Heterogeneous Oxidation Of Pesticides On The Aerosol Condensed Phase
Free (open access)
15 - 25
J. Socorro, A. Durand, B. Temime-Roussel, S. Ravier, S. Gligorovski, H. Wortham, E. Quivet
Pesticides are widely used all over the world. It is known that they exhibit adverse health effects and environmental risks due to their physico-chemical properties and their extensive use, which is growing every year. They are distributed in the atmosphere, an important vector of dissemination, over long distances away from the target area. The partitioning of pesticides between the gas and particulate phases influences their atmospheric fate. Most of the pesticides are semi-volatile compounds, emphasizing the importance of assessing their heterogeneous reactivity towards atmospheric oxidants. The photolysis processing and heterogeneous reactivity towards O3 and OH, was evaluated of eight commonly used pesticides adsorbed in silica particles. Silica particles are present in airborne mineral dust in atmospheric aerosols, and heterogeneous reactions can be different in the presence of these mineral particles. Depending on their origin and conditioning, aerosol particles containing pesticides can have complex and highly porous microstructures, which are influenced by electric charge effects and interaction with water vapour. Therefore, the kinetic experiments and consecutive product studies were performed at atmospherically relevant relative humidity (RH) of 55%. The identification of surface-bound products was performed using GC-(QqQ)-MS/MS and the gas-phase products were monitored on-line by PTRToF- MS. The obtained results will allow a better understanding of the impact of pesticides and their degradation products on human health, and to make recommendations in order to reduce population exposure to the pesticide plume and the pollution by phyto-sanitary products on the regional scale, which constitutes a necessary step in the development of environmental strategies.
pesticides, heterogeneous reaction, ozonolysis, hydroxyl radicals, kinetics, degradation products