Assessment of the Quality of Electrically Produced Standard Aerosols

ABSTRACTThe non-uniformity of particle charges is an important problem in electrical methods for producing standard aerosols, imposing strict limitations on the usability of the obtained standard aerosols. This paper examines the quality of the electrically separated aerosols, that is, the percent of singly charged particles among all charged particles in the separated aerosol. A model for the electrical separation process was developed and the separated aerosol quality was calculated as a function of parameters of the aerosol generation process. Theoretical results show that with particle sizes d >> 40 nm, a high quality standard aerosol is difficult to obtain using the common methods. Also a non-monotonic decline in quality with increasing particle size was observed, with the separated aerosol quality having a distinct minimum around the particle diameter of 200 nm. In addition to the theoretical calculations, a small number of experiments were carried out giving results (described in the appendix), which, in general, support the theoretical findings.

[1]  A. Mirme,et al.  Electrically Produced Standard Aerosols in a Wide Size Range , 2009 .

[2]  J. Mora,et al.  Molecular monodisperse mobility and mass standards from electrosprays of tetra-alkyl ammonium halides , 2005 .

[3]  J. Salm,et al.  Air ion measurements as a source of information about atmospheric aerosols , 1998 .

[4]  Benjamin Y. H. Liu,et al.  A submicron aerosol standard and the primary, absolute calibration of the condensation nuclei counter , 1974 .

[5]  Benjamin Y. H. Liu,et al.  Generation of monodisperse aerosol standards , 1973 .

[6]  O. Raabe.  The dilution of monodisperse suspensions for aerosolization. , 1968, American Industrial Hygiene Association journal.

[7]  G. W. Hewitt.  The charging of small particles for electrostatic precipitation , 1957, Transactions of the American Institute of Electrical Engineers, Part I: Communication and Electronics.

[8]  V. K. Mer,et al.  Light scattering as a measure of particle size in aerosols; the production of monodisperse aerosols. , 1949, Chemical reviews.

[9]  F. Stratmann,et al.  Differential Electrical Mobility Analysis: A Theoretical Study , 1997 .

[10]  E. Tamm.  Electrical classification as a basis of the aerosol standard , 1992 .

[11]  G. Reischl.  The relationship of input and output aerosol characteristics for an ideal differential mobility analyser particle standard , 1991 .

[12]  P. Mcmurry,et al.  A Device for Generating Singly Charged Particles in the 0.1-1.0-μm Diameter Range , 1989 .

[13]  W. A. Hoppel.  Determination of the aerosol size distribution from the mobility distribution of the charged fraction of aerosols , 1978 .

[14]  Hannes Tammet,et al.  The aspiration method for the Determination of Atmospheric-Ion Spectra , 1970 .