It was posted a while ago in the V.W. emissions thread. It's definetly interesting if stating the obvious. An old car that's euro 1 compliant is dirtier than a euro 5 compliant car. Even euro 6 cars being dirtier than euro 5 wasn't that surprising given all the press coverage of euro 6 cars totally failing to meet the criteria in real world conditions.
Interesting stuff but would have been more valid if they'd put a euro 5 petrol instead of the knackered golf.