What's that smell?

Time for me to do some research about 4-year old development...all of a sudden, Tyler has a sense of smell. Does it magically appear at this age or what? Every place we go, Tyler comments on smells. At the grocery store's fish counter, Tyler asked if I can smell that stink. At the gas station, Tyler asked what that smell was. When I looked and saw an old semi truck driving by, I said it was the smell of diesel fuel which he declared smelled good. I think so too. In the bathtub, in the living room, at the park, all these places he's been many times before, suddenly there is a smell to everything. I thought this was funny until Sunday when we had the Rusks and Bessettes over for brunch. We were all sitting around the table enjoying ourselves when Tyler turned to me and asked me if I farted because he could smell something. Nice.