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1. Production of oxygenated volatile organic compounds from the ozonolysis of coastal seawater

   https://doi.org/10.5194/acp-24-3729-2024  

   Kilgour, Delaney B; Novak, Gordon A; Claflin, Megan S; Lerner, Brian M; Bertram, Timothy H (January 2024, Atmospheric Chemistry and Physics)

   Abstract. Dry deposition of ozone (O3) to the ocean surface and the ozonolysis of organics in the sea surface microlayer (SSML) are potential sources of volatile organic compounds (VOCs) to the marine atmosphere. We use a gas chromatography system coupled to a Vocus proton-transfer-reaction time-of-flight mass spectrometer to determine the chemical composition and product yield of select VOCs formed from ozonolysis of coastal seawater collected from Scripps Pier in La Jolla, California. Laboratory-derived results are interpreted in the context of direct VOC vertical flux measurements made at Scripps Pier. The dominant products of laboratory ozonolysis experiments and the largest non-sulfur emission fluxes measured in the field correspond to Vocus CxHy+ and CxHyOz+ ions. Gas chromatography (GC) analysis suggests that C5–C11 oxygenated VOCs, primarily aldehydes, are the largest contributors to these ion signals. In the laboratory, using a flow reactor experiment, we determine a VOC yield of 0.43–0.62. In the field at Scripps Pier, we determine a maximum VOC yield of 0.04–0.06. Scaling the field and lab VOC yields for an average O3 deposition flux and an average VOC structure results in an emission source of 10.7 to 167 Tg C yr−1, competitive with the DMS source of approximately 20.3 Tg C yr−1. This study reveals that O3 reactivity to dissolved organic carbon can be a significant carbon source to the marine atmosphere and warrants further investigation into the speciated VOC composition from different seawater samples and the reactivities and secondary organic aerosol (SOA) yields of these molecules in marine-relevant, low NOx conditions. 

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2. Ozonolysis can produce long-lived greenhouse gases from commercial refrigerants

   https://doi.org/10.1073/pnas.2312714120  

   McGillen, Max R; Fried, Zachary_T P; Khan, M_Anwar H; Kuwata, Keith T; Martin, Connor M; O’Doherty, Simon; Pecere, Francesco; Shallcross, Dudley E; Stanley, Kieran M; Zhang, Kexin (December 2023, Proceedings of the National Academy of Sciences)

   Hydrofluoroolefins are being adopted as sustainable alternatives to long-lived fluorine- and chlorine-containing gases and are finding current or potential mass-market applications as refrigerants, among a myriad of other uses. Their olefinic bond affords relatively rapid reaction with hydroxyl radicals present in the atmosphere, leading to short lifetimes and proportionally small global warming potentials. However, this type of functionality also allows reaction with ozone, and whilst these reactions are slow, we show that the products of these reactions can be extremely long-lived. Our chamber measurements show that several industrially important hydrofluoroolefins produce CHF₃(fluoroform, HFC-23), a potent, long-lived greenhouse gas. When this process is accounted for in atmospheric chemical and transport modeling simulations, we find that the total radiative effect of certain compounds can be several times that of the direct radiative effect currently recommended by the World Meteorological Organization. Our supporting quantum chemical calculations indicate that a large range of exothermicity is exhibited in the initial stages of ozonolysis, which has a powerful influence on the CHF₃yield. Furthermore, we identify certain molecular configurations that preclude the formation of long-lived greenhouse gases. This demonstrates the importance of product quantification and ozonolysis kinetics in determining the overall environmental impact of hydrofluoroolefin emissions. 

