Jeffrey Siegel, Ph.D., is a Professor of Civil and Mineral Engineering at the University of Toronto and a member of the university’s Building Engineering Research Group. He holds joint appointments at the Dalla Lana School of Public Health and the Department of Physical & Environmental Sciences. He holds an M.S. and Ph.D. in Mechanical Engineering from the University of California, Berkeley as well as a B.Sc. from Swarthmore College. He is internationally recognized for his work on indoor air quality generally and air cleaning specifically and is a fellow of ASHRAE and a member of the Academy of Fellows of the International Society for Indoor Air and Climate (ISIAQ). His research interests include healthy and sustainable buildings, filtration and air cleaning, ventilation and indoor air quality in residential and commercial buildings, control of indoor particulate matter, and the impact of building systems on indoor microbiology and chemistry. He has published over 100 peer-reviewed articles on indoor air quality and related subjects and has been active in disseminating information about filtration and ventilation solutions for COVID-19.