Development of Openable Small Cyclone Device and Its Application to Particle Toxicity Assessment

NAKANO KOHEI, Hyunwoo Youn, Ayumi Iwata, Tomoaki Okuda, Keio University

     Abstract Number: 53
     Working Group: Health-Related Aerosols

Abstract
In recent years, there has been growing interest in the health effects of fine particulate matter (PM2.5) . The chemical properties of PM2.5 vary from collection point to collection point and are likely to strongly influence the toxicity assessment of PM2.5. Generally, PM2.5 is collected by filters, but this means that filter components can affect the results when analyzing PM2.5 composition and assessing its toxicity. The cyclone method, however, can collect PM2.5 directly as a powder without being affected by filter components.

In order to directly collect PM2.5 with different chemical properties at multiple locations, our laboratory developed a portable cyclone device using a small cyclone. However, with this small cyclone (conventional cyclone), it was difficult to remove all particles adhering to the inner wall, and aluminum, the material of the cyclone, was contaminated in the sample. Therefore, in this study, we fabricated a new openable cyclone, which was the same dimensions as the conventional cyclone and made of stainless steel. Then, we evaluated its performance.

In the performance evaluation, we first made a separation efficiency curve for the openable cyclone at a test flow rate of 90 LPM. The measurement results showed that the 50% cut-off diameter of the openable cyclone was approximately 0.13 μm, which was comparable to the performance of a conventional cyclone measured under similar conditions. Next, we collected PM2.5 in Yokohama using the openable cyclone in parallel with a conventional cyclone. The openable cyclone was able to collect particles adhering to the inner wall, improving the yield by about 25%. In addition, the results of component analysis showed no aluminum contamination, thus solving the problem of conventional cyclones.

The newly developed openable cyclone enabled more accurate toxicity comparisons based on differences in the chemical composition of particles between locations, without the influence of filter components.