Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
School of Architecture, Tsinghua University, Beijing, China.
J Hazard Mater. 2024 Dec 5;480:136040. doi: 10.1016/j.jhazmat.2024.136040. Epub 2024 Oct 2.
Infectious aerosols are expired in various sizes, and the number of contained virions is expected to significantly vary among expired aerosols. To evaluate the effect of the number of contained virions on infection risk, multi-virion aerosols in expired air should be first quantified. In this study, we categorised expired aerosols into traditional aerosol size bins and aerosols containing different number of virions. We quantified the number of virions in aerosols of each size bin and estimated the size distribution of aerosols which contain a certain number of virions when the viral load is known. This analysis helped us to determine the relationship between multi-size aerosols and multi-virion aerosols. Our findings indicate that for long-range airborne transmission, the airborne transmission droplets derived from four COVID-19 outbreak venues contain at most one infectious virion, supporting the one-virion assumption for the considered viral load ranges. However, for short-range airborne transmission, the impact of multi-virion aerosols on infection risk must be considered. Our quantification of multi-virion aerosols for the first time lays the groundwork for incorporating the multi-virion assumption into infection risk assessments.
传染性飞沫以各种大小释放，且所含病毒颗粒数预计在不同飞沫中存在显著差异。为评估所含病毒颗粒数对感染风险的影响，应首先定量分析呼出空气中的多病毒颗粒飞沫。在这项研究中，我们将呼出飞沫分为传统飞沫大小类别和含有不同病毒颗粒数的飞沫。我们对每个大小类别的飞沫中的病毒颗粒数进行了定量，并在已知病毒载量时估计了含有特定数量病毒颗粒的飞沫的大小分布。该分析帮助我们确定了多大小飞沫和多病毒颗粒飞沫之间的关系。我们的研究结果表明，对于长距离空气传播，源自四起 COVID-19 暴发场所的空气传播飞沫最多含有一个感染性病毒颗粒，支持在考虑的病毒载量范围内一个病毒颗粒的假设。然而，对于短距离空气传播，必须考虑多病毒颗粒飞沫对感染风险的影响。我们首次对多病毒颗粒飞沫进行定量，为将多病毒颗粒假设纳入感染风险评估奠定了基础。
