The formation of lN2O in the reactive collisional quenching of NO3 (~A2E') and NO2(~A2B1, 2B2) by N2 at 298 K was detd. using a dye laser excitation technique combined with product accumulation/gas chromatog. anal. The abs. yield of N2O was proportional to the no. of photons absorbed (Npe) into non-dissociative states of the electronically excited species. The relative N2O yields (DN2O/Npe) were detd. as f1 = (1.4 +- 0.6) * 10-2 and f2 = (4 +- 2.0) * 10-4 for the quenching of NO3* and NO2*, resp. As a consequence of high pumping rates of NO3* and NO2* in the daytime atm., these processes represent a significant in situ chem. source of atm. N2O.