Chemical and Biological Characteristics of PM₁-Associated Aerosols and Airborne Viruses in Hospital and Campus Environments during the Post-COVID Period

We utilized traditional aerosol sampling to collect PM1 samples, and further apply redundancy analysis (RDA) to investigate the association of environmental factors (including PM1 chemical composition, oxidative potential, meteorological factors and gaseous pollutants) and airborne bacterial community. Our findings revealed that Bacteroidota positively correlated with Sn and Mn, Firmicutes with local primary pollutants, and Proteobacteria with transportation-related pollutants. Variance partitioning analysis (VPA) showed that PM1 chemical composition, meteorological factors and gaseous pollutants collectively explained up to 43.7% of community variance, and synergistic effects may exist among the three factors. In contrast, oxidative potential had minimal influence. Additionally, to investigate airborne viral presence, we employed a novel bioaerosol sampler targeting SARS-CoV-2 in hospital and campus settings. Viral loads were highest in negative pressure isolation rooms, followed by general hospital and campus areas. Also, the detection rates follow the same pattern, which is 87.5%, 58.3%, and 25.0%, respectively. Notably, detection rates near isolation wards increased during patient admissions, implying possible biocontamination despite containment measures. Peak human traffic flow emerged as a significant factor influencing viral detection. These results highlight how environmental factors shaping airborne microbial communities.