Bacterial and fungal metagenomes associated with atmospheric particulates in Republic of Korea: Comparison of PM_2.5 and TSP larger than PM_2.5

Particulate matter (PM) significantly contributes to air pollution, potentially causing health issues, with PM-associated microorganisms implicated in some cases. While studies have explored microbial concentration and structure in PM based on particle size, comprehensive analysis of microbial functional traits and environmental influences is limited. This study evaluated microbial concentrations and diversity in PM with a diameter of 2.5 μm or lower (PM_2.5) and total suspended particles (TSP) greater than PM_2.5 (PM_>2.5) samples relative to air temperature and other factors. DNA extracted from PM_2.5 and PM_>2.5 filters was sequenced to characterize bacterial and fungal community structures and functional genes. Results showed that microbial concentrations and diversity were greater in PM_>2.5, with similar dominant species across PM sizes. Higher air temperatures correlated with increased microbial concentrations and diversity in PM_>2.5, attributed to enhanced microbial growth. An Asian dust event from the Mongolian desert disrupted the PM microbiome. Despite consistent species dominance, gene function analysis revealed abundant drug resistance pathways in bacterial communities of both particle types, while pathotroph prevalence was higher in PM_2.5 fungal communities. These findings indicate that PM_2.5 microbial community analysis suffices for understanding PM ecosystems, offering valuable insights for air quality management and microbial pollution control, especially concerning potential pathogens.