Development and Evaluation of a Newly Designed Forward Cyclone for a High-Volume Air Sampler

Abstract

This paper describes a newly designed forward cyclone fitted to a high-volume air sampler (hereafter HV) of which flowrate ranged from 150 to 600 L/min. The cyclone-HV system is capable of sampling PM_2.5 fractions of ambient aerosols and respirable particle factions (PM₄) at work environments. The size separation characteristics of system were evaluated with two types of tangential-air-inlets of the cyclones (7 mm and 11 mm in width of the inlet). The size separation characteristics obtained for 11 mm inlet cyclone yielded 50% cut-off aerodynamic diameter Dp₅₀ of 2.37 μm at the flow rate of 480 L/min, which is close to the size selection curve that required in the Japanese Industrial Standards Z8851. For the respirable fraction defined by ISO 7708 the same cyclone yielded Dp₅₀ of 4.0 μm at the flow rate of 240 L/min. Dp₅₀ and the size selection curve obtained for 7 mm inlet cyclone was also evaluated and the sampling of PM_2.5 fraction for 3 hours were conducted ten times at Saitama, Japan, February 2015. PM_2.5 concentrations measured by HV with 7 mm inlet cyclone and an automated PM_2.5 measurement instrument utilizing beta attenuation showed a good correlation (r² = 0.986).