Discussion on:

London bans polluting vehicles in 'Low Emission Zone'

...where these experiments can take place, and we can see for ourselves what the long term benefits and consequences might be; Will this actually improve air quality, or will it just make living in the city that much more expensive?

The ugly truth is that the air in most European cities is nearly unbreathable compared to US cities. The main reason for this is their heavy reliance upon old-tech diesel engines and autos that lack the pollution controls that we take for granted in the US today. This is the ugly trade-off that they make because they tax fuel so severely to pay for their welfare states; the old-tech diesel vehicles get much better mileage than autos in the US.

...where these experiments can take place, and we can see for ourselves what the long term benefits and consequences might be; Will this actually improve air quality, or will it just make living in the city that much more expensive?

The ugly truth is that the air in most European cities is nearly unbreathable compared to US cities. The main reason for this is their heavy reliance upon old-tech diesel engines and autos that lack the pollution controls that we take for granted in the US today. This is the ugly trade-off that they make because they tax fuel so severely to pay for their welfare states; the old-tech diesel vehicles get much better mileage than autos in the US.