Air radon equilibrium factor measurement in a Waste Water Pre-Treatment Plant

We analyze in this paper a Waste Water Pre-Treatment Plant (WWTP) located at the Mediterranean coast with air radon concentration above Spanish action level (600Bq per cubic meter). This paper presents a method for radon equilibrium determination by gamma spectrometry measuring of the radon progeny concentrations in the air, in order to estimate WWTP workers effective dose more exactly. The method is based on simultaneous sampling of air through a filter paper and alpha spectrometry measurement of radon activity concentration in the air. According to the measured radon activity concentration in the air of 368±45Bq/m3 the equilibrium factor between radon and progenies is estimated to be F=0.27, which is in good agreement with expected values. •High levels of Radon in a workplace can increase health risks in the employees.•Using the typical equilibrium factor 0.4 could lead to an error in the estimation of radon doses.•We present a method for radon equilibrium determination.•Equilibrium factor is calculated by gamma spectrometry measuring of radon progeny concentrations in the air.