1. Environment and Resources Division, Abt Associates Inc., Bethesda, Maryland, USA
2. Global Change Research Program, National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC, USA
3. Pacific Northwest National Labs, Richland, Washington, USA
4. National Exposure Research Laboratory, U.S. Environmental Protection Agency, Athens, Georgia, USA
5. Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
6. Department of Atmospheric Sciences, University of Illinois, Urbana, Illinois, USA