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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Atmospheric conditions and composition that influence PM<sub>2.5</sub> oxidative potential in Beijing, China

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(7), P. 5549 - 5573

Published: April 12, 2021

Epidemiological studies have consistently linked exposure to PM2.5 with adverse health effects. The oxidative potential (OP) of aerosol particles has been widely suggested as a measure their toxicity. Several acellular chemical assays are now readily employed OP; however, uncertainty remains regarding the atmospheric conditions and specific components that drive OP. A limited number simultaneously utilised multiple OP wide range concurrent measurements investigated seasonality In this work, filter samples were collected in winter 2016 summer 2017 during pollution human Chinese megacity campaign (APHH-Beijing), was analysed using four methods: ascorbic acid (AA), dithiothreitol (DTT), 2,7-dichlorofluorescin/hydrogen peroxidase (DCFH) electron paramagnetic resonance spectroscopy (EPR). Each assay reflects different oxidising properties PM2.5, including particle-bound reactive oxygen species (DCFH), superoxide radical production (EPR) catalytic redox chemistry (DTT/AA), combination these provided detailed overall picture at central site Beijing. Positive correlations (normalised per volume air) all mass observed, stronger compared summer. contrast, when values normalised for particle mass, days higher concentrations (μgm-3) found lower mass-normalised measured by AA DTT. This finding supports total alone may not always be best indicator Univariate analysis an extensive additional measurements, 107 total, composition, gas-phase composition meteorological data, insight into processes determine variability. Multivariate statistical analyses highlighted associations responses varying both mass- volume-normalised data. DTT well predicted small set linear regression (MLR) models indicated fossil fuel combustion, vehicle emissions biogenic secondary organic (SOA) influential sources response. Mass MLR associated compositional source profiles almost models, illustrating influence on particle-level multivariate showed cover spaces, through comparison data we demonstrate provides more nuanced drivers analysis. study constitutes one most comprehensive datasets currently available unique opportunity explore variations how they affect species.

Language: Английский

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Hydroxyl Radical Production by Air Pollutants in Epithelial Lining Fluid Governed by Interconversion and Scavenging of Reactive Oxygen Species

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(20), P. 14069 - 14079

Published: Oct. 5, 2021

Air pollution is a major risk factor for human health. Chemical reactions in the epithelial lining fluid (ELF) of respiratory tract result formation reactive oxygen species (ROS), which can lead to oxidative stress and adverse health effects. We use kinetic modeling quantify effects fine particulate matter (PM2.5), ozone (O3), nitrogen dioxide (NO2) on ROS formation, interconversion, reactivity, discuss different chemical metrics stress, such as cumulative production hydrogen peroxide (H2O2) hydroxyl radical (OH) conversion. All three air pollutants produce that accumulate ELF H2O2, serves reservoir species. At low PM2.5 concentrations (<10 μg m-3), we find less than 4% all produced H2O2 converted into highly OH, while rest intercepted by antioxidants enzymes serve buffering agents. elevated (>10 however, Fenton chemistry overwhelms effect leads tipping point fate, causing strong nonlinear increase OH production. This shift enhanced provide tentative mechanistic explanation how inhalation induces

Language: Английский

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Enhanced Nitrite Production from the Aqueous Photolysis of Nitrate in the Presence of Vanillic Acid and Implications for the Roles of Light-Absorbing Organics

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(23), P. 15694 - 15704

Published: Nov. 17, 2021

A prominent source of hydroxyl radicals (

Language: Английский

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Mass accommodation and gas–particle partitioning in secondary organic aerosols: dependence on diffusivity, volatility, particle-phase reactions, and penetration depth

