Re: Electricity pollutes as well

I didn't mean to imply aromatics were harmless - as you noted, they're not. They are thought to be one of the reasons why diesel exhaust is (most likely) a hazardous pollutant. I was simply saying that aromatics introduced into gasoline are almost entirely destroyed when the fuel is burned. Lead and other metals are not destroyed, and in fact can (and often do) form more dangerous compounds when they're burned. Organic compounds like aromatics can also form more dangerous substances when they're burned, but that fraction is usually much less then it is for metals. I should have been a bit more specific - it's very difficult to directly compare the impacts of different pollutants when you're talking about effects.
I also didn't want to give the impression that I think all combustion is evil - on the contrary, we get enormous benefits from it. But there are also bad side effects, some of which can also be enormous. Figuring out whether the side effects outweigh the benefits is not simple and often not conclusive.
Andy