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Close proximity risk assessment for SARS-CoV-2 infection
G Cortellessa1, L Stabile1, F Arpino1
1Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, FR, Italy.
The Science of the Total Environment
|July 5, 2021
Summary
Maintaining safe interpersonal distance is crucial for reducing respiratory virus transmission. This study reveals that longer exposure times necessitate greater distances, with social distances of 1 meter becoming risky for exposures exceeding one minute.
Area of Science:
- Fluid dynamics
- Infectious disease transmission
- Risk assessment
Background:
- Interpersonal distance is key in respiratory virus spread.
- Mechanisms of droplet exposure are not fully understood.
- SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) risk assessment needs further characterization.
Purpose of the Study:
- To present an integrated risk assessment for SARS-CoV-2 exposure.
- To model the spread of exhaled droplets from a speaking person.
- To validate the model with experimental data.
Main Methods:
- Developed a 3D transient numerical model for droplet spread.
- Incorporated a SARS-CoV-2 emission model.
- Validated the numerical model using Particle Image Velocimetry (PIV) measurements.
Main Results:
- Large droplet risk is negligible beyond 0.6 m.
- Risk at greater distances depends solely on airborne droplets.
- Recommended safety distances increase with exposure duration: 0.75 m (10s), 1.1 m (1 min), 1.5 m (15 min).
Conclusions:
- Close proximity exposure risk is dependent on distance and duration.
- Social distances (approx. 1 m) pose a risk for exposures over 1 minute.
- Cultural and environmental factors influence interpersonal distances and risk.
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