TY - JOUR

T1 - High-resolution large-eddy simulation of indoor turbulence and its effect on airborne transmission of respiratory pathogens

T2 - Model validation and infection probability analysis

AU - Auvinen, Mikko

AU - Kuula, Joel

AU - Grönholm, Tiia

AU - Sühring, Matthias

AU - Hellsten, Antti

N1 - Funding Information: This study was financially supported by Business Finland Corona Co-Creation Project No. 40 988/31/2020 and Co-Innovation Project No. 3884/31/2021 and by Academy of Finland COVID-19 special funding Grant No. 335 681. We warmly thank restaurateur chef Henri Alen for kindly providing one of his restaurants for our use to carry out the experiments and UniqAir Ltd for providing the air purifiers for the experiments.

PY - 2022

Y1 - 2022

N2 - High-resolution large-eddy simulation (LES) is exploited to study indoor air turbulence and its effect on the dispersion of respiratory virus-laden aerosols and subsequent transmission risks. The LES modeling is carried out with unprecedented accuracy and subsequent analysis with novel mathematical robustness. To substantiate the physical relevance of the LES model under realistic ventilation conditions, a set of experimental aerosol concentration measurements are carried out, and their results are used to successfully validate the LES model results. The obtained LES dispersion results are subjected to pathogen exposure and infection probability analysis in accordance with the Wells-Riley model, which is here mathematically extended to rely on LES-based space- and time-dependent concentration fields. The methodology is applied to assess two dissimilar approaches to reduce transmission risks: a strategy to augment the indoor ventilation capacity with portable air purifiers and a strategy to utilize partitioning by exploiting portable space dividers. The LES results show that use of air purifiers leads to greater reduction in absolute risks compared to the analytical Wells-Riley model, which fails to predict the original risk level. However, the two models do agree on the relative risk reduction. The spatial partitioning strategy is demonstrated to have an undesirable effect when employed without other measures, but may yield desirable outcomes with targeted air purifier units. The study highlights the importance of employing accurate indoor turbulence modeling when evaluating different risk-reduction strategies.

AB - High-resolution large-eddy simulation (LES) is exploited to study indoor air turbulence and its effect on the dispersion of respiratory virus-laden aerosols and subsequent transmission risks. The LES modeling is carried out with unprecedented accuracy and subsequent analysis with novel mathematical robustness. To substantiate the physical relevance of the LES model under realistic ventilation conditions, a set of experimental aerosol concentration measurements are carried out, and their results are used to successfully validate the LES model results. The obtained LES dispersion results are subjected to pathogen exposure and infection probability analysis in accordance with the Wells-Riley model, which is here mathematically extended to rely on LES-based space- and time-dependent concentration fields. The methodology is applied to assess two dissimilar approaches to reduce transmission risks: a strategy to augment the indoor ventilation capacity with portable air purifiers and a strategy to utilize partitioning by exploiting portable space dividers. The LES results show that use of air purifiers leads to greater reduction in absolute risks compared to the analytical Wells-Riley model, which fails to predict the original risk level. However, the two models do agree on the relative risk reduction. The spatial partitioning strategy is demonstrated to have an undesirable effect when employed without other measures, but may yield desirable outcomes with targeted air purifier units. The study highlights the importance of employing accurate indoor turbulence modeling when evaluating different risk-reduction strategies.

UR - http://www.scopus.com/inward/record.url?scp=85123578966&partnerID=8YFLogxK

U2 - 10.48550/arXiv.2110.14348

DO - 10.48550/arXiv.2110.14348

M3 - Article

AN - SCOPUS:85123578966

VL - 34

JO - Physics of fluids

JF - Physics of fluids

SN - 1070-6631

IS - 1

M1 - 015124

ER -