Characteristics of functional bacteria involved in carbon, nitrogen and sulfur cycles in PM2.5 under different meteorological conditions.

The meteorological conditions during dust events and rainfall have a significant impact on the composition of atmospheric microbial communities. This study investigated the microbial community structure and the characteristics of functional bacteria involved in carbon, nitrogen and sulfur cycles of bioaerosols in PM2.5. Samples were collected in central China from March to April (2023) under normal, rainfall, and dust weather conditions. Differences in the composition of bacterial communities under various meteorological conditions and the effects of the resultant changes on carbon, nitrogen, and sulfur cycling were also observed. The results showed that the dominant phyla in the bacterial aerosols were Pseudomonadota, Bacillota and Actinobacteriota, accounting for 33.7%, 27.0%, and 17.8%, respectively. Species richness and diversity varied significantly under the different weather conditions. A large proportion of airborne bacteria that are functionally associated with carbon, nitrogen, and sulfur cycles were identified, with Bacillus, Sphingomonas, Pseudomonas, Paracoccus and Acinetobacter being the dominant genera. Most bacteria are related to these material cycles. The carbon, nitrogen, and sulfur cycling pathways are potentially affected by weather conditions. The effects of environmental factors such as meteorological parameters and soluble ions on the functional bacterial community were analyzed. Relative humidity (RH), PM2.5 and ammonium (NH4+) were significantly correlated with the functional bacteria. Overall, this study discusses the effects of meteorological conditions on the distribution of bacterial communities and functional bacteria involved in carbon, nitrogen, and sulfur cycling in the atmosphere. The relationships between the metabolic activity of carbon, nitrogen, and sulfur cycling and the corresponding concentrations of atmospheric elements forms were also revealed. This study provides new perspectives on atmospheric environmental chemistry and pollution control.