@article {288, title = {Fast autoxidation of unsaturated lipid films on indoor surfaces.}, journal = {Nat Commun}, volume = {16}, year = {2025}, month = {2025 Feb 12}, pages = {1557}, abstract = {

Organic films containing unsaturated lipids are widespread, yet their oxidation pathways with associated impacts on contaminant lifetimes and human exposure remain poorly explored under indoor environmental conditions. This study demonstrates that UVA radiation and radical exposure drive rapid autoxidation of thin films of methyl linolenate (ML) and canola oil (which contains polyunsaturated triglycerides), primarily producing organic hydroperoxides. For ML films this fast chemistry occurs at the same rate under entirely dark, genuine indoor conditions as it does when the films are exposed to significantly higher OH radicals in a flow reactor. Both OH and organic radicals are detected within the oxidized films, propagating fast autoxidation in dark indoor environments with minimal sensitivity to the radical initiation rate. When mixed into the films, bisphenol A is hydroxylated, illustrating potential transformation pathways for toxic organic contaminants. This study uncovers insights into lipid autoxidation processes under environmental conditions and underscores their potential health impacts.

}, keywords = {Benzhydryl Compounds, Bisphenol A Compounds, Fatty Acids, Monounsaturated, Humans, Hydrogen Peroxide, Linoleic Acids, Oxidation-Reduction, Phenols, Rapeseed Oil, Surface Properties, Ultraviolet Rays}, issn = {2041-1723}, doi = {10.1038/s41467-025-56802-0}, author = {Wang, Xinke and Fahy, William D and Xie, Linna and Peng, Hui and Abbatt, Jonathan P D} } @article {273, title = {Hydroxyl radical oxidation of chemical contaminants on indoor surfaces and dust.}, journal = {Proc Natl Acad Sci U S A}, volume = {121}, year = {2024}, month = {2024 Nov 05}, pages = {e2414762121}, abstract = {

Humans are widely exposed to semivolatile organic contaminants in indoor environments. Many contaminants have long lifetimes following partitioning to the large surface reservoirs present indoors, which leads to long exposure times to gas-phase oxidants and multiphase chemistry. Studies have shown selective multiphase oxidation of organics on indoor surfaces, but the presence of hydroxyl radicals with nonselective reactivity and evidence of multiphase OH radical reactivity toward common indoor contaminants indicates that there may be additional unknown transformation chemistry indoors. We screened genuine indoor samples for 60 OH radical oxidation products of the common plasticizer and endocrine-disrupting contaminant bis(2-ethylhexyl) phthalate (DEHP) identified in laboratory experiments using nontargeted high-resolution mass spectrometry. At least 30 and 10 of these products are observed in indoor dust and DEHP films exposed to ambient indoor conditions, respectively, indicating that multiphase OH reactions occur indoors. Using the PROTEX model and a multimedia indoor chemical fate model, we demonstrate that these products have long indoor lifetimes and cause a higher potential for human exposure than DEHP. Some of these products are more active endocrine disruptors than DEHP itself, but most have unknown toxicities. Coexposure to all oxidation products will likely have an additive effect, leading to higher human health risks from indoor organic contaminants than previously thought. Due to the nonselective reactivity of OH radicals, it is likely that most indoor contaminants follow similar chemistry, and further study is needed to understand the prevalence and human health implications of such multiphase chemistry.

}, issn = {1091-6490}, doi = {10.1073/pnas.2414762121}, author = {Fahy, William D and Gong, Yufeng and Wang, Shenghong and Zhang, Zhizhen and Li, Li and Peng, Hui and Abbatt, Jonathan P D} } @article {276, title = {Structurally Selective Ozonolysis of -Phenylenediamines and Toxicity in Coho Salmon and Rainbow Trout.}, journal = {Environ Sci Technol}, year = {2024}, month = {2024 Nov 23}, abstract = {

