It's not just the particulates that California is crazy about, they're also too obsessed with nox and HC. That's why the BMW diesels in Europe don't need urea like the USA versions do.
All the Diesels on sale in Australia require the urea. I don't think they sell them (even in Europe) without them.
But the change in design on the CX-5 also reduces NOx as well.
Urea is therefore a requirement of the CX-7 Diesel (which we sell in Australia), and the Tiguan, and the Passat.
But the CX-5 is the first without Urea.
The Mazda technians said the Urea refills proved to be expensive for the CX-7 owners and that not requiring on the CX-5 was one of the reasons some Diesel CX-7 owners were come in to do trade ins.