Wang Qiaoqiao, Gu Jianwei, An Taicheng
Institute for Environmental and Climate Research, Jinan University, 511443, Guangzhou, China.
Guangdong-Hong Kong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, 511443, Guangzhou, China.
Build Environ. 2022 Jul 1;219:109224. doi: 10.1016/j.buildenv.2022.109224. Epub 2022 May 24.
The public transport system, containing a large number of passengers in enclosed and confined spaces, provides suitable conditions for the spread of respiratory diseases. Understanding how diseases are transmitted in public transport environment is of vital importance to public health. However, this is a highly multidisciplinary matter and the related physical processes including the emissions of respiratory droplets, the droplet dynamics and transport pathways, and subsequently, the infection risk in public transport, are poorly understood. To better grasp the complex processes involved, a synthesis of current knowledge is required. Therefore, we conducted a review on the behaviors of respiratory droplets in public transport system, covering a wide scope from the emission profiles of expiratory droplets, the droplet dynamics and transport, to the transmission of COVID-19 in public transport. The literature was searched using related keywords in Web of Science and PubMed and screened for suitability. The droplet size is a key parameter in determining the deposition and evaporation, which together with the exhaled air velocity largely determines the horizontal travel distance. The potential transmission route and transmission rate in public transport as well as the factors influencing the virus-laden droplet behaviors and virus viability (such as ventilation system, wearing personal protective equipment, air temperature and relative humidity) were also discussed. The review also suggests that future studies should address the uncertainties in droplet emission profiles associated with the measurement techniques, and preferably build a database based on a unified testing protocol. Further investigations based on field measurements and modeling studies into the influence of different ventilation systems on the transmission rate in public transport are also needed, which would provide scientific basis for controlling the transmission of diseases.
公共交通系统在封闭和有限的空间内承载大量乘客，为呼吸道疾病的传播提供了适宜条件。了解疾病在公共交通环境中的传播方式对公众健康至关重要。然而，这是一个高度多学科的问题，包括呼吸道飞沫排放、飞沫动力学和传播途径以及随后公共交通中的感染风险等相关物理过程，目前还知之甚少。为了更好地理解其中涉及的复杂过程，需要对现有知识进行综合。因此，我们对公共交通系统中呼吸道飞沫的行为进行了综述，涵盖了从呼气飞沫的排放特征、飞沫动力学和传播到新冠病毒在公共交通中的传播等广泛内容。在科学网和PubMed中使用相关关键词搜索文献并筛选其适用性。液滴大小是决定沉积和蒸发的关键参数，它与呼出空气速度一起在很大程度上决定了水平传播距离。还讨论了公共交通中的潜在传播途径和传播率以及影响载病毒飞沫行为和病毒活力的因素（如通风系统、佩戴个人防护装备、气温和相对湿度）。该综述还表明，未来的研究应解决与测量技术相关的飞沫排放特征的不确定性，最好基于统一的测试协议建立数据库。还需要基于现场测量和建模研究进一步调查不同通风系统对公共交通中传播率的影响，这将为控制疾病传播提供科学依据。
