What is this smoke like smell I keep smelling?

Okay so I need someone to help me try to figure out what I keep smelling. I know a few options to the problem but I want to know from you as well. This smell started around this past weekend. To me it seems like a cigarette smell. It smells everywhere, like the whole house and is making me cough. I have a few options to what it might be. Option 1, the basement. I checked the hot water heater and there are no signs of leaking. Option 2, the heater. I also checked the vents that connect to the main unit from the basement. I did hear something loose from 1 of them. Option 3, my dad who smokes. He has been smoking quite a bit lately like maybe more than 4 times a day. I really am hoping that it is not from him and plus I don't like the smell of cigarette smoke. Option 4, scented carpet powder or room spray. I have been using carpet powder for my who has fleas and it has been over a month. Also room spray to cover up smells. Option 5, asbestos or mold. I really am hoping that it is not this. This house is fairly old and recently was hit by a tree from the roof. Option 6, the roof. There was a little hole from the the tree that fell but was patched up. Anyway I know that this is a bit wordy but just wanted to get everything in here. Please let me know what you think of what it might be and how can I treat it. Thanks!