I seem to remember this being talked about 10 – 15 years ago. There was some evidence, at the time, that it created more ‘pollution’ to make a new car that to run a 10 year old car for some, cant remember how many, years.
I found a report from 1999 which discussed options such as scrapping of older cars and forcing upgrades to cats and other madness. At that time a significant percentage of emissions was produced by older cars but most of that was due to a relatively large number of pre-93 cars still on the road without cats. I bet that picture has changed now!
Although we have seen euro 2, 3, 4 emissions legislation go through on new cars they're really into diminishing returns now so you can't really say that a new car is significantly cleaner than, say, a 5 year old car. I bet a fair amount of motor industry investment has gone into the "research" that produces rubbish like this.
Anyway, the flavour of the month is CO2 emissions now, and that's far less about how old the car is because it's not affected by cats (other than that you have to burn more fuel and thus create more CO2 to make a cat work in the first place!).
Kevin
