ULEZ area is free for petrol cars built 2006 or later, and diesels 2012 or later. So not exactly restricted to new cars and vans, etc.
Circa half the particulates come from non engine related activity - clutch use, brakes, etc.
The ULEZ will also mean those living in the Congestion Charging Zone will finally have an incentive to consider their car use - they currently receive 90% discount on CCZ fees.
former Liberal Democrat Councillor for East Dulwich Ward (2006-2018)