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Volume 17, No. 2, February 2017, Pages 644-652 PDF(641 KB)  
doi: 10.4209/aaqr.2016.07.0293   

Development of a Sharp-Cut Inertial Filter Combined with an Impactor

Tong Zhang1, Hideaki Takahashi1, Mitsuhiko Hata2, Akira Toriba3, Takuji Ikeda4, Yoshio Otani2, Masami Furuuchi2

1 Graduate School of Natural Science & Technology, Kanazawa University, Kanazawa, 920-1192, Japan
2 College of Science and Engineering, Kanazawa University, Kanazawa, 920-1192, Japan
3 College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
4 NITTA CORPORATION, Osaka, 556-0022, Japan


  • A sharp-cut aerosol nanoparticle classifier has been developed and tested.
  • The technology is a layered mesh inertial filter combined with an impactor.
  • The hybrid inertial filter had sharper classification with less pressure drop.



A layered mesh inertial filter that was previously developed by the authors, was combined with an impactor, in which the collection efficiency curve overlaps that of the inertial filter, in order to provide a sharp-cut separation tool for aerosol nanoparticles operating at a moderate pressure drop of less than 10–15 kPa. The separation performance of the proposed “hybrid inertial filter” of the inertial filter and an impactor, such as cut-off size, steepness of the collection efficiency curve and pressure drop ΔP, was evaluated for a single nozzle type in order to confirm the proposed system. The performance of the single nozzle type, which can be used as a unit of a multi nozzle type, was compared with that of the previous type layered mesh inertial filter with a stainless steel fiber mat. The hybrid inertial filter was found to have a collection efficiency curve with a much better steepness at less ΔP compared to those of the previous type for particles with the same cut-off size: a cut-off size dp50 of 100 nm with steepness dp84/dp16 = 1.7, e.g., was obtained at ΔP ~12 kPa while dp84/dp16 = 2.4 at ~16 kPa was found for the previous type.



Keywords: Nanoparticle measurement; Impactors; Filtration; Samplers; Ambient; Classification.



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