Tyrone Burke, November 2, 2020
Photo credit: Luther Caverly, file photos
Modelling the spread of COVID-19 in indoor environments to help pinpoint transmission risk
The novel coronavirus is tiny. At just 0.12 microns across, it is less than 1/500th the width of a single human hair. It is so small that it can be carried in tiny droplets called aerosols. These are as fine as mist, and can stay aloft for hours in some indoor environments. Masks and physical distance can help prevent transmission, but we are still sorting out exactly what an airborne virus could mean for contagion.
“It’s an open question right now, because nobody knows anything about how many viral particles can people spread through breathing. But winter is coming, and we will all be locked indoors. It’s important that we understand how the disease spreads,” says Gabriel Wainer, a Professor in Carleton’s Department of Systems and Computer Engineering.
“Through our other projects, my lab has access to the Building Information Models for all of Carleton’s campus, including the ventilation systems. We know how ventilation is structured, what kind of ventilation we have, and which rooms are connected. All of that is information we have included in our model. The virus could be in a single room, but that room could have connectivity with many other rooms.”
Through an NSERC Alliance Grant, Wainer is working with Canada’s Department of National Defense to model whether a virus hotspot could move through a building, and put its occupants at risk. The mathematical models use both viral particle modelling, and carbon dioxide as a proxy for the SARS-CoV-2 virus that causes COVID-19, and track how it diffuses using sensors spread throughout campus.
It could help establish a probability of contagion for those who were in the same building as an infected person, but not necessarily in the same place at the same time. This could help guide decision-making about who should self-isolate, and enable Canada’s military to keep more of its soldiers safe. Even during a pandemic, Canada’s military continues to provide essential services like search and rescue.
Wainer was awarded a second NSERC Alliance Grant for his work with Kanata-based technology company SOLACE. The project is using the same detailed models of buildings on Carleton campus, along with geographical information and the Susceptible-Infected-Recovered (SIR) models that epidemiologists use to predict the pandemic. SOLACE’s message broker platform will provide information about the spread of the virus across a variety of digital platforms in real time.
For Wainer, it is critical that the models they are building are nimble and adaptable. New COVID-19 research is published every day, and our understanding of the virus is constantly evolving.
“There are new results coming in all the time, but nobody knows with certainty how the virus spreads indoors,” says Wainer.
“We are trying to invent methods that can easily incorporate new research, as it is published. If we learn that the virus spreads in a particular way, we need to be able modify our model, and get new results very quickly.”
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