1Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland
2Laboratory for Air Pollution and Environmental Technology, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
3Institute for Environmental Assessment and Water Research (IDAEA), CSIC, Barcelona, Spain
4School of Life Sciences and Facility Management, Wädenswil, Switzerland
5Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
6Hamburger Synchrotronstrahlungslabor at Deutsches Elektronen-Synchrotron DESY, a Research Centre of the Helmholtz Association, Hamburg, Germany
7AAAS Science and Technology Policy Fellow Hosted at the US EPA, Washington, DC, USA
8Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), FIS-LAS, Frascati, Italy
Received: 24 Dec 2010 – Discussion started: 02 Feb 2011
Abstract. Time and size resolved data of trace elements were obtained from measurements with a rotating drum impactor (RDI) and subsequent X-ray fluorescence spectrometry. Trace elements can act as indicators for the identification of sources of particulate matter <10 μm (PM10) in ambient air. Receptor modeling was performed with positive matrix factorization (PMF) for trace element data from an urban background site in Zürich, Switzerland. Eight different sources were identified for the three examined size ranges (PM1−0.1, PM2.5−1 and PM10−2.5): secondary sulfate, wood combustion, fire works, road traffic, mineral dust, de-icing salt, industrial and local anthropogenic activities. The major component was secondary sulfate for the smallest size range; the road traffic factor was found in all three size ranges. This trace element analysis is complemented with data from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (AMS), assessing the PM1 fraction of organic aerosols. A separate PMF analysis revealed three factors related to three of the sources found with the RDI: oxygenated organic aerosol (OOA, related to inorganic secondary sulfate), hydrocarbon-like organic aerosol (HOA, related to road traffic) and biomass burning organic aerosol (BBOA), explaining 60 %, 22 % and 17 % of total measured organics, respectively. Since different compounds are used for the source classification, a higher percentage of the ambient PM10 mass concentration can be apportioned to sources by the combination of both methods.
Revised: 02 Jul 2011 – Accepted: 09 Aug 2011 – Published: 02 Sep 2011
Richard, A., Gianini, M. F. D., Mohr, C., Furger, M., Bukowiecki, N., Minguillón, M. C., Lienemann, P., Flechsig, U., Appel, K., DeCarlo, P. F., Heringa, M. F., Chirico, R., Baltensperger, U., and Prévôt, A. S. H.: Source apportionment of size and time resolved trace elements and organic aerosols from an urban courtyard site in Switzerland, Atmos. Chem. Phys., 11, 8945-8963, doi:10.5194/acp-11-8945-2011, 2011.