Impulsive streamer discharges in atmospheric air for cleaning and decontamination

It has been confirmed by a number of recent studies that non-thermal plasma discharges have significant potential for decontamination of bacteria and oxidation of chemicals under atmospheric conditions. Based on this fact, practical applications of plasma discharges for air- and water-cleaning, and processing of chemical waste, are now being developed. There are several factors which lead to biological and chemical activity of plasma: in an intensive electric field, generation of chemically-active species, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), and UV photons. All of these factors can result in death of microorganisms and decomposition of chemical elements. The contributions of ROS and RNS to the plasma decontamination process are considered to be the most important factor. Products such as ozone and hydroxyl radicals are highly oxidative, and they can inflict lethal damage on microorganisms. Different types of plasma discharges in air and different energisation levels could result in different production rates of ROS and RNS in atmospheric plasma, hence the decontamination and oxidation effectiveness of plasma discharges could be different. In the present study, the oxidation effects of impulsive streamer discharges across liquid/agar surfaces were investigated.