This paper identifies the “safe ventilation rate” for eliminating airborne viral infection and preventing cross-infection of severe acute respiratory syndrome (SARS) in a hospital-based setting. We used simulation approaches to reproduce three actual cases where groups of hospital occupants reported to be either infected or not infected when SARS patients were hospitalized in nearby rooms. Simulations using both computational fluid dynamics (CFD) and multi-zone models were carried out to understand the dilution level of SARS virus-laden aerosols during these scenarios. We also conducted a series of measurements to validate the simulations. The ventilation rates (dilution level) for infection and non-infection were determined based on these scenarios. The safe ventilation rate for eliminating airborne viral infection is to dilute the air emitted from a SARS patient by 10000 times with clean air. Dilution at lower volumes, specifically 1000 times, is insufficient for protecting non-infected people from SARS exposure and the risk of infection is very high. This study provides a methodology for investigating the necessary ventilation rate from an engineering viewpoint.
Batchelor GK (1974). Transport properties of two-phase materials with random structure. Journal of Fluid Mechanics, 6: 227–255.
Chao CYH, Wan MP, Morawska L, Johnson GR, Ristovski ZD, Hargreaves M, Mengersen K, Corbett S, Li Y, Xie X, Katoshevski D (2009). Characterization of expiration air jets and droplet size distributions immediately at the mouth opening. Journal of Aerosol Science, 40: 122–133.
Dols WS, Walton GN (2002). CONTAMW 2.0 User Manual. Building and Fire Research Laboratory, National Institute of Standards and Technology (NIST).
Duguid JF (1945). The numbers and the sites of origin of the droplets expelled during expiratory activities. Edinburgh Medicine Journal, 52: 335–340.
Gold E, Nankervis GA (1989). Cytomegalovirus. In: Evans A (ed), Viral Infections of Humans. New York: Plenum Medical Book.
Junge CE (1963). Air Chemistry and Radioactivity. New York: Academic Press.
Li Y, Leung GM, Tang JW, Yang X, Chao C, Lin JH, Lu JW, Nielsen PV, Niu JL, Qian H, Sleigh AC, Su HJ, Sundell J, Wong TW, Yuen PL (2007). Role of ventilation in airborne transmission of infectious agents in the built environment — A multidisciplinary systematic review. Indoor Air, 17: 2–18.
Lumley JL (1978). Two-phase and non-Newtonain flows. In: Bradshao P (ed), Turbulence (p. 289). Berlin: Springer, 1978.
McCluskey R, Sandin R, Greene J (1996). Detection of airborne cytomegalovirus in hospital rooms of immunocompromised patients. Journal of Virological Methods, 56: 115–118.
Mendell MJ, Fisk WJ, Petersen MR (2002). Indoor particles and symptoms among office workers: results from a double-blind cross-over study. Epidemiology, 13: 296–304.
Morawska L (2006). Droplet fate in indoor environments, or can we prevent the spread of infection? Indoor Air, 16: 335–347.
Murakami S, Kato S, Nagano S, Tanaka Y (1992). Diffusion characteristics of airborne particles with gravitational settling in a convection-dominant indoor flow field. ASHRAE Transactions, 98(1): 82–97.
Nicas M, Nazaroff WW, Hubbard A (2005). Toward understanding the risk of secondary airborne infection: emission of respirable pathogens. Journal of Occupational and Environmental Hygiene, 2: 143–154.
PHOENICS Version 3.2. CHAM Ltd, UK, 2000.
Rota PA, Oberste MS, Monroe SS, Nix WA, Campagnoli R, Icenogle JP, et al. (2003). Characterization of a novel coronavirus associated with severe acute respiratory syndrome. Science, 300(5624): 1394–1399.
Wang B, Zhang A, Sun JL, Liu H, Hu J, Xu LX (2005). Study of SARS transmission via liquid droplets in air. Journal of Biomechanical Engineering: Transactions of the ASME, 127: 32–38.
WHO (2003). Access on http://www.who.int/csr/sars/country/2003_07_11/en.
Yu ITS, Li Y, Wong TW, Tam W, Chan AT, Lee JH, Leung DY, Ho T (2004). Evidence of airborne transmission of the severe acute respiratory syndrome virus. The New England Journal of Medicine, 350: 1731–1739.
Zhao B, Wu J (2005). Numerical investigation of particle diffusion in clean room. Indoor and Built Environment, 14: 469–479.
Zhao B, Zhang Z, Li X (2005). Numerical study of the transport of droplets or particles generated by respiratory system indoors. Building and Environment, 40: 1032–1039.
An erratum to this article can be found at http://doi.org/10.1007/s12273-009-9327-5
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Jiang, Y., Zhao, B., Li, X. et al. Investigating a safe ventilation rate for the prevention of indoor SARS transmission: An attempt based on a simulation approach. Build. Simul. 2, 281–289 (2009). https://doi.org/10.1007/s12273-009-9325-7
- ventilation rate