Product review (3 stars): Doesn't last 2 months if used all the time
I used one of these for about 3-4 weeks and noticed considerable white dust.  The dust doesn't settle on everything, but it does seem to be attracted to a CD or DVD that is 'read side' up.  Set an open DVD or DVD in the open somewhere and monitor it.  You'll see the white dust fairly soon.  I have my humidifier downstairs and my DVDs upstairs have white dust.