Aqueous OH Radical Production by Brake Wear Particles

Environmental Science & Technology Letters, Год журнала: 2024, Номер 11(4), С. 315 - 322

Опубликована: Март 25, 2024

Particulate matter (PM) emitted from road traffic causes adverse health effects upon inhalation and respiratory deposition. Non-exhaust emissions will eventually become the dominant source of PM transition to electric vehicles; however, non-tailpipe is currently unregulated as its impacts are still unclear. In this study, we generated brake wear particles (BWPs) with non-asbestos organic, ceramic, semimetallic pads using custom dynamometers measured aqueous-phase formation reactive oxygen species (ROS). We found that BWPs do not contain environmentally persistent free radicals (EPFRs), all types generate exclusively ·OH in water. by ceramic brakes during heavier braking lead higher yields compared gentle conditions, suggesting potential ultrafine BWPs. Chemical characterization reveals organic elemental carbon correlated positively while exhibiting negative correlations abundant metals including Fe Mn. suggest thermal decomposition hydroperoxides derived phenolic resin. oxidative quantified dithiothreitol (DTT) assay exhibited a positive correlation yield. These results provide critical insights into toxicity

Язык: Английский

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Effects of Nitrogen Oxides on the Production of Reactive Oxygen Species and Environmentally Persistent Free Radicals from α-Pinene and Naphthalene Secondary Organic Aerosols

The Journal of Physical Chemistry A, Год журнала: 2022, Номер 126(40), С. 7361 - 7372

Опубликована: Окт. 4, 2022

Reactive oxygen species (ROS) and environmentally persistent free radicals (EPFR) play an important role in chemical transformation of atmospheric aerosols adverse aerosol health effects. This study investigated the effects nitrogen oxides (NOx) during photooxidation α-pinene naphthalene on EPFR content ROS formation from secondary organic (SOA). Electron paramagnetic resonance (EPR) spectroscopy was applied to quantify formation. While no were detected SOA, we found that SOA contained about 0.7 pmol μg-1 EPFR, NOx has little influence concentrations oxidative potential. α-Pinene generated under low conditions form OH superoxide aqueous phase, which lowered substantially by 50-80% for high conditions. High-resolution mass spectrometry analysis showed substantial nitroaromatics nitrates a environment. The modeling results using GECKO-A model simulates explicit gas-phase chemistry radical 2D-VBS treats autoxidation predicted reduced hydroperoxides enhanced due reactions peroxy with instead their HO2. Consistently, presence resulted decrease peroxide contents potential SOA.

Язык: Английский

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Accelerating models for multiphase chemical kinetics through machine learning with polynomial chaos expansion and neural networks

Geoscientific model development, Год журнала: 2023, Номер 16(7), С. 2037 - 2054

Опубликована: Апрель 14, 2023

Abstract. The heterogeneous chemistry of atmospheric aerosols involves multiphase chemical kinetics that can be described by kinetic multi-layer models (KMs) explicitly resolve mass transport and reactions. However, KMs are computationally too expensive to used as sub-modules in large-scale models, the computational costs also limit their utility inverse-modeling approaches commonly infer aerosol parameters from laboratory studies. In this study, we show how machine learning methods generate inexpensive surrogate for model surface bulk (KM-SUB) predict reaction times systems. We apply compare two common openly available generation polynomial chaos expansion (PCE) with UQLab neural networks (NNs) through Python package Keras. PCE method is well suited determining global sensitivity indices KMs, demonstrate applications enabled or accelerated NN-suggested sampling. These qualities make them suitable supporting tools work interpretation data design future experiments. Overall, KM investigated study fast, accurate, robust, which suggests applicability models.

