What beats me is that the main left wing political party that drives the EPA is pulling the rug out from under some of it biggest supporters, namely the trucking industry and all of those transportation unions. Those bureaucrats seem to have about as good a sense of direction as a heard of rabbits scurrying in the headlights of a car on the highway. Just like those rabbits, they also eat and destroy everything in their path too.
I remember when they started doing the so called science studies on the diesel exhaust. Bear in mind that scientific studies are bought and have been for over twenty five years. They have perfected the art of making the science say what ever they pay for, according to what they say, or leave out, in those studies. Given the proper profit margin, you could have a scientific study done to prove Holy water caused cancer if that's the answer you needed to market your pet product.
The soot from diesel is chiefly carbon that easily falls out of the atmosphere. Carbon is inert and causes no ecologic harm. Any NOx emissions are going to be proportional to the amount of fuel burned. diesels are the big winners on fuel economy.
Another thing most people don't know is that the overall thermal efficiency of the electric grid itself only averages 35%. Even though the generating system typically used averages well over 90%, sometimes as high as 96%, most of it is lost in distribution. A Lister or Listeroid can equal the average overall grid efficiency, you can likely coax over 40% out of some of these engines with good tuning. As a matter of fact, utilizing modern technology, thermal efficiencies of "point of Use" electric generation can be had at over 80%. This won't be any reciprocating engine however. At some point in the future, with diminishing oil reserves and increasing oil prices, the grid is going to come full circle, and point of use generation will have to dominate driven by by absolute necessity.
All fellow Americans should call and lobby their Congressmen and Federal lawmakers. Congress created that out of control monster the EPA, and they can also abolish that agency, or at least put a good iron chain leash on it before it eats us all alive.