1. Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
2. Aerosol Dynamics Inc., 935 Grayson Street, Berkeley, California 94710, United States
3. Aerosol Devices Inc.,1613 Prospect Park Way, Ste 100, Fort Collins, Colorado 80525, United States
4. Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States