Face coverings and respiratory tract droplet dispersion: Dataset 1: UV light test - droplets deposition images

"Face coverings and respiratory tract droplet dispersion" Supplementary Information. # Background: # Respiratory droplets are the primary transmission route for SARS-CoV-2; a principle which drives social distancing guidelines. Evidence suggests that virus transmission can be reduced by face coverings, but robust evidence for how mask usage might affect safe distancing parameters is lacking. Accordingly, we set out to quantify the effects of face coverings on respiratory tract droplet deposition. # Methods: # We tested an anatomically-realistic manikin head which ejected fluorescent droplets of water, and human volunteers, in speaking and coughing conditions without a face covering, with a surgical mask and/or a single layer cotton face covering. We quantified the number of droplets in flight using laser sheet illumination and UV-light for those that had landed at table height, from 0·25 m up to 2 m. For human volunteers, expiratory droplets were caught on a microscope slide 5 cm from the mouth. # Findings: # Whether manikin or human, wearing a face covering decreased the number of projected droplets by > 1000-fold. The effect was so marked that wearing a face mask rendered droplets virtually undetectable at any tested distance. We also estimated that a person standing 2 m from someone coughing without a mask is exposed to over 10,000 times more respiratory droplets than someone standing 0.5 m from someone wearing a basic single layer mask. # Interpretation: # Our results indicate that face coverings show consistent efficacy at blocking respiratory droplets and thus provide an opportunity to moderate social distancing policies. However, the methodologies we employed mostly detect larger (non-aerosol) sized droplets. Whilst SARS-CoV-2 is spread by respiratory droplets and the fomites they generate, the relative importance between these modes of transmission and true aerosol transmission is uncertain. If aerosol transmission is later determined to be a significant driver of infection, then our findings may overestimate the effectiveness of face coverings.Accordingly, we set out to quantify the effects of face coverings on respiratory tract droplet deposition. # Structure: # Face coverings and respiratory tract droplet dispersion" Supplementary Information. The information is grouped into four, zipped, datasets: Dataset 1: UV light test - droplets deposition images https://doi.org/10.7488/ds/2897; Dataset 2: Microscopy tests - droplets deposition images https://doi.org/10.7488/ds/2899; Dataset 3: Laser tests - droplets path images https://doi.org/10.7488/ds/2900; Dataset 4: Shadow Imaging https://doi.org/10.7488/ds/2909. For further details, please download the ReadMe.txt file from each dataset. All the datasets are part of the Collection "Face coverings and respiratory tract droplet dispersion" https://datashare.is.ed.ac.uk/handle/10283/3729 .

《面部遮盖物与呼吸道飞沫扩散》补充材料。# 背景：# 呼吸道飞沫是严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）的主要传播途径，这一原理也是社交距离防疫指南的制定依据。现有研究表明，佩戴面部遮盖物可降低病毒传播风险，但关于口罩使用如何影响安全社交距离参数的可靠证据仍较为匮乏。为此，本研究旨在量化面部遮盖物对呼吸道飞沫沉积的影响。# 方法：# 我们采用了解剖学结构逼真的人体模型头部，其可喷射荧光水滴，并招募人类志愿者，分别在未佩戴面部遮盖物、佩戴外科口罩以及/或单层棉质面部遮盖物的情况下开展说话与咳嗽实验。我们通过激光片层照明技术量化飞行中的飞沫数量，并针对桌高位置（距离范围0.25米至2米）的沉降飞沫采用紫外光照进行检测。对于人类志愿者，我们在其口腔前方5厘米处放置显微镜载玻片以收集呼出的飞沫。# 结果：# 无论是人体模型还是人类志愿者，佩戴面部遮盖物均可使喷射出的飞沫数量减少1000倍以上。该效果极为显著，佩戴口罩后，在所有测试距离下均几乎无法检测到飞沫。我们还估算得出，与站在佩戴单层基础口罩的咳嗽者0.5米处的人员相比，站在未佩戴口罩的咳嗽者2米处的人员所接触到的呼吸道飞沫量高出10000倍以上。# 解读：# 我们的研究结果表明，面部遮盖物在阻挡呼吸道飞沫方面表现出稳定的防护效果，因此可为调整社交距离政策提供依据。不过本研究采用的方法大多仅能检测尺寸较大的（非气溶胶（aerosol）类）飞沫。虽然SARS-CoV-2可通过呼吸道飞沫及其形成的污染物表面传播，但此类传播途径与真正的气溶胶（aerosol）传播之间的相对重要性尚不明确。若后续研究证实气溶胶传播是感染的重要驱动因素，则本研究结果可能会高估面部遮盖物的防护效果。为此，本研究旨在量化面部遮盖物对呼吸道飞沫沉积的影响。# 数据集结构：# 《面部遮盖物与呼吸道飞沫扩散》补充材料包含4个经压缩的数据集：数据集1：紫外光检测-飞沫沉降图像（https://doi.org/10.7488/ds/2897）；数据集2：显微镜检测-飞沫沉降图像（https://doi.org/10.7488/ds/2899）；数据集3：激光检测-飞沫路径图像（https://doi.org/10.7488/ds/2900）；数据集4：阴影成像（https://doi.org/10.7488/ds/2909）。如需进一步了解详情，请从各数据集中下载ReadMe.txt文件。所有数据集均隶属于“面部遮盖物与呼吸道飞沫扩散”数据集合集（https://datashare.is.ed.ac.uk/handle/10283/3729）。