I'm surprised the use of diesel engines isn't being attacked from the many special interest groups:

http://www.scorecard.org/env-releases/def/hap_diesel.html
http://www.lungusa.org/site/pp.asp?c=dvLUK9O0E&b=36089

For the same load and engine conditions, diesel engines spew out 100 times more sooty particles than gasoline engines. As a result, diesel engines account for an estimated 26 percent of the total hazardous particulate pollution (PM10) from fuel combustion sources in our air, and 66 percent of the particulate pollution from on-road sources. Diesel engines also produce nearly 20 percent of the total nitrogen oxides (NOx) in outdoor air and 26 percent of the total NOx from on-road sources. Nitrogen oxides are a major contributor to ozone production and smog.


>Dragan, the new diesels can accelerate fiercely- and often without needing to drop a gear, either. Plus they have cleaner emissions than an equivalent petrol engine.