Atmospheric oxidation of Folpet initiated by OH radicals, NO 3 radicals, and O 3 .

Folpet, a nonspecific sulfenimide fungicide, is widely used to protect crops against mildew. It can be dispersed and transported over long distances. The residence time of Folpet in the atmosphere depends on the oxidation processes initiated by atmospheric oxidants such as O 3 , OH and NO 3 radicals. In this study, the reactions of Folpet with gas-phase O 3 , OH and NO 3 radicals were investigated via quantum chemical calculation methods, which can effectively provide information about the reaction intermediates and pathways. The obtained results show that the room-temperature rate constants of the reactions between Folpet and OH radicals, NO 3 radicals and O 3 are about 3.69 × 10 -14 , 5.40 × 10 -15 , and 1.73 × 10 -22 cm 3 per molecule per s at 298 K, respectively. Considering the oxidant concentration in the atmosphere, Folpet seems to be mainly scavenged by NO 3 radicals, especially at night. This study can contribute to a better understanding of the atmospheric fate of Folpet, elucidating a significant impact of NO 3 radicals on its degradation process in comparison with other oxidants such as O 3 and OH radicals.