EPA testing DIY air purifier built by fifth graders

After wildfire smoke and the COVID-19 pandemic caused a surge in demand for air purifiers, which can be expensive or out-of-stock, the “Corsi-Rosenthal” box was born.

The simple, inexpensive device is crafted from a box fan, MERV-13 air filters, and duct tape.

Ten-year-old Eniola Shokunbi, who lives in Middletown, Connecticut, had the idea to make the box with her classmates and conduct an experiment to see if better air quality improved student attendance. She reached out to researchers at the University of Connecticut, proposing a collaboration.

“She hand-wrote me a letter and I was so impressed,” said Marina Creed, the university’s Indoor Air Quality Initiative director and an adjunct instructor at the UConn’s School of Medicine.

The students decorated the box and dubbed it “Owl Force One.”

Misti Levy Zamora, an assistant professor in the university’s public health sciences department, tried the DIY air filter in her home when smoke was impacting air quality.

“The concentration reduced by over 95% within 10 minutes,” she said. “And then it maintained that low concentration throughout the wildfire event.”

The boxes have shown progress in schools, too. Kristina Wagstrom, an associate professor in chemical and biomolecular engineering at UConn, says tests in occupied classrooms have shown particle levels lowering by about 60%.

“That’s actually saying a lot, because you still have the students in the classroom creating new particles as this is going on, and it's able to lower it by that much for such a simple intervention,” Wagstrom said.

Researchers, Shokunbi and her classmates wanted to see how the box would perform against other DIY designs and off-the-shelf purifiers. After reaching out to EPA scientists, they agreed to test the box in their 3,000-cubic-foot biochamber In Research Triangle Park.

“Now we're testing these DIY air cleaners to demonstrate how effective they are against infectious aerosols,” said Katherine Ratliff, a physical scientist and principal investigator working under the Homeland Security Research Program at the U.S. Environmental Protection Agency’s Office of Research and Development.

The Corsi-Rosenthal box only takes about 30 minutes to put together at a cost of about $60.

“It really makes cleaner indoor air more accessible to a broader spectrum of folks,” Ratliff said. “If we're talking about taking an air cleaner and putting it in every classroom in a school, for example, this is a much less expensive way to do that.”

Early results show promise, a relief for Shokunbi who traveled more than 13 hours for the tests.

“I was, like, really scared and nervous,” she said. “But when I saw the graph for the practice showed how much it took out that air, I knew that it was going to work.”

The results will become publicly available after testing, which should last about two weeks.

Shokunbi says she wanted to take on the project to have cleaner air and help make the world a healthier place. The fifth grader also has high aspirations.

“I want to be — no, I’m going to be — the first African-American female president,” she said.