Recent atmospheric and laboratory experiments have shown that significant nonthermal vibrational excitation of O3 can occur near the mesopause. These results can be interpreted in terms of a steady state model in which O3(&ngr;) is formed by radiative and chemical excitation and is destroyed by radiative and collisional deactivation. The only atmospheric chemical source of O3(&ngr;) which can be clearly identified is the three-body recombination of O with O2. Little is known about the detailed, level-dependent kinetics of O3(&ngr;), and several key assumptions are required for kinetic interpretation of the data. Predicted vibrational distributions, infrared band radiances, and diurnal effects are compared to in situ data in various assumed limits, and critical processes are discussed. Possible auroral sources of O3(&ngr;) are also examined.