Indoor air quality is a critical concern, especially during times of wildfires and other environmental challenges. When smoke infiltrates homes, schools, and offices, it can have a significant impact on human health. To address this issue, researchers have developed a low-cost, durable, do-it-yourself (DIY) air cleaner that rivals more expensive HEPA filters in clearing indoor air of pollutants such as smoke particles and potentially limiting the spread of airborne diseases.
Richard Corsi, dean of the University of California, Davis (UC Davis) College of Engineering, presented the findings of his team’s DIY air filtration studies at the ACS Spring 2025 Digital Meeting hosted by the American Chemical Society. While indoor air quality has often been overlooked in the past, the COVID-19 pandemic brought attention to the importance of clean indoor air for public health.
The DIY air filtration solution, known as the Corsi-Rosenthal (CR) Box, was developed in collaboration with filtration specialist Jim Rosenthal. The CR Box consists of four HVAC air filters, a cardboard base, and a box fan to draw air through the filters and towards the ceiling. This cost-effective system is a fraction of the price of commercial HEPA filters, making it accessible to a wider audience.
In testing the CR Boxes, Corsi and his team found that they performed as well as, if not better than, comparable HEPA filters in removing particles from the air. The DIY system was particularly effective at clearing particles 1-3 micrometers in diameter, which includes smoke particles and other common indoor pollutants. While HEPA filters may be more efficient in a single pass, the CR Boxes processed more air over time, resulting in the removal of a greater number of particles.
Additionally, the researchers tested the CR Boxes’ ability to remove respiratory plumes generated by conversation or sneezing. Placing the air-filtering devices within close proximity to individuals speaking resulted in the rapid dissipation of respiratory plumes, demonstrating the effectiveness of the DIY system in reducing the spread of airborne contaminants.
Looking ahead, Corsi envisions further enhancements to the CR Boxes, such as reducing noise levels and expanding their capabilities to remove other indoor pollutants like formaldehyde and ozone. The sense of empowerment that comes from building and using a device that contributes to the health and well-being of oneself and others is a driving force behind the success of the CR Boxes.
Overall, the DIY air filtration system offers an affordable and effective solution for improving indoor air quality and protecting against the harmful effects of pollutants and airborne diseases. By empowering individuals to take control of their indoor environment, the CR Boxes represent a practical and accessible approach to safeguarding health and well-being.
