I remember the wonderful coffee roasting smells as a kid when we would drive up to our cabin in the Sierras for vacation. It would be early in the morning, like 6:00 AM and I can remember hitting "it" as soon as we rolled onto the bay bridge. Every once in a while I'll pass a local coffee house that "roasts their own" and be taken back to that time. Other great smells were bakeries. And, of course, the yummy smell of that rich burgundy elixer, Leaded Super. I can still remember my dad pulling into the Richfield Station on 28th and Judah and telling Fred to "Fill 'er up with Ethel".
Now that there are so many more people and therefore pollution sources around, we are being protected from all those smells. I think bakeries and some restaurant grills now have to have some controlls on the odors, I mean "Emissions", they generate. I guess we're better off, but fewer things to mark memories.