62. The Chair introduced GRPE-81-06 as the revised GRPE priority list following the latest guidelines received by the Administrative Committee for the Coordination of Work (WP.29/AC.2). The representative from the EC introduced GRPE-81-34 on proposed amendments to GRPE-81-06 which deleted the timeline indication for tyre wear emissions. The representative from the UK underlined that in some countries including his, tyre emissions were a high priority. The representative from the EC explained that in her view, there was not enough knowledge nor literature on the issue yet to develop regulatory material. Furthermore, she noted very few activities were expected in the near future that could feed the development of a robust test procedure. The Representative from the UK argued that priorities did not necessarily mean on-going or forthcoming activities, and that resources could be allocated based on priorities to fast track the development of knowledge for regulatory purposes.

63. The representative from OICA sought clarification on sub-23 nm PN measurements and its scope. The Chair of the IWG on PMP underlined that Sub-23 nm PN measurement was aimed for both light- and heavy-duty applications, in the laboratory and on-road. He added that the proposed Amendment 6 to UN GTR No. 15 endorsed by GRPE (para. 12-13) only covered the laboratory part for light-duty vehicles, and that on-road applications for both light and duty vehicles, and heavy-duty lab test were still to be developed.

64. The representative from Australia also emphasized that transposition of the latest European regulation on Heavy Duty (Euro VI Step E) into UN Regulation No. 49 should be prioritized.

65. GRPE agreed to such proposals and amended GRPE-81-06 into GRPE-81-06-Rev.1 during the session, and requested the secretariat to send GRPE-81-06-Rev.1 to WP.29 secretariat for further consideration by WP.29/AC.2.