Here is an interesting new study which just came my way. It is technical, but it is quite on point as EPA considers what to do about the ozone standard.
Study refutes concept of diminishing returns for smog control
Basically, it has been the “conventional wisdom” that once you hit a certain point with air quality improvements, the “marginal benefit” [the added benefit] of more pollution control drops, while the cost rises.This study challenges that “wisdom” directly. It argues that as NOx emissions drop “each additional ton of NOx reduction carries larger benefits than the previous ton.” And this is especially true in the case of mobile sources. (And it is quite possible to make huge further reductions in NOx emissions by setting much tougher NOx emission standards for new trucks.)I believe the EPA and the White House should take a close look at this study as we reach the crunch time on the ozone issue. It refutes the arguments of those who claim it would cost too much to set a more protective smog standard.