Some community members have expressed concerns about improper ventilation in campus buildings, especially given U of T’s recent announcement of a planned increase in in-person activities from February 7 onward.

In the email announcing its back-to-campus plan, U of T shared that, among other updated measures to make the campus more safe, the university will be “assessing building ventilation and air filtration.” Despite this announcement, some students remain concerned about ventilation and air quality inside the classrooms.

The Varsity spoke to Professor Jeffrey Siegel, an expert in ventilation and indoor air quality, about the effectiveness of U of T’s air quality management. 

Student questions on air quality management 

Some students have raised questions about the effectiveness of the air quality measures in some classrooms. Bo Zhao, a third-year undergraduate student, discussed his experience going to courses in person in the fall in an interview with The Varsity. “My experience was overall positive. I think, at the beginning, it was a bit scary when you had everybody packed so closely to each other,” said Zhao, noting that social distancing was not implemented in classrooms in the fall. 

Bright Lin, a third-year undergraduate student, described the air in some of his classrooms as being very “stuffy” as there were no windows, despite the fact that fans had been installed.

Explanation by ventilation and indoor air quality expert 

In an interview with The Varsity, Siegel noted that there could be some bias in the way that air quality is assessed at U of T. He wrote that the current technology in U of T’s classrooms consists of three major components: ventilation, central filtration, and room filtration.

Classroom air quality is a measure of how well respiratory particles are removed through ventilation and filtration. Siegel is concerned that this measure, known as the “effective air exchange rate,” is commonly seen as only a measure of ventilation and not filtration. This could affect the accuracy of air quality measures. 

“Many people refer to the entire system as ‘ventilation’ and make no distinction between filtration (of any kind) and ventilation,” wrote Siegel in an email to The Varsity.

U of T’s website indicates that six units of air change per hour is the ideal benchmark for classrooms, according to public health guidance from Harvard University. U of T asserts that 98 per cent of its classrooms “exceed” this rate, and rooms that have air change rates of at least six units per hour do not need air purifiers. 

Siegel wrote that the air exchange rates stated by U of T could be “biased high” and suggested that the university include additional parameters when assessing air quality — such as the decay rate of fine particulate matter and carbon dioxide — which are more reflective of the actual air exchange rate. “Such measurements would give confidence in the calculations and also allow UofT to track down any deficiencies,” wrote Siegel.

Despite the associated concerns and risks, some students are excited to return to campus. Zhao said that last semester, when most of his classes were in person, his overall experience was positive. The vaccine and mask mandate also provides him with some assurance about his safety, despite not being able to socially distance in classrooms.

Although he does not feel very reassured, Lin said he would like to be back to in-person learning regardless. “I don’t think they’ll be able to prevent outbreaks, but also I’m happy to go back in person because it is a more complete student experience,” said Lin. “I wouldn’t say I feel safe, but I’m willing to take risks.”

Editor’s note (January 24): A previous version of the article wrongly said that Siegel believes that U of T’s current measures for air filtration are effective.