In the following article, we'll discuss some benefits and potential problems with this controversial molecule.

What is it? Ozone is an unstable trivalent oxygen molecule (O3)—said to be "unstable" because it readily decomposes to ordinary oxygen, which means for maximum effectiveness it must be manufactured "on site" for specific applications. This also means it doesn't build up by "soaking into the walls", so to speak.

It is considered a germicide because it pierces the cell wall of bacteria and virus microorganisms on contact, destroying them 3,000 times faster than chlorine, and without the side effects of chlorine. As a deodorizer, it "oxidizes" or binds with many organic compounds to effectively neutralize them.

Where is it? High altitude "pure" ozone forms a protective barrier from harmful solar rays around most of the earth.

Ground level ozone occurs in unpolluted areas through certain chemical/light reactions. For example, it is created electrically in nature during active thunderstorms (producing a noticeable "sweet" and sometimes acrid smell). Ozonators use an electrical current to produce ozone indoors.

In urban areas, "impure" ozone is created during the breakdown of certain chemical byproducts of industrial processes or through photochemical production from automobile emissions and mass burners—and it's difficult to find ozone here that's not combined with and contaminated by pollutants.

What are the benefits of using ozone? Commercially, ozone has been used for purification of drinking water; treatment of industrial liquid wastes, such as cyanides and phenols; deodorization of sewage gases, rendering plant exhausts, and exhausts from other industrial processes; deodorizing air in buildings; food and plant preservation in cold storage; and sterilization of containers for aseptic packaging.

Privately, ozone has been used for purification of drinking water; "freshening" indoor air; certain types of oxygenation and oxidation therapy (along with hydrogen peroxide); and reducing bacterial and fungal counts indoors.

The private applications are of special interest to most aviculturists, in that many aviaries are set up indoors, and the problem of recycled air, including airborne pathogens, is a continuing challenge. For example, aspergillosis and candida have been shown to be negatively affected by natural (fresh air) amounts of ozone.

Manufacturers of ozonators have commissioned studies to determine just what levels to recommend (well below the current national standard of .08 ppm—you can smell it at around .04 ppm), and most stop just short of saying you can leave the machine on 24 hours a day, year round.

There are many anecdotal stories in addition to the studies which support the benefits of ozonating indoor air, including reduction of allergies, assisted recovery from bacterial and fungal respiratory infections, and improved emotional well-being.

What are the potential problems of ozonating? Laboratory studies (commissioned by the EPA) have shown that animal exposures of relatively low ozone levels, if repeated over a long period of time (e.g., months, years, lifetime), may result in lung inflammation, permanent scarring, loss of lung function, and reduced lung elasticity. This is due to the oxidative properties of ozone—it may react with almost any biological substrate, but the cell membrane appears to be the site of toxicity. The results of these studies is of concern to aviculturists because of the delicate nature of the avian respiratory system.

As a matter of fact, every chemical has the capacity to be lethal in significant doses—an example of the old adage about too much of a good thing. For instance, salt is essential for good health—nerve cells require sodium to transmit electrical signals; kidneys require some salt to function properly and filter body wastes; and replenishment of salt during periods of heat stress is essential. However, at elevated levels and for prolonged periods of exposure, too much salt can result in hypertension and cardiac failure.

Toxicology is the science of poisons, and as such, attempts to determine what effect what dose of a substance has on an organism. With some substances, it's easy to quantify how much is too much, but even toxicologists who are also aviculturists disagree about ozone usage.

One toxicologist flatly states, "My recommendation is that ozone air purifying systems should not be used around birds. There are risks to human health as well, even in low concentrations."

A second toxicologist disagrees. "I like to have an ozonator around for emergencies. Because ozone is a strong oxidizer, it will degrade almost any airborne chemical. ... I think ozonators can be used safely as long as they are turned to a level so that you can't smell the ozone. Also, in emergency situations, you can use your ozonator at a higher level to protect yourself and your birds ... where you can barely smell it, and certainly take other precautions like removing or taking care of the emergency, opening windows, using an exhaust system, etc."

So, what's the recommendation? As with many fields dealing with avians, the research is incomplete - partly because of lack of funded studies and partly because of lack of completed long-term studies. It certainly seems to be a case where if a little is wonderful, a lot is not necessarily fantastic.

On the other hand, because ozone is relatively cheap to produce, it has been suggested that some powerful pharmaceutical companies have campaigned to keep it unpopular (similar to solar vs. petroleum energy sources). However, until more long-term, specific studies are completed, usage will probably be approached with caution.

From my own interpretation of the literature reviewed, my personal conclusion is that occasional use for the beneficial aspects of ozone may be appropriate, but I could not advocate constant, continual use of ozonators indoors.

At this point in time, each steward of our feathered companions must use common sense and their own discretion—and continually self-educate—in their decision on frequency of use and acceptable ozone concentrations in their indoor aviaries.

References for further reading:

Alpine Industries. "Essential Ozone," Blain, MN

Edwards, H. Banks, P.E. "Indoor Air Quality—A Different Approach," Envirolutions, Inc., Atlanta, GA, http://www.ozonated.com.

EPA. "Air Pollutant Descriptions: Ozone," http://www.epa.gov/ region 10/www/offices/air/pollutan.html.

EPA/OAQPS. "Ozone - Good Up High, Bad Nearby," http://www.epa.gov/oaqps/ozone.html.

Milton, Mardelle & Olson, Richard. "The Ozone Story," O3 Zone, 1996, http://www.enviro.org/ozone.html

North Carolina Cooperative Extension Service. "Air Filters & Cleaners," North Carolina State University, Raleigh, N.C., 1995. http://gopher.ces.ncsu.edu/depts/fcs/docs/he3606.html.

Olcerst, Robert, Ph.D. "Ozone Monograph: Toxicity and Evaluation, " Brujos Scientific, Inc., Baltimore, Md., 1990, Alpine Air Products, Inc.

Ozone Services, Yanco Industries Ltd. "Medical Miracle or Health-Care Hoax? Ozone and Hydrogen Peroxide in Healing," Langley, B.C., 1995, http://www.o3zone.com/ ozoneser/artqanda.htm.

Winged Wisdom Note: Marcy started with a birthday parakeet at age 7 which she and her family enjoyed. Years later, she raised cockatiels, and now has expanded to pionus, conures, and Indian ringnecks. Marcy is active in an Austin, Texas bird club and in educating others about exotic birds.