Knowing the physicochemical properties of exhaled droplets and aerosol particles is a prerequisite for a detailed mechanistic understanding and effective prevention of the airborne transmission of infectious human diseases. This review provides a critical consideration and synthesis of scientific knowledge on the number concentrations, size distributions, composition, mixing state, and related properties of respiratory particles emitted upon breathing, speaking, singing, coughing, and sneezing. A parametrization of respiratory particle size distributions is derived and presented based on five log-normal modes related to different origins in the respiratory tract, which can be used to trace and localize the sources of infectious particles. This approach may support the medical treatment as well as the risk assessment for aerosol and droplet transmission of infectious diseases. It was applied to analyze which respiratory activities may drive the spread of specific pathogens, such as Mycobacterium tuberculosis, influenza viruses, and severe acute respiratory syndrome coronaviruses 2 (SARS-CoV-2). The results confirm the high relevance of vocalization for the transmission of SARS-CoV-2, as well as the usefulness of physical distancing, face masks, room ventilation, and air filtration as preventative measures against coronavirus disease 2019 and other airborne infectious diseases.

中文翻译：

---

呼吸道气溶胶和飞沫在传染病传播中的作用

了解呼出的飞沫和气溶胶颗粒的物理化学特性是详细了解和有效预防人类传染病空气传播的先决条件。这篇综述对呼吸、说话、唱歌、咳嗽和打喷嚏时排放的呼吸颗粒的数量浓度、尺寸分布、成分、混合状态和相关特性进行了批判性思考和综合。基于与呼吸道不同来源相关的五种对数正态模式，导出并呈现了呼吸颗粒尺寸分布的参数化，可用于追踪和定位传染性颗粒的来源。这种方法可以支持医疗治疗以及传染病气溶胶和飞沫传播的风险评估。它用于分析哪些呼吸活动可能驱动特定病原体的传播，例如结核分枝杆菌、流感病毒和严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2)。结果证实了发声与 SARS-CoV-2 传播的高度相关性，以及保持身体距离、戴口罩、房间通风和空气过滤作为预防 2019 年冠状病毒病和其他空气传播传染病的预防措施的有用性。