Not to rain on anyone's parade here, since I agree that cooking the data to serve the agenda is despicable, but these reductions would not have taken place without political effort to require things like scrubbers on copper smelters, catalytic converters on cars, or different fuels technology for gas turbines.
The last one is instructive. If you watch an old 707 take off, you'll see a huge trail. Watch a modern fan jet powered aircraft take off, and you'll hardly see anything. That's not an accident: it required significant changes in burner design, turbine design, and even the fuel composition.
DuPont is taking credit for things he opposed all along. While opposition may be good to moderate the demands of extremists, there's no reason conservatives can't be all for minimizing environmental impact without frivouously restraining trade. Since I've been involved with the design of machinery (like jet engines) for 20 years, I know that it can be done. If you don't believe me, compare the emissions of a 2002 Honda Accord with a 1973 Buick Skylark. And remember that in 1973 Detroit engineers were saying you couldn't build cars that get the mileage the Accord does and reduce the emissions.
So, who are the real luddites?