Ozone vacuum-ultraviolet (VUV) ozone generators, employ a light source that generates a narrow-band ultraviolet light, a subset of that produced by the Sun. The Sun's UV sustains the ozone layer in the stratosphere of Earth. UV ozone generators use ambient air for ozone production, no air prep systems are used (air dryer or oxygen concentrator), therefore these generators tend to be less expensive. However UV ozone generators usually produce ozone with a concentration of about 0.5% or lower which limits the potential ozone production rate. Another disadvantage of this method is that it requires the ambient air (oxygen) to be exposed
UV marker blood or even urine. Modern UV-invisible ink is mainly made by a fluorescent derived from things in nature that glow when exposed to an ultraviolet light. The main components include dilute laundry detergent, body fluids, tonic water and vitamin B-12 dissolved in vinegar. There are different types of UV-invisible ink: opaque, semi-opaque and translucent. All of the three contain acrylic monomers which contain a diluent and a photoinitiator to participate in the curing reaction and to respond to UV radiation. Photoinitiators is a very important element for making the ink as it is the substance that absorbs the UV mission