Calibration of Condensation Particle Counters for Legislated Vehicle Number Emission Measurements

Figures & data

FIG. 1 Schematic of the set up for the calibration of CPCs.

TABLE 1 Test TSI CPC 3790 calibration counting efficiencies according to the primary method without multiple charge correction (Supplemental information, Equation (S15)). Number in parenthesis after the material is the size (in nm) at which the linearity checks were conducted (for the last 3 columns). The fourth column gives the minimum and maximum ratios of the test CPC to electrometer concentrations. Numbers after ± indicate the CoV (ratio of the standard deviation to the mean value) of the ratio of the test CPC to the electrometer during the 2 min measurement

Material (nm)	23 nm	41 nm	> 50 nm	Slope	R ^2
NaCl (80)	—	—	0.856–0.919	0.894	0.9995
Tetracontane (70)	0.862(± 2.9%)	1.033(± 2.6%)	0.938–0.970	0.943	0.9999
CAST (60)	0.543(± 1.1%)	0.931(± 2.6%)	0.921–0.945	0.926	0.9999
Mini-CAST (50)	0.522(± 1.3%)	0.916(± 4.8%)	0.911–0.976	0.924	0.9981
Emery oil (55)	0.724(± 0.9%)	0.984(± 1.9%)	0.948–0.975	0.973	1.0000
Emery oil (repeated)	0.532(± 0.8%)	0.947(± 1.8%)	0.945–0.987	0.951	0.9998
Engine idle (120)	0.835(± 4.4%)	0.941(± 1.9%)	0.772–0.844	0.784	0.9984
Engine load (120)	0.573(± 2.3%)	0.919(± 3.2%)	0.874–1.058	0.885	0.9966

TABLE 2 Test GRIMM CPC 5.404 calibration counting efficiencies according to the primary method

Material (nm)	23 nm	41 nm	> 50 nm	Slope	R ^2
NaCl (50)	—	—	0.766–0.790	0.785	0.9997
Tetracontane (70)	0.810(± 5.7%)	0.935(± 5.6%)	0.908–0.996	0.913	0.9999
CAST (60)	0.599(± 6.9%)	0.911(± 2.8%)	0.905–0.945	0.919	0.9997
Mini-CAST (50)	0.566(± 5.1%)	0.865(± 3.4%)	0.887–0.944	0.936	0.9998
Emery oil (55)	0.726(± 5.9%)	0.954(± 3.1%)	0.949–0.963	0.954	0.9999
Emery oil (combined)	0.624(± 5.2%)	0.913(± 4.4%)	—	—	—
Engine CVS (70)	—	0.806(± 8.2%)	0.721–0.762	0.731	0.9996

TABLE 3 Reference GRIMM CPC 5.403 calibration counting efficiencies according to the primary method

Material (nm)	23 nm	41 nm	> 50 nm	Slope	R ^2
NaCl (50)	—	—	0.822–0.878	0.854	0.9994
Tetracontane (70)	0.946(± 5.6%)	0.965(± 5.4%)	0.914–0.985	0.960	0.9992
CAST (60)	0.968(± 6.3%)	0.964(± 2.8%)	0.945–0.969	0.951	0.9999
Mini-CAST (50)	0.905(± 4.2%)	0.946(± 3.3%)	0.963–1.000	0.986	0.9992
Emery oil (55)	0.952(± 5.6%)	0.976(± 3.1%)	0.960–1.026	1.007	0.9986
Engine CVS (70)	—	0.853(± 8.5%)	0.718–0.777	0.730	0.9980

FIG. 2 Primary method counting efficiency of TSI CPC 3790 (according to Equation (S15), Supplemental information). Error bars give the counting efficiency corrected for doubly charged particles (Equation (S9)).

TABLE 4 Test GRIMM CPC model 5.404 calibration counting efficiencies according to the secondary method. No linearity (slope) correction for the reference CPC

Material (nm)	23 nm	41 nm	> 50 nm	Slope	R ^2
NaCl (50)	—	—	0.889–0.933	0.919	0.9999
Tetracontane (70)	0.867(± 5.5%)	0.970(± 5.2%)	0.940–1.011	0.951	0.9994
CAST (60)	0.618(± 4.4%)	0.945(± 2.2%)	0.948–0.975	0.960	0.9996
Mini-CAST (50)	0.619(± 3.9%)	0.915(± 2.5%)	0.891–0.968	0.950	0.9998
Emery oil (55)	0.762(± 2.9%)	0.977(± 2.7%)	0.927–1.003	0.947	0.9985
Engine CVS (70)	—	0.944(± 4.7%)	0.973–1.015	1.000	0.9992

FIG. 3 Comparison of JRC workshop results with earlier measurements at JRC for the same CPC for heavy duty diesel engine particles (engine at medium load).

FIG. 4 Results from the JRC workshop TSI 3790 CPC (with the primary method, solid symbols) and from JRC lab with another TSI 3790 CPC (secondary method, open symbols) for NaCl (squares and triangles) and tetracontane (circles) particles.