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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Seasonal variation in oxygenated organic molecules in urban Beijing and their contribution to secondary organic aerosol

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(15), P. 10077 - 10097

Published: Aug. 5, 2022

Abstract. Oxygenated organic molecules (OOMs) are crucial for atmospheric new particle formation and secondary aerosol (SOA) growth. Therefore, understanding their chemical composition, temporal behavior, sources is of great importance. Previous studies on OOMs mainly focus environments where biogenic predominant, yet sites with dominant anthropogenic emissions, such as megacities, have been lacking. Here, we conducted long-term measurements OOMs, covering four seasons the year 2019, in urban Beijing. The OOM concentration was found to be highest summer (1.6×108 cm−3), followed by autumn (7.9×107 spring (5.7×107 cm−3) winter (2.3×107 suggesting that enhanced photo-oxidation together rise temperature promote OOMs. Most contained 5 10 carbon atoms 3 7 effective oxygen (nOeff=nO-2×nN). average nOeff increased increasing capacity, which lowest autumn. By performing a newly developed workflow, were classified into following types: aromatic aliphatic isoprene monoterpene Among them, (29 %–41 %) (26 main contributors all seasons, indicating Beijing dominated sources. contribution significantly (33 %), much higher than those other three (8 %–10 %). Concentrations (0.2–5.3×107 (1.1–8.4×106 lower reported at sites, they possessed nitrogen contents due high NOx levels (9.5–38.3 ppbv – parts per billion volume) With regard content two composed CHO CHON species, while CHON2 ones. Such prominent differences suggest varying pathways between these combining an dynamic model, estimated SOA growth rate through condensation could reach 0.64, 0.61, 0.41, 0.30 µg m−3 h−1 autumn, summer, spring, winter, respectively. Despite similar concentrations former had volatilities and, therefore, showed contributions (46 %–62 latter (14 %–32 contrast, limited low abundances or volatilities, 8 %–12 % %–5 %, Overall, our results improve concentration, seasonal variation, potential impacts can help formulate refined restriction policy specific control areas.

Language: Английский

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Rapid analysis of meat floss origin using a supervised machine learning-based electronic nose towards food authentication

npj Science of Food, Journal Year: 2023, Volume and Issue: 7(1)

Published: June 16, 2023

Authentication of meat floss origin has been highly critical for its consumers due to existing potential risks having allergic diseases or religion perspective related pork-containing foods. Herein, we developed and assessed a compact portable electronic nose (e-nose) comprising gas sensor array supervised machine learning with window time slicing method sniff classify different products. We evaluated four methods data classification (i.e., linear discriminant analysis (LDA), quadratic (QDA), k-nearest neighbors (k-NN), random forest (RF)). Among them, an LDA model equipped five-window-extracted feature yielded the highest accuracy values >99% both validation testing in discriminating beef, chicken, pork flosses. The obtained e-nose results were correlated confirmed spectral from Fourier-transform infrared (FTIR) spectroscopy chromatography-mass spectrometry (GC-MS) measurements. found that beef chicken had similar compound groups hydrocarbons alcohol). Meanwhile, aldehyde compounds (e.g., dodecanal 9-octadecanal) be dominant Based on performance evaluation, system shows promising food authenticity testing, which paves way ubiquitously detecting deception fraud attempts.

Language: Английский

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Atmospheric nanoparticle growth

Reviews of Modern Physics, Journal Year: 2023, Volume and Issue: 95(4)

Published: Nov. 9, 2023

Atmospheric nanoparticles can serve as nuclei for cloud droplets, thereby inducing significant but uncertain effects on the radiative forcing of climate system. This article focuses physicochemical processes that govern growth these particles from formation molecular clusters until reach sizes where they act condensation nuclei. The review describes latest developments in measurement and modeling connects domains to large-scale simulations such Earth system models. authors recommend closer coordination among laboratory studies, atmospheric measurements, understand importance

Language: Английский

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NO at low concentration can enhance the formation of highly oxygenated biogenic molecules in the atmosphere

