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
Zombies of the Stratosphere and viewers found the serial to be relatively dull and unimaginative, not as interesting as "Radar Men from the Moon". The use of stock footage from earlier serials is not quite as overwhelming as seen in the earlier or later Cody outings, as greater emphasis is placed on fistfights rather than scenes using the rocket back-pack. Holdren's performance is often stiff and amateurish, especially when compared to the professionalism of the old Republic pros who surround him on screen. Cline describes this serial as just a "quickie." Zombies of the Stratosphere Zombies of the Stratosphere is a 1952 black-and-white Republic