Recently, the importance of air filters used in air purifiers and ventilation systems is emphasized in Korea. As a result, air filter test reports are required by users to ensure the removal efficiency of particulate matter. However, the tests are conducted for the filter material alone, which lead to a possible discrepancy between the test report and actual efficiency when applied to actual devices. Therefore, in this study, the removal efficiency data of the filter test reports were compared with actual filter efficiency data after application to the ventilation systems for some ventilation systems in the market. For ventilation system A, the field test results using filter leakage test method were slightly lower than those in the test report but nearly the same. For ventilation system B, the field test result was much higher than reported in the test report. This was due to the broad range of particle sizes measured using the filter leakage test method. The field tests using the particle counter method showed that the removal efficiency of ventilation system A for 0.3 μm was under 50% which translates to less than half of those of the filter test reports. For ventilation system B, the removal efficiency was 15%~21%. much lower than reported in the filter test reports. The lower removal efficiencys are mainly assumed to be caused by leakage of the filter installation among other factors. Therefore, the field test methods for the particulate matter removal efficiency of ventilation systems should be established to verify actual efficiency and improve the efficiency in the future.