Gas phase discharges generated in close proximity to a liquid surface were demonstrated to initiate a variety of chemical effects in the liquid.Depending on the gas phase composition,various reactive oxygen(ROS)and nitrogen(RNS)based chemical species can be formed by non-thermal plasma produced by these discharges in the gas or at the gas-liquid interface,which can penetrate or dissolve into the liquid and initiate chemical and biocidal processes.These plasmas have recently received considerable interest for their potential utilization in biological and medical applications with many exciting and promising results including direct application of discharge plasma to the human body.Among various chemical species produced by air plasma at gas-liquid environment,OH radical,atomic oxygen,ozone,and hydrogen peroxide are the main oxidizing species(ROS)generally accepted to play the dominant role in the inactivation process in the non-thermal atmospheric pressure plasma systems.