Why cant you see pollution in US cities overall? Largest emission of CO2 but still looks clean. Why?

I mean US has the largest carbon dioxide emissions in the world, but still the US cities appear clean. Why arent rivers in US polluted like those in China? Or is it that US cities used to be like that in 70s, when industrial activity was very rampant? It would be great if anyone can provide any links where I can read about this. Thanks.

Public Comments

1. Man, you dont know probably too young. Rivers used to be disgusting. Raw sewage used to float by. This is in the 60s. A river in Cleveland has so much oil it caught on fire. Everything got dumped into the water and the air untreated. Things are WAY better now. That river I used to see shit floating in, you can swim there now. CO2 is invisible so you don't see it, to answer the real question. And you definitely CAN see the pollution, the smog, in most major cities. Primarily from cars. Look up the history of the Clean Air Act and Clean Water Act in the US, and the history of the EPA. That should get you started. Must be some aging hippies on here that can tell you more. I was a bit too young.