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Production of neutral molecular clusters by controlled neutralization of mobility standards

Autor(en)
Gerhard Steiner, Alessandro Franchin, Juha Kangasluoma, V M Kerminen, Markku Kulmala, T. Petäjä
Abstrakt

Measuring aerosols and molecular clusters below the 3 nm size limit is essential to increase our understanding of new particle formation. Instruments for the detection of sub-3 nm aerosols and clusters exist and need to be carefully calibrated and characterized. So far calibrations and laboratory tests have been carried out using mainly electrically charged aerosols, as they are easier to handle experimentally. However, the charging state of the cluster is an important variable to take into account. Furthermore, instrument characterization performed with charged aerosols could be biased, preventing a correct interpretation of data when electrically neutral sub-3 nm aerosols are involved. This article presents the first steps to generate electrically neutral molecular clusters as standards for calibration. We show two methods: One based on the neutralization of well-known molecular clusters (mobility standards) by ions generated in a switchable aerosol neutralizer. The second is based on the controlled neutralization of mobility standards with mobility standards of opposite polarity in a recombination cell. We highlight the challenges of these two techniques and, where possible, point out solutions. In addition, we give an outlook on the next steps toward generating well-defined neutral molecular clusters with a known chemical composition and concentration.

Organisation(en)
Aerosolphysik und Umweltphysik
Externe Organisation(en)
University of Helsinki, University of Colorado, Boulder, National Oceanic and Atmospheric Administration, Leopold-Franzens-Universität Innsbruck
Journal
Aerosol Science and Technology
Band
51
Seiten
946-955
Anzahl der Seiten
10
ISSN
0278-6826
DOI
https://doi.org/10.1080/02786826.2017.1328103
Publikationsdatum
2017
Peer-reviewed
Ja
ÖFOS 2012
103039 Aerosolphysik
Schlagwörter
ASJC Scopus Sachgebiete
Pollution, Allgemeine Materialwissenschaften, Environmental Chemistry
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/6e54b765-93ae-4cbc-a9ac-8e77150380ee