For a year or two, my father has been sniffing smoke around my house 24/7 (non-smoking household). Initially, we thought it was our neighbor who was burning wood w/ a fireplace that was creating a strong smell. That was taken care of, as we asked the neighbor to stop burning wood since it blew towards our house. Well, my father had decided to take it to a whole new level. He's added CO meters, called people out to "fix" our AC/heater system (used up most of his sick days too, also buys new filters every month for the heater), opens windows now because he doesn't want to smell food when he's napping (apparently popcorn "smoke" creates too much for him), buys room air filters and ionizers to try and "solve" the problem. The problem is, no one else smells the "smoke" he does that he still smells. Thus, he always tries to open windows and blames the family for our ignorance of not being able to smell the smoke he does. The only possible thing I recall that could've been toxic is the sealant we used to seal our concrete. Apparently it was toxic, and we didn't use gas masks for them. He reapplied it several times. (I rather not have this as the primary reason unless there is enough evidence to support this claim). We had gotten concrete installed ~2 years ago. I did some googling, and it said a possible cause could be allergies... Possible?... Thanks. (Yes, I like to ask questions. It's always nice to get opinions). Cliffs: Father smells smoke everyday for the past year or so Family doesn't. Gone on a frenzy to get rid of said smoke. What's going on? Edit: My mother told me it could possibly be related to our new furnace, but we're not sure what.