Effects of humidity on room disinfection by dielectric barrier discharge plasma

Atmospheric pressure plasma is one of the most promising low-temperature methods for room sterilization. In this study, we demonstrate that plasma with a circulation system can disinfect the entire space in a laboratory chamber with very high uniformity. We also prove that humidity can accelerate the disinfecting power of plasma by generating active species from water molecules as well as delivering them through water vapor. Compared to low humidity (20%-50%) conditions, at high humidities (70%-90%), the quantities of plasma generated reactive species, specifically OH radicals and hydrogen peroxide, are increased two-fold while the quantity of generated ozone is halved. Ultraviolet irradiation of the plasma further reduces the amount of environmentally harmful ozone. Using an atmospheric pressure non-thermal plasma device, room disinfection and the eradication drug resistant Staphylococcus aureus were successfully achieved.