The emission from a plasma generated by a high-energy electron beam in air was subjected to a comprehensive study, involving experimental test bed measurements, with specially designed equipment, and theoretical calculations of the degradation spectrum of the electron beam, the kinetics of emitting levels, and the spectral distribution of emission. The comparison of theory and experiment confirmed the validity of the theoretical model adopted. The experiments were performed in two setups: a small vacuum chamber, with pressure p = 17.3 - 33 Pa (0.13 - 0.25 ton) and electron beam power W = 50 - 300 W, and a large vacuum chamber with p less than or equal to 10 kPa (75 ton), and W less than or equal to 40 kW.