The paper presents the results of studies of the possible influence of electromagnetic radiation from wireless communication systems on a man in natural conditions. The studies were performed by the method of auxiliary sources (MAS). On the basis of computer simulation, the field distributions in rooms containing a model of a man and a radiator are investigated. The dependence of the radiation pattern on the position of the model and the radiator with allowance for the open part in the form of a window is studied. As a rule, the walls of a room have a certain transparency, depending on their design and the incident frequency. The simulation by the MAS method shows how this transparency can be regulated. Due to the resonance phenomena, the amplitude of the resonant field at certain frequencies and the transparency of the walls become extremely large, which is the reason for large values of absorbed electromagnetic energy and its undesirable effect on a man.