Covid-19 is mainly spread through close contact, but a group of mechanical engineers at a Canadian university are looking at a lesser-known possibility — airborne transmission. HVAC systems may spread the novel coronavirus through multi dwelling and commercial properties.
Bringing safe and healthy air to spaces — everything from apartment buildings to schools to offices — is the central theme of the project, according to University of Alberta engineering professor Lexuan Zhong, who is leading the research.
She called the effort a “non-pharmaceutical intervention” that, if successful, could avoid “extensive consequences.”
“It’s just as valuable as vaccine research,” she told Global News.
“Improving ventilation systems in high-occupancy structures could be a critical way to contain the pandemic… This work has the potential to impact millions of people living and working in these buildings.”
The Alberta engineers are working in collaboration with the university’s faculty of medicine to better understand how viruses can travel through air currents. They want to come up with effective design upgrades or changes to standard heating, ventilation and air conditioning (HVAC) systems to foster guidelines that buildings across the country could adapt to.
It’s being funded by a $440,000 federal government grant from the Canadian Institutes of Health Research and Alberta Innovates.
Zhong pointed to research out of China as what is, in part, guiding their colossal research effort.
Back in January, a restaurant in Guangzhou, China was linked to an outbreak of the virus.
Researchers believe an asymptomatic woman who dined at the restaurant was the source of the outbreak. She later developed symptoms, visited a hospital and tested positive for the virus.
Within two weeks, four of the woman’s family members fell ill, as did five other people from two other families who were dining in the restaurant at the time.
According to the research, published in the journal of Emerging Infectious Diseases earlier in April, the families were all seated farther apart than one meter — droplets don’t commonly travel more than a meter or two.
While only preliminary, the findings led the scientists to believe that the restaurant’s air conditioning system may have blown the viral droplets farther.
Airborne transmission is not as common as droplet transmission, which occurs when an infected person coughs or sneezes — dispelling droplets — near a healthy person.
The World Health Organization stands by droplet transmission as the main way people can contract COVID-19, hence the emphasis on physical distancing measures, hand-washing and shuttered public spaces.
But, as Chinese and Australian air quality experts point out in a recent paper, “the fact that there are no simple methods for detecting the virus in the air does not mean that the viruses do not travel in the air.”
Those researchers used SARS as an example.
Some evidence has suggested it was possible for SARS — which is of the same family of coronaviruses as SARS-CoV-2, the virus that causes COVID-19 — to spread through the air. They argued that as viral droplets are expelled, they start to evaporate, becoming so small that they are more easily transported by air and can be carried “tens of meters from where they originated.”
When this happens, “we end up losing track of where they go,” said Brian Fleck, a mechanical engineer and professor at the University of Alberta, who is part of the Canadian project.
“They sort of move around the building,” he said.
“While it’s not the most powerful method of transmission, it’s certainly one that makes people worry because we have a difficult time controlling it.”
At this point in the coronavirus pandemic, which has already infected more than three million people worldwide, he said researchers should look toward anything that could help.
“Even if we can reduce the transmission rate a couple of per cent, that’s worth it,” he said, adding it’s all the more important as provinces and states look ahead to reopening certain services and spaces.
“People are spending most of their time indoors these days. And for places with air pollution, it’s even more important because the clear air is indoors in these highly-polluted megacities.”
He said it will be particularly difficult to determine how to control air currents in large spaces, like grocery stores and large cubicle-based office spaces.
But a key aspect will be to find inexpensive solutions, Fleck said. At this point, he suspects increased filtration methods and less reliance on recycled air will be important modifications.
“As we’ve already seen with the shutdown, every time you compromise the economy, people are concerned about the trade-offs,” he said.
“It’s really important that the solutions we get — which could affect countless buildings — are reasonably priced. We need a cost-effective solution, not a platinum-plated one.”
The research will unfold in three parts: a systematic review of research on air circulation and viruses, determining an effective strategy and then testing out that strategy on buildings at the Edmonton campus “to create a real-world model of what should be done,” Zhong said.
By the end, Zhong and Fleck, along with co-researcher Lisa Hartling and others, hope to answer a number of questions about airborne transmissibility, but ultimately advise “direct guidelines” on how buildings can continue running HVAC systems safely.
“It’s certainly a possible method of transmission,” he said. “If we can find ways to reduce or eliminate that, we can literally save lives.”