1. a Desert Research Institute , Reno , NV , USA
2. b Lovelace Respiratory Research Institute , Albuquerque , NM , USA
3. c U.S. Environmental Protection Agency , Office of Research and Development , Research Triangle Park , NC , USA
4. d Electric Power Research Institute , Palo Alto , CA , USA
5. e University of Washington , Seattle , WA , USA
6. f Envair/Aerochem , Placitas , NM , USA
7. g Consultant , San Francisco , CA , USA
8. h Fort Bend Medical Clinic , Houston , TX , USA
9. i Air Improvement Resource, Inc. , Novi , MI , USA
10. j General Motors Public Policy Center , Detroit , MI , USA
11. k Brigham Young University , Provo , UT , USA
12. l Harvard School of Public Health , Boston , MA , USA