Язык: Английский

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Iron and Copper Alter the Oxidative Potential of Secondary Organic Aerosol: Insights from Online Measurements and Model Development

Environmental Science & Technology, Год журнала: 2023, Номер 57(36), С. 13546 - 13558

Опубликована: Авг. 25, 2023

The oxidative potential (OP) of particulate matter has been widely suggested as a key metric for describing atmospheric particle toxicity. Secondary organic aerosol (SOA) and redox-active transition metals, such iron copper, are drivers OP. However, their relative contributions to OP, well the influence metal-organic interactions chemistry on remains uncertain. In this work, we simultaneously deploy two novel online instruments first time, providing robust quantification We utilize AA (OPAA) 2,7-dichlorofluoroscein (ROSDCFH) methods investigate Fe(II) Cu(II) OP secondary (SOA). addition, quantify OH production (OPOH) from these mixtures. observe range synergistic antagonistic when mixed with representative biogenic (β-pinene) anthropogenic (naphthalene) SOA. A newly developed kinetic model revealed reactions among SOA components, ascorbate, influencing OPAA. Model predictions agree OPAA measurements, highlighting metal-ascorbate -naphthoquinone-ascorbate important simultaneous application multiple assays provides new insights into metal

Язык: Английский

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Influence of ambient and endogenous H₂O₂ on reactive oxygen species concentrations and OH radical production in the respiratory tract

Environmental Science Atmospheres, Год журнала: 2023, Номер 3(7), С. 1066 - 1074

Опубликована: Янв. 1, 2023

A multiphase kinetic model analysis quantifies effects of air pollutants on reactive oxygen species production and oxidative stress in the respiratory tract.

Язык: Английский

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A possible unaccounted source of nitrogen-containing compound formation in aerosols: amines reacting with secondary ozonides

Atmospheric chemistry and physics, Год журнала: 2024, Номер 24(1), С. 155 - 166

Опубликована: Янв. 5, 2024

Abstract. Nitrogen (N)-containing compounds have a significant impact on the optical and toxicological properties of aerosols. 1,2,4-Trioxolanes, known as secondary ozonides (SOZs), i.e., key products from ozonolysis biogenic terpenoids, are readily taken up into atmospheric aerosols act oxidants, potentially interacting with amines in atmosphere. In present work, we carefully investigated component particles produced by β-caryophyllene (β-C) presence ethylamine (EA), methylamine (MA), dimethylamine (DMA), or ammonia. The mass spectrometric results show that SOZ is dominant product β-C. It reacts EA MA but has inert reactivities toward DMA Similar experimental were achieved α-humulene (α-H), an isomer β-C, was used place Additionally, D2O H218O solvents for characterization products. revealed intriguing phenomenon where β-C α-H reacting same amine (EA MA) possessed different functional groups, despite fact they isomerized species identical chemical structure (1,2,4-trioxolane). This indicates conformation SOZs strong influence how react amines. For first time, derived reported this study; may represent hitherto unrecognized source N-containing compound production

Язык: Английский

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Rapid Iron-Mediated Aqueous-Phase Reactions of Organic Peroxides from Monoterpene-Derived Criegee Intermediates and Implications for Aerosol and Cloud Chemistry

Environmental Science & Technology, Год журнала: 2025, Номер unknown

Опубликована: Янв. 19, 2025

Fenton-like reactions between organic peroxides and transition-metal ions in the atmospheric aqueous phase have profound impacts on chemistry, composition, health effects of aerosols. However, kinetics, mechanisms, key influencing factors such remain poorly understood. In this study, we synthesized a series monoterpene-derived α-acyloxyalkyl hydroperoxides (AAHPs), an important class formed from Criegee intermediates during ozonolysis alkenes, investigated their with iron phase. We found that AAHPs are essentially chemically inert to Fe3+ but highly reactive toward Fe2+. The aqueous-phase reaction rate constant Fe2+ (kIIAAHP+Fe(II)) was determined range 11.0 ± 0.8 150.0 3.3 M–1 s–1, depending positively solution pH (1–3), water content (50%–90%), temperature (8–25 °C). Meanwhile, kIIAAHP+Fe(II) value is linearly correlated O/C ratio AAHPs, which allows for estimation reactivity based oxygenation level. addition, decomposition via predominantly yields alkoxy (RO) radicals production yield OH smaller than 16%. Similar several abundant including pinonic acid-derived AAHP exhibit high low dissolved α-pinene secondary aerosol. A quantitative analysis measured kinetics suggests even dominant drivers behind transformation atmosphere, would significantly affect multiphase chemistry aerosol impacts.

