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Article

The Impact of Large Mobile Air Purifiers on Aerosol Concentration in Classrooms and the Reduction of Airborne Transmission of SARS-CoV-2

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Institute of Fluid Dynamics and Thermodynamics, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany
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Institute of Process Engineering, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany
*
Author to whom correspondence should be addressed.
Academic Editors: Tareq Hussein and Paul B. Tchounwou
Int. J. Environ. Res. Public Health 2021, 18(21), 11523; https://doi.org/10.3390/ijerph182111523
Received: 11 August 2021 / Revised: 20 October 2021 / Accepted: 27 October 2021 / Published: 2 November 2021
(This article belongs to the Collection COVID-19 Research)
In the wake of the COVID-19 pandemic, an increased risk of infection by virus-containing aerosols indoors is assumed. Especially in schools, the duration of stay is long and the number of people in the rooms is large, increasing the risk of infection. This problem particularly affects schools without pre-installed ventilation systems that are equipped with filters and/or operate with fresh air. Here, the aerosol concentration is reduced by natural ventilation. In this context, we are investigating the effect of large mobile air purifiers (AP) with HEPA filters on particle concentration and their suitability for classroom use in a primary school in Germany. The three tested APs differ significantly in their air outlet characteristics. Measurements of the number of particles, the particle size distribution, and the CO2 concentration were carried out in the classroom with students (April/May 2021) and with an aerosol generator without students. In this regard, the use of APs leads to a substantial reduction of aerosol particles in the considered particle size range of 0.178–17.78 µm. At the same time, the three APs are found to have differences in their particle decay rate, noise level, and flow velocity. In addition to the measurements, the effect of various influencing parameters on the potential inhaled particle dose was investigated using a calculation model. The parameters considered include the duration of stay, particle concentration in exhaled air, respiratory flow rate, virus lifetime, ventilation interval, ventilation efficiency, AP volumetric flow, as well as room size. Based on the resulting effect diagrams, significant recommendations can be derived for reducing the risk of infection from virus-laden aerosols. Finally, the measurements were compared to computational fluid dynamics (CFD) modeling, as such tools can aid the optimal placement and configuration of APs and can be used to study the effect of the spread of aerosols from a source in the classroom. View Full-Text
Keywords: airborne transmission; SARS-CoV-2; air purifiers; COVID-19 airborne transmission; SARS-CoV-2; air purifiers; COVID-19
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MDPI and ACS Style

Duill, F.F.; Schulz, F.; Jain, A.; Krieger, L.; van Wachem, B.; Beyrau, F. The Impact of Large Mobile Air Purifiers on Aerosol Concentration in Classrooms and the Reduction of Airborne Transmission of SARS-CoV-2. Int. J. Environ. Res. Public Health 2021, 18, 11523. https://doi.org/10.3390/ijerph182111523

AMA Style

Duill FF, Schulz F, Jain A, Krieger L, van Wachem B, Beyrau F. The Impact of Large Mobile Air Purifiers on Aerosol Concentration in Classrooms and the Reduction of Airborne Transmission of SARS-CoV-2. International Journal of Environmental Research and Public Health. 2021; 18(21):11523. https://doi.org/10.3390/ijerph182111523

Chicago/Turabian Style

Duill, Finn F., Florian Schulz, Aman Jain, Leve Krieger, Berend van Wachem, and Frank Beyrau. 2021. "The Impact of Large Mobile Air Purifiers on Aerosol Concentration in Classrooms and the Reduction of Airborne Transmission of SARS-CoV-2" International Journal of Environmental Research and Public Health 18, no. 21: 11523. https://doi.org/10.3390/ijerph182111523

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