Representativeness of airborne brake wear emission for the automotive industry: A review

Brake wear gives 16%–55% by mass to total non-exhaust traffic related PM10 emissions in urban environments. While engines have become cleaner in the past decades, few improvements were made to lower non-exhaust emission until recently. Researchers have developed several experimental methods over the past years to assess brake emissions. However, observations tend to differ from a method to another with respect to many disciplines, ranging from particle system characterization to brake cycles, and it remains difficult to compare results of different research groups. It is so crucial to get a consensus on the standard experimental method. The following article lists limits which influence measurements and has to be taken into account when comparing works from different laboratories. This article also discusses how to design tests to get a relevant braking particle system characterization.