Abstract View
Medium Scale Wind Tunnel Testing of Aerosolized Coronavirus Collection and Inactivation in Recirculating Air Purification Systems
YUECHEN QIAO, My Yang, Ian Marabella, Devin McGee, Bernard Olson, Montserrat Torremorell, Christopher J. Hogan, University of Minnesota
Abstract Number: 62
Working Group: Infectious Aerosols in the Age of COVID-19
Abstract
A number of recirculating air purification technologies are available for consumers, which are now marketed towards effectively reducing concentrations of virus-carrying particles indoors. These products can incorporate a wide variety of control technologies, including but not limited to fibrous filters and UV sources. However, the majority of such technologies remain untested not only in their ability to collect particles, but to collect and inactivate airborne viruses. We have developed a method to directly evaluate the single-pass efficiency of the consumer available recirculating air purification technologies marketed for removal of infectious aerosol airborne viruses. Specifically, inspired by the ASHRAE 52.2 testing protocol, we have designed wind tunnel which can operated from 283 L min-1 to 2406 L min-1, and by sealing recirculating air purifiers within it, upstream and downstream sampled virus concentration measurements yield single-pass removal efficiency and single pass log-reduction. To date we have tested several technologies with three aerosolized viruses: porcine respiratory coronavirus, bovine coronavirus, and influenza (H1N1). Upstream and downstream sampling of virus-laden aerosols in the wind tunnel enables log reduction in viral and particle concentration via fluorimetry (detected fluoroscien, spiked into nebulized viral suspensions), virus titration, and RT-qPCR measurements; comparison of titration and RT-qPCR results enables inference of inactivation based log reduction. To date, virus aerosol capture and inactivation performance has been determined for three air purification technologies with this wind tunnel: (1). a UV-C ducted system which is designed purely for virus inactivation; (2) a recirculating fibrous filter system containing a photoelectrochemical oxidation (PECO) layer, and (3) a combined electrostatic precipitator (ESP) and HEPA filter system. This presentation will discuss design and operation of the wind tunnel for such tests, as well as results to date for virus inactivation and removal for the aforementioned systems.
References:
[1] Qiao Y, Yang M., Marabella I. A., McGee D. A. J., Aboubakr H., Goyal S., Hogan C. J., Olson B. A. & Torremorell M. (2021) Greater than 3-Log Reduction in Viable Coronavirus Aerosol Concentration in Ducted Ultraviolet-C (UV-C) Systems. Environmental Science and Technology. 55, 4174–4182. 10.1021/acs.est.0c05763
[2] Qiao Y, Yang M., Marabella I. A., McGee D. A. J., Olson B. A., Torremorell M., & Hogan C. J. (2021) Wind tunnel‐based testing of a photoelectrochemical oxidative filter‐based air purification unit in coronavirus and influenza aerosol removal and inactivation. Indoor Air. In press. 10.1111/ina.12847