'I am angry': Alberta farmers will continue fight over world class motorsport resort
The rolling hills leading to the hamlet of Rosebud are dotted with sprawling farms and cattle pastures -- and a sign sporting a simple message: No Race Track.
This fall, teachers and parents have been sharing photos on social media of do-it-yourself air purifiers that they’ve made for classrooms to help protect kids from COVID-19 transmission.
But do these low-cost purifiers actually work?
According to researchers, they do.
They’re called Corsi-Rosenthal Boxes, a DIY air purifier that was first conceived of in the summer of 2020 by two air filtration experts, Richard Corsi and Jim Rosenthal.
Since then, their effectiveness has been backed up by scientists, studies and a company that makes air filters.
Studies have shown that poor ventilation is associated with much higher spread of COVID-19. But many buildings in Canada, including schools and workplaces, are still not equipped with proper ventilation systems or HEPA purifiers.
Unlike HEPA purifiers, which can cost from $200 to upwards of $500, a Corsi-Rosenthal Box can be made for around $100 with materials that can be purchased at any hardware store.
A York University engineering professor who has been carting his Corsi-Rosenthal Box with him across campus this past week says he heard about them on social media in mid-2021.
“Some ventilation engineers were talking about them and they seemed like a practical and easy way to get more clean air into schools and into my home,” James Andrew Smith told CTVNews.ca in an email.
“I don’t believe that we’re doing enough for clean air,” he added, saying that he feels better about the risk level in his classroom when he uses the DIY air purifier along with other measures.
The boxes also seem to have longevity.
“This guy behind me just turned eight months a couple days ago,” Corsi said in a Twitter video Monday, referring to his own Corsi-Rosenthal Box humming away past his shoulder. “Still doing its job, still lowering inhalation-dosed aerosol particles, including virus-laden respiratory aerosol particles. It’s not rocket-science, folks.”
There are variations, but the basic Corsi-Rosenthal Box is made of four air filters, one box fan and some cardboard, all taped together to make a cube. A University of California, Davis tutorial specifies to use MERV-13 filters.
The box fan should have the airflow pointing outward, and all edges should be sealed with duct tape. The final sixth side of the cube should be closed off with cardboard or even a fifth air filter.
To make the filter more efficient, you can also cut a circle out of a piece of cardboard and tape it overtop of the outward face of box fan to reduce backflow.
The idea behind the Corsi-Rosenthal configuration is that the air that enters the box will be passing through multiple filters for purification, and the sealed cube means that only filtered air will then be blown out into the room by the fan.
Studies indicate that while it won’t be able to filter out quite as many particles as a HEPA filter can, a Corsi-Rosenthal Box can cycle the air in a room at a rate that sometimes outstrips HEPA purifiers, removing viral particles from the air at a fraction of the cost.
A study published in March in the journal Aerosol Science and Technology, which included Corsi as one of its authors, found that the boxes were able to quickly filter an entire room at a much faster rate than the HEPA purifiers.
When looking at the “cost-per-unit-air-cleaned,” the study said that “the DIY air filter is approximately one-tenth the initial cost of a commercially available HEPA-based air cleaners.”
3M, a company that makes air filters, said in a February press release that their scientists had studied Corsi-Rosenthal Boxes and that the DIY idea works.
“Indoor air is shared air,” Kelsey Hei, a 3M Filtrete brand engineer, said in the release. “Many viruses like COVID-19 are airborne and can become highly concentrated in poorly ventilated spaces. I’m heartened to see so many people advocating for the importance of clean air, especially in schools.”
Another study published in September in the journal Science of the Total Environment looked at nine different configurations of DIY air purifiers and compared them to three HEPA purifiers.
The study found that the DIY options, including a single filter with a box fan, Corsi-Rosenthal Boxes, and a variation on them that uses three filters and two box fans in a cube, were all comparable or better than HEPA purifiers in terms of the speed in which they filtered the air.
When it became clear that COVID-19 was spread through airborne transmission, scientists began to emphasize the importance of good ventilation as a tool to slow transmission.
An Italian study published last March that looked at more than 10,000 classrooms found that efficient ventilation systems were able to reduce transmission of COVID-19 in schools by more than 80 per cent.
Infections were much lower in the 316 classrooms that were equipped with a mechanical ventilation system, compared to those without them. When the ventilation systems cycled to completely replace the classroom’s air with new air 2.4 times an hour, infections were reduced by 40 per cent. If they replaced the air six times an hour, the infections were reduced by 82 per cent, the study found.
With few public health measures still in place for back to school, teachers have been increasingly turning to tools like the Corsi-Rosenthal Box to make their classrooms safer.
As students returned to classrooms this fall, teachers and parents took to social media to share photos of their Corsi-Rosenthal Boxes. On Twitter, the hashtag #CorsiRosenthalBox includes numerous creative designs aimed to be kid-friendly.
