Characterisation of corona-generated ions used in a Neutral cluster and Air Ion Spectrometer (NAIS)

Hanna E. Manninen (Corresponding Author), A. Franchin, S. Schobesberger, A. Hirsikko, J. Hakala, A. Skromulis, J. Kangasluoma, M. Ehn, H. Junninen, A. Mirme, S. Mirme, T. Petäjä, D. R. Worsnop, Markku Kulmala

Research output: Contribution to journalArticleScientificpeer-review

37 Citations (Scopus)


We characterized size and chemical composition of ions generated by a corona-needle charger of a Neutral cluster and Air Ion Spectrometer (NAIS) by using a high resolution differential mobility analyzer and a time-of-flight mass spectrometer. Our study is crucial to verify the role of corona-generated ions in the particle size spectra measured with the NAIS, in which a corona charger is used to charge aerosol particles down to the size range overlapping with the size of generated ions. The size and concentration of ions produced by the corona discharging process depend both on corona voltage and on properties and composition of carrier gas. Negative ions were <1.6 nm (0.8 cm2 V&minus;1 s-1 in mobility) in all tested gas mixtures (nitrogen, air with variable mixing ratios of water vapour), whereas positive ions were <1.7 nm (0.7 cm2 V-1 s&minus;1). Electrical filtering of the corona generated ions and not removing all charged particles plays an important role in determining the lowest detection limit. Based on our experiments, the lowest detection limit for the NAIS in the particle mode is between 2 and 3 nm

Original languageEnglish
Pages (from-to)2767-2776
Number of pages10
JournalAtmospheric Measurement Techniques
Issue number12
Publication statusPublished - 2011
MoE publication typeA1 Journal article-refereed


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