What makes a city smell like morning?

I’ve been thinking about this for weeks—how certain cities have a distinct morning scent. Not just the coffee or bread, but something deeper: wet pavement after rain, diesel from early buses, that faint salt tang in coastal towns. I was on a dock in Reykjavík at 5am last month, and the air smelled like cold iron and old rope. It stayed with me all day. What’s your city’s first breath? And why does it stick?