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A little info from the EPA
( U.S. Environmental Protection Agency )
Testimonials are great...but
here are the facts...
Available scientific evidence shows that at concentrations
that do not exceed public health standards, ozone has little potential to remove
indoor air contaminants.
Some manufacturers or vendors suggest that ozone will render
almost every chemical contaminant harmless by producing a chemical reaction
whose only by-products are carbon dioxide, oxygen and water. This is misleading.
- First, a review of scientific research shows that, for many of the
chemicals commonly found in indoor environments, the reaction process with
ozone may take months or years (Boeniger, 1995). For all practical purposes,
ozone does not react at all with such chemicals. And contrary to specific
claims by some vendors, ozone generators are not effective in removing carbon
monoxide (Salls, 1927; Shaughnessy et al., 1994) or formaldehyde (Esswein and
Boeniger, 1994).
- Second, for many of the chemicals with which ozone does readily react, the
reaction can form a variety of harmful or irritating by-products (Weschler et
al., 1992a, 1992b, 1996; Zhang and Lioy, 1994). For example, in a laboratory
experiment that mixed ozone with chemicals from new carpet, ozone reduced many
of these chemicals, including those which can produce new carpet odor.
However, in the process, the reaction produced a variety of aldehydes, and the
total concentration of organic chemicals in the air increased rather than
decreased after the introduction of ozone (Weschler, et. al., 1992b). In
addition to aldehydes, ozone may also increase indoor concentrations of formic
acid (Zhang and Lioy, 1994), both of which can irritate the lungs if produced
in sufficient amounts. Some of the potential by-products produced by ozone’s
reactions with other chemicals are themselves very reactive and capable of
producing irritating and corrosive by-products (Weschler and Shields, 1996,
1997a, 1997b). Given the complexity of the chemical reactions that occur,
additional research is needed to more completely understand the complex
interactions of indoor chemicals in the presence of ozone.
- Third, ozone does not remove particles (e.g., dust and pollen) from the
air, including the particles that cause most allergies. However, some ozone
generators are manufactured with an "ion generator" or "ionizer" in the same
unit. An ionizer is a device that disperses negatively (and/or positively)
charged ions into the air. These ions attach to particles in the air giving
them a negative (or positive) charge so that the particles may attach to
nearby surfaces such as walls or furniture, or attach to one another and
settle out of the air. In recent experiments, ionizers were found to be less
effective in removing particles of dust, tobacco smoke, pollen or fungal
spores than either high efficiency particle filters or electrostatic
precipitators. (Shaughnessy et al., 1994; Pierce, et al., 1996). However, it
is apparent from other experiments that the effectiveness of particle air
cleaners, including electrostatic precipitators, ion generators, or pleated
filters varies widely (U.S. EPA, 1995).
There is evidence
to show that at concentrations that do not exceed public health standards, ozone
is not effective at removing many odor-causing chemicals.
- In an experiment designed to produce formaldehyde concentrations
representative of an embalming studio, where formaldehyde is the main odor
producer, ozone showed no effect in reducing formaldehyde concentration (Esswein
and Boeniger, 1994). Other experiments suggest that body odor may be masked by
the smell of ozone but is not removed by ozone (Witheridge and Yaglou, 1939).
Ozone is not considered useful for odor removal in building ventilation
systems (ASHRAE, 1989).
- While there are few scientific studies to support the claim that ozone
effectively removes odors, it is plausible that some odorous chemicals will
react with ozone. For example, in some experiments, ozone appeared to react
readily with certain chemicals, including some chemicals that contribute to
the smell of new carpet (Weschler, 1992b; Zhang and Lioy, 1994). Ozone is also
believed to react with acrolein, one of the many odorous and irritating
chemicals found in secondhand tobacco smoke (US EPA, 1995).
If used at
concentrations that do not exceed public health standards, ozone applied to
indoor air does not effectively remove viruses, bacteria, mold, or other
biological pollutants.
- Some data suggest that low levels of ozone may reduce airborne
concentrations and inhibit the growth of some biological organisms while ozone
is present, but ozone concentrations would have to be 5 - 10 times higher than
public health standards allow before the ozone could decontaminate the air
sufficiently to prevent survival and regeneration of the organisms once the
ozone is removed (Dyas, et al.,1983; Foarde et al., 1997).
- Even at high concentrations, ozone may have no effect on biological
contaminants embedded in porous material such as duct lining or ceiling tiles
(Foarde et al, 1997). In other words, ozone produced by ozone generators may
inhibit the growth of some biological agents while it is present, but it is
unlikely to fully decontaminate the air unless concentrations are high enough
to be a health concern if people are present. Even with high levels of ozone,
contaminants embedded in porous material may not be affected at all.
Whether in its
pure form or mixed with other chemicals, ozone can be harmful to health.
When inhaled, ozone can damage the lungs. Relatively low
amounts of ozone can cause chest pain, coughing, shortness of breath and,
throat irritation. It may also worsen chronic respiratory diseases such as
asthma as well as compromise the ability of the body to fight respiratory
infections.
Some studies show
that ozone concentrations produced by ozone generators can exceed health
standards even when one follows manufacturer’s instructions.
Many factors affect ozone concentrations including the amount
of ozone produced by the machine(s), the size of the indoor space, the amount
of material in the room with which ozone reacts, the outdoor ozone
concentration, and the amount of ventilation. These factors make it
difficult to control the ozone concentration in all circumstances.
Available
scientific evidence shows that, at concentrations that do not exceed public
health standards, ozone is generally ineffective in controlling indoor air
pollution.
The concentration of ozone would have to greatly exceed health
standards to be effective in removing most indoor air contaminants. In the
process of reacting with chemicals indoors, ozone can produce other chemicals
that themselves can be irritating and corrosive.
Visit :
http://www.epa.gov/iedweb00/pubs/ozonegen.html
Also :
The Inside Story :
A Guide to Indoor Air Quality
http://www.cpsc.gov/CPSCPUB/PUBS/450.html
Learn more about the C.A.R.E 2000 air
purification system
at the Care Air Source
www.careairsource.com
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