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Methodology for risk assessment of COVID-19 pandemic propagation
Journal of Loss Prevention in the Process Industries ( IF 3.5 ) Pub Date : 2021-06-23 , DOI: 10.1016/j.jlp.2021.104584
Maria Portarapillo 1 , Almerinda Di Benedetto 1
Affiliation  

This paper proposes a methodology to perform risk analysis of the virus spread. It is based on the coupling between CFD modelling of bioaerosol dispersion to the calculation of probability of contact events. CFD model of near-field sneeze droplets dispersion is developed to build the SARS-CoV-2 effect zones and to adequately capture the safe distance. The most shared classification of droplets size distribution of sneezes was used.

Droplets were modeled through additive heating/evaporation/boiling laws and their impact on the continuous phase was examined. Larger droplets move behind the droplet nuclei front and exhibit greater vertical drop due to the effect of gravity. CFD simulations provided the iso-risk curves extension (i.e., the maximum distance as well as the angle) enclosed by the incident outcome effect zone. To calculate the risk indexes, a fault tree was developed and the probability of transmission assuming as of the top event “COVID-19 infection” was calculated starting from the virus spread curve, as main base case. Four phases of virus spread evolution were identified: initiation, propagation, generalised propagation and termination. For each phase, the maximum allowable close contact was computed, being fixed the values of the acceptable risk index. In particular, it was found that during the propagation case, the maximum allowable close contacts is two, suggesting that at this point lockdown should be activated. The here developed methodology could drive policy containment design to curb spread COVID-19 infection.



中文翻译:

COVID-19 大流行传播风险评估方法

本文提出了一种对病毒传播进行风险分析的方法。它基于生物气溶胶分散的 CFD 建模与接触事件概率计算之间的耦合。开发了近场喷嚏飞沫扩散的 CFD 模型,以构建 SARS-CoV-2 效应区并充分捕捉安全距离。使用最常见的喷嚏液滴大小分布分类。

通过附加加热/蒸发/沸腾定律对液滴进行建模,并检查了它们对连续相的影响。较大的液滴在液滴核前沿后面移动,并且由于重力的作用表现出更大的垂直下落。CFD 模拟提供了由事件结果影响区域包围的等风险曲线扩展(即,最大距离和角度)。为了计算风险指数,开发了一个故障树,并假设从病毒传播曲线开始计算顶级事件“COVID-19 感染”的传播概率,作为主要基础案例。确定了病毒传播演变的四个阶段:启动、传播、普遍传播和终止。对于每个阶段,计算允许的最大密切接触,并固定为可接受的风险指数值。特别是,发现在传播情况下,允许的最大密切接触为两个,这表明此时应激活锁定。这里开发的方法可以推动政策遏制设计,以遏制 COVID-19 感染的传播。

更新日期:2021-06-28
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