The Particle Measurement Programme informal group was established to develop a more sensitive particle measurement system than the long-standing particulate matter mass measurement system. This phase concluded with the adoption into UN Regulations 83 (light duty emissions) and 49 (heavy duty emissions) of the particle number (PN) counting method, together with enhancements to the particulate mass (PM) measurement procedure. Initially the PN protocol was applied for diesel engines/vehicles only in R83.06 and [R49.0x] and subsequently has been extended to cover to spark ignition direct injection engined vehicles R83.06 (draft).
The European Union (EU) has requested further investigation of particle number emissions from spark ignition engines relating to particle size (reduction of the d50 cut off specification) and to emissions under rich operation conditions. Further activities to adapt the procedures/measurement equipment and establish appropriate limit values may be necessary based on the results of these investigations.
The PMP group expects to complete its current mission by June 2016. However, the group’s mandate could be extended in order to transpose the developed procedures into emissions-related global technical regulations, including the upcoming GTR on light vehicle emissions (WLTP).
Moreover, concerns over additional sources of particulates, such as tire and brake wear, have been raised and may require measurement procedures as well. The PMP group is developing GTR provisions for brake wear. Foundational documents can be found here.
| PMP informal group: Agenda for the 26 February 2026 web conference |
| Reference Number: PMP-56.1-01 |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 24 Feb 26 |
| Relevant to: WP.29 Discussion Topic | Particle Measurement Programme, GTR No. 24 | Laboratory Measurement of Brake Emissions for Light-Duty Vehicles, WP.29 Regulatory Project | Heavy-duty Vehicle Brake Particle Emissions Measurement, and UN Regulation No. 179 | Approval of vehicles with regard to the particle emissions of their braking system |
| Click here to view the full document file |
| Brake emissions from non-original parts |
| Reference Number: PMP-56.1-02 |
| Submitted by: CLEPA |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 24 Feb 26 |
| Relevant to: WP.29 Regulatory Project | Approval of Non-Original and Identical Brake Parts with regard to the Particulate Emissions |
| Click here to view the full document file |
| Particle emissions of replacement brake components: Proposal for a new UN Regulation |
| Reference Number: PMP-56.1-03 |
| Submitted by: CLEPA |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 24 Feb 26 |
| Relevant to: WP.29 Regulatory Project | Approval of Non-Original and Identical Brake Parts with regard to the Particulate Emissions |
| Click here to view the full document file |
| Replacement brake particle emissions: Comments on proposal for a new UN Regulation |
| Reference Number: PMP-56.1-04 |
| Submitted by: JASIC |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 26 Feb 26 |
| Relevant to: WP.29 Regulatory Project | Approval of Non-Original and Identical Brake Parts with regard to the Particulate Emissions |
| Click here to view the full document file |
| Coated Disc Brake Torque Variation |
| Reference Number: PMP-56.1-05 |
| Submitted by: JARI and JASIC |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 26 Feb 26 |
| Relevant to: GTR No. 24 | Laboratory Measurement of Brake Emissions for Light-Duty Vehicles |
| Click here to view the full document file |
| HDV Brake Enclosure |
| Reference Number: PMP-56.1-06 |
| Submitted by: JARI and JASIC |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 26 Feb 26 |
| Relevant to: UN Regulation No. 90 | Replacement Brake Linings, Discs, and Drums, WP.29 Regulatory Project | Heavy-duty Vehicle Brake Particle Emissions Measurement, and WP.29 Regulatory Project | Approval of Non-Original and Identical Brake Parts with regard to the Particulate Emissions |
| Click here to view the full document file |
| Front Solid Disc Brake Temperature Criteria |
| Reference Number: PMP-56.1-07 |
| Submitted by: JARI and JASIC |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 26 Feb 26 |
