Development of a high-volume PM_2.5 particle sampler using impactor and cyclone techniques

Detailed mechanisms of the cellular biochemical reactions associated with the toxicity of PM_2.5 have not been elucidated well so far, because it is difficult to collect a sufficient amount of PM_2.5 particles to carry out toxicity assays using cells. A high-volume PM_2.5 particle sampler using the impactor and cyclone techniques has been developed in this study. The 50% cut-points of the impactor and cyclone for ambient aerosols at 1,100 L/min of air flow were 2.0 μm and 0.15–0.18 μm, respectively. The separation characteristics of the impactor were similar to those of the WINS impactor. The contents of EC, which is an aggregate/agglomerate of primary particles with sizes less than 100 nm, in the cyclone particles was similar to that in the filter particles. The contents of organic matter and ammonium in the particles collected using the cyclone system were lower than those in the particles collected using traditional filter sampling. We propose that the highvolume PM_2.5 particle sampler developed in this study can collect a large amount of aerosol particles in a “powder form” and can also avoid certain sampling artifacts caused by the adsorption of volatile organic compounds and gaseous ammonia to particles on the filter media. The sampling device developed in this study allows researchers to collect a sufficient amount of PM_2.5 particles for cell exposure studies without the use of filters.