A recent study reported that an aerosolized virus (COVID-19) can survive in the air for a few hours. It is highly possible that people get infected with the disease by breathing and contact with items contaminated by the aerosolized virus. However, the aerosolized virus transmission and trajectories in various meteorological environments remain unclear. This paper has investigated the movement of aerosolized viruses from a high concentration source across a dense urban area. The case study looks at the highly air polluted areas of London: University College Hospital (UCH) and King's Cross and St Pancras International Station (KCSPI). We explored the spread and decay of COVID-19 released from the hospital and railway stations with the prescribed meteorological conditions. The study has three key findings: the primary result is that the concentration of viruses decreases rapidly by a factor of 2-3 near the sources although the virus may travel from meters up to hundreds of meters from the source location for certain meteorological conditions. The secondary finding shows viruses released into the atmosphere from entry and exit points at KCSPI remain trapped within a small radial distance of < 50 m. This strengthens the case for the use of face coverings to reduce the infection rate. The final finding shows that there are different levels of risk at various door locations for UCH; depending on which door is used there can be a higher concentration of COVID-19. Although our results are based on London, since the fundamental knowledge processes are the same, our study can be further extended to other locations (especially the highly air polluted areas) in the world.

中文翻译：

---

伦敦 COVID-19 时空传播的数值研究。

最近的一项研究报告称，雾化病毒（COVID-19）可以在空气中存活几个小时。人们很可能通过呼吸和接触被雾化病毒污染的物品而感染该疾病。然而，各种气象环境下的气溶胶病毒传播和轨迹仍不清楚。本文研究了来自高浓度源的气溶胶病毒在密集城市地区的移动。该案例研究着眼于伦敦空气污染严重的地区：大学学院医院 (UCH) 以及国王十字和圣潘克拉斯国际车站 (KCSPI)。我们研究了在规定的气象条件下从医院和火车站释放的 COVID-19 的传播和衰减情况。该研究有三个关键发现：主要结果是，尽管在某些气象条件下，病毒可能会从距离源头位置数米到数百米的地方传播，但病毒在源头附近的浓度迅速下降2-3倍。第二项发现显示，从 KCSPI 入口和出口点释放到大气中的病毒仍被困在 < 50 m 的小径向距离内。这强化了使用面罩来降低感染率的理由。最终调查结果显示，不同门口位置的水下文化遗产存在不同程度的风险；根据使用的门，可能会有更高浓度的 COVID-19。虽然我们的结果是基于伦敦，但由于基本知识过程是相同的，我们的研究可以进一步扩展到世界其他地方（特别是空气污染严重的地区）。