Abstract Number: 400 Working Group: Instrumentation and Methods
Abstract In order to evaluate the adverse human effect of PM2.5, generally, these particles have been collected on a filter. However, this method is potentially unsuitable for toxicity evaluation of the particles. The reasons for that are as follows: (1) some previous studies have reported that the collected volatile components are evaporated from the filter during sampling periods (negative artifact), and (2) particles collected and entangled in the filter fibers are difficult to be removed and thus it is difficult to conduct the biological exposure experiments. Therefore, filter method is not suited for toxicity evaluation of the particles. Our previous work developed a high volume cyclone sampler to overcome these above problems. As a result, we could collect a large amount of atmospheric particles as powder form, thus we could conduct these exposure experiments. However, we did not conduct the detailed performance evaluation of our sampler. We further improved this cyclone sampler, and demonstrated that the new sampler is more suitable for measuring the chemical compositions and toxicities of the particles. According to the separation performance measurement for the previous cyclone sampler using monodisperse fluorescent particles, this sampler was found not to collect smaller particles than 0.7 µm at 1,200 LPM. In order to solve these problems, we improved by using a smaller cyclone. The separation performance measurements with this improved cyclone method indicated that the larger atmospheric particles than approximately 0.14 µm at 125 LPM could be collected. Furthermore, the comparison of chemical composition measurement in filter sample and cyclone sample revealed that the cyclone method significantly prevents the negative artifact than the filter method. Therefore, this new cyclone sampler was improved to solve the potential problems with filter sampling and previous cyclone sampling. We will also show the toxicity analysis result of the particles collected with this cyclone.