Assessment and mitigation of aerosol airborne SARS-CoV-2 transmission in laboratory and office environments

Abstract

Bioaerosols are known to be an important transmission pathway for SARS-CoV-2. We report a framework for estimating the risk of transmitting SARS-CoV-2 via aerosols in laboratory and office settings, based on an exponential dose-response model and analysis of air flow and purification in typical heating, ventilation, and air conditioning (HVAC) systems. High-circulation HVAC systems with high-efficiency particulate air (HEPA) filtration dramatically reduce exposure to the virus in indoor settings, and surgical masks or N95 respirators further reduce exposure. As an example of our risk assessment model, we consider the precautions needed for a typical experimental physical science group to maintain a low risk of transmission over six months of operation. We recommend that, for environments where fewer than five individuals significantly overlap, work spaces should remain vacant for between one (high-circulation HVAC with HEPA filtration) to six (low-circulation HVAC with no filtration) air exchange times before a new worker enters in order to maintain no more than 1% chance of infection over six months of operation in the workplace. Our model is readily applied to similar settings that are not explicitly given here. We also provide a framework for evaluating infection mitigation through ventilation in multiple occupancy spaces.

Keywords:

• Airborne viral transmission
• coronavirus
• risk analysis
• SARS-CoV-2

Acknowledgments

We gratefully acknowledge Loic Anderegg, Louis Baum, Richard L. Garwin, Christian Hallas, Nathaniel Vilas, and Xing Wu for providing feedback on this manuscript. BLA acknowledges support from the NSF GRFP and HS from the Ezoe Memorial Recruit Foundation.

Additional information

Funding

We gratefully acknowledge funding from the Heising-Simons foundation.