How Do Different Locations,Floors and Aspects Influence Indoor Radon Concentrations? An Empirical Study Using Neural Networks for a University Campus in Northwestern Turkey

Abstract

Indoor radon (²²²Rn) concentrations were measured at a 10-min interval during October 2011 and January 2012. The monitoring followed a randomised and repeated pattern of experimental design, and was carried out at six faculty buildings of the Abant Izzet Baysal University, on five floor levels and two aspect directions (south vs. north) using an AlphaGUARD P30 Radon Monitor. The University campus area located in northwestern Turkey is near the North Anatolian Fault, a major active right lateral-moving strike-slip fault which runs along the transform boundary between the Eurasian Plate and the Anatolian Plate. Best artificial neural networks (ANNs) emulating indoor ²²²Rn levels were selected as a function of air temperature (T_a), air pressure (P_a), relative humidity (RH), T_a by RH interaction, local time, location, floor and aspect. Elevated levels of indoor ²²²Rn concentrations were measured at the south-facing offices and on the first floor levels of the building. Lower concentrations were found on the upper floor levels. Out of 27 ANNs, GFF-1-B-L and MLP-2-B-L performed best and could be contributing to the 35.6% and 87.2% of variations in spatio-temporal dynamics of indoor ²²²Rn levels as a function of location or floor level and aspect, respectively, in addition to T_a, P_a, RH, T_a by RH interaction and time.