Calls grow for HEPA air filters in Canadian classrooms

As the highly transmissible Omicron variant fuels record-high case counts, and schools across Canada delay in-person learning, calls are growing for another layer of protection to be added to classrooms — HEPA filters. 

Air purifiers with high efficiency particulate air (HEPA) filters can reduce the concentration of some viruses in the air by capturing small particles, such as the water droplets that can carry the coronavirus.

Jill Davies-Shaw’s daughter is in Grade Six at Glenora School in Edmonton.

In the fall, she and other parents fundraised to buy a portable purifier with a HEPA filter for the classroom.

Davies-Shaw says, with more acknowledgement that the coronavirus is airborne, there was concern about sending her daughter to in-person learning every day.

“Worrying about virus building up throughout the day and certainly in a classroom, especially in a space where children are removing masks to eat lunch, where they’re spending a long time throughout the day — that was something that just made sense,” she said.

But parents were told by the school board that ventilation was adequate. The unit was returned.

Now, the Edmonton Public School Board tells CBC News that it is looking into the possibility of installing HEPA filters.

“I think that the time for this is yesterday and it really needs to happen urgently at this point,” Davies-Shaw said.

“I think at this point with how easily Omicron is spreading and how important it is for children to be able to be in-person in the classroom, learning with their peers, that we have to use all of the measures that we have available to us.”

The Public Health Agency of Canada says the effectiveness of HEPA filters against the transmission of the SARS-CoV-2 virus has not been demonstrated yet. It says the filters can be used as an additional tool but should not replace other public health measures.

Despite that, some provincial governments are moving forward.

Ontario has sent thousands to certain schools and will be buying more before students return after the winter break, B.C. has promised them and New Brunswick is looking into the matter.

“This pandemic is definitely a really good reason to accelerate all this,” said Stephane Bilodeau, an indoor ventilation expert at the University of Sherbrooke who has a PhD in mechanical engineering.

Bilodeau says, because Omicron is so transmissible, it’s better to have more layers of protection in the classroom.

“When you reduce the amount of particles, especially these aerosols which can be loaded with viruses or active RNA, a virus, you are definitely improving or in fact reducing the risk for their children to have transmission,” he said.

Proactive steps

Fresh Air Schools Alberta is a community organization calling on the province to fund airborne mitigation strategies, such as HEPA filters or other standalone filtration units, in classrooms.

“It’s something that benefits the people in the space regardless of what you’re using it for. Because better air quality is better for learning. It’s better for everybody’s health,” said advocate Amanda Hu.

“And so it seemed to me to be a no-brainer in terms of, you know, improving air quality for kids in the schools.”

Parents and staff at Leo Nickerson Elementary School in St. Albert, Alta., took matters into their own hands and built their own air purifiers, after a parent with an engineering background came forward with a design.

The units, which are made with MERV 13 filters, another type of filter, and a box fan, now run in 23 classrooms.

“Our filters will be good for the next six months,” said principal Helen Nowell.

“If we need to replace those filters … we’re prepared to do that with materials on hand.”

She said the purifiers provide peace of mind.

“People want to know they’re doing everything they can personally do and then that extra layer for our families to know that the school is willing to look a little bit above and beyond and creatively to ensure that we’ve got the best space possible for our kids,” Nowell said.

“One more measure does make you feel that you are doing something that we’re not rejecting an idea out of fear. We’re actually going to try it.”

CBC