Resumen
The results of the study of the polycristallibe material composition in soil and its corresponding atmosphere in four differente zones of Mexico, are presented. the analyses were carroed out by x-ray diffraction. for the first time, the composition of the cristalline phase of backgrond aerosol in rural, maritime, suburban and urban atmosphere, was obtained. it was found out that the urban atmosphere is particularly rich in crystalline phases in comparison with the other areas.