Ozone generators, also known as air cleaners, create the gas ozone by an electrical spark discharge. Ozone kills bacteria, mold spores, and mildew. It also destroys odors, and can fresh smoke filled air under most conditions. But these devices can’t remove carbon monoxide and formaldehyde. Levels of ozone that clean air effectively are unsafe to human health. And no agency of the federal government has approved ozone-generating air purifiers for use in occupied spaces.
 Ozone may be dangerous and cause problems with your respiratory apparatus. Especially children and the elderly must beware of excessive amount of ozone. Recommended guidelines call for between .01 and .05 parts per million of ozone versus air. But it is very difficult to control ozone exposure with ozone purifiers, because it depends on many factors. The following causes have influence on concentrations:
1. how powerful device is used;
2. a small or a large space is;
3. if interior doors are closed or open;
4. how much materials and furnishings that adsorb or react with ozone are there;
5. the proximity to the ozone generator.
Ozone generators are often equipped with regulator of ozone output. But the ozone output of these devices is usually not proportional to the control setting. Now it is produced units with an ozone sensor that turns the device on and off to maintain ozone concentrations in the ambit health standards.
Sometimes high concentrations of ozone in air are used to help purify an unoccupied space from certain chemicals, biological contaminants and odors. But concentration of the gas should be sufficiently controlled to assure that no person or pet becomes unprotected. Ozone can damage indoor plants, and materials such as rubber, electrical wire coatings, and fabrics and art work containing susceptible dyes and pigments.
Ozone generators work by splitting electrically charged particles into the surrounding atmosphere. These devices only pass inside air and do not operate the surrounding air flow.
Besides, ozone does not take away particles (e.g., dust and pollen) from the air, including the particles that cause most allergies. In addition it is not known enough about the potential by-products produced by ozone’s reactions with other chemicals. Ozone’s reactions with many of the chemicals usually dwelling in indoor environments, may take months. Moreover the reaction with some of chemicals can produce irritating by-products, e.g. aldehydes and formic acid. Some of them are themselves very reactive and able of producing irritating and corrosive by-products. Commonly with the help of its smell ozone hides odor but not destroy it.
Ozone-generating air purifiers produce low levels of ozone, recommended by public health standards, which can’t effectively prevent the growth of biological organisms and remove biological pollutants. Besides ozone is helpless against biological contaminants which set in porous material even at high concentrations.
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