I found a question from 1/2004 about the Calutech UV air purifiers. 
After reviewing the information at
http://www.UltravioletAirPurifiers.com and http://www.Purifier.org
(both appear the same people as calutech.com) I bought one.  I've
noticed an immediate change in the air but am too concerned about UV
radiation.  I looked into the other one, Second Wind, as commented on
on March 9th, 2005 in the 1/2004 listing, but found out from local
health dept. that this catalyst type system produces ions which are a
form of bad ozone.  I'm pretty sure I made the right choice but want
to know if someone can tell me if this UV can really penetrate my air
ducts with radiation, affecting my family, or if it really is used by
hospitals and is safe?

I am aware of this brand and I can assure you that you don't need to
worry about radiation going through an air duct.  These operate just
like the sun outside.  UV from the sun will not harm you if you are
indoors, eg. you don't get sunburn.  The same goes for this type of UV
air purifier.  The radiation produced is UV radiation, not the same as
radiation from something like an X-Ray machine.  You are also correct
about catalyst style systems.  They were originally believed to
eliminate VOCs but further study has determined that the hydroxyl
radical produced by this type of system is short-lived.  They die as
fast as they are produced and don't really clean the air everywhere
outside the air duct as many claim.  You can learn more about this
subject from your local health department, as you have referred to
previously for advice, or even the EPA.  What I can offer to you is a
recommendation.  Calutech is a superior system, an exact match in
power offered by Honeywell at a fraction of the cost, and their
product is USA made, not China/Malaysia, etc. like their competitor. 
After reviewing their site I see the FAA and United Nations have
chosen this company, as well as two well known state university /
colleges.  I think you have made a good choice, possibly the best.

I am very familiar with both compaines (Calutech and Second Wind) and
both are extrememly excellent products.  However, I think you have
been misinformed as far as the Second Wind UV Air Purifier is
considered.  The Second Wind (as does all UV air purifiers) produces
minut amounts of ozone...but nothing that is harmful.  The ozone
emitted fromt hese air purifiers is less than that of a copy machine! 
Read more at http://www.breathemoreeasily.com