Abstract: Masks are an important defense line to prevent respiratory infectious diseases. The mask respirator particle leakage rate tester is used to measure the ratio of the particle matter concentration that leaks into the mask from all other parts except the filter element of the mask to ambient particle matter concentration outside the mask during inhalation. At present, there are many domestic manufacturers of mask respirator particle leakage rate testers, but there are some common problems such as inconsistent technical parameters and obvious differences performance of different instruments. However, the existing standards do not make requirements for the performance detection. In other words, under the current circumstances, the accuracy of mask particle leakage rate tests cannot be guaranteed. Thus, it is of great significance to ensure the measurement accuracy of particle leakage rate testers for controlling the protective performance of masks. 
The mask respirator particle leakage rate tester generally consists of an aerosol generator, aerosol concentration monitoring devices and a test chamber. The test chamber is airtight in which human subjects can complete the required motions. The aerosol generator generates aerosol particles with the specific concentration and size distribution. The generated aerosol particles are imported into the test chamber through the top interface. After active mixing, it is discharged from the exhaust port at the bottom of the test chamber. Human subjects perform multiple required actions. During each action, the particle matter concentration in the test chamber and the mask was monitored simultaneously. Thus, the leakage rate of masks can be calculated. 
As there is no standard test equipment or standard filtration membrane with metrological traceability for the leakage rate at present, the conditions for comparative evaluation are not available. According to the working principle of the tester, the performance of each key component of the tester needs to be measured and verified by the partial method to ensure the accuracy and consistency of the measurement, including aerosol generation performance, aerosol mixing performance and aerosol collection and detection performance.
In this paper, according to the technical route of aerosol generation-aerosol mixing-aerosol collection and detection, the metrological calibration method of the mask particulate leakage rate tester is studied. Specifically, it involves six items, namely flow rate of aerosol generation, test concentration of aerosol, particle size distribution and median diameter of tested aerosol, aerosol particle space uniformity in the test chamber, flow rate of aerosol collection, and indication error of aerosol mass concentration. These calibration items ensure the accuracy of aerosol generation, mixing and detection, respectively. Thus, the accuracy of mask particle leakage rate tests is guaranteed. 
In this study, the selection of calibration equipment and calibration methods are described in detail. The feasibility and effectiveness of the proposed calibration methods are verified by the analysis of the calibration results of the particulate matter leakage tester of different application institutions.

Key words: aerosol concentration, leakage rate, calibration, particle size distribution, spatial uniformity

摘要： 口罩是预防呼吸道传染病的重要防线，确保口罩颗粒物泄漏率测试仪的计量准确性对于控制口罩防护性能具有十分重要的意义。依照气溶胶发生-气溶胶混匀-气溶胶采集检测这一技术路线开展气溶胶发生介质为NaCl颗粒物的口罩颗粒物泄漏率测试仪的校准方法研究，具体涉及到气溶胶发生流量、气溶胶颗粒物测试浓度、气溶胶颗粒物粒径分布及质量中位径、检测仓内气溶胶颗粒物空间均匀性、气溶胶采集流量、气溶胶质量浓度示值误差6个项目，分别确保气溶胶发生、混匀、检测3个环节的准确性，从而确保口罩颗粒物泄漏率测试的量值准确。文中重点对校准设备的选取和校准方法进行了详细的阐述，并通过实施校准测试实验，验证了相应校准方法的可行性和有效性。

关键词: 气溶胶浓度, 泄漏率, 校准, 粒径分布, 空间均匀性