Air Disinfection by Atmospheric Pressure Grating-like Dielectric Barrier Discharge Plasma

Air purification and disinfection are effective measures for the control of respiratory infectious diseases. Dielectric barrier discharge (DBD) is a promising method for air disinfection due to its high efficiency, large discharge area, and low airflow resistance; however, the research on its disinfection characteristics, factors, and dosage is rarely available in the literature. This paper provides a brief introduction of the recent research progress in air disinfection by grating-like DBD plasma from the Gas Discharge and Plasma Research Team in the Department of Electrical Engineering at Tsinghua University. In terms of disinfection characteristics, the effects of discharge structural parameters, humidity, microbial species, voltage type, and other factors was mainly investigated. It was found that narrowing the gap, increasing electrode size, and increasing airflow humidity could all improve both efficiency and Z-value. When the relative humidity (RH) was 60%, the Z-value could reach 1.68 L/J. The single-pass removal efficiency of MS2 bacteriophage aerosol could reach 99.5%~99.9%. In terms of bactericidal factors, experiments showed that gas-phase short-lived species were the major contributors to bacterial inactivation, with long-lived species accounting for at most 30% of the total bactericidal effect. In terms of disinfection dosage, specific energy density (SED) was proposed as the dose parameter for plasma-based air disinfection. Based on the chemical kinetic model of wet-air plasma discharge, a linear relationship between single-specie dose and power density was discovered, illustrating why SED could be served as the dose. This study can provide theoretical and engineering support for DBD-plasma-based air disinfection. © 2024 Science Press. All rights reserved.