The tire-rubber-derived ozonation product of -(1,3-dimethylbutyl)-{\textquoteright}-phenyl--phenylenediamine (6PPD), -(1,3-dimethylbutyl)-{\textquoteright}-phenyl--phenylenediamine-quinone (6PPD-Q), was recently discovered to cause acute mortality in coho salmon (). -Phenylenediamines (PPDs) with variable side chains distinct from 6PPD have been identified as potential replacement antioxidants, but their toxicities remain unclear under environmentally relevant ozone conditions. We herein tested the multiphase gas-surface ozone reactivity of four select PPDs [6PPD, -isopropyl-{\textquoteright}-phenyl--phenylenediamine (IPPD), ,{\textquoteright}-diphenyl--phenylenediamine (DPPD), and -phenyl-{\textquoteright}-cyclohexyl--phenylenediamine (CPPD)] and evaluated the toxicity of their reaction mixtures in coho salmon, rainbow trout (), and fathead minnow (). 6PPD and IPPD were found to rapidly react with ozone, while no significant multiphase ozone reactivity was observed for DPPD or CPPD. The viability of coho salmon CSE-119 cells was strongly affected by the ozonolysis products of 6PPD but not by those of the other three PPDs. Acute mortality was only observed in juvenile rainbow trout that were exposed to oxidized 6PPD, suggesting a common mechanism of toxic action in the two salmonid fish species. This study reports the structurally selective ozone reactivity of PPDs and the unique toxicity of 6PPD ozonolysis mixtures, which demonstrates that other PPDs are potential alternative antioxidants.

}, issn = {1520-5851}, doi = {10.1021/acs.est.4c04817}, author = {Xie, Linna and Yu, Jie and Nair, Pranav and Sun, Jianxian and Barrett, Holly and Meek, Oliver and Qian, Xing and Yang, Diwen and Kennedy, Lisa and Kozakiewicz, Derek and Hao, Chunyan and Hansen, John D and Greer, Justin B and Abbatt, Jonathan P D and Peng, Hui} } @article {222, title = {Dynamic Wood Smoke Aerosol Toxicity during Oxidative Atmospheric Aging.}, journal = {Environ Sci Technol}, year = {2023}, month = {2023 Jan 11}, abstract = {

Wildfires are a major source of biomass burning aerosol to the atmosphere, with their incidence and intensity expected to increase in a warmer future climate. However, the toxicity evolution of biomass burning organic aerosol (BBOA) during atmospheric aging remains poorly understood. In this study, we report a unique set of chemical and toxicological metrics of BBOA from pine wood smoldering during multiphase aging by gas-phase hydroxyl radicals (OH). Both the fresh and OH-aged BBOA show activity relevant to adverse health outcomes. The results from two acellular assays (DTT and DCFH) show significant oxidative potential (OP) and reactive oxygen species (ROS) formation in OH-aged BBOA. Also, radical concentrations in the aerosol assessed by electron paramagnetic resonance (EPR) spectroscopy increased by 50\% following heterogeneous aging. This enhancement was accompanied by a transition from predominantly carbon-centered radicals (85\%) in the fresh aerosol to predominantly oxygen-centered radicals (76\%) following aging. Both the fresh and aged biomass burning aerosols trigger prominent antioxidant defense during the exposure, indicating the induction of oxidative stress by BBOA in the atmosphere. By connecting chemical composition and toxicity using an integrated approach, we show that short-term aging initiated by OH radicals can produce biomass burning particles with a higher particle-bound ROS generation capacity, which are therefore a more relevant exposure hazard for residents in large population centers close to wildfire regions than previously studied fresh biomass burning emissions.

}, issn = {1520-5851}, doi = {10.1021/acs.est.2c05929}, author = {Wang, Shunyao and Gallimore, Peter J and Liu-Kang, Carolyn and Yeung, Kirsten and Campbell, Steven J and Utinger, Battist and Liu, Tengyu and Peng, Hui and Kalberer, Markus and Chan, Arthur W H and Abbatt, Jonathan P D} }