Abstract:In order to effectively control mobile source particulate matter emissions and mitigate the increasingly severe issue of atmospheric pollution, environmental regulations in China have imposed strict control requirements on the particle number (PN) concentration of diesel vehicles since the National V stage. These requirements were further expanded in the National VI stage to include light-duty vehicles. However, the current market features a multitude of PN detection devices from various manufacturers. Although specific regulations for key technical parameters—such as PN counting efficiency and counting linearity—have been promulgated, a unified and traceable calibration system remains absent. This lack of a robust metrological traceability chain compromises data consistency and undermines measurement reliability, posing significant challenges to the implementation of National VI Standards. To address this critical gap, this paper designs and develops a calibration system based on transverse-quenched soot particle generation system. This system is capable of generating soot particles that are stable, controllable, and highly similar in morphology and properties to real vehicle exhaust emissions. From a metrological perspective, the system measures the micro-current induced by charged particles, directly tracing the particle number concentration to the ampere, a base unit of the International System of Units (SI). This approach eliminates reliance on secondary transfer standards, enabling rapid, high-precision, and reliable calibration of PN detectors. Rigorous laboratory tests were conducted to validate the metrological performance of the system. The results indicate that the developed soot particle generation device exhibits exceptional stability, capable of producing standard soot particles in the 10–100 nm size range. The differential mobility analyzer (DMA), a core component for particle sizing, demonstrates superior performance, with sizing deviations strictly controlled to less than 2.0% across all key particle size nodes from 10 nm to 100 nm. Furthermore, the Faraday cup aerosol electrometer (FCAE), serving as the reference standard, shows excellent linearity in measuring various particle sizes, with a linearity coefficient better than 99.6%, and its counting efficiency is stably maintained within the range of 100.0% to 110.0%. Application test results demonstrate that the system possesses outstanding versatility in practical engineering applications. In calibration experiments involving both bench-top PN equipment and the portable emissions measurement system particle number module (PEMS-PN), the system exhibited excellent applicability. The counting efficiency obtained from the calibration aligns closely with the manufacturers' nominal factory values, with absolute errors consistently less than ± 6.7%. These results verify the precision of the proposed calibration system and provide strong technical support for solving the traceability issues of PN equipment under the National VI Standards. Close-