Proficiency testing (PT) can evaluate the performance of testing companies, and participating in the proficiency testing program helps verify the reliability of the testing results. However, developing a proficiency testing system that simultaneously evaluates both the sampling process and the measurement results poses a significant challenge for particulate pollutants. The National Environmental Research Academy (NERA) has established the simulation stack to enhance domestic testing capabilities. By generating various air velocities and particulate matter concentrations, this system allows NERA to conduct comparisons for proficiency tests. The simulation stack can provide a stable air velocity and mass concentration for testing. The operable air velocity range is 3 – 18 m/s, and the mass concentration range is 1 - 300 mg/Nm3, covering the majority of pollutant concentration ranges found in domestic stationary emissions. By accumulating test data, a model for air velocity and mass concentration can be established to evaluate the technical capabilities of testing entities. Simultaneously, through the guidance process, areas requiring improvement during the PT programs can be identified, thus enhancing the overall quality of testing companies. The testing has been completed for 24 companies, and two company did not pass due to the failure to meet the air velocity item requirement; the rest have passed. Over the years (2002 - 2023), a total of 384 tests have been conducted, with a pass ratio of 89%. The pass ratios for velocity measurements and mass concentrations are 94.72% and 95.1%, respectively. The wind speed and mass concentration models have become stable and have sufficient representativeness. The checklist developed by this project can be helpful in the process of counseling. The areas for test companies to improve fall into six categories: water content measurement, ORSAT operation, pressure measurement, sampling volume measurement, particulate matter sampling process and safety. Over the years, PT data also demonstrates that implementing this program can reduce errors in test results and enhance the testing company's sampling techniques and analytical capabilities.

PM sampling, stack, particulate matter