Aluminum Oxide or Aluminum DiOxide?
 
I have found all forms of Aluminum having been detected in Aerosolized particulates....just to note:  The Al Oxide are glasses of Silica.....the DiOxides are softer, not as hard as the Alumina (Oxides)
 
also providing a short snippett on another source of Aluminum DiOxide, but in the form of Toothpaste....makes the point dramatic about
Aluminum in any form and the infirmaries caused by ingestion with Humans (or other Life Forms)

http://www.rense.com/general37/toth.htm