but that 1970 Beetle spews a lot more pollution than today's Excursion (or any other new vehicle). Cars built back then routinely spewed about 400 times the pollution of today's vehicles because, unless you're talking about the ones built for the California market, none of them had much in the way of emissions controls. We Colorado drivers who live along the Front Range have to have our vehicles tested every year or two for emissions. Those old cars are effectively given a pass - they can pollute as much as they want.

I had to laugh last year when I saw an old Beetle with an Earth First bumper sticker. I get better gas mileage in my Honda CR-V and emit only a tiny fraction of that car's pollutants. If the owner really cared about the environment, he'd scrap that old, inefficient, high-polluting vehicle and get a new car. He doesn't have to get an SUV - he could buy something like a Focus.

The problem of pollution from old cars is especially bad in developing nations, as discussed in this UN report.