This work is a further investigation of increases in violet and UV fluorescence in various flowing nitrogen afterglows, when oxygen discharged in a microwave ( μ− w) cavity is added to active nitrogen and oxygen mixtures downstream of the μ− w discharge zones of nitrogen and oxygen. The present N 2 second positive band system (pbs) fluorescence (i.e. N 2( C 3 Π u , υ′→ B 3 Π g , υ″)+ hν) increases also occur, when an orange flame (previously reported) is visually observed in nitrogen afterglows of active nitrogen and oxygen, by adding μ− w discharged O 2. The orange flame is reported to result from a collisional energy transfer between excited molecular oxygen and molecular nitrogen species. (Nitrogen was activated by two ways: (i) with or without argon in a μ− w discharge cavity and (ii) by reacting gaseous nitrogen with metastable argon, Ar( 3P 0,2), generated in μ− w discharged Ar.) The present, as well as previous, results indicate that the well-known metastable energy donor, N 2 ( A 3 Σ u + ) , is also an efficient energy acceptor from non-nitrogen species, namely from excited O 2, most probably O 2( α 1 Δ g ). In addition, by analyzing experimental results using two different conventional chemical kinetics approximations, a lower limit estimate (∼1×10 −10 molecule −1 cm 3 s −1) is deduced of the pseudo-unimolecular chemical reaction rate constant, k αA , for the energy transfer between O 2( α 1 Δ g ), as the energy donor, and N 2 ( A 3 Σ u + ) , as the energy acceptor. Further, enhanced intensities of background N 2 + first negative band system (nbs) emissions (i.e. N 2 ( B 2 Σ u + → X 2 Σ g + ) + h ν ) are observed along with enhanced background N 2 second pbs emissions intensities caused by discharged oxygen, near a nitrogen pink afterglow. The energy transfer, responsible for the enhanced N 2 first and second pbs emissions intensities and N 2 + first nbs emissions intensities, may contribute to the corresponding upper atmospheric and space emissions, in particular to the various visible and UV short-lived (lasting a few to ∼ a thousand ms) emissions discovered since 1989, termed upper atmospheric “transient luminous events”.