Experimental investigation of ion-ion recombination under atmospheric conditions

Autor(en)

A. Franchin, S. Ehrhart, J. Leppa, T. Nieminen, S. Gagne, S. Schobesberger, D. Wimmer, J. Duplissy, F. Riccobono, E. M. Dunne, L. Rondo, A. Downard, F. Bianchi, A. Kupc, G. Tsagkogeorgas, K. Lehtipalo, H. E. Manninen, J. Almeida, A. Amorim, P. E. Wagner, A. Hansel, J. Kirkby, A. Kuerten, N. M. Donahue, V. Makhmutov, S. Mathot, A. Metzger, T. Petaja, R. Schnitzhofer, M. Sipila, Y. Stozhkov, A. Tome, V. -M. Kerminen, K. Carslaw, J. Curtius, U. Baltensperger, M. Kulmala

Abstrakt

We present the results of laboratory measurements of the ion–ion

recombination coefficient at different temperatures, relative humidities and

concentrations of ozone and sulfur dioxide. The experiments were carried out

using the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at CERN, the walls

of which are made of conductive material, making it possible to measure small

ions. We produced ions in the chamber using a 3.5 GeV c⁻¹ beam of

positively charged pions (π⁺) generated by the CERN Proton Synchrotron

(PS). When the PS was switched off, galactic cosmic rays were the only

ionization source in the chamber. The range of the ion production rate varied

from 2 to 100 cm⁻³ s⁻¹, covering the typical range of ionization

throughout the troposphere. The temperature ranged from −55 to

20 °C, the relative humidity (RH) from 0 to 70 %, the SO₂

concentration from 0 to 40 ppb, and the ozone concentration from 200 to

700 ppb. The best agreement of the retrieved ion–ion recombination

coefficient with the commonly used literature value of

1.6 × 10⁻⁶ cm³ s⁻¹ was found at a temperature of

5 °C and a RH of 40 % (1.5 ± 0.6)

× 10⁻⁶ cm³ s⁻¹. At 20 °C and 40 % RH, the

retrieved ion–ion recombination coefficient was instead (2.3 ± 0.7)

× 10⁻⁶ cm³ s⁻¹. We observed no dependency of the

ion–ion recombination coefficient on ozone concentration and a weak

variation with sulfur dioxide concentration. However, we observed a more than

fourfold increase in the ion–ion recombination coefficient with decreasing

temperature. We compared our results with three different models and found an

overall agreement for temperatures above 0 °C, but a disagreement at

lower temperatures. We observed a strong increase in the recombination

coefficient for decreasing relative humidities, which has not been reported

previously.

Organisation(en)

Aerosolphysik und Umweltphysik

Externe Organisation(en)

University of Helsinki, European Organization for Nuclear Research (CERN), Johann Wolfgang Goethe-Universität Frankfurt am Main, Dalhousie University, Environment and Climate Change Canada, Paul Scherrer Institute, Finnish Meteorological Institute, California Institute of Technology (Caltech), Eidgenössische Technische Hochschule Zürich, Leibniz-Institut für Troposphärenforschung, Universidade de Lisboa, Leopold-Franzens-Universität Innsbruck, Carnegie Mellon University, Russian Academy of Sciences, University of Leeds

Journal

Atmospheric Chemistry and Physics

Band

15

Seiten

7203-7216

Anzahl der Seiten

14

ISSN

1680-7316

DOI

https://doi.org/10.5194/acp-15-7203-2015

Publikationsdatum

07-2015

Peer-reviewed

Ja

ÖFOS 2012

105904 Umweltforschung, 103039 Aerosolphysik, 103008 Experimentalphysik

Schlagwörter

ASJC Scopus Sachgebiete

Atmospheric Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/e3990879-54ca-4ceb-9738-a5fdadd9413a