B. Giechaskiel (JRC) presented the draft guidelines for standardising measurement of sub-23 nm particles. The presentation (30-02) also included information on regeneration.

There was significant discussion on the specification / details for the catalytic stripper (CS) – JRC reported that they had tested 3, with and without sulphur trap.

• Characterisation of losses – propane (gas) / tetracontane (PN/ add SO2 to see when get breakthrough.
• Formulation
• Position

Ricardo-AEA and Horiba proposed CS with regenerative S-trap to avoid that it has to be sized for one year operation.

Discussion on CPC specification – eg how to define a 10nm CPC. TSI suggested for 10 nm CPC, that 50% cut off at 10nm, 90% at 20nm. Noted that a smaller D90 would be challenging. A 50-70% efficiency at 10nm would include many of the the existing CPCs

Agreed to review aircraft industry work with 10nm CPCs (no CS) and noted that JRC might be included in the German project on CS.

Next steps:

• JRC to issue an updated document, clearly defining the open points.
• Measurement data using guideline protocol to be gathered and reviewed for future discussion. Timeline approx. 12 months.
• H-G Horn to consider what it would take to re-use existing CPCs vs starting again.
• Horiba report 2014-01-1604 (publication due April 2014) to be reviewed as includes attempt to characterise CS
• Bochum report on Aircraft measurements expected soon.