The artificially ionized layers in the atmosphere caused by microwave pulses are actively studied for possible application to communication services. The possible negative influences of this project on the environment will be considered. They are connected with the synthesis of nitric oxide, which is aggressive to the ozone layer. The mechanism of nitric oxide synthesis in the ionized region is based on the chemical reactions of molecules and atoms in the metastable electronic states excited by electron impact. These reactions are effective under conditions which are optimum for the formation of an artificially ionized layer. The concentration of nitrogen oxide produced in the ionized region is estimated for a variety of parameters of microwave pulses which can be used for breakdown of the atmosphere. The spatial shape of the artificial NOx cloud formed by the atmospheric wind and diffusion is studied. Artificially ionized layers are considered as the anthropogenic source of NOx on an annual global basis and compared to the existing natural sources. It is shown that the worldwide net of these layers does not appear to be sufficient to be of environmental concern. ¿ American Geophysical Union 1990