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Human Research Study of Particulate Propagation Distance From Human Respiratory Function
Jonathan Reyes1, Bernhard Stiehl1, Juanpablo Delgado1
1Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida, USA.
The Journal of Infectious Diseases
|January 13, 2022
Summary
Wearing face coverings significantly reduces the spread of airborne viral pathogens like SARS-CoV-2. A 3-foot distance with a mask is as effective as 6 feet without one.
Area of Science:
- Aerosol science
- Public health
- Respiratory pathogen transmission
Background:
- Airborne viral pathogens, such as SARS-CoV-2, spread through respiratory droplets and aerosols.
- Understanding droplet/aerosol transmission is crucial for public health interventions.
Purpose of the Study:
- To quantify the reduction in droplet/aerosol spread with different face coverings.
- To compare the effectiveness of face coverings combined with physical distancing.
Main Methods:
- Measured droplet/aerosol spread during speech and cough events for participants without coverings, with single-layer cloth, and with 3-layer disposable masks.
- Utilized planar particle imagery, light-sheet illumination, and aerosol/droplet probes (phase Doppler interferometry, aerodynamic particle sizer).
Main Results:
- Without masks, droplets traveled up to 1.37 m (4.5 ft).
- Cloth masks reduced spread to 0.67 m (2.2 ft), and disposable masks to 0.15 m (0.5 ft).
- Face coverings substantially decreased the number of expelled aerosols.
Conclusions:
- Physical distancing of 0.914 m (3 ft) with face coverings is as effective as 1.829 m (6 ft) without.
- Face coverings are a critical tool for reducing aerosol/droplet exposure and transmission.
