TY - JOUR
T1 - Modelling aerosol transport and virus exposure with numerical simulations in relation to SARS-CoV-2 transmission by inhalation indoors
AU - Vuorinen, Ville
AU - Aarnio, Mia
AU - Alava, Mikko
AU - Alopaeus, Ville
AU - Atanasova, Nina
AU - Auvinen, Mikko
AU - Balasubramanian, Nallannan
AU - Bordbar, Hadi
AU - Erästö, Panu
AU - Grande, Rafael
AU - Hayward, Nick
AU - Hellsten, Antti
AU - Hostikka, Simo
AU - Hokkanen, Jyrki
AU - Kaario, Ossi
AU - Karvinen, Aku
AU - Kivistö, Ilkka
AU - Korhonen, Marko
AU - Kosonen, Risto
AU - Kuusela, Janne
AU - Lestinen, Sami
AU - Laurila, Erkki
AU - Nieminen, Heikki J.
AU - Peltonen, Petteri
AU - Pokki, Juho
AU - Puisto, Antti
AU - Råback, Peter
AU - Salmenjoki, Henri
AU - Sironen, Tarja
AU - Österberg, Monika
N1 - Funding Information:
This work was supported by the Academy of Finland Grant Nos. 314487 and 309570 , and by the Scientific Advisory Board for Defense (MATINE) Grant No. VN/627/2020-PLM-9 . We acknowledge CSC-IT center for science Ltd for offering the supercomputing resources for the present work. The Authors wish to thank all individuals and family members who have supported the work. In particular, Riikka Haikarainen, Kalle Kataila, Minna Hölttä, Esko Kauppinen, Olli Ranta, Otto Blomstedt, Cheng Qiang, Muhammad Saad Akram, Rahul Kallada Janardhan, Randy McDermott, and Marcos Vanella.
Funding Information:
This work was supported by the Academy of Finland Grant Nos. 314487 and 309570, and by the Scientific Advisory Board for Defense (MATINE) Grant No. VN/627/2020-PLM-9. We acknowledge CSC-IT center for science Ltd for offering the supercomputing resources for the present work. The Authors wish to thank all individuals and family members who have supported the work. In particular, Riikka Haikarainen, Kalle Kataila, Minna Hölttä, Esko Kauppinen, Olli Ranta, Otto Blomstedt, Cheng Qiang, Muhammad Saad Akram, Rahul Kallada Janardhan, Randy McDermott, and Marcos Vanella.
Publisher Copyright:
© 2020 The Authors
PY - 2020/10
Y1 - 2020/10
N2 - We provide research findings on the physics of aerosol and droplet dispersion relevant to the hypothesized aerosol transmission of SARS-CoV-2 during the current pandemic. We utilize physics-based modeling at different levels of complexity, along with previous literature on coronaviruses, to investigate the possibility of airborne transmission. The previous literature, our 0D-3D simulations by various physics-based models, and theoretical calculations, indicate that the typical size range of speech and cough originated droplets (d⩽20μm) allows lingering in the air for O(1h) so that they could be inhaled. Consistent with the previous literature, numerical evidence on the rapid drying process of even large droplets, up to sizes O(100μm), into droplet nuclei/aerosols is provided. Based on the literature and the public media sources, we provide evidence that the individuals, who have been tested positive on COVID-19, could have been exposed to aerosols/droplet nuclei by inhaling them in significant numbers e.g. O(100). By 3D scale-resolving computational fluid dynamics (CFD) simulations, we give various examples on the transport and dilution of aerosols (d⩽20μm) over distances O(10m) in generic environments. We study susceptible and infected individuals in generic public places by Monte-Carlo modelling. The developed model takes into account the locally varying aerosol concentration levels which the susceptible accumulate via inhalation. The introduced concept, ’exposure time’ to virus containing aerosols is proposed to complement the traditional ’safety distance’ thinking. We show that the exposure time to inhale O(100) aerosols could range from O(1s) to O(1min) or even to O(1h) depending on the situation. The Monte-Carlo simulations, along with the theory, provide clear quantitative insight to the exposure time in different public indoor environments.
AB - We provide research findings on the physics of aerosol and droplet dispersion relevant to the hypothesized aerosol transmission of SARS-CoV-2 during the current pandemic. We utilize physics-based modeling at different levels of complexity, along with previous literature on coronaviruses, to investigate the possibility of airborne transmission. The previous literature, our 0D-3D simulations by various physics-based models, and theoretical calculations, indicate that the typical size range of speech and cough originated droplets (d⩽20μm) allows lingering in the air for O(1h) so that they could be inhaled. Consistent with the previous literature, numerical evidence on the rapid drying process of even large droplets, up to sizes O(100μm), into droplet nuclei/aerosols is provided. Based on the literature and the public media sources, we provide evidence that the individuals, who have been tested positive on COVID-19, could have been exposed to aerosols/droplet nuclei by inhaling them in significant numbers e.g. O(100). By 3D scale-resolving computational fluid dynamics (CFD) simulations, we give various examples on the transport and dilution of aerosols (d⩽20μm) over distances O(10m) in generic environments. We study susceptible and infected individuals in generic public places by Monte-Carlo modelling. The developed model takes into account the locally varying aerosol concentration levels which the susceptible accumulate via inhalation. The introduced concept, ’exposure time’ to virus containing aerosols is proposed to complement the traditional ’safety distance’ thinking. We show that the exposure time to inhale O(100) aerosols could range from O(1s) to O(1min) or even to O(1h) depending on the situation. The Monte-Carlo simulations, along with the theory, provide clear quantitative insight to the exposure time in different public indoor environments.
KW - Aerosol
KW - Airborne transmission
KW - CFD
KW - coughing
KW - COVID-19
KW - Droplet
KW - Large-Eddy Simulation
KW - Monte-Carlo
KW - SARS-CoV-2
KW - Virus
UR - http://www.scopus.com/inward/record.url?scp=85086590250&partnerID=8YFLogxK
U2 - 10.1016/j.ssci.2020.104866
DO - 10.1016/j.ssci.2020.104866
M3 - Article
C2 - 32834511
AN - SCOPUS:85086590250
VL - 130
JO - Safety Science
JF - Safety Science
SN - 0925-7535
M1 - 104866
ER -