Development of a new personal air filter test system using a low-cost particulate matter (PM) sensor

Abstract

The extensive uses of the air filters have encouraged the advancement of air filter technology on both fabrication and characterization. Due to the high demand to those filters, the quality assessment to the filters are massively needed with a lower test cost and accessible. We developed a personal air filter test (PAFT) system for measuring the filter pressure drop, efficiency, and quality factor. The PAFT system utilized a PM sensor (Sharp, GP2Y1010AU0F) for measuring the filtration efficiency. Accordingly, performance evaluation and optimization to the PM sensor were done to guarantee their compatibility for this application. The performance evaluation studied the sensor output responses to sampling flow, particle diameter, and PM sources. We also improved the sensor sensitivity. The experimental results show that the sensor has no significant influences on the sampling flow. The sensor output was highly dependent on the particle size and PM source, but their response curves remained linear, which was an advantage for filter efficiency measurement. We measured the efficiency of nanofiber filters having various efficiencies, and comparing the results to reference efficiency as measured by a CPC (TSI, 3772). The test resulted in a filtration coefficient (K_f), which was used to correct the PAFT efficiency measurement results. We also conducted the test to some commercial mask filters, and the filtration efficiency measurement results showed a good agreement to the reference with a small average error of about 2.5%. The complete design of the PAFT and experimental methods will be discussed in detail.