UBC’s approach to reducing the risk of airborne COVID-19 transmission follows recommended principles but leaves questions about whether all classrooms are equally protected.
Earlier this month, UBC’s COVID-19 heating, ventilation and air conditioning (HVAC) working group announced several recommended changes to UBC’s campus including increased ventilation, improved filtration, enhanced maintenance and air monitoring.
While people primarily transmit SARS-CoV-2 in close range, the BC Centre for Disease Control (BCCDC) said smaller aerosols can linger in the air, particularly in crowded and poorly ventilated indoor spaces. Accordingly, recognizing airborne transmission has heightened concerns about HVAC systems in UBC’s campus return plan.
The HVAC working group assessed over 900 teaching spaces to determine the ventilation status for each room. According to the evaluation summary, 96 per cent of teaching spaces are equipped with mechanical ventilation and can therefore be used at pre-pandemic capacity.
In addition to flushing air before occupancy, the working group recommended increasing the amount of outdoor air above American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards during operating hours but notes the exact level of increased air will vary for each teaching space. ASHRAE sets the global standard for indoor air quality.
The Harvard School of Public Health recommends the equivalent of four to six air changes per hour (ACH) to mitigate the risk of COVID-19 transmission. Guidance from the school’s healthy buildings program suggests an average classroom pre-pandemic has an equivalent ACH of two to three at ASHRAE design levels.
When asked if UBC has a target ACH or outdoor air rate, John Metras, associate vice-president of facilities, said that “the level of increased outdoor air will depend on equipment design limitations.” In contrast, following community advocacy, the University of Toronto equipped all active classrooms at six ACH or greater and posted the ACH rate for each classroom.
As part of the ventilation FAQ, the working group indicated HVAC systems bring in “very little” outdoor air during the winter months to ensure a comfortable temperature indoors. However, when asked what steps UBC will take to improve ventilation during this period, Metras did not address the question.
The second part of UBC’s plan centres on upgrading air handling units to MERV 13 or higher filters. Minimum Efficiency Reporting Value (MERV) reports a filter’s ability to capture particles of various sizes. Though UBC’s HVAC page said most units were already using MERV 13 filters or have since been upgraded, Metras cautioned that UBC cannot upgrade some units due to system design and environmental limitations.
When asked which buildings could not be upgraded and if portable air cleaners would be installed in lieu, Metras again did not provide this information.
In comparison, the University of Toronto posted the filtration level for each building and the installed location of nearly 300 portable purifiers.
Other notable interventions recommended by the UBC working group include physical inspections of all HVAC equipment and air monitoring in teaching spaces without mechanical ventilation.
Continued community concerns
Although significant concerns regarding ventilation and filtration remain, advocates and experts agreed it is only part of the equation.
Indoor air experts told The Ubyssey that vaccines and masks are necessary to reduce the risk of transmission in close contact.
“No amount of ventilation or filtration will remove the possibility of transmission for people in very close contact … if transmission [is] high, masks would be a more effective approach as masks work regardless of the ventilation status of a building,” said Dr. Michael Brauer, a professor at UBC’s school of public health.
Dr. Steven Rogak, director of the UBC aerosol laboratory, agreed. “It would be nice to attain six ACH but ... much less important than [vaccine and mask requirements].”
In July, a group of over 200 UBC faculty members called for continued physical distancing and universal masking until vaccine rates on campus match the provincial average.
One of the signatories is Dr. Sylvia Fuller. She has an immunocompromised partner and said she’s not comfortable teaching in person with current measures and worries about taking home a breakthrough infection.
“The reality is I’m looking at a full room, with students who may or may not be vaccinated, and may or may not be wearing masks ... good ventilation alone [isn’t] a silver-bullet against COVID-19, especially the Delta variant,” said Fuller in a written statement.
Eshana Bhangu, AMS VP academic and university affairs, also said UBC’s broader response falls short.
“The ventilation upgrades are only a start … [The AMS] has been pushing hard to mandate masks in classrooms and require vaccines in student residences … we’ll continue to fight for students to ensure a safe return to campus.”
The province announced a mask mandate in indoor spaces and a vaccine mandate in student housing on Tuesday, August 24. UBC announced mandatory rapid testing for unvaccinated students on Friday, August 27. But no matter what protective measures UBC takes, Fuller says the campus return plan must be more inclusive.
“How can [students and faculty] participate as equal members … if coming to campus means risking their lives? We need stronger protective measures ... to ensure people vulnerable to COVID-19 aren’t marginalized and excluded.”