Regulations Work

Scientific American:

In the four-county Los Angeles Basin, home to about 18 million people, emissions from fuel-burning vehicles and industries, coupled with sunny days, low rainfall, stagnant air and pollutant-trapping mountains, are a recipe for particle pollution.
Under the old standard in effect now, U.S. cities’ annual average cannot exceed 15 micrograms of fine particles per cubic meter of air.
As recently as 2001, air in the Riverside area averaged more than double that concentration.
But in 2012, the entire four counties complied, except for one monitoring station in Riverside County’s Mira Loma, which was just 0.1 micrograms too high. The standard was violated on six days in Mira Loma last year, compared with 108 in 2001. That’s a 94 percent reduction. Last year’s preliminary data shows even Mira Loma complied.
“The average concentration as a whole has been cut in half since the 1990s and we expect all of the counties to be under the former standard by the end of 2014," Atwood said.
And the trend is nationwide.
Over the past 10 years, tons of PM2.5 emitted into the nation’s air have declined 45 percent, while the concentrations people breathe have dropped 33 percent, according to EPA estimates.
All four of Chicago’s monitoring sites comply with the old standard, and in New York City, all eight comply. Across the nation, just four non-California counties exceeded it in 2012 – Lemhi County, Idaho, Ravalli County, Mont., Doña Ana County, N.M., and Philadelphia County, Pa. All are expected to dip below it by December.
Much of the credit goes to cleaner diesel engines, mandated by national standards.
It would take 60 new diesel trucks to produce the same amount of PM2.5 as a heavy-duty truck manufactured in 1988, based on EPA’s emission standards. The amount of soot allowable from a new truck declined 99 percent over the past 25 years.

I'm not sure why the captains of industry hate regulations so much.  Sure, they are a challenge for engineers to meet, and can bring about disruptive technology, but in any other circumstances, they would consider those good things.  All I heard about with Tier II and III and IV was how terrible things were going to be when they finally went into place.  Well, they are in place, and the salespeople went from pushing the old models before the regs went into effect, to pushing the new models as soon as the old ones were gone.    I tend to think that the diesel emissions regulations were a textbook example of how to improve things by rule-making.  They set a goal, and provided several targets for incremental improvement.  Industry was given leeway on how to meet the standards, some companies used one technology, some used another.  Each has its benefits and its drawbacks.  Some companies couldn't come up with a novel way of meeting the regs, and left the business to focus on a different product.  Life goes on, and things get better.