Bacterial Aerosol Inactivation by DBD Plasma: Mechanisms, Kinetic Model, and Disinfection Dose

Abstract

Atmospheric pressure dielectric barrier discharge (DBD) plasma has emerged as a promising method for efficient air disinfection in building environments. However, the mechanisms, kinetics, and disinfection doses required for bioaerosol inactivation by plasmas remain inadequately understood. In this study, we first applied optical photothermal infrared (O-PTIR) spectroscopy to examine the biological responses of bacterial aerosols to plasmas at the single-cell level. Significant carbonylation was observed in plasma-treated cells, indicating that oxidation is a crucial mechanism in bacterial aerosol inactivation. A preliminary multispecies kinetic model was proposed for bioaerosol disinfection by plasmas. By differentiating the roles of charged particles and neutral chemical species, the equivalent total chemical dose (ETCD) and equivalent total ionic dose (ETID) were introduced. ETCD primarily considers the oxidation potential of the reactive species in the plasma. The proposed model was applied to a DBD plasma-based air disinfection system and preliminarily validated. The relationship between the macroscopic dose (specific energy density, SED) and microscopic dose (ETCD) was uncovered. This study provides valuable insights into the modeling of plasma-bioaerosol interactions and the underlying mechanisms, offering a theoretical foundation for practical applications.