The Virtual Cyclone as a Personal Respirable Sampler

Author： Chen Chih-Chieh Huang Sheng-Hsiu Lin Wen-Yinn Shih Tung-Sheng Jeng Fu-Tien

ISSN： 1521-7388

Source： Aerosol Science and Technology, Vol.31, Iss.6, 1999-12, pp. : 422-432

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Abstract

Aerosol exposure via the inhalation route is a primary concern in occupational health. A researcher must perform aerosol size-selective sampling because respiratory deposition is dependent on aerosol size. The optimal sampling instrument is therefore the one that provides the most accurate measurement of the atmospheric dust component, thus showing the extent of a health hazard. However, the most commonly used respirable samplers today can only meet the 50% cut-off point and not the slope of the respirable convention prescribed by the American Conference of Governmental Industrial Hygienists (ACGIH), the Inter national Standard Organization (ISO), and the Comite European de Normalisa tion (CEN). These conventional cyclones are also found to be affected by the aerosol deposition and accumulation on the wall of the cyclone body, which leads to a significant decrease in aerosol penetration. In the present study, a miniature, compact, rugged virtual cyclone, which employs a nonimpact particle separation, was developed and constructed to overcome the drawbacks of the conventional cyclones. An Aerodynamic Particle Sizer (APS) was used for measuring the particle size distributions and the number concentrations upstream and downstream in the conventional and the virtual cyclones. A square virtual cyclone (21 X 21 X 10 mm, having a curvature radius of 10 mm, outlet width of 1 mm, and inlet width of l mm) was designed to perfectly fit the respirable convention. This new sampler showed almost no decrease in aerosol penetration due to particle loading when operated at a sampling flow rate of 3.3 L / min and aerosol mass concentration of 4.6 mg / m³ for 3 h. Moreover, this virtual cyclone can be used with a conventional 37 mm cassette through an adapter.