At least newer diesels are a lot better about particulates than the older ones, the EPA has mandated particulate filters since 2007 and they reduce them by ~85-95%.
The crazy thing about the VW scandal: their cars still met the legal requirements for maximum allowed emissions even without the cheat module (at least here in the USA)!
How would they possibly rig the numbers on a particulate filter? The cheating was achieved through engine control software selectively disabling parts of the emissions control system when it detected testing was not occurring. You cannot use software to selectively disable a particulate filter bolted onto the exhaust pipe.