Investigation of the gas phase reaction of dinitrogen pentoxide with water vapor

The gas phase reaction of N2O5 with water vapor was investigated in a 17.3‐m3 Teflon lined chamber. Temporal concentration profiles for ozone, total nitrogen oxides, and nitrogen dioxide were measured. Concentration profiles for N2O5 and HNO3 were calculated from a combination of measurements of nitrogenous species. A kinetic mechanism with an adjustable value for the rate constant of N2O5 + H2O was used to model the experiments. From this analysis an upper limit value of k ⩽ 4 × 10−7 ppm−1 min−1 for the gas phase reaction N2O5 + H2O → 2HNO3 was derived.