Parham Azimi, Dan Zhao, Brent Stephens Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, Chicago, IL, USA Received 31 July 2014, Revised 26 August 2014, Accepted 3 September 2014, Available online 4 September 2014. Abstract This work uses 194 outdoor particle size distributions (PSDs) from the literature to estimate single-pass heating, ventilating, and air-conditioning (HVAC) filter removal efficiencies for