posted on 2014-04-15, 00:00authored byWilliam Gehling, Lavrent Khachatryan, Barry Dellinger
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.