Workplace ventilation improvement to address coronavirus disease 2019 cluster occurrence in a manufacturing factory

  1. Hiroko Kitamura
  2. Yo Ishigaki
  3. Hideaki Ohashi
  4. Shinji Yokogawa

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Abstract

Aim and Methods

A coronavirus disease 2019 (COVID-19) cluster emerged in a manufacturing factory in early August 2021. In November 2021, a ventilation survey using tracer gas and data analysis was performed to reproduce the situation at the time of cluster emergence and verify that ventilation in the office increased the risk of aerosol transmission; verify the effectiveness of measures implemented immediately in August; and verify the effectiveness of additional measures when previously enforced measures proved inadequate.

Results

At the time of cluster emergence, the average ventilation frequency was 0.73 times/h, less than the 2 times/h recommended by the Ministry of Health, Labour, and Welfare; as such, the factory’s situation was deemed to have increased the risk of aerosol transmission. Due to the measures already taken at the time of the survey, the ventilation frequency increased to 3.41 times/h on average. It was confirmed that ventilation frequency increased to 8.33 times/h on average, when additional measures were taken.

Conclusion

To prevent the re-emergence of COVID-19 clusters, it is necessary to continue the measures that have already been implemented. Additionally, introduction of real-time monitoring that visualizes CO 2 concentrations is recommended. Furthermore, we believe it is helpful that external researchers in multiple fields and internal personnel in charge of health and safety department and occupational health work together to confirm the effectiveness of conducted measures, such as this case.

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    SciScore for 10.1101/2022.04.04.22271935: (What is this?)

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

    Table 1: Rigor

    NIH rigor criteria are not applicable to paper type.

    Table 2: Resources

    No key resources detected.

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  2. Version published to 10.1101/2022.04.04.22271935v1 on medRxiv