Do-it-yourself box filter knew the air from interior pollutants

When forest fires threaten people’s communities, human health becomes much further than hell. RESTRIOK distributes in the wind, infiltrating houses, schools and offices.

To help people protect themselves and their families, researchers have developed a cheap, sustainable, do-it-yourself (do-it-yourself) air cleaner that works, as well as more expensive HEPA filters to erase indoor air of pollutants such as smoke and possibly limit the impact of the air department distribution.

Richard Corsi, dean of the University of California, Davis (UC Davis) College of Engineering, presented results of the DIY Air Filtration Studies of his team at the ACS Spring 2025 Digital Meeting, a meeting of the American Chemical Society.

Despite advice to stay inside on Smoggy Dagen or when the air fills with natural fires, human exposure to air pollution is dominated by air pollutants indoors – including pollutants that have been brought in from the outside. Nevertheless, research to indoor air quality has traditionally taken a back seat for other concerns such as waste water pollution.

That changed with the COVID-19 Pandemie.

“The media do not pay much attention to indoor air quality, and then the pandemic hit and suddenly there was a huge opportunity to inform the public about the issue,” says Corsi.

Knowing that not everyone could work from home and that children should eventually have to return to school, Corsi realized that people needed an affordable way to keep indoor air as safe as possible.

“That is when we came up with the idea of ​​a cheap, effective air cleaner that people can build themselves,” he explains. Corsi hoped to reach as many people as possible who could not resign hundreds of dollars for a commercial HEPA air filter.

The DIY solution, the Corsi-Rosenthal (CR) box, was a coding with filtration specialist Jim Rosenthal. The CR box consists of four air filters that are often used for heating, ventilation and air conditioning (HVAC); a cardboard base; And a box fan to pull air through the filters and to the ceiling. Because the components are relatively cheap, the CR box is a fraction of the costs of a HEPA air filter.

As Corsi emphasizes during his presentation, he and his colleagues tested the sustainability and performance of CR boxes by installing units at four locations on the UC Davis campus. They walked them 2500-hour equivalent of two K-12 school years.

The CR filters also performed or better than comparable HEPA filters. The DIY -the self -system was also more effective when cleaning up particles 1-3 micrometer in diameter than particles 0.35 -1 micrometer. For a feeling of dish, typical smoke particles are smaller than 1 micrometer, while dust and pollen are 0.5-3 micrometer.

Although HEPA filters are more efficient in removing particles in a single pass than the HVAC filters used in the DIY system, Corsi explains, passes much more air through the CR boxes, so that more particles are removed from the air.

Although the effectiveness of the CR boxes decreased over time, they still performed better than new and more expensive HEPA air filters for the larger particle size and competed with HEPA for smaller particles during the extensive study period.

To see if the CR boxes could also remove particles that were exhausted by people or during sneezing, the researchers then tested the systems on breathing plumes.

“We have set up a situation in which two people talk about the table alongside a simulator for breathing plum simulator,” Corsi explains. “Then we measured the decline of that plume without CR box and with boxes that are located around the room and run at different speeds.”

They discovered that when the CR box within 3 to 4 feet (91 to 120 centimeters) of the people who speak, the breathing plume disappears within a few seconds at a distance from the air filter device.

For future improvements, Corsi wants to re -design the fan magazines to make the CR boxes quieter, and he sees it potential to adjust the filters to remove other indoor contaminating fabrics, such as Formaldehyde of furniture and building materials, and Ozon from Smog and some office equipment.

On a more personal comment, he appreciates the feeling of empowerment CR boxes give people.

“One thing that has been so satisfactory to me is the number of people who told me that they get such a great personal satisfaction by knowing that they are building something that helps them and their families or their students,” he says.