William C. Hinds, ScD, was Emeritus Professor in the Department of Environmental Health Sciences at the UCLA Fielding School of Public Health. His research studied aerosols and industrial control of airborne contaminants. Yifang Zhu, PhD, is Professor in the Department of Environmental Health Sciences at the UCLA Fielding School of Public Health. Her research focus is on air pollution, environmental exposure assessment, and aerosol science and technology.