A kind of simple do-it-yourself air filter can be an effective way to filter out pollutants in indoor air – Zoo House News
A team of researchers from Brown University’s School of Public Health, Brown’s School of Engineering, and the Silent Spring Institute found that simple air filtration devices called Corsi-Rosenthal boxes are effective at reducing indoor air pollutants.
The study, which analyzed the effectiveness of Corsi-Rosenthal boxes installed at the School of Public Health to prevent the spread of COVID-19, is the first peer-reviewed study of the boxes’ effectiveness, according to the authors Indoor pollutants.
According to lead author Joseph Braun, associate professor of epidemiology at Brown University, reducing indoor levels of common chemicals known to pose a risk to human health is one way to improve the health of occupants .
“The results show that an inexpensive, easy-to-design air filter can protect not only against diseases caused by viruses, but also by chemical pollutants,” Braun said. “This type of accessible public health intervention can empower community groups to take action to improve their air quality, and therefore their health.”
Corsi-Rosenthal boxes or cubes can be built using materials found at hardware stores: four MERV-13 filters, duct tape, a 20-inch box fan, and a cardboard box. As part of a school-wide project, boxes were assembled by students and members of the campus community and installed in the School of Public Health and other buildings on the Brown University campus.
To assess the cubes’ effectiveness in removing chemicals from the air, Braun and his team compared the levels of semi-volatile organic compounds in a room before and during the operation of the box.
The results, published in Environmental Science & Technology, showed that Corsi-Rosenthal boxes significantly reduced levels of several PFAS and phthalates in 17 rooms at the School of Public Health during the period they were in use (February through March 2022). PFAS, a type of synthetic chemical found in a range of products such as detergents, textiles and wire insulation, fell by 40% to 60%; Phthalates, commonly found in building materials and personal care products, have been reduced by 30% to 60%.
PFAS and phthalates have been linked to various health problems, including asthma, decreased immunization response, decreased birth weight, altered brain development in children, altered metabolism and some cancers, said Braun, who studies the effects of these chemicals on human health. They are also considered endocrine disrupting chemicals that can mimic or disrupt the body’s hormones. Additionally, PFAS have been associated with reduced vaccine response in children and may also increase the severity and susceptibility to COVID-19 in adults.
“The reduction in PFAS and phthalates levels is a wonderful side benefit of the Corsi-Rosenthal boxes,” said study co-author Robin Dodson, a research scientist at the Silent Spring Institute and an expert on indoor chemical exposure. “These boxes are accessible, easy to manufacture and relatively inexpensive, and they are currently being used in universities and homes across the country.”
“The Corsi-Rosenthal box was designed as a simple, cost-effective tool to promote accessible and effective air purification during the COVID-19 pandemic; the fact that the boxes also effectively filter out airborne pollutants is a fantastic discovery,” said Richard Corsi, one of the inventors of the boxes and dean of the College of Engineering at the University of California, Davis. “I’m thrilled that researchers at Brown University and the Silent Spring Institute have identified a significant co-benefit of the boxes in terms of reduced exposure to two harmful classes of indoor pollutants: PFAS and phthalates.
The opinion was shared by Jim Rosenthal, Corsi’s employee and CEO of Air Relief Technologies, the company that makes the MERV-13 filters used in Corsi-Rosenthal boxes.
“This interesting research, showing that the air filters not only reduce particles that carry the SARS-CoV-2 virus but also reduce other indoor air pollutants, could be of great importance as we continue to work towards cleaner and safer ones to create indoor air,” said Rosenthal.
The researchers also found that the Corsi-Rosenthal boxes increase noise levels by an average of 5 decibels during the day and 10 decibels at night, which could be considered annoying in certain environments such as classrooms. However, according to Braun, the health benefits of the box likely outweigh the audio side effects.
“The box filters make some noise,” Braun said. “But you can build them quickly with hardware store supplies for about $100 a unit. Not only are they highly effective, they are also scalable.”
The Brown study authors include Kate Manz and Kurt Pennell of the School of Engineering, and Jamie Liu, Shaunessey Burks and Richa Gairola of the School of Public Health. This research was supported by the National Science Foundation and the National Institute of Environmental Health Sciences.