Relationships between Airborne Bacterial Community, Heating Supply Activity and Particulate Matter Properties

Airborne microbes play critical roles in human health, while the connections of microbial community with anthropogenic activity, such as heating supply activity, heating supply patterns and particulate matter (PM) chemical compositions, remain unclear. The present study demonstrated that heating supply activity exhibited higher microbial richness than non-heating supply, and microbial richness in PM1 (aerodynamic diameter = 1 µm) was significantly lower than that in PM10 (aerodynamic diameter = 10 µm). Gram-positive bacteria were dominant, and Bacilli accounts for 85% of the microbes at the class level. The total concentrations of heavy metals, polycyclic aromatic hydrocarbons and water-soluble ions increased with PM sizes. Heavy metals and polycyclic aromatic hydrocarbons in non-central heating supply regions showed significantly higher concentrations than that in central heating supply regions. Most of tested chemical compositions negatively contributed to microbial community diversity, except for Zn, Cr, Pry, and Bap. The above results were also influenced by heating supply patterns. There was a positive correlation between microbial community richness and •OH concentration, and microbial community richness decreased with PM specific surface area increasing. This work establishes connections between the properties of Ms and the microbial community with heating supply activity, and gives novel insights to indoor air quality and human health.