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