Distribution characteristics of airborne bacterial community in different anthropogenic activity regions across Nanchang, China

Bacteria are widely dispersed in the atmosphere by attaching on the particulate matters (PM), which have profound implications for public health and global climate. The association between anthropogenic activity and airborne bacteria remains unclear. To reveal it, the bacterial diversity and community structures of PM2.5 collected from five different anthropogenic activity regions in Nanchang, China, were compared. We found that bacteria in UPM and SPM with relatively intensive anthropogenic activities had higher richness and diversity than the other three regions, which was confirmed by the strongly positive correlations between richness/diversity indices and PM10/NO2 concentrations. Moreover, the phyla Actinobacteria and Deinococcus-Thermus were enriched in UPM and SPM, and several soil-sourced genera such as Deinococcus, Rumbellimicrobium, and Blastococcus, were also dominant in UPM and SPM. Mantel test and correlation analysis showed that human-related air pollutants were one main reason for the disparities of airborne bacterial community (r = 0.26, p < 0.01). And the above taxa in UPM and SPM showed significantly correlation with air pollutants, while several dominant taxa such as Cyanobacteria in TPM and Chloroflexi in FPM had no obvious relationship. The results suggested that the disturbance of intensively anthropogenic activities facilitated some soil derived bacteria to enter into the air. Notably, part of them such as Kocuria, Arthrobacter, and Paracoccus, were human opportunistic pathogens. This work further our understanding of anthropogenic activity impacts on airborne bacteria, especially human pathogens.