A surface wave (2.45GHz) driven, atmospheric plasma torch in air with a small admixture of water vapor (2%) is investigated as a source of exogenic NO. A 1D theoretical model of this source based on a self-consistent treatment of particles kinetics, gas dynamics, gas thermal balance, and wave electrodynamics is developed. Mass spectrometry is used to determine the relative NO(X) number density in the exhaust stream and validate the model predictions. The relative NO(X) density reaches values of up to 3% in the discharge zone, the maximum values being observed at the higher powers (400W) and the lower gas flow rates (500sccm). The NO(X) relative density is nearly constant along the afterglow plasma jet, with values between 1.1% and 1.6% for microwave powers and gas flow rates in the range 200–400W and 500–2000sccm, respectively.