Accessing of Viable Bacteria Captured by Antimicrobial Filters in a Metropolitan Subway of South Korea

In subway stations, where passengers are crowed in enclosed spaces with restricted ventilation, airborne microorganisms have been detected, potentially contributing to the spread of infectious aerosols. In South Korea’s metropolitan subways, air purifiers are installed on platforms to reduce particulate matter. Efficiency particulate air (EPA) filters in air purifiers lack disinfection capabilities and can serve as a source of airborne pathogens during filter replacement. In this field study, antimicrobial filters were applied to air purifiers installed on a subway platform to assess their ability to reduce the captured microorganisms. After 1 week of operation, the microbiomes were collected from both the control and test filters, followed by microbial identification. Additionally, the composition of metal elements was analyzed using particulate matter collected by the EPA filters. While 19 types of bacterial species were detected in control filters, the antimicrobial filters showed the presence of 15 bacterial species, with overall 64.71% of antibacterial efficacy. Specifically, the antimicrobial filter exhibited 100% reduction in Micrococcus and 93.75% reduction in Staphylococcus genus, related to anthropogenic sources.