Environmental effects of ozone depletion, UV radiation and interactions with climate change: UNEP Environmental Effects Assessment Panel, update 2017

Photochemical & Photobiological Sciences, Год журнала: 2018, Номер 17(2), С. 127 - 179

Опубликована: Фев. 1, 2018

Язык: Английский

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Halogen Radical Oxidants in Natural and Engineered Aquatic Systems

Environmental Science & Technology, Год журнала: 2018, Номер 52(17), С. 9579 - 9594

Опубликована: Авг. 6, 2018

Photochemical reactions contribute to the transformation of contaminants and biogeochemically important substrates in environmental aquatic systems. Recent research has demonstrated that halogen radicals (e.g., Cl•, Br•, Cl2•-, BrCl•-, Br2•-) impact photochemical processes sunlit estuarine coastal waters rich halides chloride, Cl-, bromide, Br-). In addition, participate contaminant degradation some engineered processes, including chlorine photolysis for drinking water treatment several radical-based brine wastewater treatment. Halogen react selectively with (with bimolecular rate constants spanning orders magnitude) via potential chemical mechanisms. Consequently, their role remains challenging assess. This review presents an integrative analysis chemistry contribution photochemistry surface We evaluate existing data on generation, speciation, reactivity radicals, as well experimental computational approaches used obtain this data. By evaluating identifying major uncertainties, provides a basis assess both saline

Язык: Английский

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Multiple Roles of Dissolved Organic Matter in Advanced Oxidation Processes

Environmental Science & Technology, Год журнала: 2022, Номер 56(16), С. 11111 - 11131

Опубликована: Июль 7, 2022

Advanced oxidation processes (AOPs) can degrade a wide range of trace organic contaminants (TrOCs) to improve the quality potable water or discharged wastewater effluents. Their effectiveness is impacted, however, by dissolved matter (DOM) that ubiquitous in all sources. During application an AOP, DOM scavenge radicals and/or block light penetration, therefore impacting their toward contaminant transformation. The multiple ways which different types sources impact oxidative purification are critically reviewed. inhibit degradation TrOCs, but it also enhance formation and reactivity useful for elimination alter transformation pathways contaminants. An in-depth analysis highlights inhibitory effect on efficiency TrOCs based DOM's structure optical properties its oxidants as well synergistic contribution from redox transient intermediates. AOPs influence types, mechanisms, extent byproducts formation. Research needs proposed advance practical understanding how be exploited purification.

Язык: Английский

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Sunlight-mediated inactivation of health-relevant microorganisms in water: a review of mechanisms and modeling approaches

Environmental Science Processes & Impacts, Год журнала: 2018, Номер 20(8), С. 1089 - 1122

Опубликована: Янв. 1, 2018

Inactivation occursviadirect and indirect processes in sunlit waters.

Язык: Английский

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Aging of Atmospheric Brown Carbon Aerosol

ACS Earth and Space Chemistry, Год журнала: 2021, Номер 5(4), С. 722 - 748

Опубликована: Апрель 5, 2021

Emitted by numerous primary sources and formed secondary sources, atmospheric brown carbon (BrC) aerosol is chemically complex. As BrC ages in the atmosphere via a variety of chemical physical processes, its composition optical properties change significantly, altering impacts on climate. Research past decade has considerably expanded our understanding reactions both gas condensed phases. We review these recent advances aging chemistry with focus phase leading to formation, aqueous in-cloud particle reactions. Connections are made between single component proxies more complex mixtures as well laboratory field measurements chemistry. General conclusions that can darken particles over short time scales hours close source considerable photobleaching oxidative whitening will occur when day or removed from source.

Язык: Английский

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Environmental effects of ozone depletion and its interactions with climate change: Progress report, 2016

Photochemical & Photobiological Sciences, Год журнала: 2017, Номер 16(2), С. 107 - 145

Опубликована: Янв. 26, 2017

Язык: Английский

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Singlet Oxygen Quantum Yields in Environmental Waters

Chemical Reviews, Год журнала: 2021, Номер 121(7), С. 4100 - 4146

Опубликована: Март 8, 2021

Singlet oxygen (1O2) is a reactive species produced in sunlit waters via energy transfer from the triplet states of natural sensitizers. There has been an increasing interest measuring apparent 1O2 quantum yields (ΦΔ) aquatic and atmospheric organic matter samples, driven part by fact that this parameter can be used for environmental fate modeling contaminants to advance our understanding dissolved photophysics. However, lack reproducibility across research groups publications remains challenge significantly limits usability literature data. In first review, we critically evaluate experimental techniques have determine ΦΔ values matter, identify quantify sources errors potentially explain large variability literature, provide general recommendations future studies. second part, qualitative overview known trends as function type, isolation extraction procedures, bulk water chemistry parameters, molecular spectroscopic features, chemical treatments, wavelength, season, location. This review supplemented with comprehensive database samples.