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: June 8, 2023

The interaction between nitrogen monoxide (NO) and organic peroxy radicals (RO2) greatly impacts the formation of highly oxygenated molecules (HOM), key precursors secondary aerosols. It has been thought that HOM production can be significantly suppressed by NO even at low concentrations. Here, we perform dedicated experiments focusing on from monoterpenes concentrations (0 - 82 pptv). We demonstrate such enhance modulating RO2 loss favoring alkoxy continue to autoxidize through isomerization. These insights suggest yields typical boreal forest emissions vary 2.5%-6.5%, will not completely inhibited high Our findings challenge notion monotonically reduces extending knowledge RO2-NO interactions low-NO regime. This represents a major advance towards an accurate assessment budgets, especially in environments, which prevails pre-industrial atmosphere, pristine areas, upper boundary layer.

Language: Английский

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Kinetics, SOA yields, and chemical composition of secondary organic aerosol from <i>β</i>-caryophyllene ozonolysis with and without nitrogen oxides between 213 and 313 K

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(9), P. 6001 - 6020

Published: May 6, 2022

Abstract. β-caryophyllene (BCP) is one of the most important sesquiterpenes (SQTs) in atmosphere, with a large potential contribution to secondary organic aerosol (SOA) formation mainly from reactions ozone (O3) and nitrate radicals (NO3). In this work, we study temperature dependence kinetics BCP ozonolysis, SOA yields, chemical composition dark absence presence nitrogen oxides including We cover range 213–313 K, representative tropospheric conditions. The oxidized components both gas particle phases were characterized on molecular level by ionization mass spectrometer equipped filter inlet for gases aerosols using iodide as reagent ion (FIGAERO-iodide-CIMS). batch mode experiments conducted 84.5 m3 aluminium simulation chamber AIDA at Karlsruhe Institute Technology (KIT). oxides, temperature-dependent rate coefficient endocyclic double bond reacting between 243–313 K negatively correlated temperature, corresponding following Arrhenius equation: k= (1.6 ± 0.4) × 10−15 exp((559 97)/T). yields increase 16 5 % 37 11 %, temperatures decreasing 313 243 total 10 µg m−3. variation ozonolysis leads substantial impact abundance individual molecules. monomers C14−15H22−24O3−7 (37.4 %), dimers C28−30H44−48O5−9 (53.7 trimers C41−44H62−66O9−11 (8.6 %) are abundant phase 213 K. At observed more (mainly C14−15H22−24O6−9, 67.5 C27−29H42−44O9−11, 27.6 highly molecules (HOMs; C14H22O7,9, C15H22O7,9C15H24O7,9), which can be formed via hydrogen shift mechanisms, but no significant trimers. organonitrate fraction increased 3 12 49 respectively. Most organonitrates C15 skeletons only group. More oxygenated higher temperatures, their signal-weighted O:C atomic ratio increasing 0.41 0.51 New dimeric trimeric species without atoms (C20, C35) 298–313 indicating new reaction pathways. Overall, our results show that lead relatively small decrease strong yields. contrast, HOMs increases significantly temperature.

Language: Английский

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Molecular Characterization of Oxygenated Organic Molecules and Their Dominating Roles in Particle Growth in Hong Kong

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(20), P. 7764 - 7776

Published: May 8, 2023

Oxygenated organic molecules (OOMs) are critical intermediates linking volatile compound oxidation and secondary aerosol (SOA) formation. Yet, the understanding of OOM components, formation mechanism, impacts still limited, especially for urbanized regions with a cocktail anthropogenic emissions. Herein, ambient measurements OOMs were conducted at regional background site in South China 2018. The molecular characteristics revealed dominant nitrogen-containing products, influences different factors on composition state elucidated. Positive matrix factorization analysis resolved complex species to featured fingerprint from pathways. A new method was developed identify key functional groups OOMs, which successfully classified majority into carbonyls (8%), hydroperoxides (7%), nitrates (17%), peroxyl (10%), dinitrates (13%), aromatic ring-retaining (6%), terpenes (7%). volatility estimation improved based their identified used simulate growth process contributed by condensation those low-volatile OOMs. results demonstrate predominant role contributing sub-100 nm particle SOA highlight importance products multistep oxidation.

