Seeking Out all Mechanical Vulnerabilities to the Transmission of COVID-19

"We want to save lives, let's cut right to the chase."
"There are so many, many buildings ... This affects absolutely everybody. Billions of people. If we are able to cut down the transmission rate by a percent, that's a lot of people."
"This has been on people's radar for quite a while. Somebody on a different floor sneezes ... The particle can stay airborne long enough to go all the way through the [air conditioning] system and then pop out in somebody else's office." 
"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."
"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."
Professor Brian Fleck, scientific study, University of Alberta

"It is  highly likely that the SARS-CoV-2 virus also spreads by air, [requiring] all possible [action in response, including modifications in ventilation systems]."
"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."
"We predict that ... failure to immediately recognize and acknowledge the importance of airborne transmission and to take adequate actions against it will result in additional cases."
Chinese and Australian air-quality experts

"[The effort represents a] non-pharmaceutical intervention [that, if successful, could avoid] 
extensive consequences. It’s just as valuable as vaccine research."
"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 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."
Lexuan Zhong, engineering professor, University of Alberta

An African restaurant is closed off along with other businesses in Guangzhou's Sanyuanli area, where a neighborhood is in lockdown after several people tested positive for the novel coronavirus disease (COVID-19), in Guangdong province, China April 13, 2020. - REUTERS/David Kirton

Engineering professor Lexuan Zhong is leading a project involving the university's civil engineers funded by the Canadian Institutes for Health Research at the University of Alberta, consisting of three phases; systematically reviewing literature on air circulation and viruses, determining the strategies that would be effective, and finally conducting a detailed audit of all buildings on the Edmonton campus with the intention of creating a real-world model of what should be done in response to their conclusions.

Their interest in the possible role that building HVAC systems (heating, ventilation and air conditioning) may play a role in the transmission of the novel coronavirus stemmed from a case in Guangzhou, China detailed in a U.S.Centers for Disease Control online journal. Researchers had reached the conclusion that flow from an air conditioner moved over three occupied tables in the restaurant, carrying virus droplets from an infected patron at the middle table to the far table, then back to diners closer to the air conditioner.

It was a puzzle at first how eight diners at the restaurant all were infected with the coronavirus. A visitor from Wuhan, the coronavirus epicentre, suspected of being the vector had travelled to the Guangzhou region and happened to enter the restaurant. A team of local scientists came to a conclusion that tiny particles of virus had floated around on currents created by the restaurant's air conditioning, despite the prevailing view that the coronavirus is transmitted solely by heavier 'droplets'.

Now, the civil engineers at the University of Alberta have taken up the intriguing concept, one they are familiar with, hearking back to Legionnaire's Disease, a bacterial pneumonia transmitted in a hotel setting through the air conditioning system. Engineers are well acquainted with building ventilation systems as efficient distributors of viruses and other pathogens. They have set out to prove that COVID-19 falls into the same category. What now consumes their interest is conceiving of practical ways to curb infection risk; a "non-pharmaceutical" intervention.

"The HVAC system in most non-medical buildings play only a small role in infectious disease transmission, including COVID-19", responded the American Society of Heating, Refrigerating, and Air-conditioning Engineers, in defence of their product and their livelihood. The smaller, lighter aerosol particles capable of spreading through a ventilation system is still questioned by some: "the truth is that we still don't really know if the (COVID-19) virus can be spread by aerosols", virus expert Matthew Miller at McMaster University responded.

However, in a paper published earlier in the month, Chinese and Australian air-quality experts basing their hypothesis partly on the SARS experience, argued in their own study that as droplets from an infected person begin evaporating, the resulting smaller particles indeed may become airborne; evidence that passengers confined to their cabins on cruise ships was cited such that they may have been infected through the air ducts of the vessels.

Canadian cases

CONFIRMED

50,015

(Today: +1,526)

DEATHS

2,859

(Today: +152)

RECOVERED

19,203

(Today: +922)

782,541 tests administered  (Today: +28,023)