Condensation particle counters (CPCs) are widely used for the measurement of aerosol particle number concentrations in the size range from approximately 3 nm to 3 m. For an SI-traceable calibration of the size-dependent counting efficiency, which is advisable on a regular basis and required in several applications, Faraday cup aerosol electrometers (FCAEs) are considered to be a suitable SI-traceable reference. While the volumetric aerosol inlet flowrate and the electrical current measurement in FCAEs can be related to respective SI references, inter-comparison exercises for FCAEs are still performed on a regular basis to establish reliable uncertainty budgets and to further investigate the influences of designs and operational parameters on comparability. This is strongly demanded in the international community of metrological institutes and aerosol calibration facilities around the world, which provide CPC calibrations. In the present study, the performance of FCAEs was investigated, using Ag test aerosol particles with a 30 nm particle diameter by varying the inlet flowrates from 0.5 l min⁻¹ to 4 l min⁻¹. From our experimental results, significant deviations were observed in FCAE currents at sample flowrates smaller than 1.5 l min⁻¹. It is recommended that these discrepancies should be quantified before an FCAE is used for CPC calibration at low sample flowrates and small particle sizes in the sub-30 nm size range.

冷凝粒子计数器 (CPC) 广泛用于测量大小范围从大约 3 nm 到 3 m 的气溶胶粒子数浓度。对于尺寸相关计数效率的 SI 可追溯校准（建议定期进行且在多种应用中需要），法拉第杯气溶胶静电计 (FCAE) 被认为是合适的 SI 可追溯参考。虽然 FCAE 中的体积气溶胶入口流速和电流测量可以与各自的 SI 参考相关，但仍定期进行 FCAE 的比对练习，以建立可靠的不确定性预算并进一步研究设计和操作参数的影响关于可比性。世界各地提供 CPC 校准的计量机构和气溶胶校准设施的国际社会强烈要求这样做。在本研究中，通过将入口流速从 0.5 l min 改变，使用粒径为 30 nm 的 Ag 测试气溶胶颗粒研究了 FCAE 的性能^-1到 4 l min ^-1。根据我们的实验结果，在样品流速小于 1.5 l min ^{-1 时}观察到 FCAE 电流的显着偏差。建议在将 FCAE 用于 CPC 校准之前，在低样品流速和亚 30 nm 尺寸范围内的小粒径范围内量化这些差异。