Air exists everywhere on our planet Earth. It is present outdoors in natural environments, as well as indoors. It is man’s responsibility to ensure that air that becomes contaminated is cleaned so that it may be reused by the organization or next person needing it.
Ambient outdoor air can become fouled with odorants, contaminants discharged from industrial plants, exhausts from power plants, automobiles, buses, trucks, trains, aircraft, tractors, etc. Indoor air in homes can be contaminated by normal household activities such as cooking, washing laundry, cleaning, burning wood in fireplaces, painting, and the like. However, indoor air also can become contaminated by smoking odors, mold and mildew, and volatile organic compounds that slowly evaporate from modern plastics and glues used in building and furniture making materials. Many food processing facilities and areas of wholesale and retail grocery stores and supermarkets face control of odors and bacteria throughout their establishments constantly. Air in hospitals, medical laboratories and nursing homes can be contaminated by all of the above-mentioned contaminants, as well as by volatile medicinal compounds. Air conditioning ducting and mechanical systems need to be kept free of microorganisms. Casinos, night clubs, bars, etc., where smoking is allowed, have a need to cope with smoke odors and volatile organic compounds.
ROLES FOR OZONE IN AIR TREATMENT
Ozone is both a strong oxidizing agent as well as a strong disinfectant. Because of this, both benefits (oxidation and disinfection) can be achieved during the single step of ozonation. When considering oxidation, however, one must also recognize that not all oxidizable substances can be totally destroyed even by ozone, the strongest oxidant and disinfectant commercially available, e.g., mineralized in the case of organic substances, to produce carbon dioxide and water. In most cases, oxidation reactions proceed through intermediate stages, arriving at CO 2 and water only when the pollutant is provided with a sufficient concentration of ozone for a sufficient period of time to allow complete oxidation (mineralization).
Therefore, when considering ozone for treating contaminated air, one also should consider the partial oxidation products from ozonation of` organic contaminants. This situation is not unique to ozone. All oxidants do their work through multiple intermediate stages, thus forming byproducts. Ozone however, consisting of nothing but oxygen, forms intermediates by the mechanisms of increasing incorporation of oxygen atoms into the intermediate structures. Usually, this results in decreasing toxicological effects compared to those of the starting compound.
It is not healthful to breathe ozone, in any concentration. Thus treatment of air with ozone is never recommended when humans or pets are present to breathe the air during treatment.