Analysis of the potential atmospheric impact of the reaction of N2O with OH

Highlights: • Nitrous oxide is a greenhouse gas and a potential O₃-depleting substance. • OH, Cl, and NO₃ do not react so rapidly with N₂O. • These reactions cannot be measured using the best of laboratory techniques. • A reaction of N₂O with OH would impact the atmospheric lifetime of N₂O. • Mechanism and kinetics of the N₂O + OH reaction have been studied. The reaction of nitrous oxide (N₂O) with hydroxyl (OH) is studied using high-level quantum chemistry and advanced chemical kinetics techniques. Three reaction mechanisms including a direct O-abstraction, an unusual indirect O-abstraction, and OH-addition/NO-elimination have been characterized. Reaction enthalpies calculated from first principles agree well with those of experiment. Chemical kinetics results show that the title reaction is not a candidate for short or long-time removal of N₂O (with an atmospheric lifetime of at least 1 × 10¹³ years) from the atmosphere but may play a minor role in high-temperature combustion where it may convert N₂O pollutants to N₂.