Question: How Much Has The Conquest Of Smog Cost?

I`m mulling over a major article about the differences between liberalism and conservatism, and I`d like to use an example that I`ve never seen anybody fully work out.

There is vastly less smog in Los Angeles today than when I was a kid. It`s a real triumph of environmental regulation. 

On the other hand, it`s not exactly a cost-free triumph. For example, do you remember decades ago when you went to the car dealership and the EPA gas mileage sticker offered two different estimates: the national miles per gallon number and the California number, which was about 10% worse? 

As I seem to recall, people would go to Las Vegas or Phoenix to buy a car without California pollution controls on it because they would save maybe 10% of the cost of gasoline for a year, which is not a small number in aggregate.

After awhile, though, there stopped being two numbers because the feds applied many of the California emission control standards on cars to the entire country to keep more polluting non-California cars from slipping into California. (Thank you, non-Californians for helping us out with our smog problem.)

Has anybody ever seen a study adding up all the costs of the Defeat of Smog?