Note final three paragraphs.
Some air cleaners use ultraviolet (UV) light technology intended to
destroy pollutants in indoor air. These air cleaners are called
ultraviolet germicidal irradiation (UVGI) cleaners and photocatalytic
oxidation (PCO) cleaners. Ozone generators that are sold as air
cleaners intentionally produce ozone gas, a lung irritant, to destroy
Ozone is a lung irritant that can cause adverse health effects.
* UVGI cleaners use ultraviolet radiation from UV lamps that may
destroy biological pollutants such as viruses, bacteria, allergens,
and molds that are airborne or growing on HVAC surfaces (e.g., found
on cooling coils, drain pans, or ductwork). If used, they should be
applied with, but not as a replacement for, filtration systems.
* PCO cleaners use a UV lamp along with a substance, called a
catalyst, that reacts with the light. They are intended to destroy
gaseous pollutants by converting them into harmless products, but are
not designed to remove particulate pollutants.
* Ozone generators use UV light or an electrical discharge to
intentionally produce ozone. Ozone is a lung irritant that can cause
adverse health effects. At concentrations that do not exceed public
health standards, ozone has little effect in removing most indoor air
contaminants. Thus, ozone generators are not always safe and effective
in controlling indoor air pollutants. Consumers should instead use
methods proven to be both safe and effective to reduce pollutant
concentrations, which include eliminating or controlling pollutant
sources and increasing outdoor air ventilation.
Visit www.epa.gov/iaq/pubs/ozonegen.html for more information
on ozone generators sold as air cleaners.
In-duct Pollutant Destruction
UVGI cleaners may not reduce allergy or asthma symptoms.
There is no standard measurement for the effectiveness of UVGI
cleaners. Typical UVGI cleaners used in homes have limited
effectiveness in killing bacteria and molds. Effective destruction of
some viruses and most mold and bacterial spores usually requires much
higher UV exposure than is provided in a typical home unit.
Furthermore, dead mold spores can still produce allergic reactions, so
UVGI cleaners may not be effective in reducing allergy and asthma
There is no standard measurement for the effectiveness of PCO
cleaners. The use of PCO cleaners in homes is limited because
currently available catalysts are ineffective in destroying gaseous
pollutants from indoor air. Some PCO cleaners fail to destroy
pollutants completely and instead produce new indoor pollutants that
may cause irritation of the eyes, throat, and nose.
Thanks. I went to the link which seems to give a lot of information. It's
a little unclear when they mention UGVI cleaners whether they mean those
cleaners in the duct system or a UV light in where the coils or drip pan
This part of the quote that you posted was interesting:
I can understand how a UV light would help by preventing growth in and
around the coil. I personally doubt that bacteria, respiratory viruses,
etc., spread by coughing/sneezing, etc., would be diminished. What is the
velocity of the air stream (ft/min), so the contact time in about 1 linear
foot or so, is nil.
Not my area of expertise. Like I said the hospital use them...So your
premise may not be valid. Suggest you seek out and pay for expert
advice. The manufacturers should be able to give professional references.
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