Gaps between observed and perceived indoor environmental quality: An integrated assessment in multiple university library spaces

Library spaces vary greatly in terms of location, size, equipment, noise sources, and operating hours, underscoring the need for a comprehensive assessment of indoor environmental quality (IEQ). Despite this, few studies have simultaneously considered both objectively measured IEQ data and users’ subjective perceptions. This study addresses this research gap by integrating sensor-based objective measurements with survey-based subjective assessments to evaluate IEQ across multiple spaces within the Pao Yue-Kong Library in Hong Kong. Four key IEQ parameters were analyzed: thermal comfort, indoor air quality (IAQ), visual comfort, and acoustic comfort. Results indicated that thermal comfort and IAQ conditions were largely rated as “excellent” across spaces. However, notable differences emerged for visual and acoustic comfort. Additionally, varying user expectations contributed to differences in user satisfaction, even under similar objective conditions. These findings provide library facility managers with critical insights for informed decision-making, optimizing space utilization, and improving user satisfaction.