Atmospheric Chemistry Program Seminar

Heterogeneity in Airborne Transmission of COVID-19 by Respiratory Aerosols

Prasad Kasibhatla (Duke Univ., CIRES Visiting Fellow)

"The recognition of the importance of airborne transmission of the SARS-CoV-2 virus by respiratory aerosols has spurred several research groups to develop and apply simple mechanistic aerosol models to investigate COVID-19 outbreaks associated with specific events. These studies have highlighted the importance of layered, non-pharmaceutical intervention strategies such as masking, ventilation, and air cleaning to mitigate transmission risk. To date, however, there is a disconnect between these micro-scale mechanistic aerosol models and the macro-scale epidemiological models that have been used to study large-scale COVID-19 disease dynamics. In this talk, I will discuss my recent research to try to close this gap. I will present a Monte Carlo analysis of transmission risk and secondary infections arising in social settings by modeling aerosol transmission of COVID-19 in thousands of indoor locations in the United State. I will show that variability of viral load among index cases plays a key role in shaping the variability in transmission risk at these locations. I will further demonstrate that aerosol transmission is consistent with the observation that COVID-19 transmission is overdispersed and will provide a mechanistic explanation for this large-scale characteristic of the pandemic. Implications of this finding with regards to the effectiveness of non-pharmaceutical interventions in curbing the pandemic will be discussed. Finally, I will outline my ideas for the next steps in this research that I will be working on during my sabbatical at CIRES."