I've had a similar experience smelling candle smoke. There were no candles lit anywhere, yet it smelled like a candle was just blown out. I've been told it could be a spirit guide or "someone visiting" you. I only had this happen one time, but it was a strange feeling, like someone or something was in the room with me. It didn't last more than a few seconds or so, but it made the hair on my arms stand up.