Small particulate matter (PM10, PM2.5) is a nasty pollutant that is prevalent in a lot of cities.
Some of these emissions come from exhausts (tailpipes); regulation has spurred on technological developments, and modern clean fossil-fuel engines have much lower particulate emissions.
However, particulate levels are still high, and a large part of the problem is that transport causes a lot of these, from abrasion of tyres, road surface, brakes and clutch.
I can imagine lots of possible routes to curbing these, from changes to materials used in making the sources of the particulates to suppress their creation, to cleaning / scrubbing regimes to prevent their atmospheric suspension. And presumably curbing vehicle flows is a very effective mechanism.
Beyond curbing vehicle flows, What is best practice in reducing the pollution of non-exhaust transport-sourced particulates?