title: Atmospheric aqueous-phase photoreactivity: correlation between the hydroxyl radical photoformation and pesticide degradation rate in atmospherically relevant waters.
abstract: In the present study, we investigated the correlation between the hydroxyl radical formation rate (R(˙OH) ) and the degradation of a pesticide (mesotrione) in synthetic cloud water solutions and in two real atmospheric cloud waters collected at the top of puy de Dôme station (France). Using terephthalic acid as the hydroxyl radical chemical probe, we established the linear correlation between the photogenerated hydroxyl radical under polychromatic wavelengths and the pesticide degradation rate: (M s(-1)) = (1.61 ± 0.15) × 10(-1) (M s(-1)). Moreover, the formation rate of hydroxyl radical in two natural cloud waters was estimated considering H(2)O(2) and NO(3)(-) and the difference between the predicted values and those experimentally obtained could be attributed to the presence of other photochemical sources: iron-complexes and total organic matter. The organic constituents could play a dual role of sources and scavengers of photoformed hydroxyl radicals in the aqueous phase.
authors: Laboratoire de Photochimie Moléculaire et Macromoléculaire, Clermont Université, Université Blaise Pascal, Clermont-Ferrand, France.
authors: Tiffany
authors: T
authors: Charbouillot
authors: Marcello
authors: M
authors: Brigante
authors: Laurent
authors: L
authors: Deguillaume
authors: Gilles
authors: G
authors: Mailhot