Hydroxyls have been called "Mother Nature's Broom” because of their ability to clean the air. Hydroxyl molecules play a crucial role in keeping the earth's atmosphere clear of chemical pollutants as well as help to break down potentially harmful airborne organic compounds. Hydroxyls are highly reactive molecules that pop in and out of existence within the atmosphere. Hydroxyl molecules are so small that 10 billion of them would fit into one raindrop. Despite their small size, hydroxyls are probably the single most important cleansing agent for our environment.
Hydroxyls are not naturally occurring indoors, so the ODOROX Hydroxyl generator is an excellent solution to produce outdoor clean air indoors. Hydroxyl molecules are produced when an O-H bond of the water molecule is broken to form a hydrogen atom (H-) and a hydroxyl radical (HO-). The hydrogen atom can then react with another water molecule to form hydrogen and a second hydroxyl radical, or with an oxygen molecule (O2) to form a second hydroxyl radical and an oxygen atom. The new oxygen atom can then react with another water molecule to form two new hydroxyl radicals.
It is possible to make beneficial use of hydroxyl molecules by cleansing the air inside in the same way they work to cleanse the earth's atmosphere. The key is to make wavelengths of strong ultraviolet (UV) light, which, in the presence of water molecules occurring as moisture in the air to produce hydroxyl molecules. This process mimics the natural production of hydroxyl in the atmosphere through ultraviolet radiation emitted by the sun and results in the breakdown of organic material in the air by the hydroxyl. The organic particles in room air are decomposed into harmless amounts of carbon dioxide and water through a chemical action.
Hydroxyl ions are extremely short-lived molecules. They usually exist for no longer than a second or so before becoming involved in an air-cleansing chemical reaction. That is precisely the reason why it has been so difficult to accurately measure hydroxyl levels in the earth's atmosphere. But it also means that there is no concern about hydroxyl molecules accumulating inside the home. On the other hand, many ozone-generating air purifiers have the ability to quickly raise the ozone concentration in a room to potentially unhealthy levels if not carefully monitored.
Through the use of hydroxyl-generating air purifying equipment in the home, office or plant we can enjoy cleaner, fresher air in our indoor environment.

http://www.agu.org/sci_soc/khalil.html
According to a New York Times article (May, 2001), hydroxyl radicals are thought by atmospheric chemistry scientists to purge more than half the sulfur dioxide added to the air by smokestacks, volcanoes and other sources.
An international study being conducted over the Indian Ocean which, in part, measured hydroxyl radical levels, led a team of atmospheric experts to conclude that without hydroxyl radicals, air pollution can remain at toxic and harmful levels for much longer, increasing the likelihood of negative effect on humans. More than half a million people die in India every year from pollution-related respiratory ailments; similar numbers are recorded in other Asian countries. It is a known fact that hydroxyl radicals are necessary for natural air cleansing and toxin removal. Hydroxyls are why our planet hasn't choked itself to death and the reason we can live in our cities.