Insights into bacteria characteristics and potential pathogen in rural indoor households in Fenwei Plain, China

Indoor air quality in rural households significantly impacts public health, yet bioaerosol characteristics in these environments remain poorly understood. This study investigates the characteristics of bioaerosols and bacterial communities in rural households of the Fenwei Plain, China, comparing indoor and outdoor environments and contrasting rural-urban differences. The peak concentrations of total airborne microbes (TAMs), viable bacteria, non-viable bacteria, and viability showed pronounced indoor/outdoor variations, meanwhile, rural areas exhibited significantly lower bioaerosol concentrations than urban areas. The bacterial communities displayed distinct indoor-outdoor patterns: Actinobacteria (40.5% and 27.3%) and Proteobacteria (34.5% and 40.3%) were the predominant phyla detected in kitchen and living room, respectively, while Bacteroidetes (41% and 51.5) for chimney and outdoor environment. Notably, rural areas showed 2.8 and 8 times higher relative abundances of Firmicutes and Bacteroidetes compared to urban areas, indicating fundamentally different microbial ecosystems. At the genus level, the top two bacteria were Vibrio and Chloroplast in indoor areas, whereas the predominant genera in outdoor areas included Prevotella, Faecalibacterium, and Bacteroides. Bacterial communities in urban and rural areas displayed significant heterogeneity. The peak and valley relative abundance of potential pathogenic bacteria in rural areas appeared in the chimney area (62.7%) and in the living room (18.3%), respectively. Rhodococcus and Prevotella were the indicator pathogenic bacteria for urban and rural sites, respectively, with links to pulmonary infections and intestinal diseases. This study provides valuable insights into the characteristics of bioaerosols and their implications for human health protection in rural areas.