Validation of an experimental setup to study atmospheric heterogeneous ozonolysis of semi-volatile organic compounds

Abstract

Abstract. There is currently a need of reliable experimental procedure to follow the heterogeneous processing simulating the atmospheric conditions. This work offers a new experimental approach to study the reactivity and the behaviour of SVOC associated with atmospheric particles. The heterogeneous ozonolysis of naphthalene adsorbed on silica and XAD-4 particles is investigated in specially designed flow tube reactors. The experimental procedure consists in adsorbing gaseous naphthalene on particles before exposing it to ozone. By this novel approach the kinetics is determined following the consumption of naphthalene. Using this procedure, the rate constant kO3 of naphthalene is equal to (2.26±0.09)×10−17cm3.molec−1.s−1 and (4.31±1.07)×10−19cm3.molec−1.s−1 at 25°C for silica and XAD-4, respectively. The results show both that nature of the particles significantly affects the kinetics and that heterogeneous ozonolysis of naphthalene is faster than in the gaseous phase.