PSI-SCAC: description and transnational access

1. Introduction

The PSI Simulation Chamber for Atmospheric Chemistry is a medium sized indoor chamber. It is a tool to investigate atmospheric processes like gas phase oxidation mechanisms, particle nucleation, aerosol formation, composition and ageing. The facility is equipped with a large suite of state of the art instruments. PSI-SCAC is part of the Transnational Access of Euochamp-2.

2. Description of the research facility

The PSI SCAC provides a platform to investigate atmospheric processes at high as well as ambient relevant concentrations of precursors. These can be volatile organic compounds or complex mixtures like diesel exhaust or wood burning emissions. Specific projects and questions addressed so far include:

• Investigation of oligomer formation in SOA
• Determination of SOA yields from various precursor compounds
• Investigation of the influence of organics and sulfuric acid on nucleation
• Investigation of cloud forming potential of SOA
• Intercomparison of instruments
• Investigation of composition, gas/particle partitioning and volatility of SOA
• Evaluation of photochemical mechanisms
• Investigation of SOA formation from diesel and wood burning emissions

2.1. Technical data

The chamber is a 27-m³ (3×3×3 m) flexible bag made of 125 μm Teflon® fluorocarbon film (FEP). The bag is suspended in a temperature controlled wooden enclosure having dimension 4×5×4 m (L×W×H). Temperature can be stabilized to 1°C within the range of 17 to 25 °C. Four xenon arc lamps (4 kW rated power, lumens each) are used as light source. The light is filtered with borosilicate glass plates to reduce the high actinic UV below the wavelength of 300 nm and to simulate the solar light spectrum. A NO2 photolysis rate of min-1 is obtained.

Purified air is supplied by an AADCO (737-250 series, AADCO Instruments, Inc., USA) pure air generation system. Gaseous components (NO, NO₂, gaseous organic compounds) can be delivered to the smog chamber. An ozone generator can provide ozone levels from ppb to ppm concentrations in the chamber. The chamber can be humidified with ultrapure water up to 80 %RH. A particle generation system is available for seed particle experiments. Three manifolds (inlet and outlet) made of stainless steel and Teflon® allow for easy installation of additional inputs and sampling lines.

The smog chamber is equipped with a fixed set of instruments which are regularly operated. Additionally, there are many special state of the art instruments of our own which are available for specific campaigns.

2.2. Images

2.3. Publications

Kalberer, M., D. Paulsen, M. Sax, M. Steinbacher, J. Dommen, A. S. H. Prévôt, R. Fisseha, E. Weingartner, V. Frankevich, R. Zenobi, and U. Baltensperger (2004), Identification of Polymers as Major Components of Atmospheric Organic Aerosols, Science, 303, 1659-1662.

Paulsen, D., J. Dommen, M. Kalberer, A. S. H. Prévôt, R. Richter, M. Sax, M. Steinbacher, E. Weingartner, and U. Baltensperger (2005), Secondary Organic Aerosol Formation by Irradiation of 1,3,5-Trimethylbenzene-NOx-H2O in a New Reaction Chamber for Atmospheric Chemistry and Physics, Environ. Sci. Technol., 39, 2668-2678.

Gross, D. S., M. E. Gälli, M. Kalberer, A. S. H. Prevot, J. Dommen, J. Duplissy, A. Gascho, A. Metzger, M. R. Alfarra, K. Gaeggeler, and U. Baltensperger (2006), Real time measurement of oligomeric species in secondary organic aerosol with the aerosol time-of-flight mass spectrometer, Anal. Chem., 78, 2130-2137.

Metzger, A., Dommen, J., Gaeggeler, K., Duplissy, J., Prevot, A., Kleffmann, J., Elshorbany, Y., Wisthaler, A., Baltensperger, U. (2008), Evaluation of 1,3,5 trimethylbenzene degradation in the detailed tropospheric chemistry mechanism, MCMv3.1, using environmental chamber data. Atmos. Chem. Phys., 8, 11567-11607.

Metzger, A.; Verheggen, B.; Dommen, J.; Duplissy, J.; Prevot, A. S. H.; Weingartner, E.; Riipinen, I.; Kulmala, M.; Spracklen, D. V.; Carslaw, K. S.; Baltensperger, U. (2010), Evidence for the role of organics in aerosol particle formation under atmospheric conditions. Proc. Natl. Acad. Sci., doi:10.1073/pnas.0911330107.

A detailed list of publications is provided here.

2.4. Access to the chamber under Eurochamp TA

Access to PSI SCAC is provided through Eurochamp-2 Transnational Access and other collaborations. Interested users should contact us to discuss their interest and ideas. Typically, measurements are performed in a collaborative effort. Users can bring their instruments to our chamber. Modifications of inlet lines can be provided on request. Access to laboratories can be provided after consultation.

3. Institution in charge of the laboratory facility

The Paul Scherrer Institute, PSI, is the largest research centre for natural and engineering sciences within Switzerland, with its research activities concentrated on three main subject areas: Structure of Matter, Energy and the Environment, and Health. PSI belongs as an autonomous institution to the Swiss ETH domain. The PSI SCAC is operated by the Laboratory of Atmospheric Chemistry (LAC).

PSI is partner 7 in Eurochamp-2.

3.1. Contact Information

 Prof. Urs Baltensperger, phone: +41 56 310 24 08

 Dr. Josef Dommen, phone: +41 56 310 29 92

4. Additional Information

More information can be found on the internet.
Paul Scherrer Institute
Laboratory of Atmospheric Chemistry
PSI SCAC