No Way Back

The United States has made tremendous progress in reducing air pollution during the last few decades. But many environmental activists, newspaper editorialists and other opinion leaders believe that Bush administration policies will cause increases in air pollution, and that stringent new pollution control measures are necessary if air pollution is to improve. They are incorrect. It would be virtually impossible for anyone, no matter how tenacious or determined, to prevent continued and substantial reductions in air pollution:

Most air pollution comes from motor vehicles. But emissions data collected on the road and in vehicle inspection programs shows that with each new model-year, automobiles have been starting out and staying cleaner than previous models. Fleet turnover to progressively cleaner vehicles has been reducing emissions by about 10 percent per year.  These reductions will continue as earlier vehicle models are replaced by vehicles built during the last several years. Much tougher standards that start phasing in this year will also continue these ongoing reductions. Even after accounting for population growth and the popularity of SUVs, and suburbs, total vehicle emissions will drop at least 80 percent during the next 20 years. These reductions are unstoppable, because they depend only on older vehicles being retired, rather than on additional requirements for new vehicles.

From Official Site.