Brake Wear Emissions

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. Particle emissions from the brakes not only affect air quality and human health but can also have effect on operation and safety of the brakes themselves.

Dekati® Solutions for brake wear measurements include:

  • Real-time particle concentration and size distribution 6 nm 10 µm
  • Sample conditioning and dilution solutions

Download brochure on break wear emissions here.


Dekati® ELPI®+ and Dekati® High Resolution ELPI®+ are unique instruments ideal for brake wear emission measurements. Both instruments can measure particle size distribution between 6 nm and 10 µm in real- time covering the complete size range needed to characterize brake wear emissions. The ELPI®+ systems use one measurement method and one instrument throughout the complete size range eliminating the need for complicated calculation routines needed to combine data from several different instruments into one size distribution result. The ELPI®+ instruments additionally collect the particles in 14 size fractions during the real-time measurement; these collected particles can be analyzed after the real-time measurement with different chemical or physical analysis methods to gain further understanding on the composition and source of the particles in different size fractions.

The wide particle size range of brake wear emissions can be a challenge to sample conditioning systems. The sample conditioning and dilution system needs to be designed so that particle losses through diffusion, impaction, gravitation and electrostatic phenomena are minimized. A commonly used dilution system in brake wear measurements is e.g. the Dekati® ejector Diluter with dilution factors between 1:8 and 1:100 available. Dekati also provides several other suitable sample conditioning systems for brake wear emission measurements including customized solutions that fulfill specific requirements of different measurement locations. Combined with the ELPI®+ products, we’re able to provide a complete and accurate measurement solution for brake-wear emission characterization.

ELPI®+ features:

  • Real-time particle concentration and size distribution 6 nm 10 µm
  • 10 Hz sampling rate to detect small timescale changes in the sample
  • Up to 500 size classes with the Dekati® High Resolution ELPI®+
  • Independent stand-alone operation or control via laptop using ELPI+VI software
  • Analogue inputs and outputs for data integration
  • Wide operational concentration range suitable for direct sampling or sampling via a dilution system
  • Suitable also for tailpipe and blow-by emission measurements

ELPI®+ setup options for brake wear measurements:















Break wear emissions measured with HR-ELPI®+. Mainly large particles (1 - 10 µm) are generated during braking but also small nucleation particles (6 - 200 nm) are formed during different stages of the braking cycle. Particles with different sizes can have different origin and particle composition analysis gives valuable information on the origin and formation mechanisms of the particles.

Download brochure on break wear emissions here.