How come the apocalypse is always brown and dirty? Do people realize that most cities are coastal? Was the apocalypse so dastardly that it killed the wind too? See, trash gets blown around by the wind, and eventually it ends up in the lake, ocean, river etc. The Pacific Ocean collects trash from the entire continent. Given enough years, America would be glossed over with a polished sheen.
Now, if the apocalypse kills off all the plants too, then it's a total reverse scenario. Natural disasters like the Dust Bowl were caused in part because there weren't enough plants holding the soil down and breaking the wind. So there's a good chance the continent would be covered in blankets of dirt and sand. On the plus side, our stone buildings would be polished like jewels from the rough winds!