Язык: Английский

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A numerical compass for experiment design in chemical kinetics and molecular property estimation

Journal of Cheminformatics, Год журнала: 2024, Номер 16(1)

Опубликована: Март 22, 2024

Abstract Kinetic process models are widely applied in science and engineering, including atmospheric, physiological technical chemistry, reactor design, or optimization. These rely on numerous kinetic parameters such as reaction rate, diffusion partitioning coefficients. Determining these properties by experiments can be challenging, especially for multiphase systems, researchers often face the task of intuitively selecting experimental conditions to obtain insightful results. We developed a numerical compass (NC) method that integrates computational models, global optimization, ensemble methods, machine learning identify with greatest potential constrain model parameters. The approach is based quantification output variance an solutions agree data. utility NC demonstrated multi-layer describing heterogeneous ozonolysis oleic acid aerosols. show how neural network surrogate chemical system used accelerate application comprehensive mapping analysis conditions. also uncertainty quantitative structure–activity relationship (QSAR) models. calculated molecules extend training data correlates reduction QSAR error. code openly available Julia package KineticCompass . Graphical

Язык: Английский

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Aerosol Toxicokinetics: A Framework for Unraveling Toxicological Dynamics from Air to the Body

Environmental Science & Technology, Год журнала: 2025, Номер unknown

Опубликована: Март 25, 2025

Exposure to atmospheric aerosols threatens human health and is yet be effectively addressed globally. Aerosol toxicity strongly depends upon components whose chemical profiles concentrations can constantly evolve throughout transformation, inhalation, distribution, metabolism, excretion. Despite the abundant studies on aerosol their toxic effects, dynamics in component related biological effects from air body remain unclear. Here, we propose a conceptual toxicokinetic framework mathematically deduce bioavailable concentration changing bulk of constituents atmosphere. The single or multiple are further predicted via toxicodynamic modeling according concentrations. Atmospheric composition turn regulated by risk-based guidelines, aiming alleviate vivo effects. This perspective demonstrates how serial toxicokinetic-toxicodynamic equations bridge knowledge gap between ambient associated bodies. prediction an inhalation also allows connecting with exposomes aggregate exposure pathways. We call for development model validity integrate quantitative adverse outcome pathways apply exposure-disease modeling, providing novel insights into quality policymaking public management.

Язык: Английский

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Persistent Uptake of H₂O₂ onto Ambient PM_2.5 via Dark-Fenton Chemistry

Environmental Science & Technology, Год журнала: 2022, Номер 56(14), С. 9978 - 9987

Опубликована: Июнь 25, 2022

Particulate matter (PM) and gaseous hydrogen peroxide (H2O2) interact ubiquitously to influence atmospheric oxidizing capacity. However, quantitative information on H2O2 loss its fate urban aerosols remain unclear. This study investigated the kinetics of heterogeneous reactions PM2.5 explored how these processes are affected by various experimental conditions (i.e., relative humidity, temperature, concentration). We observed a persistent uptake (with coefficients (γ) 10-4-10-3) exacerbated aerosol liquid water confirming critical role water-assisted chemical decomposition during process. A positive correlation between γ values ratio dissolved iron concentration suggests that Fenton catalytic may be an important pathway for conversion under dark conditions. Furthermore, basis kinetic data gained, parameterization was developed applied into box model. The good agreement simulated measured uncovered significant plays in sink atmosphere. These findings suggest composition-dependent particle reactivity toward should considered models elucidating environmental health effects ambient aerosols.

Язык: Английский

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