1. Harvard School of Public Health, Harvard University, Boston, Massachusetts 02115;
2. Energy and Resources Group, University of California, Berkeley, California 94720;,
3. Center for Sustainability and the Global Environment, Gaylord Nelson Institute for Environmental Studies, University of Wisconsin, Madison, Wisconsin 53726;
4. E.O. Lawrence Berkeley National Laboratory, Berkeley, California 94720;
5. Industrial and Systems Engineering Department, P. Universidad Catolica de Chile, Santiago 6904411, Chile;
6. Medical Research Council of South Africa, Houghton 2041, South Africa;
7. Energy-Environment Technology Division, The Energy and Resources Institute, New Delhi 110003, India;
8. Environmental & Natural Resource Economics, Division of Resource Management, West Virginia University, Morgantown, West Virginia 26506;