Turbulent Gas Clouds and Respiratory Pathogen Emissions

Recent work has demonstrated that exhalations, sneezes, and coughs comprise a multiphase turbulent gas (puff) cloud of exhaled air that entrains ambient air and traps and carries within it clusters of mucosalivary fluid droplets with a continuum of droplet sizes. The droplets of all sizes are created both within and outside of the respiratory tract.

The video below demonstrates the phenomena in human sneezes visualized by light scattering toward the camera from multiple optical sources and at different distances. It illustrates how mucosalivary liquid emissions, in the form of droplets of a continuous size range, are coupled with the hot, moist, and high momentum gas cloud, which traps and carries them forward up to 7 to 8 m (26 ft). This newer understanding of respiratory emission dynamics has implications for mask and respiratory design, social distancing recommendations, and other public health interventions during and after the COVID-19 pandemic.

Click the related article button for complete details, recently published by the Journal of the American Medical Association.

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