A scheme for molecular tagging velocimetry is presented that can be usedin air f lows without any kind of seeding. The method is based on thelocal and instantaneous creation of nitric oxide (NO) molecules fromN2 and O2 in the waist region of a focused ArFexcimer laser beam. This NO distribution is advected by the flow and canbe visualized any time later by laser-induced fluorescence in the γ bands. The creation of NO is confirmed byuse of an excitation spectrum. Two examples of the application of thenew scheme for air-flow velocimetry are given in which single laserpulses are used for creation and visualization of NO.