One user based in Manitoba posted a photo of a Corsi-Rosenthal Box for his son’s classroom that had been upgraded to look like a robot, with googly eyes, antennae and arms.
Other designs utilized big eyes, brightly coloured paints and a variety of animal ears to transform the boxes into friendly creatures.
In Quebec, parents and teachers have posted a petition calling for Jean-Francois Roberge, Minister of Education, to allow them to provide Corsi-Rosenthal Boxes to their children’s schools, saying citizen initiatives have “come up against strong administrative resistance.”
“Installing homemade air purifiers, known as Corsi-Rosenthal cubes, is an effective and inexpensive way to improve air quality in indoor spaces,” the description reads.
The petition, started last month, has more than 1,600 signatures.
At York`s Lassonde School of Engineering, Smith says that carting around a Corsi Rosenthal Box has spurred questions and curiosity from students.
“How much do I care about my students? Enough to build them a wheeled #CorsiRosenthalBox to bring to class,” he tweeted Monday.
Smith and other faculty members have been calling for the Dean’s Office of York’s Lassonde School of Engineering to fund and distribute portable air purifiers to faculty members, but so far, these motions have been denied.
“Personally, I think that they're a no-brainer,” Smith told CTVNews.ca. “They're easy to install, easy to operate, aren't nearly the controversial topics that vaccines or masks are. They make the air cleaner for smog, smoke, dust... they're just generally a great idea.”
These boxes are being used in classrooms across the globe.
In November 2021, the Brown University School of Public Health in Rhode Island launched a project to build Corsi-Rosenthal Boxes for classrooms and study them, and have since installed boxes in numerous classrooms and student lounges.
Oliver Patrick, a county councillor in the U.K., started a GoFundMe last month to provide Corsi-Rosenthal Boxes for schools in his district, stating that he was concerned about the lack of public health measures in place in his region.
“I want to make sure we do as much as we can to make sure school is as safe as possible for children,” Patrick wrote.
The California Department of Public Health listed Corsi-Rosenthal Boxes as a recommended option for classrooms in a February bulletin for improving air quality in schools to fight COVID-19.
The rolling hills leading to the hamlet of Rosebud are dotted with sprawling farms and cattle pastures -- and a sign sporting a simple message: No Race Track.
Dozens of Ontarians are expressing frustration in the province’s health-care system after their family doctors either dropped them as patients or threatened to after they sought urgent care elsewhere.
For decades, North Bay, Ontario's water supply has harboured chemicals associated with liver and developmental issues, cancer and complications with pregnancy. It's far from the only city with that problem.
A man who tried to access Drake’s Bridle Path mansion earlier this week returned to the property Saturday and was apprehended again for allegedly trespassing, Toronto police say.
Multiple people at the protest camp torn down at the University of Alberta campus Saturday say police's actions against protesters were "violent" and "disproportionate."
When West Virginia Republicans vote in Tuesday's primary, they will have a hard time finding a major candidate on the ballot in any statewide race who openly acknowledges that U.S. President Joe Biden won the 2020 election.
Amazon's paid subscription service provides free delivery for online shopping across Canada except for remote locations, the company said in an email. While customers in Iqaluit qualify for the offer, all other communities in Nunavut are excluded.
Two daughters and a mother were reunited online 40 years later thanks to a DNA kit and a Zoom connection despite living on three separate continents and speaking different languages.
U.S. President Joe Biden on Saturday called Donald Trump “clearly unhinged” and claimed that “something snapped” in the former president after he lost the 2020 election.
A family of fifth generation farmers from Ituna, Sask. are trying to find answers after discovering several strange objects lying on their land.
A Listowel, Ont. man, drafted by the Hamilton Tigercats last week, is also getting looks from the NFL, despite only playing 27 games of football in his life.
The threat of zebra mussels has prompted the federal government to temporarily ban watercraft from a Manitoba lake popular with tourists.
A small Ajax dessert shop that recently received a glowing review from celebrity food critic Keith Lee is being forced to move after a zoning complaint was made following the social media influencer’s visit last month.
The Canada Science and Technology Museum is inviting visitors to explore their poop. A new exhibition opens at the Ottawa museum on Friday called, 'Oh Crap! Rethinking human waste.'
The Regina Police Service says it is the first in Saskatchewan and possibly Canada to implement new technology in its detention facility that will offer real-time monitoring of detainees’ vital health metrics.
Just as she had feared, a restaurant owner from eastern Quebec who visited Montreal had her SUV stolen, but says it was all thanks to the kindness of strangers on the internet — not the police — that she got it back.
The stakes have been set for a bet between Vancouver and Edmonton's mayors on who will win Round 2 of the Stanley Cup playoffs.
A grieving mother is hosting a helmet drive in the hopes of protecting children on Manitoba First Nations from a similar tragedy that killed her daughter.