Interesting summary of short vs. long-term effects:

Diesel Versus Gasoline: Which Is Best For The Climate? - CICERO

There a bit in here about theoretical vs. actual NOx emissions of diesel vs. gasoline, but it's a bit dated:


http://www.fischer-tropsch.org/DOE/_...0799_pg461.pdf

And if you are really, really, really interested in emissions technology and where diesel and gasoline are going, try this one:

http://www1.eere.energy.gov/vehicles...09_johnson.pdf