Аннотация:Information on the characteristics of atmospheric plasma at various altitudes and possible conditions for its formation is of great importance for the preparation of flight tests using gas-discharge devices, for improving the operation of satellite positioning devices. In this work, we determined the concentration of oxygen at-oms of the background plasma at an altitude of 95 -105 km, the appearance of which is caused by photo dissociation processes at these altitudes, the main pro-cesses that lead to the production of oxygen atoms and their death in the processes of three-particle atom recombination are identified. Their concentrations have been calculated, allowing a comparison with the results of existing experiments and find out the reliability of theoretical calculations of the contributions of spectral intervals to the photodissociation rate at these heights presented in the well-known monograph