From: Indoor Air
Pollution: An Introduction for
Health Professionals -
http://www.epa.gov/iaq/pubs/hpguide.html
Ion generators act by
charging the particles in a room so
that they are attracted to walls,
floors, tabletops, draperies,
occupants, etc. Abrasion can result
in these particles being resuspended
into the air. In some cases these
devices contain a collector to
attract the charged particles back
to the unit. While ion generators
may remove small particles (e.g.,
those in tobacco smoke) from the
indoor air, they do not remove gases
or odors, and may be relatively
ineffective in removing large
particles such as pollen and house
dust allergens. Although some have
suggested that these devices provide
a benefit by rectifying a
hypothesized ion imbalance, no
controlled studies have confirmed
this effect.
Ozone, a lung
irritant, is produced indirectly by
ion generators and some other
electronic air cleaners and directly
by ozone generators. While indirect
ozone production is of concern,
there is even greater concern with
the direct, and purposeful
introduction of a lung irritant into
indoor air. There is no difference,
despite some marketers' claims,
between ozone in smog outdoors and
ozone produced by these devices.
Under certain use conditions ion
generators and other ozone
generating air cleaners (see
www.epa.gov/iaq/pubs/ozonegen.html)
can produce levels of this lung
irritant significantly above levels
thought harmful to human health. A
small percentage of air cleaners
that claim a health benefit may be
regulated by FDA as a medical
device. The Food and Drug
Administration has set a limit of
0.05 parts per million of ozone for
medical devices. Although ozone can
be used in reducing odors and
pollutants in unoccupied spaces
(such as removing smoke odors from
homes involved in fires) the levels
needed to achieve this are above
those generally thought to be safe
for humans.
See also: