Diesel exhaust contains far more carcinogenic materials than gasoline exhaust. The particulates you mentioned do much damage. The carcinogenic compounds are adsorbed onto the particles, then slowly desorb over time leading to cancer. There is mountains of data on this fact. The good thing is that recirculation systems and the new catalytic converters and particulate traps that are coming out soon will eleviate the PM concerns. Diesel may become the way to go for fuel economy considerations (like in Europe). You are also incorrect, in that motor vehicles account for the majority of air pollution in many our major cities. And studies, some done by the auto indusrty themselves, show direct correlations to many of the cancer cases for non smokers. I do not want to be cruel about this, but most of you guys are in over your heads on this air pollution issue. There are many issues and technologies that I would defer to most others on, the mechanics of volvos probably being one, but this issue is most likely not one of them. Please do some research and at least consider the issues. I understand someone having a contrary view when they do not have the data. If you see what I have in 30+ years (it has been part of my job), I believe you'd agree.