Abstract View
Effect of Low-Cost Air Purification on Aerosol Dispersion and Droplet Deposition in a Conference Room
LINHAO LI, Stephanie Eilts, Zachary Pope, Meng Kong, Clay Maranville, John Jaranson, John Elson, Rainer Vogt, Christopher J. Hogan, Well Living Lab
Abstract Number: 237
Working Group: Indoor Aerosols
Abstract
Respiratory particles and droplets exhaled when an infected individual coughs, sneezes, or speaks, as well as during normal breathing, can result in indoor virus transmission. A portable air purification unit can reduce virus transmission risk by decreasing the overall aerosol concentration in a room by filtering and recirculating the air that passes through the unit. This is important in rooms with poorer ventilation and an inability to be ventilated with adequate amounts of fresh outdoor air. The whole-room and localized impact of portable air purification on aerosol dispersion and deposition has not been well studied. We conducted a series of experiments in a simulated conference room (6.04m × 2.31m × 2.6m) assessing the particle removal rate and deposition change owing to the presence of a low-cost portable air purifier comprised of a Lasko Model 3733 box fan and TriDim MERV 13 filter placed within a custom-built cardboard frame. A breathing simulator manikin was developed to provide physiologically correct inhalation and exhalation, with the manikin itself being anatomically correct. During operation, this breathing simulator ejected fluorescein-tagged particles in the 1-3 um size range. We measured deposition flux on upward- and downward-facing horizontal surfaces throughout the room and discerned aerosol mass concentration using impingers. The collected data enabled us to calculate surface-specific deposition velocity using deposition flux mass concentration measurements. Aerosol size distributions within the room were also quantified using a TSI 3330 Optical Particle Sizer. Two conditions were investigated: (1) Normal HVAC operation (44 CFM supply; Baseline), and (2) Normal HVAC operation + low-cost air purifier with filter. Results suggested this low-cost air purifier increased effective air exchange rate by 3.3x over baseline (15.6 vs. 4.7 h-1), but also introduced greater deposition to surfaces near the breathing simulator manikin versus baseline.