This paper is devoted to analysis of humid air plasmas of pulsed discharge application possibilities for heating of thin layers over water surface where the concentration of water molecules in a layer over water surface contains ~0.5%-4% of water molecules in the temperature range 30 °C-110 °C. Main neutral and charged components have been calculated with the help of detailed plasma-chemical code. Considerable generation of ozone has been detected. This can explain the results of successful discharge sterilization experiment.