"CO and CO2 on the other hand(which gassers mainly emit) do stay in the air regardless of where you are at."
Shiner, you generally put a lot of thought and intelligence in your posts. Surely you are not claiming that the carbon in diesel fuel is somehow converted into NOx instead of CO and CO2. And, since diesel has a higher percentage of carbon in it that gasoline a pound of diesel will make more carbon byproducts than a pound of gasoline.
Production of NOx is an endothermic process which means that it absorbs energy and increases demand for carbon based fuel. Once it is discharged it starts breaking down and creates nitric acid which slowly dissolves most everything.
"Trust me, the EPA is not perfect, but some seem to take what they say as the word of God without question or even knowing what the regulation is."
I wholeheartedly agree with this. In fact, they probably did more harm than good with the regulations in the 1970's that made many cars more than double their fuel requirements and thus CO2 emissions.