The mixture of air/ozone affects substantial removal of contaminants such as various man-made volatile hydrocarbons including chlorinated hydrocarbons, chlorinated olefins such as tetrachloroethylene, trichloroethylene, cis 1,2-dichloroethene and vinyl chloride and other compounds e.g., aromatic ring compounds, propellants, explosives, and so forth that are found as contaminants.