title: Hydroxyl radical generation from environmentally persistent free radicals (EPFRs) in PM2.5.
abstract: Hydroxyl radicals were generated from an aqueous suspension of ambient PM2.5 and detected utilizing 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap coupled with electron paramagnetic resonance (EPR) spectroscopy. Results from this study suggested the importance of environmentally persistent free radicals (EPFRs) in PM2.5 to generate significant levels of ·OH without the addition of H2O2. Particles for which the EPFRs were allowed to decay over time induced less hydroxyl radical. Additionally, higher particle concentrations produced more hydroxyl radical. Some samples did not alter hydroxyl radical generation when the solution was purged by air. This is ascribed to internal, rather than external surface associated EPFRs.
authors.affiliation: Department of Chemistry, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
authors.forename: William
authors.initials: W
authors.lastname: Gehling
authors.forename: Lavrent
authors.initials: L
authors.lastname: Khachatryan
authors.forename: Barry
authors.initials: B
authors.lastname: Dellinger
mesh_terms: D053000:Analytic Sample Preparation Methods; D003497:Cyclic N-Oxides / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D010316:Particle Size; D052638:Particulate Matter / Q000737:chemistry*; D011809:Quinones / Q000737:chemistry; D013535:Suspensions
chemical_list: D003497:Cyclic N-Oxides; D005609:Free Radicals; D052638:Particulate Matter; D011809:Quinones; D013535:Suspensions; D017665:Hydroxyl Radical; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D006861:Hydrogen Peroxide; D009584:Nitrogen