Language: Английский

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Chemical characterization of organic vapors from wood, straw, cow dung, and coal burning

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(4), P. 2707 - 2724

Published: March 3, 2025

Abstract. Solid fuel (SF) combustions, including coal and biomass, are important sources of pollutants in the particle gas phase therefore have significant implications for air quality, climate, human health. In this study, we systematically examined gas-phase emissions, using Vocus proton-transfer-reaction time-of-flight (PTR-TOF) mass spectrometer, from a variety solid fuels, beech logs, spruce/pine branches needles, straw, cow dung, coal. The average emission factors (EFs) organic vapors ranged 4.8 to 74.2 g kg−1, depending on combustion phases types. Despite slight differences modified efficiency (MCE) some experiments, increasing EFs were observed with lower MCE. relative contribution different classes showed large similarities between logs stove burning, change observed. CxHyOz family is most abundant group vapor emitted all SF combustion. However, among these greater nitrogen-containing species CxHy families (related polycyclic aromatic hydrocarbons) dung burning respectively. Intermediate-volatility compounds (IVOCs) constituted fraction emissions combustion, ranging 12.6 % 39.3 %. This was particularly notable needles (39.3 %) (31.1 %). Using Mann–Whitney U test studied identified specific potential new markers fuels based measurements. product pyrolysis coniferyl-type lignin extract cedar pine needle as open (e.g., C10H14O2, C11H14O2, C10H10O2). (C9H12O) marker log burning. Many series homologues C10H11–21NO, C12H11–21N, C11H11–23NO, C15H15–31N) acetonitrile, acrylonitrile, propanenitrile, methylpentanenitrile) specifically emissions. Polycyclic hydrocarbons (PAHs) 9–12 carbons significantly higher abundance compared other fuels. composition reflects burned types can help constrain regional models.

Language: Английский

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Ammonium CI-Orbitrap: a tool for characterizing the reactivity of oxygenated organic molecules

Atmospheric measurement techniques, Journal Year: 2024, Volume and Issue: 17(17), P. 5413 - 5428

Published: Sept. 13, 2024

Abstract. Oxygenated organic molecules (OOMs) play an important role in the formation of atmospheric aerosols. Due to various analytical challenges with respect measuring vapors, uncertainties remain regarding and fate OOMs. The chemical ionization Orbitrap (CI-Orbitrap) mass spectrometer has recently been shown be a powerful technique that is able accurately identify gaseous compounds due its greater resolution. Here, we present ammonium-ion-based CI-Orbitrap (NH4+-Orbitrap) as capable wide range performance NH4+-Orbitrap compared state-of-the-art spectrometers, including nitrate-ion-based pressure interface coupled time-of-flight (NO3--LTOF), new generation proton transfer reaction-TOF (PTR3-TOF), iodide-based CI-TOF equipped Filter Inlet for Gases AEROsols (I−-CIMS). instruments were deployed simultaneously Cosmic Leaving OUtdoors Droplets (CLOUD) chamber at European Organization Nuclear Research (CERN) during CLOUD14 campaign 2019. Products generated from α-pinene ozonolysis under experimental conditions measured by spectrometers. was widest OOMs (i.e., O ≥ 2), less-oxidized species highly oxygenated (HOMs). Excellent agreement found between NO3--LTOF characterizing HOMs PTR3-TOF monomeric species. OOM concentrations estimated using calibration factors derived high time-series correlations side-by-side measurements. As other spectrometry techniques used this campaign, detection sensitivity greatly affected relative humidity, which may related changes efficiency and/or multiphase chemistry. Overall, study shows NH4+-ion-based chemistry associated resolution analyzer can measure almost all inclusive compounds. result, it now possible cover entire compounds, lead better understanding oxidation processes.

Language: Английский

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Incomplete mass closure in atmospheric nanoparticle growth

npj Climate and Atmospheric Science, Journal Year: 2025, Volume and Issue: 8(1)

Published: Feb. 26, 2025

Language: Английский

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