The time series of seismic noise, geomagnetic variationsandradon activity concentration in the atmosphericboundary layer were studied. The data were obtained by geophysical systems providing monitoring measurements inthe Republic of Karelia, Russia. The power spectrawere calculated and analyzed for the series recorded under low seismic and geomagnetic activity. The similarity of the detected periods of the spectra with periods of the Earth’s natural oscillations is regarded as evidence of a modulating and synchronizing role of these oscillations. The modulation of the radon activity concentration in the atmosphere by the Earth’s own oscillations is explained by the transport of radon to the Earth’s surface by bubble hydrogen formations.