Comparison for particle number concentration up to 500'000 cm-3

Project Description

Metric: Aerosol particle number concentration (PNC)
Concentration range: 3 target concentrations in the range 20'000 cm-3 - 500'000 cm-3
Particle size range: 3 target particle sizes in the range 20 nm -200 nm (mobility diameter)
Test aerosol: Polydisperse soot aerosol from combustion generator
Measuring instrument: Condensation Particle Counter (CPC)

The aim of the comparison is to compare the accuracy of National Metrology Institutes‘ when measuring high particle number concentrations in the CPC plateau region.


Progress Report 2023-04-13

Just beforehand in September 2022, the consortia have decided that the exercise will be downgraded to a technical workshop for high particle number range up to 500'000 cm-3 without a protocol. The results from the exercise cannot be used to support CMC claims. There is no commitment to publish the results of the comparison. The decision was agreed by all former participants like METAS, LNE, NPL, NMIJ and PTB. However, in Oct. 2022 the technical workshop took place at PTB only with NPL and TROPOS.

Additionally, it was agreed to do instead a pilot study in CCQM-GAWG with same polydisperse concentration levels up to 500.000 particle/cm³. A first proposal was submitted to GAWG by Oct 2022. 

No further activities will be expected here for this, and status of EURAMET project can be closed.


Progress Report 2022-06-22

The comparison took place at METAS from 3 to 6 February 2020. The participants submitted their results electronically in September 2020. The data analysis showed large deviations between participants. Moreover, two participants had either not fully calibrated their measurement devices on their own or relied on the measurement uncertainties provided by the manufacturers. Two more participants had to partially withdraw their results due to data handling errors. As a result, the reference value suffers from large uncertainties.

Kriss and JRC join the comparison as further participants.
The Consortium has decided to repeat the inter-comparison at PTB in autumn 2022 under the same registration number. METAS will hand over coordination of the Pilot Project to PTB.


Progress Report 2021-04-20

The comparison took place at METAS from 3 to 6 February 2020. The participants submitted their results electronically in September 2020. The data analysis showed large deviations between participants. Moreover, two participants had not fully calibrated their measurement devices according to traceable national standards but relied on calibration certificates by instrument manufacturers. Two more participants had to partially withdraw their results due to data handling errors. As a result, the reference value suffers from large uncertainties.

The Consortium proposes to repeat the inter-comparison at PTB in spring 2022 under the same registration number (1480). METAS will hand over coordination of the Pilot Project 1480 to PTB.


Progress Report 2020-02-26

The comparison took place at METAS from 3 to 6 February 2020. The participants are expected to submit the results electronically by 15 May 2020.

Subjects
Metrology in Chemistry (MC)
Coordinating Institute
PTB (Germany)
Further Partners
AIST (Japan), Kriss (Republic of Korea), JRC