Effect of human movement on a patient's exhaled viral particle transmission: A numerical study
WU Jialin1,2, WENG Wenguo1,2, FU Ming3,4
1. Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing 100084, China; 2. Beijing Key Laboratory of City Integrated Emergency Response Science, Beijing 100084, China; 3. Hefei Institute for Public Safety Research, Tsinghua University, Hefei 230601, China; 4. Anhui Province Key Laboratory of Human Safety, Hefei 230601, China
Abstract：Droplet transmission and aerosol transmission are both possible transmission pathways for many respiratory infections (e.g., COVID-19) and human movements may affect these viral particle transmission pathways. Realistic 3-D human models were used here in a computational fluid dynamics (CFD) study to analyze the effect of human movements on the transmission of virus particles exhaled by a patient. The changes in the airflow, pressure and particle diffusion were compared with experimental data to verify the accuracy of the computations. The results show that when a person passes by a sitting patient in a poorly ventilated room, the wake velocities can reach 1.6~2.0 m/s. The airflow velocity can reach 0.53 m/s at 0.10 m from the moving person, 0.22 m/s at 0.25 m away, and 0.13 m/s at 0.55 m away. The airflow fluctuations can last more than 10 s. Double peak airflow velocities are found near the moving person. The pressure difference of 0.49 Pa caused by the moving person moves the air and the viral particles into the wake of the moving person and slows the nearby droplet deposition. More than 50% of the viral particles are deposited on the moving person's body or spread further. Thus, this study recommends less cross-area movement in epidemic areas and that all people should wear masks and use personalized ventilation equipment.
吴家麟, 翁文国, 付明. 人员移动对患者呼出病毒颗粒传播影响的数值研究[J]. 清华大学学报（自然科学版）, 2022, 62(6): 1044-1051.
WU Jialin, WENG Wenguo, FU Ming. Effect of human movement on a patient's exhaled viral particle transmission: A numerical study. Journal of Tsinghua University(Science and Technology), 2022, 62(6): 1044-1051.
[1] JAYAWEERA M, PERERA H, GUNAWARDANA B, et al. Transmission of COVID-19 virus by droplets and aerosols:A critical review on the unresolved dichotomy[J]. Environmental Research, 2020, 188:109819. [2] NAZAROFF W W. Indoor aerosol science aspects of SARS-CoV-2 transmission[J]. Indoor Air, 2022, 32(1):e12970. [3] WANG C C, PRATHER K A, SZNITMAN J, et al. Airborne transmission of respiratory viruses[J]. Science, 2021, 373(6558):eabd9149. [4] MIRIKAR D, PALANIVEL S, ARUMURU V. Droplet fate, efficacy of face mask, and transmission of virus-laden droplets inside a conference room[J]. Physics of Fluids, 2021, 33(6):065108. [5] LIU F, LUO Z W, LI Y G, et al. Revisiting physical distancing threshold in indoor environment using infection-risk-based modeling[J]. Environment International, 2021, 153:106542. [6] LIU L, LI Y, NIELSEN P V, et al. Short-range airborne transmission of expiratory droplets between two people[J]. Indoor Air, 2017, 27(2):452-462. [7] LI W X, CHONG A, LASTERNAS B, et al. Quantifying the effectiveness of desk dividers in reducing droplet and airborne virus transmission[J]. Indoor Air, 2022, 32(1):e12950. [8] SHI Q L, HU Y Y, PENG B, et al. Effective control of SARS-CoV-2 transmission in Wanzhou, China[J]. Nature Medicine, 2021, 27(1):86-93. [9] CAO S J, CEN D D, ZHANG W R, et al. Study on the impacts of human walking on indoor particles dispersion using momentum theory method[J]. Building and Environment, 2017, 126:195-206. [10] MAZUMDAR S, POUSSOU S B, LIN C H, et al. Impact of scaling and body movement on contaminant transport in airliner cabins[J]. Atmospheric Environment, 2011, 45(33):6019-6028. [11] BLOCKEN B, MALIZIA F, VAN DRUENEN T, et al. Towards aerodynamically equivalent COVID191.5 m social distancing for walking and running[Z/OL]. 2020. http://www.urbanphysics.net/Social%20Distancing%20v20_White_Paper.pdf. [12] BHATTACHARYA A, PANTELIC J, GHAHRAMANI A, et al. Three-dimensional analysis of the effect of human movement on indoor airflow patterns[J]. Indoor Air, 2021, 31(2):587-601. [13] WU J L, WENG W G, SHEN L C, et al. Transient and continuous effects of indoor human movement on nanoparticle concentrations in a sitting person's breathing zone[J]. Science of the Total Environment, 2022, 805:149970. [14] LICINA D, PANTELIC J, MELIKOV A, et al. Experimental investigation of the human convective boundary layer in a quiescent indoor environment[J]. Building and Environment, 2014, 75:79-91. [15] HAN Z Y, WENG W G, HUANG Q Y. Numerical and experimental investigation on the dynamic airflow of human movement in a full-scale cabin[J]. HVAC&R Research, 2014, 20(4):444-457. [16] LIU Z J, LIU H Y, RONG R, et al. Effect of a circulating nurse walking on airflow and bacteria-carrying particles in the operating room:An experimental and numerical study[J]. Building and Environment, 2020, 186:107315. [17] 吴家麟, 翁文国. 新冠肺炎病毒颗粒在空调大巴中的传播与乘客感染风险[J]. 清华大学学报(自然科学版), 2021, 61(2):89-95. WU J L, WENG W G. Transmission of COVID-19 viral particles and the risk of infection among passengers in air-conditioned buses[J]. Journal of Tsinghua University (Science and Technology), 2021, 61(2):89-95. (in Chinese) [18] LUO N, WENG W G, XU X Y, et al. Experimental and numerical investigation of the wake flow of a human-shaped manikin:Experiments by PIV and simulations by CFD[J]. Building Simulation, 2018, 11(6):1189-1205. [19] LIU Y, NING Z, CHEN Y, et al. Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals[J]. Nature, 2020, 582(7813):557-560. [20] AI Z T, MAK C M, GAO N P, et al. Tracer gas is a suitable surrogate of exhaled droplet nuclei for studying airborne transmission in the built environment[J]. Building Simulation, 2020, 13(3):489-496. [21] WU J L, WENG W G. Quantitative infection risk assessment of indoor COVID-19 airborne transmission based on rebreathed fraction[C]//The 12th International Symposium on Heating, Ventilation and Air Conditioning. Seoul, Republic of Korea, 2021.
2022, Vol. 62 
