Low ozone concentration and negative ions for rapid SARS-CoV-2 inactivation

  1. Davide De Forni
  2. Barbara Poddesu
  3. Giulia Cugia
  4. Giovanni Gallizia
  5. Massimo La Licata
  6. Julianna Lisziewicz
  7. James Chafouleas
  8. Franco Lori

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

Ozone is a powerful anti-bacterial, anti-fungal and anti-viral agent, yet exposure to high levels of ozone can pose risks to human/animal health and, in the long term, corrode certain objects. In order to overcome these risks, we evaluated the potential of using a relatively short exposure of a low concentration of ozone to disinfect an indoor environment in the absence of individuals and animals. ICON3 by O3ZONO/M2L, a new disinfection device generating both ozone and negative ions, was selected to assess the potential of this strategy to inactivate different viral isolates of SARS-CoV-2.

Tests under controlled laboratory conditions were performed in a system consisting of an ozone-proof airtight plastic box inside a biological safety cabinet, where suspensions of two strains of SARS-CoV-2 were exposed to ozone and negative ions and virucidal activity was measured by means of two complementary methodologies: viral replication capacity and viral titer determination.

These studies revealed that low concentration ozone (average 3.18 ppm after the peak) inactivated up to >99% of SARS-CoV-2 within 20 minutes of exposure. Under controlled conditions, similar ozone exposure was recreated with ICON3 in different volume rooms (15, 30, 60 m 3 ) where a linear relationship was observed between the room volume and the time of continuous ozone/ions flow required to reach and maintain the desired ozone levels used in the laboratory studies.

These studies suggest that ICON3 may have the potential for use in the disinfection of SARS-CoV-2 in indoor environments in the absence of individuals and animals, under properly controlled and monitored safety conditions.

Article activity feed

  1. Version published to 10.1101/2021.03.11.434968v4 on bioRxiv
  2. Version published to 10.1101/2021.03.11.434968v3 on bioRxiv
  3. ScreenIT

    SciScore for 10.1101/2021.03.11.434968: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Experimental Models: Cell Lines
    SentencesResources
    Vero E6 cells (kidney epithelial cells from African green monkey, ATCC CRL-1586) were maintained at their optimal density based on the ATCC datasheet.
    Vero E6
    suggested: None

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    One of the main limitations of chemicals is that the efficiency of virus inactivation in the air and surfaces is somewhat problematic and it depends on human factors. For example, 1000 ppm hypochlorite could inactivate the vast majority of pathogens according to WHO [22], but several surfaces including furniture, mobile phones, computers, and other electronic devices, would be damaged by repeated spraying and infectious droplets would remain on these surfaces and mediate virus transmission. More importantly, cleaners use different chemicals, equipment, procedures, and their performances are not comparable nor reproducible. High concentrations (over 350 ppm) of ozone are used to inactivate SARS-CoV-2 in healthcare facilities, however, such high ozone concentrations are not commonly used in public offices and households because of safety concerns. To overcome the limitations of chemical disinfection and high concentration of ozone the ICON3 device was calibrated to emit low concentration ozone and ions to effectively and reproducibly inactivate SARS-CoV-2. Although ions produced by the ICON3 are not expected to directly inactivate SARS-CoV-2 they might contribute to precipitate virus-containing droplets and decrease the levels of small particles that are associated with increased transmission of COVID-19 [19]. The objective of this study was to keep the ozone concentration around 3 ppm for a relatively short time (i.e., 20 minutes), conditions that expected to not damage the su...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We found bar graphs of continuous data. We recommend replacing bar graphs with more informative graphics, as many different datasets can lead to the same bar graph. The actual data may suggest different conclusions from the summary statistics. For more information, please see Weissgerber et al (2015).

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  4. Version published to 10.1101/2021.03.11.434968v2 on bioRxiv
  5. Version published to 10.1101/2021.03.11.434968v1 on bioRxiv