• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1874-1879
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• 2008

It is not easy to detect nano-sized airborne particles (< 100 nm in diameter) in air. Therefore, the condensation of the nanoparticles alongside of the size-classification is needed for their detection. This paper proposes a hybrid (aerodynamic+electrical) particle classification and condensation device using a micro virtual impactor (${\mu}VI$). The ${\mu}VI$ can classify the nanoparticles according to their size and condense the number concentration of nanoparticles interested. Firstly, the classification efficiency of the ${\mu}VI$ was measured for the particles, polystyrene latex (PSL), ranging from 80 to 250 nm in diameter. Secondly, the nanoparticles, NaCl of 50 nm in diameter, were condensed by 4 times higher. In consequence, the output signal was amplified by 4 times (before condensation: 4 fA, after condensation: 16 fA). It is expected that the proposed device will facilitate the detection of nanoparticles.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.121-123
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• 1999

Bio-Aerosol Concentrator Inlets were made to collect particles of which size was $2\mu\textrm{m}$ as aerodynamic diameter or larger. The Concentrator Inlets were designed by using virtual impactors, because the virtual impactors are known for high efficiency. In a virtual impactor, the intake air is typically divided into two streams with the major and the minor flow. In this work, several types of the acceleration nozzles and collection probes were designed. Subsequently, the results were evaluated experimentally. It was found that if controled properly, the velocity can improve substantially the aerosol concentration performance. The diameter of acceleration nozzle and type of collection probe were varied to obtain the optimum design. Subsequently, the different designs were compared respectively and the best design among them was identified. It is expected that this new finding can help improve design of future Aerosol Concentrator for high concentration rate.