Pollution profiles, pathogenicity, and toxicity of bioaerosols in the atmospheric environment of urban general hospital in China

Airborne microorganisms in hospitals present significant health risks to both patients and employees. However, their pollution profiles and associated hazards in different hospital areas remained largely unknown during the extensive use of masks and disinfectants. This study investigated the characteristics of bioaerosols in an urban general hospital during the COVID-19 pandemic and found that airborne bacteria and fungi concentrations range from 87±35 to 1037±275 CFU/m³ and 21±15 to 561±132 CFU/m³, respectively, with the outpatient clinic and internal medicine ward showing the highest levels. The operating room (OR) and clinical laboratory (LA) had lower bioaerosol levels but higher microbial activities, suggesting that disinfection procedures used to clean bioaerosols may change them into a viable but non-culturable state. The dominant fungi were Cladosporium, Aspergillus, and Penicillium, while the most common viruses were human associated gemykibivirus 2 and human alpha herpesvirus 1. Besides, the dominant pathogens were Staphylococcus aureus, Salmonella enterica, and Pseudomonas aeruginosa. Bacitracin and macrolides resistance genes bacA and ermC were the most prevalent subtypes of antibiotic resistance genes. Compared to the control sample, hospital-acquired bioaerosols, particularly from the outpatient examination room and emergency room can trigger higher levels of inflammatory factors and cell toxicity but lower cell proliferation rates. Lower cell toxicity was observed in low-risk areas (intensive care unit, LA, and OR). This study provides a new method for assessing bioaerosol health risks and enhances understanding of nosocomial and opportunistic infections and their control.