After comparing the energy spectrum of nucleon-antinucleon at very high altitude with the Bess experiment, we have simulated the fluxes of antiprotons and antineutrons generated at various atmospheric depths. The simulations are carried out with the help of CORSIKA program involving a primary energy spectrum starting above the energy threshold of antiparticle production up to 1 PeV. Different abundances of alpha and heavy primaries in the primary composition are combined. Specific effects are investigated when the energy of the an-tiparticles is close to the maximum of the annihilation cross section in antiproton-air interaction. Typical signatures are expected in detectors at atmospheric depths of 100-300 g/cm 2 .