Some new air cleaning devices are using free radicals or Reactive Oxygen Species (ROS) to "oxidize" indoor air. Free radicals have been shown to be damaging to human health. Testing is lacking on the by-products of the reactions between free radicals and the components of indoor air.

Here is a quote from a brochure on another "cure-all for indoor air" product. It is a cause for concern. "When the HVAC system is in operation the cell creates an Advanced Oxidation Process consisting of Hydroxyl Radicals, Super Oxides, Hydroperoxides (Hydrogen Peroxide), UV light and ozonides (ozone)." It goes on to say: "All are friendly oxidizers. By friendly oxidizers we mean oxidizers that revert back to oxygen and hydrogen after the oxidation of the pollutant." However, these are not "friendly oxidizers." They are well known as Reactive Oxygen Species (ROS) or free radicals and are involved in a whole host of health problems from cancer to heart disease.

Free radicals (like the Hydroxyl Radical) are very reactive. It is this reactivity which enables them to participate in unwanted side reactions resulting in cell damage. Many forms of cancer are thought to be the result of reactions between free radicals and DNA, resulting in mutations that can adversely affect the cell cycle and potentially lead to malignancy. Some of the symptoms of aging such as atherosclerosis are also attributed to free radical induced oxidation of chemicals making up the body. In addition free radicals contribute to alcohol-induced liver damage, perhaps more than alcohol itself. Free radicals may also be involved in Parkinson's disease, emphysema, deafness, schizophrenia, Alzheimer's, diabetes, skin damage, aging and more. But don't take our word for it. Spend 5 minutes researching the effects of free radicals and you, too, will have details on the sobering litany of health problems associated with this chemistry.

Not only are free radicals not "friendly," they will not revert back to oxygen and hydrogen. Here's why: a radical is a molecule that has an unpaired electron (the Hydroxyl Radical is OH). As a rule the radical needs to pair its unpaired electron with another and will react with another molecule in order to obtain this missing electron. If a radical achieves this by "stealing" the electron from another molecule, that other molecule itself becomes a free radical and a self-propagating chain reaction is begun. A single circulating free radical in a cell can damage tens or even hundreds of enzymes, membranes, proteins or DNA molecules through this chain reaction. The reaction will continue until it is ultimately quenched. These reactions seldomly, if ever, produce oxygen and hydrogen.

Unfortunately, we do not know all of what they do produce. Indoor air can contain over 1,000 different chemicals from a wide range of different sources including flooring materials, paints, furniture, fabrics, cleaning chemicals, electronic equipment, smoke, etc.. When you throw the free radicals into the mixture, you wind up with what the EPA describes as the "chemical soup" of IAQ.

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