Global Meta-analysis of Airborne Bacterial Communities and Associations with Anthropogenic Activities

Airborne microbiome
alterations, an emerging global health concern,
have been linked to anthropogenic activities in numerous studies.
However, these studies have not reached a consensus. To reveal general
trends, we conducted a meta-analysis using 3226 air samples from 42
studies, including 29 samples of our own. We found that samples in
anthropogenic activity-related categories showed increased microbial
diversity, increased relative abundance of pathogens, increased co-occurrence
network complexity, and decreased positive edge proportions in the
network compared with the natural environment category. Most of the
above conclusions were confirmed using the samples we collected in
a particular period with restricted anthropogenic activities. Additionally,
unlike most previous studies, we used 15 human-production process
factors to quantitatively describe anthropogenic activities. We found
that microbial richness was positively correlated with fine particulate
matter concentration, NH3 emissions, and agricultural land
proportion and negatively correlated with the gross domestic product
per capita. Airborne pathogens showed preferences for different factors,
indicating potential health implications. SourceTracker analysis showed
that the human body surface was a more likely source of airborne pathogens
than other environments. Our results advance the understanding of
relationships between anthropogenic activities and airborne bacteria
and highlight the role of airborne pathogens in public health.