• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.2175-2178
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• 2014

• Asian Journal of Atmospheric Environment
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• 제11권2호
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• pp.131-137
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• 2017

A cyclone is an effective tool to facilitate the collection of aerosol particles without using filters, and in cell exposure studies is able to collect a sufficient amount of aerosol particles to evaluate their adverse health effect. In this study, we examined two different methods to improve the aerosol particle collection efficiency of a cyclone. The individual and combined effects of reducing the surface roughness of the inner wall of the cyclone and of using a circular cone attachment were tested. The collection efficiency of particles of diameter $0.2{\mu}m$ was improved by approximately 10% when using a cyclone with a smoothened inner wall (average roughness $Ra=0.08{\mu}m$) compared with the original cyclone ($Ra=5.1{\mu}m$). A circular cone attachment placed between the bottom section of the cyclone and the top section of a collection bottle, resulted in improved collection of smaller particles without the attachment. The 50% cutoff diameter of the modified cyclone (combined use of smoothened inner wall and attachment) was $0.23{\mu}m$ compared to $0.28{\mu}m$ in the original model. The combined use of these two techniques resulted in improved collection efficiency of aerosol particles.

• Asian Journal of Atmospheric Environment
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• 제9권2호
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• pp.137-145
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• 2015

This study focused on the measurement of the actual charging state of ambient aerosol particles, which is important for understanding the intricate process of adverse health effects caused by particulate matter (PM). The net electrostatic charging state of $PM_{2.5}$ collected on filter media was measured in this study. The Faraday cage method and surface potential measurements were used in this study. The results showed that the polarities of the net charging state measured using these two methods were in agreement for 42 out of 48 samples (87.5%), and 36 samples (75%) were negatively charged. The filters were not significantly charged by friction between the filters and air not containing PM. Charge addition to or leakage from the filters was not observed over a two-month storage period. Net charging state of $PM_{2.5}$ collected on the filters was concluded to be negative in most cases, based on data's support of the assumption that aerosol charging state is not altered by the process of PM collection using filter.

• Asian Journal of Atmospheric Environment
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• 제12권1호
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• pp.78-86
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• 2018

Filter-based sampling techniques are the conventional way to collect particulate matter, but particles collected and entangled in the filter fibers are difficult to be removed and thus not suited for the following cell- and animal-based exposure experiments. Collecting aerosol particles in powder form using a cyclone instead of a filter would be a possible way to solve this problem. We developed a hybrid virtual-impactor/cyclone high-volume fine and coarse particle sampler and assessed its performance. The developed system achieved 50% collection efficiency with components having the following aerodynamic cut-off diameters: virtual impactor, $2.4{\mu}m$; fine-particle cyclone, $0.18-0.30{\mu}m$; and coarse-particle cyclone, $0.7{\mu}m$. The virtual impactor used in our set-up had good $PM_{2.5}$ separation performance, comparable to that reported for a conventional real impactor. The newly developed sampler can collect fine and coarse particles simultaneously, in combination with exposure testing with collected fine- and coarse-particulate matter samples, should help researchers to elucidate the mechanism by which airborne particles result in adverse health effect in detail.

• 대한화학회지
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• 제26권1호
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• pp.36-42
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• 1982

대기중의 암모니아가스와 암모늄염의 필터포집법에 관하여 연구하였다. 표준가스 발생장치로 발생시킨 암모니아가스를 3% 붕산-25% 글리세린 혼합액이 스며든 유리섬유 필터에 포집하였다. pH조절법으로 발생시킨 암모니아가스와 대기중의 암모니아를 5회씩 포집하여 측정한 결과 포집효율은 각각 96.4${\pm}$ 2.15%와 97.4${\pm}$1.06%였다. 시판되는 유리섬유 필터 및 Polycarbonate 필터에 대하여 암모니아가스의 흡착 및 탈리현상을 검토한 결과 유리섬유 및 석영 섬유 필터에서는 암모니아가스의 흡착과 약간의 암모늄염이 탈리되었으나, Polycarbonate 필터는 대기중의 암모늄염을 포집하는데 적합한 것으로 판단되었다. 지름 47mm의 필터에 20l/min의 유량으로 60분동안 대기를 포집하여 인도페놀법에 의한 분광광도법으로 측정 할 경우, 측정가능한 암모니아가스의 최저농도는 0.83ppb (약 0.63$\mug$/$m^3$)이다. 이 방법은 종래의 용액포집법에 의한 분광광도 측정법에 비하여 감도가 20배나 높으므로 대기중의 암모니아 농도의 변화를 단시간(약 60분)내에 측정할 수 있다.