An approach to predicting indoor radon concentration based on depressurisation measurements

Abstract

Exposure to radon is recognised as the second-leading cause of lung cancer after tobacco smoke. The passive measurements typically take up to three months to be representative of the annual radon concentration. A recently developed approach depressurises a dwelling to heighten the convective radon flux determining radon entry rate coefficients. The current study characterises the ventilation status, air tightness and eight selected hourly air change rates measurements, of a sample of naturally ventilated dwellings in Ireland. The household averaged air change rate ranged from 0.28 to 1.87 h⁻¹ and airtightness measurements ranged from 4.830 to 9.423 m³ h⁻¹ m⁻² @ 50 Pa, depending on the building characteristics. The experimentally obtained values were used to parameterise a computational model for these selected dwellings and to predict radon concentrations. The radon entry rate power laws ranged from 0.18ΔP^0.97 to 1.28ΔP^1.18Bq s⁻¹. Probabilistic functions were generated based on the experimental data and predicted radon concentrations were within one standard deviation of the experimentally measured values in three out of four cases. The data generated can be used in modelling simulations to predict indoor radon concentrations based on local meteorological conditions, building characteristics, ventilation guidelines and energy-retrofit measurements.