Rotating Dielectric Barrier Discharge Plasma Source for Effective Bacterial Decontamination of Bioaerosols

Abstract

The airborne transmission of pathogens such as bacteria and viruses via aerosols is one of the most insidious ways of spreading diseases, such as COVID-19, hospital-acquired infections (HAIs), and, in the food industry, contamination of processed foods with food pathogens. Due to their small size, the nuclei of such aerosol droplets can remain suspended in the air for a long time and travel long distances. It is thus of high importance to identify increasingly effective solutions in terms of microbial decontamination of air to be used as a stand-alone application or in synergy with traditional techniques (e.g., filters and UV lamps). In this study, a DBD architecture, rotating dielectric barrier discharge, (RDBD) was devised. Its efficacy as a plasma source was tested inside a chamber containing bioaerosols contaminated with <i>Staphylococcus epidermidis</i>. The results showed that RDBD achieves bacterial inactivation levels greater than 3.6 Log 10 CFU, comparable to those achieved with a commercial device operating at comparable ozone concentrations. Moreover, an observable distinction lies in the reduced average discharge power exhibited by RDBD compared to the power output of the commercial device. Additionally, it is noteworthy that the air flow rate elaborated by RDBD surpasses that of the commercial device by a factor of 3.5. Furthermore, the empirical demonstration established a strong correlation between mean discharge power and resulting ozone concentration, underscoring their pivotal roles in bacterial inactivation. Conversely, the voltage range examined in this investigation does not manifest any discernible effect on the inactivation of microorganisms, given comparable power levels and ozone concentrations. Consequently, these last parameters are critical in scaling a plasma source for air decontamination.