This is such a nice haiku. The smell is definitely one of our strong senses. I like the phrase "suddenly I'm six again" from your haiku. I guess you are experiencing a new type of smell memory through your son's memory, just like when you experienced the smell of memory when you were young.

I remember some movies tried to give the audience a smell, like man-made chocolate smells or something, but our best memories of smells are from real life, like your pizza store!