Design and characterization of a sequential cyclone system for the collection of bulk particulate matter.

In this paper, we describe the design, development and characterization of a high-volume sequential cyclone system for the collection of size-segregated PM in dry bulk form from the ambient environment in sufficient quantity for physical, chemical and toxicological characterization. The first stage of the system consists of a commercially available high volume PM(10) inlet. The second stage cyclone was designed by us to collect inhalable coarse particles (<10 µm and >2.5 µm). When tested individually with a challenge aerosol, a D(50) cut-size of this stage was found to be 2.3 µm at a flow rate of 1 m(3) min(-1). The third stage, a commercially available cyclone designed for surface dust sampling, had a D(50) cut-size of 0.3 µm when tested at the same flow rate. The purpose of the third stage is to collect the fine particle portion of PM(2.5) or accumulation mode (PM <2.5 µm and >0.1 µm). Thus, the sequential cyclone system will collect bulk samples of both the inhalable coarse particles and the fine particle portion of PM(2.5). The operation and maintenance of the new system are straightforward and allow for reliable collection of dry bulk ambient PM at relatively low cost.