RAPID: Coronavirus: Understanding aerosol transmission and potential control measures in indoor environments

Engineering - COVID-19 is a worldwide pandemic caused by the Coronovirus SARS-CoV2. COVID-19 is reported to be transmitted through direct surface exposure and through close personal contact within a short distance. Recent studies demonstrate that the virus can survive in small airborne particles (less than 5 micrometers) for hours and accumulate indoors. This result suggests a strong possibility for airborne transmission of COVID-19 in occupied spaces. However, there is a present lack of science-based information on how the virus-laden particles disperse in indoor environments. This RAPID proposal responds to the urgent need to better understand the airborne transmission and potential SARS-CoV2 control measures in indoor environments. The goal of this project is to investigate the transport mechanisms of the virus particle transport around the human body and reveal how the concentrations of virus particles are affected by human coughing and breathing, as well as ventilation rates and indoor airflow patterns. This information will be used to evaluate the effectiveness of control measures such as ventilation, filtration, and zone partitioning on aerosol transmission in densely occupied environments. Results will be used to help protect vulnerable population groups in clinical settings and senior living facilities. Successful completion of this research will more broadly inform medical health professionals, scientists, engineers, and policymakers to make decisions regarding the types of ventilation strategies and personal protective equipment that can be used to prevent aerosol transmission indoors.

The COVID-19 pandemic is a health emergency of global scale. Emerging science suggests a high potential for airborne exposure to SARS-CoV2 (the virus responsible for COVID-19) as a significant exposure pathway. However, there are major gaps in our understanding that prevent efficient use of control strategies for indoor environments. The overall objectives of this research project are to address this knowledge gap by: (1) developing a mechanistic understanding of SARS-CoV2 aerosol transport in indoor environments due to coughing, talking, normal breathing, and breathing with a mask under various ventilation rates and air mixing conditions; (2) assessing airborne infection risk using inhalation intake of SARS-CoV2 aerosols released from an infector assuming steady-state, well-mixed air conditions; and (3) evaluating the effectiveness of ventilation, filtration, and zone partitioning for controlling aerosol transmission in densely occupied environments. This will be achieved using a mathematical infection risk model coupled with computational fluid dynamics simulations of aerosol transport to provide new information critical to our understanding of virus aerosol transport and associated airborne infection risk in indoor environments. The analysis will fill a critical information gap in our understanding of the transport mechanisms of infectious aerosols in the human breathing zone. Key parameters to be assessed include the emission mode of the infector (i.e. coughing, talking, breathing); the infectious aerosol mass and diameter; and the ventilation strategy and indoor air mixing rate. Parametric analysis of the effectiveness of infection control measures will inform guidelines for building system design and operations for the protection of human health.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.