REFLECTIONS ON THE INDOOR ENVIRONMENTAL MONITORING SYSTEM OF THE HERITAGE BUILDINGS IN THE PALACE MUSEUM – A CASE STUDY OF THE MERIDIAN GATE EXHIBITION HALL

Abstract. The indoor micro-environment monitoring system of the Forbidden City aims to explore the thresholds of environmental indicators under the presence of coexistence of multiple cultural relics through the analysis of environmental monitoring data and the deterioration of cultural heritiges, and to develop the optimal strategies for the protection and utilization of cultural heritiges. The objects of interest include historic buildings with modernised interior or those used for the storage of movable cultural relics. Several environmental indicators are employed to quantify the dynamic changes of the indoor environment. In order to meet the requirements of 24-hour data collection, real-time data transmission, and easy management and maintenance, the indoor micro-environmental monitoring system has been continuously upgraded and the "LoRa-based Hybrid Self-Organising Network System Deployment Solution" was deployed to satisfy the demands of high precision, low energy consumption, constant stability, and low cost. Taking the Meridian Gate exhibition hall of the Forbidden City during the exhibition "Splendor Forever: Six Centuries of the Forbidden City" as an example, we discussed the relationship between temperature, humidity, carbon dioxide (CO₂) concentrations and visitor volumes, and the results provide a basis for optimizing the management of the exhibition. Future improvements to the indoor environment monitoring should focus on strengthening the in-depth mining of data and multi-factor correlation analysis, so as to gradually form a systematic and comprehensive monitoring management system.