Large-scale Evaluation of Additive Air Cleaning Effects by Filtration and Ionization Against Infectious Aerosols

KATHERINE RATLIFF, Lukas Oudejans, M. Worth Calfee, John Archer, Marc Carpenter, Jerome Gilberry, Robert Yaga, William Schoppman, U.S. Environmental Protection Agency

     Abstract Number: 672
     Working Group: Indoor Air Purification Technologies, Best Practices, and their Health Impacts

Abstract
The COVID-19 pandemic has raised interest in technologies that are intended to reduce concentrations of infectious aerosols, which can potentially reduce the risk of disease transmission and improve overall indoor air quality, through either pathogen capture or inactivation. It has proven challenging, however, to predict how well these technologies will work against bioaerosols in real-world settings. Laboratory testing is often conducted at a small scale and under optimal conditions for technology performance, and technologies are largely tested in isolation, even when they are expected to operate in tandem as part of a larger system. This poster will provide an overview of methods and results from tests conducted with both an ionization device and a MERV13 filter by the U.S. Environmental Protection Agency in a large bioaerosol test chamber with the bacteriophage MS2 as a surrogate for human viral pathogens. Testing was conducted with both technologies operating in isolation and together. Although a clean air delivery rate (CADR) can be calculated for each technology operating alone, the data suggest that these CADRs are not always additive when the technologies are operating simultaneously. These results are important for informing standardized test methods for air cleaning technologies, as well as for their use under emerging indoor air quality guidance and targets (e.g., the Centers for Disease Control and Prevention’s ventilation guidance and ASHRAE Standard 241, Control of Infectious Aerosols), and for optimizing performance in applied settings.