What does a city smell like at 5am?

I’ve been watching the shift from night to dawn on the docks lately—just before the ferries start up, when the air’s still thick with salt and diesel, but something else too. Like wet concrete and old paper, maybe? Or is that just memory? I keep wondering if other people notice it, or if it’s just me. What’s the first thing you smell in your city when the world wakes up?