Effects of ventilation rate and social distancing on risk of transmission of disease: A numerical study using Eulerian-Lagrangian method

ABSTRACTThis study utilized the Eulerian-Lagrangian method to investigate the risk of transmission of disease by tracking particles generated through coughing. The effects of ventilation rates (0.5, 5.0, and 10 ACH) and social distancing (0.9 and 1.8 m) were examined in a small office room using a displacement ventilation system. Numerical simulations considered different particle sizes (1, 5, 10, 20, 40, and 80 μm) to understand particle behavior and transmission routes. The airflow resulting from human coughing was validated with experimental data. Results showed that at a social distance of 0.9 m, increasing the ventilation rate led to a higher fraction of particles directly inhaled by susceptible individuals, potentially causing droplet and airborne transmission. However, maintaining a social distance of 1.8 m and a ventilation rate of 10 ACH significantly reduced the fraction of inhaled particles. Larger particles tended to deposit on floors and surfaces, while smaller particles remained suspended in the air. Higher ventilation rates increased particle deposition on the body surface of susceptible individuals, whereas increasing social distance reduced particle deposition. These findings highlight the importance of appropriate ventilation rates and social distancing in reducing the risk of infection transmission. Maintaining a social distance of 1.8 m combined with increased ventilation effectively reduced the fraction of inhaled particles. Larger particles were more likely to deposit on surfaces, emphasizing the need for regular disinfection. Understanding the dynamics of infectious particles and implementing effective ventilation and distancing measures can help mitigate the spread of infectious diseases in indoor environments.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgementsThis research was supported by JSPS KAKEHI (Grant Number 21K18763).Supplementary informationThe supplementary information includes Appendix A, Appendix B, and Appendix C.Supplementary data for this article is available online at the provided DOI: https://doi.org/10.1080/02786826.2023.2271954.