Researchers build web-based tool to reduce risk of indoor SARS-CoV-2 transmission

Thanks to CityRPI, users can pick any building in the Montreal region and the tool will guide them through a personalized airborne virus risk assessment.

With colder weather just around the corner, Montrealers soon will be spending more and more time indoors, increasing the likelihood of a spike in COVID-19 cases in the city.

To help slow the spread of the new coronavirus during the cold season, a team of researchers led by Leon Wang, associate professor of building, civil and environmental engineering at the Gina Cody School of Engineering and Computer Science, has built a web-based tool to estimate the risk of indoor airborne transmission of the virus in Montreal’s buildings.

Wang, alongside PhD students Ali Katal and Maher Albettar, developed the City Reduced Probability of Infection (CityRPI) site the Concordia University Building Environment Lab. It calculates the probability of infection through aerosol transmission in indoor spaces.

Wang, an expert in building airflow and thermal management, says that a proper understanding of ventilation and air quality in indoor spaces could help slow the spread of the virus.

“Until recently, the importance of aerosol transmission had been overlooked, but now it’s clear that this is one of the major routes of infection, especially for poorly ventilated spaces,” he says.

A young man with short dark hair, of asian heritage, wearing steel-rimmed glasses and a brown suit.Leon Wang: “The website aims to help policymakers and the general public make informed decisions about how to slow the spread of airborne viruses.” | Photo by David Ward

Site shares measures to reduce transmission

The web-based tool calculates the probability of infection in a building by using publicly available data from building standards and codes and geographic information from various sources such as OpenStreetMap, Microsoft Building Footprints and the City of Montreal.

Users can pick any building in the Montreal region. The tool will guide them through a personalized assessment, prompting them to provide information such as air exchange rates, ventilation, air filtration conditions, occupation density, staying time and whether or not occupants are required to wear a mask.

“The research used to develop this tool shows that there’s a correlation between indoor airborne virus transmission risk, the number of people in a space and how long they stay there,” Wang adds. “This confirms that wearing a mask indoors can be critical in slowing the spread of the virus.”

Based on the building parametres fed into the site, Wang’s tool provides a list of measures to help building owners reduce the risk of indoor infections due to airborne virus aerosols.

“The website aims to provide a quality scientific method on building ventilation to help policy-makers and the general public make informed decisions about how to slow the spread of the new coronavirus from airborne aerosol transmission,” Wang notes.

“Other precaution and mitigation measures must also be strictly maintained, such as social distancing and frequent disinfection, to reduce the risks due to contact and droplet transmissions indoors.”

CityRPI was built using an open-source tool developed by Wang’s collaborators Shelly Miller and a team led by Jose Jimenez, both at the University of Colorado Boulder. It was funded thanks to a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada.

Here are some best practices to minimize the risk of airborne virus transmission indoors

  • Wear a face mask
  • Upgrade to high-efficiency duct filters in HVAC systems
  • Regularly change air filters in ventilation systems and air cleaners
  • Use portable air cleaners in poorly ventilated and/or crowded spaces
  • Spend less time in public spaces indoors
  • Reduce the number of occupants in a space

Check out the City Reduced Probability of Infection (CityRPI) site and [Nimle] about Concordia’s Gina Cody School of Engineering and Computer Science.

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