Associations of Indoor Nighttime Ventilation with the Relative Abundances of Typical Pathogenic Bacteria and Fungi in Settled Dusts from Floor, Desk, and Bed of University Dormitories

Inadequate ventilation in university dormitories risks microbial exposure, but its association with pathogen prevalence in dust across indoor surfaces remains unclear. In this study, we monitored nocturnal air exchange rates (AERs) over a year in dormitory rooms and collected settled dust samples from beds, desks, and floors across four seasons. Based on the World Health Organization (WHO) priority bacterial and fungal pathogen lists, 34 pathogenic species were initially identified from gene sequencing data. We built multivariate regression models to evaluate the associations of daily cumulative ventilation status before dust sampling with the distribution of these pathogens. The results indicated a low compliance rate (AER ≥ 0.7 h−1, 43.2–52.1%) for ventilation in the dormitories. Fusarium and Acremonium were detected in most samples (92.3–99.5%). The modulatory effect of nighttime cumulative ventilation varied heavily across pathogen species and surface types. The relative abundance of Candida tropicalis on bed dust exhibited a stable negative correlation with long-term cumulative AER (β: −0.42 to −0.50), whereas the relative abundance of Salmonella correlated positively with higher AERs. This study demonstrates that ventilation is not a universal pathogen-control measure, revealing its temporal cumulative characteristics and spatial heterogeneity of ventilation in modulating indoor pathogens, and provides a theoretical foundation for implementing precision ventilation strategies in university dormitory environments.