I was smelling a phantom smoke smell for a couple of weeks.  It was annoying, since I didn't smoke.  I tried to figure out what had changed over the last couple of weeks and realized I had started taking a Thyroid supplement from the Health Store called, TriStar Naturals Thyroid Plus Supplement.  I decided to stop taking the supplement to see if it made a difference.  After a few days the smoke smell went away and after a couple of weeks I couldn't smell the smoke.  I don't know for sure if the supplement caused this condition, however, it has not returned.  Hope this may be helpful to someone.