Atmospheric loss of nitrous oxide (NO) is not influenced by its potential reactions with OH and NO radicals

The rate coefficient for the possible reaction of OH radical with N 2 O was determined to be k 1 < 1 × 10 −17 cm 3 molecule −1 s −1 between 253 and 372 K using pulsed laser photolysis to generate OH radicals and pulsed laser induced fluorescence to detect them. The rate coefficient for the reaction of NO 3 radical with N 2 O was measured to be k 2 < 5 × 10 −20 cm 3 molecule −1 s −1 at 298 K using a direct method that involves a large reaction chamber equipped with cavity ring down spectroscopic detection of NO 3 and N 2 O 5 . Various tests were carried out ensure the accuracy of our measurements. Based on our measured upper limits, we suggest that these two reactions alter the atmospheric lifetime of N 2 O of ∼120 years by less than 4%. The rate coefficient for the possible reaction of OH and NO 3 radical with N 2 O are shown to be, respectively,