Re.: 080309 MMDigest, "Air Cleaner & Purifier for a Dusty Room",
by Bruce Clark.

It would be very helpful to have a better description of this problem,
as it would be of interest to many people.  First, are we talking
about just one room that is dusty, or is this a whole house problem?
Or are we interested in just a shop or working area?

Second, is there an hot air heating and cooling system in the house or
something like radiators or baseboard heat -- no ducts?

What is meant by "living under very dusty conditions" -- what is the
source of the dust?  Is it typical house dust, construction happening
outdoors, shop or wood dust?  And are you trying to make for less
house cleaning or are there allergies to contend with or is there too
much dust in the pianos?

Even before knowing all the parameters, I can say that an electronic
air cleaner produces ionized air even without the extra ionizer, it's
just not as much.  If you're talking about one of those shoebox-size
units that blows out ionized air, I'd avoid them like the plague.
They can do real damage to both you and anything that can possibly
be corroded.

I worked at Xerox for 30 years so I have some first-hand knowledge
with electrostatics.  Some of the larger and older Xerox copiers
produced so much ozone that we had to design the corrotrons with
a vacuum system that pulled the air around them through a filter to
remove it.  (The corrotron is the high voltage discharge device that
charges the drum or belt to accept the images.)

An example.  There was a office near mine that had a large copier.
When I walked down the isle nearby, I could smell a very strong odor.
It was the 'fresh spring thunderstorm' odor of nitrous oxide.  This
is produced by excess oxygen atoms (from the decomposition of ozone)
combining with nitrogen in the air.  See Bill Finch's article in MMD
from 2002.

After a few days I asked the people nearby if they weren't bothered by
it.  They described various respiratory ailments that they associated
with the dry air in the building.  Then I pointed out that every
exposed metal surface in the area was coated with corrosion: all the
plated trim in their chairs, desks and wall panels -- everything that
was not painted was rusted.  And all the rubber bands were hardened.
I made them shut off the machine and have the filter system replaced.

One last note.  An ozone generator will remove odors and various gasses
and it will kill microorganisms.  The are used in various industrial
areas and to remove odors in hotel rooms.  They do little to remove
particulate matter (dust).  To do that, you would need a negative ion
generator.  Electrostatic air filters are neither.  They charge
particles when the particles pass between high voltage wire grids and
then collect the charged particles on oppositely charged plates.

Regards,
Craig Smith

 [ See http://www.mmdigest.com/Archives/KWIC/O/ozone.html
 [ -- Robbie