For years I have experienced intermittant smells of cigarette smoke (thought it was my dead father visiting me!). Anyway, for the past few months, I've had the smell of burning rubber or plastic in my nostrils. I keep thinking there's an electical fire but no one else smells it. It's very irritating. I'm healthy, don't smoke and don't have any allergies or sinus problems. Is there research out there connecting this phenomenom to brain tumors? should I be worried?