Dynamics, deterministic nature and correlations of outdoor 222Rn and 220Rn progeny concentrations measured at Bacău, Romania

► Radon and thoron progeny concentrations measured on a period of 16 years. ► 5 h, daily, monthly and annual patterns are pointed out. ► Autocorrelation functions prove non-randomness of concentrations. ► Deterministic nature of time series of concentrations is demonstrated. ► Correlations with meteorological data are studied.