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(3), P. 1565 - 1580

Published: Feb. 4, 2021

Abstract. Mass accommodation is an essential process for gas–particle partitioning of organic compounds in secondary aerosols (SOA). The mass coefficient commonly described as the probability a gas molecule colliding with surface to enter particle phase. It often applied, however, without specifying if and how deep has penetrate beneath be regarded being incorporated into condensed phase (adsorption vs. absorption). While this aspect usually not critical liquid particles rapid surface–bulk exchange, it can important viscous semi-solid or glassy solid distinguish resolve kinetics at surface, transfer across interface, further transport bulk. For purpose, we introduce novel parameter: effective αeff that depends on penetration depth function coefficient, volatility, bulk diffusivity, particle-phase reaction rate coefficient. Application traditional Fuchs–Sutugin approximation mass-transport interface yields SOA results are consistent detailed kinetic multilayer model (kinetic interactions clouds, KM-GAP; Shiraiwa et al., 2012) two-film solutions (Model Simulating Aerosol Interactions Chemistry, MOSAIC; Zaveri 2014) but deviate substantially from earlier modeling approaches considering influence related parameters. highly particles, show remains similar case low-volatility compounds, whereas decrease by several orders magnitude semi-volatile compounds. Such effects explain apparent inconsistencies between studies deriving coefficients experimental data molecular dynamics simulations. Our findings challenge approach models using fixed regardless state depth. introduced study provides efficient new way accounting reactions well regional global air quality models. limitations may planetary boundary layer (PBL), likely amorphous free upper troposphere (FT–UT) PBL low relative humidity temperature.

Language: Английский

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Are reactive oxygen species (ROS) a suitable metric to predict toxicity of carbonaceous aerosol particles?

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(3), P. 1793 - 1809

Published: Feb. 7, 2022

Abstract. It is being suggested that particle-bound or particle-induced reactive oxygen species (ROS), which significantly contribute to the oxidative potential (OP) of aerosol particles, are a promising metric linking compositions toxicity and adverse health effects. However, accurate ROS quantification remains challenging due short-lived nature many components lack appropriate analytical methods for reliable quantification. Consequently, it difficult gauge their impact on human health, especially identify how particle sources atmospheric processes drive formation in real-world urban environment. In this study, using novel online instrument (OPROSI), we comprehensively characterized compared secondary organic aerosols (SOAs) generated from compounds represent anthropogenic (naphthalene, SOANAP) biogenic (β-pinene, SOAβPIN) precursors. The SOA mass was condensed onto soot particles (SP) under varied atmospherically relevant conditions (photochemical aging humidity) mimic mixing traffic-related carbonaceous primary volatile (VOCs). We systematically analyzed ability aqueous extracts two types (SOANAP-SP SOAβPIN-SP) induce production OP. further investigated cytotoxicity cellular after exposing lung epithelial cell cultures (A549) aerosols. A significant finding study more than 90 % all both have short lifetime, highlighting need develop instruments meaningful ROS. Our results also show photochemical promotes enhances OP Compared SOAβPIN-SP, SOANAP-SP elicited higher acellular production, OP, lower viability. These consistent between chemical-based biological-based analyses indicate could be feasible predict Moreover, caused by exposure not only depends type but affected dose, process deposition cells interactions as realistically possible avoid unknown biases.

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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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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Environmentally Persistent Free Radicals, Reactive Oxygen Species Generation, and Oxidative Potential of Highway PM_2.5

ACS Earth and Space Chemistry, Journal Year: 2021, Volume and Issue: 5(8), P. 1865 - 1875

Published: July 9, 2021

In urban environments, vehicle exhaust and nonexhaust emissions represent important sources of fine particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5), which plays a central role in adverse health effects oxidative stress. We collected PM2.5 filter samples from two highway sites (Anaheim Long Beach, CA) site (Irvine, to quantify environmentally persistent free radicals (EPFRs) contained the generation radical forms reactive oxygen species (ROS) water using electron paramagnetic resonance spectroscopy. The EPFR concentrations were 36 ± 14 pmol m–3 at sites, about times higher those site. EPFRs correlate positively well CO, NOx, elemental organic carbon, indicating that are emitted vehicular exhaust. Good correlations Fe Cu may indicate stabilized by tire brake wears. negatively correlated ozone, suggesting photochemistry does not play large formation possibly also quenched ozone. Highway found generate mainly OH aqueous phase. generated ROS mass show good correlation EPFRs, implying generation. potentials as quantified dithiothreitol (DTT) assay ROS, OH, for Anaheim, whereas little observed Beach. These findings highlight interplay various PM redox-active chemical components complex relationship between DTT activity.

Language: Английский

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Wildfire particulate matter as a source of environmentally persistent free radicals and reactive oxygen species

Environmental Science Atmospheres, Journal Year: 2023, Volume and Issue: 3(3), P. 581 - 594

Published: Jan. 1, 2023

Wildfire particulate matter contains high amounts of environmentally persistent free radicals and generates reactive oxygen species with implications for air quality public health.

Language: Английский

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