35. Giorgio Martini reminded the PMP group that the EU Com wanted to review because of GRPE documents from Russia. PMP agreed to start with a literature review, following which PMP could then decide whether to go forward, stop or assign to another group.

36. Giorgio Martini presented the interim status of the literature survey so far. A more comprehensive presentation will be available for discussion at the next meeting. Essentially there is a large body of work since 2000, but many issues in assessing the information due to non-standardised testing methods.

37. Preliminary findings:

• Non exhaust emissions (includes resuspension) currently estimated for 50% of traffic related PM emissions in urban env. relatively increasing because other sources are decreasing rather than because absolute levels increase.
• Brake wear in urban location 16-55%, approx. 50% by mass brake wear particles become airborne – the others expected to be too big to be airborne.
• In coarse particle fraction mean diameter 5-6 um, but found transition metals in fine fraction of airborne brake wear particles
• Tyre wear: 5-30 % generated tyre wear particles emitted as PM10 depending on the driving conditions. Non exhaust PM10 contains 11-20% tyre wear particles
• Coarse fraction >7um, but PN 30-60nm mode has been reported at non-steady state driving conditions with stops.
• Transitions metals Fe, Cu, Zn, have been found in tyre wear debris – also organic compounds PAH, benzothiazole etc.
• Emission factors – major gaps in knowledge found.

38. ERTICO reminded the group that we should refer to ‘tyre/road’ particles as without the road, the tyre does not wear. The group accepted the recommendation for clarity in future presentations.

39. The group briefly discussed other papers known to them and members – especially ERTICO offered to send papers / links to JRC for inclusion in their study. More details in Jan 2014 PMP-29th session.