Язык: Английский

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Molecular Composition and Photochemical Reactivity of Size-Fractionated Dissolved Organic Matter

Environmental Science & Technology, Год журнала: 2017, Номер 51(4), С. 2113 - 2123

Опубликована: Янв. 25, 2017

The photochemical production of reactive species, such as triplet dissolved organic matter (3DOM) and singlet oxygen (1O2), contributes to the degradation aquatic contaminants is related an array DOM structural characteristics, notably molecular weight. In order relate weight, optical properties, species production, Suwannee River (SRFA) Pony Lake fulvic acid (PLFA) isolates are fractionated by sequential ultrafiltration, resultant fractions evaluated in terms composition reactivity. UV–visible measurements aromaticity increase with weight both acids, while PLFA shown be structurally similar Fourier-transform ion cyclotron resonance mass spectrometry. addition, Bray–Curtis dissimilarity analysis formulas identified their size reveal that SRFA have distinct compositions. Quantum yields 3DOM, measured electron energy transfer probes, 1O2 decreased Decreasing [3DOM]ss derive from elevated quenching high fractions, rather than increased 3DOM formation. This work has implications for photochemistry waters undergoing natural or engineered treatment processes alter photooxidation biological degradation.

Язык: Английский

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Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

Photochemical & Photobiological Sciences, Год журнала: 2021, Номер 20(1), С. 1 - 67

Опубликована: Янв. 1, 2021

Abstract This assessment by the Environmental Effects Assessment Panel (EEAP) of United Nations Environment Programme (UNEP) provides latest scientific update since our most recent comprehensive (Photochemical and Photobiological Sciences, 2019, 18, 595–828). The interactive effects between stratospheric ozone layer, solar ultraviolet (UV) radiation, climate change are presented within framework Montreal Protocol Sustainable Development Goals. We address how these global environmental changes affect atmosphere air quality; human health; terrestrial aquatic ecosystems; biogeochemical cycles; materials used in outdoor construction, energy technologies, fabrics. In many cases, there is a growing influence from seasonality extreme events due to change. Additionally, we assess transmission severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which responsible for COVID-19 pandemic, context linkages with UV radiation Protocol.

Язык: Английский

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The Role of Dissolved Organic Matter Composition in Determining Photochemical Reactivity at the Molecular Level

Environmental Science & Technology, Год журнала: 2019, Номер 53(20), С. 11725 - 11734

Опубликована: Сен. 11, 2019

Dissolved organic matter (DOM) composition influences its ability to form photochemically produced reactive intermediates (PPRI). While relationships have been established between bulk DOM properties and triplet (3DOM) singlet oxygen (1O2) quantum yields, contradictory evidence exists for hydroxyl radical (•OH) hydroxylating species. Furthermore, little is known about these at the molecular level. We evaluated photochemical reactivity of water samples from a wastewater treatment plant St. Louis River in Minnesota Wisconsin, U.S.A. Bulk characterization using ultraviolet-visible spectroscopy demonstrates that color apparent size decrease downstream, while analysis Fourier-transform ion cyclotron resonance mass spectrometry reveals saturation chemodiversity highest near Lake Superior. 3DOM yield coefficients 1O2 yields increase downstream correlate strongly with saturated formulas. Similar results are observed carbon-normalized photodegradation rate constants atorvastatin, carbamazepine, venlafaxine, which react primarily 1O2. In contrast, •OH lowest less saturated, more oxygenated DOM, suggesting not major precursor. Mixed DEET, reacts multiple PPRI. Molecular-level compositional data reveal insights into differing formation pathways individual PPRI, but information specific contaminants needed predict their fate.

Язык: Английский

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