Products and Kinetics of the Heterogeneous Reaction of Suspended Vinclozolin Particles with Ozone

Vinclozolin is a widely used fungicide that can be released into the atmosphere via application and volatilization. This paper reports an experimental investigation on the heterogeneous zonation of vinclozolin particles. The zonation of vinclozolin adsorbed on azelaic acid particles under pseudo-first-order conditions is investigated online with a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS). The zonation products are analyzed with a combination of VUV-ATOFMS and GC/MS. Two main ozonation products are observed. The formation of the zonation products results from addition of O-3 on the C-C double bond of the vinyl group. The heterogeneous reactive rate constant of vinclozolin particles under room temperature is (2.4 +/- 0.4) x 10(-17) cm(3) molecules(-1) s(-1), with a corresponding lifetime at 100 ppbv O-3 of 4.3 +/- 0.7 h, which is almost comparable with the estimated lifetime due to the reaction with atmospheric OH radicals (similar to 1.7 h). The reactive uptake coefficient for O-3 on vinclozolin particles is (6.1 +/- 1.0) x 10(-4).