A study of the chemical degradation of ClONO 2 in the stratosphere

The flash photolysis‐resonance fluorescence technique has been utilized to measure the rate constants for the reactions of chlorine nitrate (ClONO 2 ) with two stratospheric radicals, O(³P) and OH. Both rate constants were measured at a pressure of 20 Torr and a temperature of 245 K. The reactions with their corresponding rate constant in units of cm −3 molecule −1 s −1 are: O(³P) + ClONO 2 → Products, k 1 = (2.0 ± 0.2) × 10 −13 ; OH + ClONO 2 → Products, k 2 = (3.7 ± 0.2) × 10 −13 . The above results, coupled with the photolysis rate of ClONO 2 , indicate that these chemical degradation pathways contribute less than 10% to the removal of ClONO 2 in the stratosphere.