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.