Originally Posted by Spiff
Very unlikely. While sulphur is used for those purposes, the more reactive component is sodium/potassium nitrate, in gunpowder and other conventional explosives. Its presence is more indicative of an explosive than elemental sulphur is.
Everyone exhales sulphur. It is one of the sources of halitosis.
You certainly seem to know a lot about the uses of sodium/potassium nitrate (not to mention bad breath). Must be the academia in you. Still, just to be safe, I'm going to refer you to the TSA and make sure you end up on the no-fly list. I know it may make it a little inconvenient for you but, well, you know, anything for security...
Mike