Energetic electrons are the major sources which produce reactive species when the atmospheric pressure plasma source (jet or DBD) is operated in gas phase. When the operation of the device is above liquid solution/ skin, the reactive species are also produced inside the solution/skin. Of course, UVs initiated from the plasma source in gas phase could cause the production of RONS inside the solution/skin.

Some authors mention that there are " aqueous electrons" which produce RONS inside liquid solution/skin when the plasma source is operated above the target material. I do not understand, are these aqueous electrons so much energetic that they can cause the production of RONS inside liquid solution ? Do they penetrate from the gas phase or are generated directly inside the liquid solution ?