That's right and a big part of is the much higher gasoline taxes in Europe. Interestingly, I can't recall where I read this, but allegedly particles big enough

That's right and a big part of is the much higher gasoline taxes in Europe. Interestingly, I can't recall where I read this, but allegedly particles big enough to cause smog are easily filtered by the human body. Where as particles so small they don't cause smog tend to be absorbed more easily. And so some clean air regulations might have actually made things worse.