An ozone generator comprising at least one but preferably a plurality of electrostatic ozone generating units located in a first enclosed compartment and being individually powered by respective transformers which are located in a second enclosed compartment and which are air cooled by blower means. The air flowing over the transformers is then fed into the compartment including the ozone generating units where ozone is generated and fed therefrom. In another embodiment, a booster is coupled to the ozone generating compartment for blending a large volume of outside air with the generated ozone and includes another housing or compartment including second blower means therein as well as a bifurcated input mixing tube having a pair of input arms and a single output arm and wherein one of the input arms is connected to the second blower means while the other input arm is connected to the ozone generating compartment. The single output arm delivers a relatively large volume of an air and ozone mixture into the surrounding atmosphere.