Radiological characterisation and radon equilibrium factor in the outdoor air of a post-industrial urban area

The obtained results show that activity concentration values for long-lived radionuclides that precede radon and thoron are in the order of 10−6 Bq m−3 and long-lived ones after radon are around 10−4 Bq m−3. Thoron progeny are around 2 × 10−2 Bq m−3 and radon progeny are around 1.8 Bq m−3. The mean radon equilibrium factor was 0.18. All of these values are close to the minimum UNSCEAR values, but show some variability, which highlights the importance of determining activity concentrations for each naturally occurring radionuclide and the equilibrium factor in the outdoor air.