This paper presents the results of modeling studies on the formation and destruction of NO in pulsed harrier discharges in nitrogen and air. The goals of this work are to identify the major processes involved in the formation and destruction of NO in air discharges, to distinguish between oxidative and reductive paths for NO destruction, to explore the potential importance of excited state reactions, to evaluate the role of water in such systems, and to identify the "final" products in the absence of heterogeneous processes. In all cases, the systems were modeled with 100 x 10(4)% (100ppm) of added NO, with and without 3% added water. The focus in all of this work is chemistry in the post-pulse regime.