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.

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).

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.

41. GRPE noted the request for a meeting room for a day during the GRPE week in January 2021 to host the workshop on brake emissions.