Unsure
The Germ Guardian GG-1000 UV-C Sanitizer seems to work fine but there's really no way of knowing for sure.  Air is not something you can see or measure in any conventional way.  This product seems to work like a little fan but omits a very loud sound that can be heard in adjoining rooms.  All one can do is have faith that it does what it claims.
Rating: 3 stars