Elemental composition of ambient aerosols measured with high temporal resolution using an online XRF spectrometer

This study has been partly funded by the Swiss Federal Office for the Environment (FOEN). M. C. Minguillon acknowledges the Ramon y Cajal Fellowship awarded by the Spanish Ministry of Economy, Industry and Competitiveness. We thank Rene Richter and Roland Scheidegger of PSI for their support during the field campaign. We are grateful to Chris Koch and John Cooper of Cooper Environmental Services for instructions on instrument operation and numerous discussions on the results. Andres Alastuey, Xavier Querol, and laboratory personnel from IDAEA-CSIC are also acknowledged. We also thank Julie Swift and Randy Mercurio of ERG for the ICP-MS analyses.