David Biello at Scientific American has a nice writeup on the recent Obama decision not to lower ozone levels:
Had the new regulations been enacted, the bottom line would have been:
$100 B/yr in health costs
probably tens of millions of dollars/yr in crop damages
Instead Obama clearly capitulated for the sake of getting reelected. It was probably a good decision from a purely political point of view, but it probably won't help It certainly won't help the people breathing in all this crap.