Impact of Test Methodology on the Efficacy of Triethylene Glycol (Grignard Pure) against Bacteriophage MS2

AbstractThe COVID-19 pandemic has raised interest in using chemical air treatments as part of a strategy to reduce the risk of disease transmission, but more information is needed to characterize their efficacy at scales translatable to applied settings and to develop standardized test methods for characterizing the performance of these products. Grignard Pure, a triethylene glycol (TEG) active ingredient air treatment, was evaluated using two different test protocols in a large bioaerosol test chamber and observed to inactivate bacteriophage MS2 in air (up to 99.9% at 90 minutes) and on surfaces (up to 99% at 90 minutes) at a concentration of approximately 1.2 – 1.5 mg/m3. Introducing bioaerosol into a TEG-charged chamber led to overall greater reductions compared to when TEG was introduced into a bioaerosol-charged chamber, although the differences in efficacy against airborne MS2 were only significant in the first 15 minutes. Time-matched control conditions (no TEG present) and replicate tests for each condition were essential for characterizing treatment efficacy. These findings suggest that chemical air treatments could be effective in reducing the air and surface concentrations of infectious pathogens in occupied spaces, although standard methods are needed for evaluating their efficacy and comparing results across studies. The potential health impacts of chronic exposure to chemicals should also be considered, but those were not evaluated here.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgementsThe authors gratefully acknowledge members of the EPA Project Team, the members of Jacobs Technology, Inc. (JTI) supporting the EPA Homeland Security and Materials Management Microbiology lab and the JTI Aerosol Science Team, Adam Burdsall and Marc Carpenter for internal technical reviews of this manuscript, and Ramona Sherman and for quality assurance support.DisclaimerThe EPA, through its Office of Research and Development, directed the research described herein conducted through contract 68HERC20D0018 with Jacobs Technology, Inc. It has been subjected to the Agency's review and has been approved for publication. Mention of trade names, products or services does not convey official EPA approval, endorsement, or recommendation.Declaration of InterestsThe authors report there are no competing interests to declare.Data AvailabilityThe data that support the findings of this study are openly available at https://doi.org/10.23719/1528421.