1. Institute of Energy Economics and the Rational Use of Energy, University of Stuttgart, Hessbruehlstrasse 49a, 70565 Stuttgart, Germany
2. Institute of Environmental Engineering, Swiss Federal Institute of Technology Zurich, CH-8093 Zurich, Switzerland
3. Institute of Agriculture and Food Research and Technology, 08348 Cabrils, Barcelona, Spain
4. Environmental Health Sciences, School of Public Health, University of Michigan, 109 S. Observatory, Ann Arbor, Michigan 48109-2029, United States
5. Quantis, EPFL Science Park (PSE-D), CH-1015 Lausanne, Switzerland