I have a very powerful sense of smell. I can tell who slept in my bed if I know that person well. It happened to me once in a college dorm, where a roommate slept in my bed while I was home for the weekend.
I can smell tobacco from far away too. Before anyone notices it.
I know if the cake in the oven is ready, by the smell it sends inti the living room, which has a dining room and a hallway in between.
Unfortunately, I can also smell bad smells very powerfully.