The temporal fluctuations of particulate matter time series of three reference European stations have been investigated, by using the power spectrum analysis. Our results point out to the presence in particulate matter of annual periodicities superimposed on a scaling behaviour with exponent ranging between ~1.4 and ~1.6, indicating quite high persistent correlations. Furthermore, a crossover timescale at about 1 month, evidenced in all the signals analysed, could be linked with chemical-physical processes in which aerosol particles are involved during their atmospheric lifetimes.