1. National Center for Environmental Assessment; Office of Research and Development; U.S. Environmental Protection Agency (8623-P); 1200 Pennsylvania Avenue NW Washington D.C. 20460 USA
2. RTI International; 3040 East Cornwallis Road, P.O. Box 12194 Research Triangle Park North Carolina 27709 USA
3. National Exposure Research Laboratory; U.S. Environmental Protection Agency; Research Triangle Park North Carolina 27709 USA
4. Office of Atmospheric Programs; U.S. Environmental Protection Agency; 1200 Pennsylvania Ave NW Washington D.C. 20460 USA