That blue glow is corona or excess electrons building on the screen. When the air passes through the filter the air is charged to O volts and as the fan pulls the air through the machine the oxygen atoms become more negative charged on the atoms. The important thing to remember and know is ozone machines are dangerous to breath in prolong exposure. The charged atoms combine with anything organic and begin to break it down or oxidation. This is bad for your lungs. Most people use them for getting a smell out of rug, so put the rug and ozone machine in a closet for 12 hours. When you open the closet, ventilate the room for your own safety. John