Ozone tagging velocimetry (OTV), a nonintrusive, unseeded, time-of-flight v
elocity measurement technique, consists of a write step, where a 193-nm pul
sed excimer laser creates an O-3 line via O-2 uv absorption, and a subseque
nt read step, where a 248-nm excimer laser photodissociates the O-3 and flu
oresces the vibrationally excited O-2 product, revealing the tag line displ
acement. For the first time, instantaneous OTV images and velocity measurem
ents are reported in airflows at room temperature. The narrowband lasers ar
e tuned to the O-2 Schumann-Runge transitions improving the OTV signal stre
ngth by a factor of six over that obtained using two broadband lasers. This
improvement is less than expected from absorption ratio estimates, due in
part to incomplete laser locking efficiency and possibly to laser bleaching
. Diffusion of the O-3 tag line is shown to be important only for write-rea
d delay times of the order of milliseconds or greater. Modeling of O-3 conc
entration vs time shows O-3 is long lived at room temperature and relativel
y insensitive to water vapor, but O-3 peak concentration and lifetime great
ly decrease at high temperature, though high pressure increases peak O-3 co
ncentration.