Mechanism for N 2 O formation from NO at ambient temperature

N 2 O was reported to form in sample containers of flue gases containing NO and SO 2 . This could have significant implications for the evaluation of N 2 O buildup in the atmosphere. Existing models are based either on liquid‐phase reactions, which cannot account for N 2 O formation at low humidity, or on termolecular reactions, which are not likely to occur at low concentrations. In this work, we propose mechanisms for N 2 O formation based on gas‐phase reactions, which address the effect of SO 2 , O 2 , and moisture. Analytical expressions of the formation rate were derived and compared to reported rates, and rate constants were estimated for limiting cases. The current analyses suggest that N 2 O 2 could be an important precursor for N 2 O formation from NO, and the mechanism may be important for N 2 O formation in power‐plant plumes.