Understanding Seasonal Indoor Radon Variability from Data Collected with a LoRa-Enabled IoT Edge Device

The long-term assessment of radon (Rn) is a critical factor in evaluating the exposure risk faced by building occupants, and it plays a significant role in determining the implementation of Rn remediation strategies aimed at enhancing indoor air quality (IAQ). Meteorological parameters, such as temperature, relative humidity, and atmospheric pressure, as well as geological factors, such as soil properties, uranium content, rock formations, parent rock weathering, and water content, can significantly impact the assessment of Rn exposure risk and the selection of appropriate mitigation measures. A continuous monitoring campaign of a National Architectural Heritage building serving as a museum open to the public for a period of 546 consecutive days was conducted. The results of the in situ investigation revealed a broad range of seasonality in indoor Rn emission, with a negative correlation observed between Rn concentration and air temperature. The data indicated that indoor Rn concentration increases in the winter months as a result of reduced indoor air temperature and decreased air exchange, while it decreases in the summer months due to increased air temperature and enhanced natural ventilation. However, the implementation of high ventilation rates to improve IAQ may result in significant heat losses, thereby affecting the thermal comfort of building occupants during the winter months. Therefore, it is imperative to achieve a balance between ventilation practices and energy efficiency requirements to ensure both IAQ and thermal comfort for building occupants.