Airborne total bacteria contamination in a university student lounge: evaluation and control strategies

Indoor air quality (IAQ) has emerged as a critical public health concern, particularly in confined spaces where young adults spend much of their daily lives. In this study, we aimed to quantify the total airborne bacterial load in a student lounge environment using quantitative PCR (qPCR) and to evaluate the effectiveness of different cleaning interventions. Air samples were collected over a 1-month period under various conditions (control, wet mopping, alcohol wipes, vacuuming, and operation of a mechanical air cleaner). The analysis examined the correlations between microbial concentrations and environmental factors, including temperature, humidity, carbon dioxide, usage frequency, and activity level. We found that conventional surface cleaning methods, such as wet mopping, cleaning with alcohol wipes, and vacuuming, were not consistently effective in reducing airborne microorganisms and, in some cases, contributed to microbial resuspension. In contrast, the use of air purifiers demonstrated a strong negative correlation with most microbial concentration and activity-related environmental factors, indicating its superior effectiveness in reducing bio-aerosol levels. However, no statistically significant differences were observed across the cleaning methods (p = 0.721), suggesting complex interactions among the environmental variables. These findings underscore the limitations of surface-oriented cleaning for controlling indoor airborne microorganisms and highlight the importance of continuous air purification strategies and adequate ventilation. This study provides insights into effective IAQ management, particularly in spaces with limited regulatory oversight, such as university student lounges.