Particle Measurement Programme (PMP)
Inter-laboratory correlation exercise with condensation particle counters (CPCs)
A limit on particle number (PN) has been part of the European vehicle emission legislation since EURO 5b from 2011. However, the legislation does not define or recommend a single calibration aerosol for PN. Since the counting efficiencies of CPCs complying with UNECE R49/R83 regulations are known to exhibit strong material dependence on the type of calibration aerosol, standardisation of the calibration aerosol would be advantageous. The selection of an appropriate calibration aerosol needs to consider the associated repeatability and the reproducibility in the measurements.
A strong effect of the aerosol material was observed at the steep part of the counting efficiency curve of the CPC. The average counting efficiency of soot-like aerosol was between 27% and 32% (depending on generator type) at a mobility diameter of 23nm and between 77% and 80% at 41nm. Emery oil averaged 50% and 91%, respectively. Thus, existing CPCs calibrated with emery oil will have to be adjusted to meet the legally defined counting efficiency limits of 50% ±12% at 23nm ±1nm and >90% at 41nm ±1nm with soot-like aerosol. However, the feasibility of such adjustment (and the associated variability) was not investigated in this study. As the difference between emery oil and soot was bigger than previously reported in the literature, it is possible that there is no universally applicable factor.
TERRES Alexander;
EBERT Volker;
NOWAK Andreas;
ROSAHL Johannes;
HILDEBRANDT Margit;
SOUTHGATE Jason;
MARSHALL I.;
MAMAKOS Athanasios;
CRESNOVERH Martin;
USAREK Sebastian;
KAATZ Manuel;
HORN Hans-Georg;
BACHER Heinz;
GIECHASKIEL Barouch;
2019-01-09
Publications Office of the European Union
JRC112336
978-92-79-88006-3,
1831-9424,
EUR 29277 EN,
OP KJ-NA-29277-EN-N,
https://publications.jrc.ec.europa.eu/repository/handle/JRC112336,
10.2760/859241,
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