Surface Virus Inactivation by Impinging Flow Nonthermal Plasma Reactor

Infectious viruses can survive on surfaces for hours; they can be responsible for the fomite transmission mechanism of many diseases. We report the development and evaluation of a compact nonthermal plasma (NTP) flow reactor and its application for disinfection of surfaces. The concentric flow reactor produces a high concentration of reactive species by ionizing air flow passed through the reactor; the ionized jet exiting the reactor is impinged on the surface, exposing pathogens to high concentrations of reactive oxygen and nitrogen species. The reactor performance is characterized by measuring ozone concentration for various geometries and operating conditions. The ozone concentration reaches saturation at the exit for electrical power input above 100 W. The approach was tested for the inactivation of MS2 bacteriophage on surfaces with varied exposure times. We observed a 1.3-log reduction in viable virus counts at the exposure of 30 s and a 5.3-log reduction at 120-s exposure. The ozone production rates suggest that the reactor can be scaled to operate at higher flow rates, producing a concentration of reactive species sufficient for virus inactivation.