Proposal from the Particle Measurement Programme informal group to:

• Modify the existing solid PN measurement methodology having a 50% cut-off size at 23 nm (SPN23) in order to allow the use of catalyzed volatile particle remover (VPR) and introduce minor improvements, and
• Include as a second option a solid PN measurement methodology with a 65% cut-off size at 10 nm (SPN10).

12. The representative from EC, drafting coordinator for WLTP activities, introduced ECE/TRANS/WP.29/GRPE/2020/14, as amended by GRPE-81-14, as draft Amendment 6 to UN GTR No. 15, together with its technical report (GRPE-81-15). The Chair from the IWG on Particulate Measurement Protocol (PMP) also presented GRPE-81-10 introducing revisions also to be included in ECE/TRANS/WP.29/GRPE/2020/14 as part of Amendment 6 to UN GTR No. 15 on a supplementary methodology to measure sub-23nm particulates. The Chair of the IWG on PMP also introduced GRPE-81-11 providing explanatory note on the sub-23nm procedure part of Amendment 6 to UN GTR No. 15. He also informed GRPE that GRPE-81-11 had been included in the technical report of Amendment 6 to UN GTR No. 15 (GRPE-81-11 is included in GRPE-81-15).

13. GRPE adopted ECE/TRANS/WP.29/GRPE/2020/14, GRPE-81-14 and GRPE-81-10 as amended by Addendum 1 to this chair’s notes. GRPE also adopted the technical report (GRPE-81-15) as reproduced in Annex V. GRPE requested the secretariat to submit Addendum 1 and Annex V to WP.29 and Executive Committee of the 1998 Agreement (AC.3) for consideration and vote at their November 2020 sessions as draft Amendment 6 to UN GTR No. 15.

The first part of the PMP Brake Protocol for measuring brake particle emissions and addresses items using a new WLTP-Brake Cycle in conjunction with an inertia dynamometer test. The PMP Brake protocol will include three sections aiming to provide a comprehensive protocol for testing facilities:

• Inertia Dynamometer Protocol to Measure and Characterise Brake Emissions Using the WLTP-Brake Cycle;
• Part 2: Minimum Requirements and Guidelines for Sampling and Measurement of Brake Emissions for Particle Number and Particle Mass;
• Part 3: Reporting Test Results from Brake Emissions Testing.

38. The expert from EC, Chair of the task forces on brake emissions introduced GRPE-81-12 on an interim report on the activities on brake emissions. He detailed the achievements reached so far, including the definition of the brake emissions test cycles taken from the WLTC database, as part of the activities of the task force 1. He highlighted the on-going work on defining a procedure (task force 2) to measure brake dust emissions had been slowed down because of the Co-VID19 crisis and the difficulty to perform lab and other types of physical tests.

39. The representative from the UK highlighted non-exhaust are becoming a priority for come CPs, and that for example, microplastics from tyre wear represented a significant share of microplastics in the environment. The expert from EC explained that tyre wear was indeed a topic of high interest and that a research project was expected to be initiated soon at the European level to look closely at this issue. GRPE congratulated the excellent feedback on the brake emissions activities and encouraged regular updates on progress of this item that is part of GRPE priority list (Chapter XIV).

Proposal to update the PMP mandate with a view to delivering the following results:

• Proposal for a new methodology for exhaust PN measurement with a d50 cut-off size reduced to 10 nm: June 2020
• Proposal for HD raw exhaust PN sampling and extension of sub-23 nm procedure to HD engines: January 2021
• Proposal for LD PN-PEMS 10 nm specifications : June 2021 (tbc)
• Proposal for a common test procedure for the measurement of particle brake emissions from conventional ICE LDVs: December 2021.

40. The Chair of the IWG on PMP introduced GRPE-81-13 on a revision of the Terms of References (ToRs) of the IWG to include on-road test procedure definitions, which are expected to be developed for light- and heavy- duty application concerning the sub-23 nm PN emissions. GRPE agreed to revise the ToRs of the IWG on PMP as proposed in GRPE-81-13.

36. The representative from the EC, chair of the IWG on PMP, introduced GRPE-81-31, presenting a status report of the activities of the IWG on PMP since the last session of GRPE. He highlighted the strong progress made by the IWG on both exhaust and non-exhaust emissions sources that, for example, led to the inclusion of sub-23 nm PN methodology in Amendment 6 to UN GTR No. 15 (para. ‎12). He also described the latest activities on non-exhaust particulate emissions and requested GRPE to host a one-day workshop on brake emission in conjunction with the next GRPE in January 2021.

37. The representatives from the UK and EC explained they would now like, as a next step, to include sub-23 PN requirements into UN GTR No. 4 on emissions from Heavy Duty Vehicles (HDV). The representative from EC also offered the possibility to host the workshop on brake emissions at the EC facilities in Geneva. The representative from OICA sought clarifications on the inclusion of sub-23 PN in UN GTR No. 4 and how differences between light duty vehicles and HDVs could be taken into account when designing a procedure for HDVs. The Chair of the IWG on PMP said initial thoughts would be to sample directly raw exhaust in the case of HDVs and stated no preferences with respect to the process of its inclusion in HDV legislation. The representative from EC added that how and when it would be included was still being discussed among interested parties.