Overlooked Significant Impact of Trace Metals on the Bacterial Community of PM2.5 in High‐Time Resolution

Bioaerosol has been increasingly recognized as a hazardous factor, possibly leading to environmental issues and health risks. However, the driving factors were rarely investigated, which impeded comprehensive assessment of environmental quality. Herein ambient trace metals and bacterial community in PM2.5 and their interactions during severe pollution were characterized in high time resolution. The results showed that the mass concentrations of total trace elements in PM2.5 were 1.4-9.4 mu g m(-3), with As and Cr exceeding the national standard, which might pose health risks to humans, especially children with frequently hand-to-mouth activity. The airborne bacterial community structure responded to the changing environmental and meteorological variables including PM2.5, related water-soluble ions, SO2, O-3,O- temperature, relative humidity, and wind speed. Our results suggested that the trace metal was an overlooked factor in shaping the bacterial community compared to PM2.5, related water-soluble inorganic ions, trace gases, and meteorological variables based on the aggregated boosted tree. Cd, Ga, and Nb were main trace metals factors affecting the bacterial community. The better knowledge of airborne bacterial diversity in high-time resolution were essential to assess the environmental quality and help to explore the interactions of bioaerosols and atmospheric pollutants in PM2.5. The synergistic toxicity effects for the combination of trace metals and bioaerosol should be considered in future studies when evaluating their health effects.