This is bugging/bothering me. About 6 months ago I noticed I could smell cigarette smoke/ash. I thought it was coming from the neighbour underneath and I was very sensitive. This disappeared and now its back again while in my bedroom with all windows closed! I googled it and it seems to be a thing to do with olfactory disturbance. It could be nasal related, or it also mentioned its a symptom of brain tumour?! This has now freaked me out, bad Dr Google. Has anyone else experienced this?