Gas-Phase Reactions of Chlorine Oxide Anions with Ozone: Atmospheric Implications

Abstract

Understanding the mechanism for catalytic destruction of stratospheric ozone by chlorine radicals led to international restrictions on the emission of harmful chemicals. Measurements of chlorate (ClO3-) and perchlorate (ClO4-) anions in the atmosphere suggest that chloride and chlorine oxide anions could also play a role in ozone destruction, but the pathways for these gas-phase reactions are poorly understood. Here, reactions of hypochlorite (ClO-) and chlorite (ClO2-) with ozone were directly observed using linear ion-trap mass spectrometry and rate constants determined to be 6.6 (±0.7) × 10-11 cm3 molecule-1 s-1 (6.7% collision efficient) and 3.5 (±0.4) × 10-10 cm3 molecule-1 s-1 (38% eff..