Unfortunately, UV-C also creates ozone. Ozone belongs in the ozone layer; in the lower atmosphere, it is a powerful irritant and polutant. You wouldn’t want that in your home.

FYI, UV light creates ozone—O3, which then absorbs UV light better than the plain oxygen (three O2 molecules into two O3 molecules) its made from. The problem is that Chloro-flouro-carbons destroy the O3 at a rate fast enough to impact their contribution to UV absorbtion.

Now, the ozone created may also be negligible, but it all depends on now strong that UV-C lamp is. Someone needs to test this, but my suspicion is that any light strong enough to kill all airborn mold spores and germs has got to be pretty strong, and may end up putting enough O3 into the air, enough to be a problem

So true

so.. which would be a good air purifier ? that doesnt create ozone?

Why doesn't the Germ Guardian emit ozone?
The type of UV-C bulb used in the Germ Guardian is a special one that does not emit ozone out of the product.

What about all the UVC lamps in almost all filtered pond's...won't that create a problem???