) ammonium, amino acids, methylamine at different pH's were characterized detail by liquid chromatography-photodiode array-high resolution tandem mass spectrometry. total, 180 are identified, accounting for 29-79% light absorption bulk reactions. Thereinto, 155 newly chromophores, including 76 imidazoles, 57 pyrroles, 10 pyrazines, 9 pyridines, 3 imidazole-pyrroles, explain additionally 9-69% absorption, mainly involve four previously unrecognized ammonia methylglyoxal dimer pyrroles. The also shows remarkable on transformation chromophores; e.g., increase from 5.0 to 7.0, contributions imidazoles decrease 72% 65%, while pyrazines 5% 13% + reaction; meanwhile, more small nitrogen heterocycles transformed into oligomers (e.g., C9 C12 pyrroles) via reaction methylglyoxal. These proposed pathways instructive future field studies aqueous-phase BrC.

Language: Английский

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Opinion: Atmospheric multiphase chemistry – past, present, and future

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(17), P. 9765 - 9785

Published: Sept. 4, 2023

Abstract. Multiphase chemistry occurs between chemicals in different atmospheric phases, typically involving gas–solid and gas–liquid interactions. The importance of multiphase has long been recognized. Its central role extends from acid precipitation stratospheric ozone depletion to its impact on the oxidizing capacity troposphere roles that aerosol particles play driving chemistry–climate interactions affecting human health. This opinion article briefly introduces subject tracks development before after start Atmospheric Chemistry Physics. Most focuses research opportunities challenges field. Central themes are a fundamental understanding at molecular level underpins ability accurately predict environmental change discipline is strongest when tightly connected modeling field observations.

Language: Английский

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Hydrogen peroxide serves as pivotal fountainhead for aerosol aqueous sulfate formation from a global perspective

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: May 30, 2024

Abstract Traditional atmospheric chemistry posits that sulfur dioxide (SO 2 ) can be oxidized to sulfate 4 2– through aqueous-phase reactions in clouds and gas-phase oxidation. Despite adequate knowledge of traditional mechanisms, several studies have highlighted the potential for SO oxidation within aerosol water. Given widespread presence tropospheric aerosols, 2− production water could a pervasive global impact. Here, we quantify contributions aqueous pathways formation based on GEOS-Chem simulations subsequent theoretical calculations. Hydrogen peroxide (H O significantly influences continental regions both horizontally vertically. Over past two decades, shifts typical cities reveal an intriguing trend: despite reductions emissions, increased capacities, like rising H levels, prevent steady decline concentrations. Abating oxidants would facilitate benefit reduction positive feedback mitigation.

Language: Английский

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