咳嗽呼出气溶胶人工模拟技术的研究

Study on artificial simulation of cough expelled particles

目的使用人工喷射液滴模拟咳嗽所产生飞沫,研究呼吸道传染病经空气传播的路径,评估室内感染呼吸道传染病的风险建立实地研究方法。方法在洁净度为100级的洁净实验室内以可控方式使用喷嘴喷射含有与人类唾液相似非挥发性的液滴,使用基于光学干涉Mie成像技术的Particle Master IMI系统对液滴的数量及粒径分布进行测量,找到与文献报道的咳嗽所产生颗粒物数量及粒径分布相近数据。结果在选定的喷嘴喷射流量情况下,持续时间为1s喷射过程中,喷嘴出口的液滴数量浓度为4个/mm3,相当于总共喷射出40 500个液滴;喷射液滴粒径的分布特征与从文献数据获得的咳嗽呼出颗粒物的粒径分布曲线非常吻合,其最小平方相关系数(又称决定系数)r2=0.88。结论成功使用具有唾液相似非挥发性组分人工合成物,采用可控方式制造出与咳嗽呼出颗粒物具有类似粒径分布的液滴谱系,为室内呼吸道传染病的飞沫传播路径及其感染风险研究提供了一种实地研究方法。

OBJECTIVE To establish a field research method for studying the transmission path of respiratory infec‐tious diseases via air and evaluating the indoor infectious risk by using artificial expelled droplets to simulate cough‐induced droplet nuclei .METHODS Expelled droplets containing similar non‐volatile components as human spittle were ejected by using well‐controlled nozzle in 100‐class clean operating laboratory .The quantity and the size dis‐tribution of the expelled droplets were measured using the optical Interferometric Mie Imaging （IMI） method .Da‐ta of the quantity and the size distribution of the expelled droplets that were close to those reported in literatures were found .RESULTS With the chosen nozzle injection flow rates ,the measured quantity concentration at the jet outlet was about 4/mm3 which was tantamount to a total of 40500 droplets injected in each 1 s injection .The size distribution of the measured expelled droplet matched the data reported in literatures ,with the least square regres‐sion coefficient （coefficient of determination） r2 =0 .88 .CONCLUSION This study provided a field study mechan‐ics in studying the transmission path of droplet nuclei of indoor respiratory infectious diseases and evaluating the corresponded infectious risk by successful application of an artificial cloud of expelled droplets containing similar non‐volatile components as human spittle with the droplet size distribution comparable to that in a cough event by a controllable means .