Indoor volatile organic compounds in densely occupied education buildings of four universities: Target list, concentration levels and correlation analysis

Abstract Although significant progress had been made in characterizing indoor volatile organic compounds (VOCs) during the past decades, much was unknown considering the impact of human emissions on indoor VOCs in actual densely occupied spaces. In this context, this study investigated the indoor VOCs in densely occupied education buildings of four universities to identify the species, target list, concentration levels and possible relevance. A total number of 89 VOC species with high detection rate (≥50%) were mostly detected, including 24 alkanes and alkenes, 20 esters and alcohols, 14 ketones and aldehydes, 5 halides, 22 aromatics and 4 other VOCs. Among them, 33 VOC species were categorized into a target list determined by individual detection rate, concentration level and potential significance. The main concentration range of most individual targeted VOCs was 0–7.6 μg/m³ with a few exceptions. Several actual scenarios, including occupied condition, season and function room type were analyzed for identifying targeted VOCs and their possible factors correlated with human related emissions. The univariate analysis indicates that occupied condition, season, and function room type may yield a significant concentration difference of some targeted VOC individuals. However, no consistent results of each targeted VOC can be obtained under those three actual scenarios due to the complex effects of indoor natural ventilation, sources and sinks, T/RH and so on. This study could be a better understanding of actual indoor human-related VOC pollution in densely occupied buildings.