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3. Ozonolysis Dissociation Kinetics for the Relative Quantification of Geometrical Phosphatidylcholine Isomers

   https://doi.org/10.1021/acs.analchem.5c00670  

   Scoggins_IV, Troy R; Guo, Yingchan; Zerebinski, Paul; Prentice, Boone M (June 2025, Analytical Chemistry)

   The structural diversity of lipids presents significant challenges for accurate identification and characterization, ne-cessitating advanced analytical tools. Among these challenges is the differentiation between cis and trans isomers of lipids, which differ only by the geometry of a carbon-carbon double bond. This study employs ozonolysis kinetics to distinguish these isomers based on the reactivity of their gas phase ions with ozone. To achieve precise differentia-tion, it is essential to use an ion adduct that enhances reactivity, thereby improving the sensitivity of the kinetic assays. We evaluated various ion types, including protonated lipids as well as lipids cationized with lithium, sodium, and potassium, using a modified quadrupole ion trap mass spectrometer. Our results demonstrate that lithium-adducted lipids exhibit the highest reaction efficiency and greatest sensitivity for distinguishing between cis and trans isomers. Subsequent analysis of cis and trans isomer mixtures of PC 18:1/18:1 (Δ9), PC 16:1/16:1 (Δ9), and PC 14:1/14:1 (Δ9) confirmed the method's robustness. 

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4. Chemistry and Human Exposure Implications of Secondary Organic Aerosol Production from Indoor Terpene Ozonolysis

   https://doi.org/10.1126/sciadv.abj9156  

   Rosales, C.M.F.; Jiang, J.; Lahib, A.; Bottorff, B.P.; Reidy, E.K.; Kumar, V.; Tasoglou, A.; Huber, H.; Dusanter, S.; Tomas, A.; et al (January 2022, Science advances)

   Surface cleaning using commercial disinfectants, which has recently increased during the coronavirus disease 2019 pandemic, can generate secondary indoor pollutants both in gas and aerosol phases. It can also affect indoor air quality and health, especially for workers repeatedly exposed to disinfectants. Here, we cleaned the floor of a mechanically ventilated office room using a commercial cleaner while concurrently measuring gas-phase precursors, oxidants, radicals, secondary oxidation products, and aerosols in real time; these were detected within minutes after cleaner application. During cleaning, indoor monoterpene concentrations exceeded outdoor concentrations by two orders of magnitude, increasing the rate of ozonolysis under low (<10 ppb) ozone levels. High number concentrations of freshly nucleated sub–10-nm particles (≥105 cm−3) resulted in respiratory tract deposited dose rates comparable to or exceeding that of inhalation of vehicle-associated aerosols. 

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5. Ozonolysis of phenolic aldehydes from industrial-based lignin wastewaters

   https://doi.org/10.1016/j.scitotenv.2025.180190  

   Witt, Reagan Patton; Todd, Mia B; Oladele, Motunrayo E; Guzman, Marcelo I (August 2025, Science of The Total Environment)

   Gan, Jay; Hopke, Philip; Ouyang, Wei; Paoletti, Elena (Ed.)

   Phenolic aldehydes are widespread pollutants in water and soil, originating from lignin-based agro-industries. With increasing wastewater pollution, improved treatment systems are necessary to degrade phenolic aldehydes into less hazardous compounds. Over the past two decades, ozonolysis wastewater treatment has been implemented in the United States, Japan, and South Korea. However, the mechanistic understanding of phenolic aldehyde ozonolysis in water remains incomplete. This study investigates the ozonolysis of three model phenolic aldehydes (syringaldehyde, vanillin, 4-hydroxybenzaldehyde) in representative concentrations for wastewater of 0.5–1.5 mM and pH 4–8. Each compound solution was sparged for 30 min at a fixed O3(g) flow (0.20 to 1.00 L min−1), providing steady-state dissolved concentrations of 5.4 to 16.2 μM. Reactant loss and product generation were monitored using UV–visible (UV–vis) spectroscopy, ultra-high pressure liquid chromatography (UHPLC) with UV–vis and mass spectrometry (MS) detection, and ion chromatography with conductivity and MS detection of anions. Identified products based on their mass-to-charge ratio (m/z−) included oxalic acid (89), glycolic acid (75), formic acid (45), and maleic acid (115). Additional intermediate products were identified under various reaction conditions, revealing competing mechanisms in the degradative oxidation of aqueous phenolic aldehydes exposed to O3(g). A unifying mechanism is proposed to explain the production of smaller, less toxic molecules during phenolic aldehyde ozonolysis, enhancing water quality. This mechanism serves as a basis for evaluating the implementation of ozonolysis in scaled-up water treatment processes. 

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