Hi, I don't know how to answer the questions so this is my way of doing that.  I just wanted to let everyone know this is my own personal experience and my sisters.  I was having this same issue of smelling smoke and dirty ashtrays all the time and none were around. Nothing seemed to work to get rid of it and I tried everything,  Since then I found out that I had a thyroid issue and now am on medicine. Last week my sister went on vacation and forgot her thyroid medicine and was telling me how she kept having this weird issue about smelling smoke or something burnt all the time.  I figured it out that it is related to the thyroids.