Hybrid measurement of respiratory aerosol reveals a dominant coarse fraction resulting from speech that remains airborne for minutes.
Hybrid measurement of respiratory aerosol reveals a dominant coarse fraction resulting from speech that remains airborne for minutes.
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DOI：
10.1073/pnas.2203086119
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发表时间：
2022-06-28
影响因子：
11.1
通讯作者：
Bax, Adriaan
中科院分区：
文献类型：
--
作者：
Shen, Yang;Courtney, Joseph M.;Anfinrud, Philip;Bax, Adriaan
Respiratory droplets are widely recognized as the primary vehicle in viral respiratory disease transmission. Accurate information on their number and size distributions is important for appropriate mitigation strategies, for quantitative modeling of airborne disease transmission, and for evaluating the relative importance of droplets originating from saliva versus airway lining fluid. A straightforward experimental setup using inexpensive, readily available components is developed for simultaneous characterization of larger particles by video analysis of laser light scattering and monitoring of smaller sizes by an optical particle counter. Measurements indicate that in a healthy volunteer, the airborne mass of speech aerosol far exceeds that generated by breathing, even when accounting for faster sedimentation of the larger particles. Accurate measurements of the size and quantity of aerosols generated by various human activities in different environments are required for efficacious mitigation strategies and accurate modeling of respiratory disease transmission. Previous studies of speech droplets, using standard aerosol instrumentation, reported very few particles larger than 5 μm. This starkly contrasts with the abundance of such particles seen in both historical slide deposition measurements and more recent light scattering observations. We have reconciled this discrepancy by developing an alternative experimental approach that addresses complications arising from nucleated condensation. Measurements reveal that a large volume fraction of speech-generated aerosol has diameters in the 5- to 20-μm range, making them sufficiently small to remain airborne for minutes, not hours. This coarse aerosol is too large to penetrate the lower respiratory tract directly, and its relevance to disease transmission is consistent with the vast majority of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections initiating in the upper respiratory tract. Our measurements suggest that in the absence of symptoms such as coughing or sneezing, the importance of speech-generated aerosol in the transmission of respiratory diseases is far greater than generally recognized.
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影响因子：
3.4
作者：
Courtney JM;Bax A
通讯作者：
Bax A
DOI：
10.1093/cid/ciab797
发表时间：
2022-08-24
期刊：
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America
影响因子：
--
作者：
Adenaiye OO;Lai J;Bueno de Mesquita PJ;Hong F;Youssefi S;German J;Tai SHS;Albert B;Schanz M;Weston S;Hang J;Fung C;Chung HK;Coleman KK;Sapoval N;Treangen T;Berry IM;Mullins K;Frieman M;Ma T;Milton DK
通讯作者：
Milton DK
影响因子：
5
作者：
CHENG, YS;WANG, CS
通讯作者：
WANG, CS
影响因子：
18.2
作者：
Dickson RP;Erb-Downward JR;Martinez FJ;Huffnagle GB
通讯作者：
Huffnagle GB
影响因子：
4.6
作者：
Dalla Barba, F.;Wang, J.;Picano, F.
通讯作者：
Picano, F.