Development of a high volume cascade impactor for toxicological and chemical characterization studies

Academic Article

Abstract

  • This paper presents the design and development of a compact high volume cascade impactor (HVCI). The HVCI operates at a flow rate of 900 l/min and consists of 4 impaction stages equipped with circular slit-shaped acceleration nozzles and a backup filter. The backup filter is placed downstream of the fourth stage and is used to collect the ultrafine particles (dp < 0.1 μm). The major feature of this novel sampler is its ability to collect relatively large amounts of particles (mg-g levels) onto relatively small polyurethane foam substrates without using adhesives. As previously reported, the capacity of the impaction substrate is 2.15 g of collected particles per cm2 of foam. Although the impaction substrates are not coated with adhesives such as grease or mineral oil, particle bounce and re-entrainment losses were found not to be significant. Particles can be easily recovered from the foam substrates using aqueous extraction. The impactor was calibrated using polydisperse particles. The 50% cutpoints of the 4 stages were 9.90, 2.46, 1.0, and 0.1 μm, respectively. Interstage losses of ultrafine and fine particles were <10% and for coarse particles were < 20%. The pressure drop across the 4 stages and the backup filter were 0.25, 0.75, 1.25, 19.9, and 3.3 kPa, respectively.
  • Authors

    Published In

    Digital Object Identifier (doi)

    Author List

  • Demokritou P; Kavouras IG; Ferguson ST; Koutrakis P
  • Start Page

  • 925
  • End Page

  • 933
  • Volume

  • 36
  • Issue

  • 9