| Relevant to: GTR No. 24 | Laboratory Measurement of Brake Emissions for Light-Duty Vehicles |
| Click here to view the full document file |
| PMP Task Force 4 (EMB) – Status |
| Reference Number: PMP-56.1-08 |
| Submitted by: Aumovio |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 26 Feb 26 |
| Relevant to: GTR No. 24 | Laboratory Measurement of Brake Emissions for Light-Duty Vehicles and WP.29 Regulatory Project | Electromechanical Braking Systems |
| Click here to view the full document file |
| Comments for GTR 24 and UN R179 amendment |
| Reference Number: PMP-56.1-09 |
| Submitted by: LINK |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 26 Feb 26 |
| Relevant to: GTR No. 24 | Laboratory Measurement of Brake Emissions for Light-Duty Vehicles and UN Regulation No. 179 | Approval of vehicles with regard to the particle emissions of their braking system |
| Click here to view the full document file |
| Heavy vehicle brake emissions: Overview of informal HD GTR |
| Reference Number: PMP-56.1-10 |
| Submitted by: EC |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 26 Feb 26 |
| Relevant to: WP.29 Regulatory Project | Heavy-duty Vehicle Brake Particle Emissions Measurement |
| Click here to view the full document file |
| UN R179: Document WP.29/2026/36 findings and proposed changes |
| Reference Number: PMP-56.1-11 |
| Submitted by: AVL |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 26 Feb 26 |
| Relevant to: UN Regulation No. 179 | Approval of vehicles with regard to the particle emissions of their braking system |
| Click here to view the full document file |
| GTR 24: Procedure for vehicles with limited speed |
| Reference Number: PMP-56.1-12 |
| Submitted by: OICA |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 03 Mar 26 |
| Relevant to: GTR No. 24 | Laboratory Measurement of Brake Emissions for Light-Duty Vehicles |
| Click here to view the full document file |
| Heavy-duty vehicle brake emissions: Working draft for a new UN GTR |
| Reference Number: PMP-56.2-01 |
| Meeting Sessions: PMP-56.2 (13 Mar) |
| Document date: 10 Mar 26 |
| Relevant to: WP.29 Regulatory Project | Heavy-duty Vehicle Brake Particle Emissions Measurement |
| Click here to view the full document file |
| Particle Measurement Programme: Minutes of the 56th (February 2026) session |
| Reference Number: PMP-56.1-13 |
| Meeting Sessions: PMP-56.1 (26 Feb) |
| Document date: 27 Mar 26 |
| Relevant to: GTR No. 24 | Laboratory Measurement of Brake Emissions for Light-Duty Vehicles, WP.29 Regulatory Project | Electromechanical Braking Systems, WP.29 Regulatory Project | Heavy-duty Vehicle Brake Particle Emissions Measurement, UN Regulation No. 179 | Approval of vehicles with regard to the particle emissions of their braking system, and WP.29 Regulatory Project | Approval of Non-Original and Identical Brake Parts with regard to the Particulate Emissions |
| Click here to view the full document file |
| Particle Measurement Programme: Minutes of the 13 March 2026 session |
| Reference Number: PMP-56.2-02 |
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The PMP session discussed revisions to the group’s terms of reference to address overlapping technical issues with GTR 24, UN R179, and replacement parts regulations. Three task forces were proposed: TF3a on layout and testing, TF3b on speed-limited vehicles, and TF4 on electromechanical brakes. Topics included non-original brake parts regulations, UN R179 amendments for new vehicle categories, and GTR heavy-duty brake particle emissions standards. The next meeting was scheduled for end of April 2026. |
| Meeting Sessions: PMP-56.2 (13 Mar) |
| Document date: 27 Mar 26 |
| Relevant to: GTR No. 24 | Laboratory Measurement of Brake Emissions for Light-Duty Vehicles, WP.29 Regulatory Project | Electromechanical Braking Systems, WP.29 Regulatory Project | Heavy-duty Vehicle Brake Particle Emissions Measurement, UN Regulation No. 179 | Approval of vehicles with regard to the particle emissions of their braking system, and WP.29 Regulatory Project | Approval of Non-Original and Identical Brake Parts with regard to the Particulate Emissions |
| Click here to view the full document file |