MARGARITA KUQALI, YLLI KAÇIU, BLERIM RRAKAQI, NJOMZA ELEZAJ, ISMET BAJRAMI, GAZMEND NAFEZI
Abstract
This study investigates short-term indoor radon variability using high- resolution hourly monitoring data collected from five indoor environments with different ventilation conditions, occupancy patterns, and structural characteristics. Indoor radon concentrations were continuously measured using RadonEye RD200 detectors, yielding approximately 3,300 hourly observations during the monitoring period from November to December 2025. Indoor temperature was simultaneously monitored to support environmental interpretation. The monitored environments included storage rooms, office spaces, technical infrastructure areas, and continuously occupied working rooms distributed across different floor levels. Hourly radon concentrations ranged from approximately 1 to 265 Bq m3, with the highest average concentrations observed in the working room and the lowest in the archive room. Short-term radon accumulation events were most evident during periods of reduced ventilation and limited room occupancy, while rapid concentration declines were consistently observed following natural ventilation or routine human activity. The dataset was analysed using exploratory time-series analysis, heatmaps, diurnal profiling, and stratified comparisons. The results revealed reproducible daily radon patterns and substantial room-specific variability strongly influenced by ventilation behaviour and occupancy conditions. The findings highlight the importance of high-resolution monitoring for understanding short-term indoor radon dynamics that may remain hidden when relying solely on long-term average measurements and demonstrate a practical framework for applied indoor environmental analysis.
Key words: Indoor radon, time-series analysis, radonEye RD200, data visualisation, temporal dynamics.