Alright, I'll continue the thread drift; can someone fill me in on how diesel cars are so bad that cities are looking at measures to ban them?
Diesel CO emissions are half of petrol, diesel particulates (the sooty stuff?) is the same, but their NOx levels are slightly higher.
I believe the NOx / CO difference is down to the difference in the chemistry of petrol / diesel burn, but I'm open to being educated.
First, it is a political and ideologic hunt, not a facts driven one.
Second, NOx is that tad higher that Diesel qualifies as "we make the world better" pretend-carrier.
Third, a problem is soot. As long as we had the old Diesel engines, soot was only a problem for the mom with her clotheline very close to the streets, but - every dumb idiot was able to see the black stuff. Then they invented the Diesel cat, the visible soot disappeared, but the physics got a lot worse as Diesels now produced tiny and airborne particles instead of the black rocks collected at the curbstone. They invented a bigger problem by solving a visible unseemliness. Then somebody even found out that tiny particles could have a medical impact and boom, next wave. Had they left it at the old soot throwers, we would not face the problem.