[nabilhat]

Gasoline engines without catalytic converters as well. When I'm on a sidewalk and an old car drives by, the familiar smell takes me back to my youth. Riding in traffic with the windows down, or field trips to some destination in the city full of flatulent traffic. It's the smell of childhood summer when the air was calm and exhaust hung in the air forever.

I was also around dairy farms a lot as a kid. Like the ironically adjective'd "pre-smog" engines, it only smells like nostalgia for a minute or so.