So a few months ago, because I could not find the information anywhere on the entire internet, I did a back-of-the-envelope calculation to estimate how much more polluted the air in the U.S. is as a result of the VW emissions cheat. The answer is that the air is about zero percent more polluted because of that cheat.
The reason for that is that baseline emissions of diesel exhaust pollutants in the U.S. is so enormous. Commercial diesel tractor trailers emit pollutants at a much higher rate than do VW cars because the engines are so much larger and consume fuel at higher rates. The trucks run many more miles per years than the cars. There are many more diesel trucks than diesel cars. (There a lot of trucks and VW diesel cars are not huge sellers in the U.S.) So the net percentage increase in pollution because of that cheat calculates out to about zero.
VW is worth a lot of money and has not much political clout in the U.S. so this turned into feeding frenzy for lawyers. Penalties of this size are entirely unjustified by the degree of harm.
There should be a price for polluting, based strictly on the types and volumes of pollutants, and it should be applied to all, regardless of the type of vehicle or its nation of origin, or its owner. The right solution here is to tax vehicle exhaust emissions at a single universal rate and let manufacturers and buyers decide what to make and what to buy.
What we have instead is sanctioned pillaging.