COVID-19 is spread via different routes, including virus-laden airborne particles generated by human respiratory activities. In addition to large droplets, coughing and sneezing produce a lot of small aerosol particles. While face coverings are believed to reduce the aerosol transmission, information about their outward effectiveness is limited. Here, we determined the aerosol concentration patterns around a coughing and sneezing manikin and established spatial zones representing specific elevations of the aerosol concentration relative to the background. Real-time measurements of sub-micrometer aerosol particles were performed in the vicinity of the manikin. The tests were carried out without any face covering and with three different types of face covers: a safety faceshield, low-efficiency facemask and high-efficiency surgical mask. With no face covering, the simulated coughing and sneezing created a powerful forward-propagating fine aerosol flow. At 6 ft forward from the manikin head, the aerosol concentration was still 20-fold above the background. Adding a face covering reconfigured the forward-directed aerosol transmission pattern. The tested face coverings were found capable of mitigating the risk of coronavirus transmission; their effectiveness is dependent on the protective device. The outward leakage associated with a specific face covering was shown to be a major determinant of the exposure level for a person standing or seating next to or behind the coughing or sneezing “spreader” in a bus/train/aircraft/auditorium setting. Along with reports recently published in the literature, the study findings help assess the infectious dose and ultimately health risk for persons located within a 6-ft radius around the “spreader.”

COVID-19 通过不同途径传播，包括人类呼吸活动产生的载有病毒的空气传播颗粒。除了大飞沫外，咳嗽和打喷嚏还会产生许多小气溶胶颗粒。虽然人们认为面罩可以减少气溶胶传播，但有关其外在效果的信息有限。在这里，我们确定了咳嗽和打喷嚏的人体模型周围的气溶胶浓度模式，并建立了代表气溶胶浓度相对于背景的特定高度的空间区域。亚微米气溶胶颗粒的实时测量是在人体模型附近进行的。测试是在没有任何面罩的情况下进行的，使用了三种不同类型的面罩：安全面罩、低效口罩和高效外科口罩。在没有面罩的情况下，模拟的咳嗽和打喷嚏产生了强大的向前传播的细小气溶胶流。在人体模型头部前方 6 英尺处，气溶胶浓度仍比背景高 20 倍。添加面部覆盖物重新配置了前向气溶胶传播模式。经过测试的面罩被发现能够降低冠状病毒传播的风险；它们的有效性取决于保护装置。与特定面罩相关的向外泄漏被证明是决定在公共汽车/火车/飞机/礼堂环境中站在或坐在咳嗽或打喷嚏“传播者”旁边或后面的人的暴露水平的主要决定因素。连同最近在文献中发表的报告，