A new aerosol separator (44 x 40 x 65 mm 3) was developed and fabricated in this study. The design of the aerosol separator is based on virtual cyclones and impingers. In addition, the aerosol separator employs two stages to achieve a high collection efficiency. The virtual cyclone, often referred to as an anticyclone, employs nonimpact aerosol separation. In this device, particles are separated from the main flow by crossing a dividing streamline that separates the main flow stream from adjacent flow. Polystyrene latex particles ranging from an aerodynamic diameter of 0.4 to 4.0 mum were generated and measurements were performed at flowrates of 30, 45, 60 and 75 l/min for each particle size. The collection efficiency of the separators increases linearly from a flowrate of 30 to 75 l/min. Two different nozzles were designed and tests showed that longer nozzles provided somewhat higher collection efficiencies. Thus, cutoff diameters are dependent on both the nozzle length and the flowrate. The developed aerosol separator produced good results such as the small 50% cutoff diameter and the sharp slope of the particle size vs. penetration relationship. (C) 2002 Elsevier Science Ltd. All rights reserved.