Surveillance of Airborne Microorganisms and Associated Influencing Factors at an International Airport in China, 2019-2020

As a major international transportation hub, airports are critical nodes for cross-border and regional spread of respiratory diseases. Real-time airborne microbial monitoring facilitates surveillance and control of travel-related infections, strengthens early warning, and supports public health interventions. Air samples were collected weekly from November 2019 to August 2020 at two security checkpoints of an international airport in China (288 samples total) using two air samplers (FJ and SKC). qPCR detected bacteria ( Streptococcus , Staphylococcus , Micrococcus ), fungi, and six respiratory viruses; SARS-CoV-2 was added following the COVID-19 outbreak. Spearman correlation analysis was performed to evaluate relationships between microbial detection rates and environmental parameters. Binary logistic regression was employed to evaluate the impact of sampling and environmental factors on detection rates. Passenger throughput demonstrated significant positive correlations with temperature, particulate matter concentration, and detection rates of Streptococcus / Staphylococcus . Staphylococcus showed the highest detection rate (37.50%). The SKC biosampler outperformed FJ for bacterial detection, while FJ was superior for fungal detection. Fungal detection rates exceeded 60% and correlated positively with humidity. All samples collected after the COVID-19 outbreak tested negative for SARS-CoV-2. Other six respiratory viruses were detected in 12 samples, which exhibited higher detection rates in the post-pandemic period. Particulate matter concentration negatively correlated with viral detection. Airport airborne microbial monitoring can serve as an early-warning signal for emerging respiratory infectious diseases. Interventions including mask-wearing, environmental disinfection, and passenger flow control significantly reduced airborne pathogen detection rates, providing a scientific basis for optimizing ventilation systems, formulating cleaning and disinfection protocols, and establishing comprehensive infectious disease prevention and control systems.