Abstract
High-energy interactions of gamma rays and protons with the Earth atmosphere have been simulated by means of the CORSIKA Monte Carlo code, and the secondary-particle density distributions in the resulting extensive air showers, at ground level, have been studied. It is shown that the fluctuations of the density distributions as a function of the polar angle have features typical of a 1/f noise. The sample is then analysed in order to study its scaling behaviour and we find that it can be parametrized by means of a universal multifractal approach.