A possible measurement method is depicted in the picture. There, you see a real time particle size and mass concentration measurement setup in a brake test stand, using a High Resolution ELPI^®+ and a Dekati^® ejection Diluter (DI-1000).

As exhaust emissions from engine tailpipe have been decreasing in recent years through development of engines and exhaust after-treatment systems, non-exhaust emissions have become a major contributor to total particle emissions from vehicles. Non-exhaust emissions have been estimated to contribute to almost 50 % of total PM2.5 and PM10 emissions from vehicles and one of the main sources of non-exhaust emissions is particles emitted from brake-wear.

Since the particle emissions from the brake wear are formed through different mechanisms and contain particles of various sizes, an instrument with a very wide particle size range is needed to accurately characterize these emissions – as for instance, the Dekati ELPI^®+ impactor.