2. Mr. Rijnders, Chair of GRPE, opened the meeting, held as hybrid session, with all participants attending virtually because of the sanitary situation, and welcomed the participants. The Chair of the Informal Working Group (IWG) on Particle Measurement Programme (PMP) requested to remove ECE/TRANS/WP.29/GRPE/2021/17 from the agenda as the IWG on PMP could not finalize the proposal in time for a consideration by GRPE. The Chair of the IWG on Electric Vehicles and the Environment (EVE) requested to remove ECE/TRANS/WP.29/GRPE/2021/18 from the agenda as the IWG on EVE could not finalize the proposal in time for a consideration by GRPE.

3. GRPE acknowledged both requests by the IWGs on PMP and EVE and adopted the provisional agenda of the eighty-third session (ECE/TRANS/WP.29/GRPE/2021/9), as updated and consolidated in GRPE-83-03-Rev.4, and GRPE-83-02-Rev.1 as a tentative running order. GRPE took note of GRPE-83-01 on the organization of GRPE Informal Working Group (IWG) meetings held during the weeks prior to this meeting.

34. The representative from the EC, Chair of the IWG on PMP, introduced GRPE-83-21 giving a status report of the activities of the IWG on PMP. He explained the reasons for requesting to remove ECE/TRANS/WP.29/GRPE/2021/17 from the agenda. He detailed such request was due to diverging views on the possibility of sampling directly from raw exhaust, requiring additional tests to be performed over the 2021 summer.

43. The representative from the EC, Chair of the IWG on PMP, introduced GRPE-85-37-Rev.1 giving a status report of the activities of the IWG on PMP. He started with all topics related to exhaust particulates measurement and explained that the consideration of ECE/TRANS/WP.29/GRPE/2022/17, as amended by GRPE-85-04-Rev.1, as reflected in Addendum 1, was ready for a consideration by GRPE.

44. The representative from Germany requested more information about the test procedure included in the draft resolution. The Chair of the IWG on PMP clarified that the draft proposal of a new Consolidated Resolution to allowed for SPN10 of SPN23 for Heavy Duty as per the procedure adopted for light duty vehicles (as specified in Amendment 6 to UN GTR No. 15).

45. The Chair asked about a timeline to include the content of the resolution into a UN Regulation or UN GTR. The Chair of the IWG on PMP informed that the first step was to gain experience with the procedure before including it within legally binding regulations.

46. GRPE adopted Addendum 1 and requested the secretariat to submit it to WP.29 for consideration at their June 2022 sessions as draft Consolidated Resolution concerning Exhaust Ultra-Fine Particle Number Measurement For Heavy Duty Engines.