As wildfire incidents increase worldwide, particularly in regions of India, air quality has become a significant problem. Smoke from wildfires, industrial emissions, and vehicle pollution contaminates homes, schools, and offices, causing serious health concerns. In response, researchers created a low-cost do-it-yourself (DIY) air cleaner that can compete with commercial HEPA filters, providing a feasible alternative for cities such as Delhi. 

Richard Corsi, dean of the UC Davis College of Engineering, presented data on the Corsi-Rosenthal (CR) Box, a DIY air filtering system, at the ACS Spring 2025 Digital Meeting. The device, co-designed with filtration expert Jim Rosenthal, is made up of four HVAC air filters, a cardboard base, and a box fan. It produces equivalent results to pricey HEPA filters, but at a fraction of the price. 

In thorough research at UC Davis, CR Boxes were evaluated for 2,500 hours—equivalent to two school years—and exhibited exceptional durability and performance. They outperformed HEPA filters in removing particles measuring 1-3 micrometres, such as dust and pollen, while remaining competitive with HEPA filters for smaller particles. 

Corsi highlighted that, while HEPA filters can remove more particles in a single pass, the CR Box compensates by processing a larger volume of air, resulting in more efficient air cleaning over time. "The media didn't pay much attention to indoor air quality, and then the pandemic hit... suddenly there was this tremendous opportunity to educate the public about the issue," Corsi recalled. 

Researchers also tested the CR Box to remove respiratory particles. Researchers simulated human interactions and discovered that within a 3 to 4-foot range, the gadget dissolved respiratory plumes in seconds. This research is especially timely given worries regarding airborne disease transmission, such as Covid-19. 

Delhi, infamous for its poor air quality, routinely encounters AQI values that surpass permissible standards, especially during the winter when stubble burning and haze raise pollution levels. Residents frequently struggle to buy expensive HEPA filters, leaving millions vulnerable to hazardous particles. 

However, Delhi's schools, hospitals, and residences can build the CR Box as a low-cost alternative using commonly accessible materials. This makes it a promising alternative for Delhi's schools, hospitals, and residences, as it provides economical pollution control. The CR Box's capacity to reduce respiratory plumes makes it ideal for public settings and educational organisations. 

Delhi's air quality crisis necessitates effective and scalable remedies. The CR Box, with its proven efficiency and low cost, perfectly fits the city's urgent demand for better indoor air quality. Implementing this technology in schools, hospitals, and government offices could drastically reduce health hazards, particularly among vulnerable groups. 

Governments and non-governmental organisations (NGOs) should consider organising workshops to teach residents how to build and maintain these DIY air filters. Empowering communities with simple, efficient solutions is an important step towards regaining breathing air in cities.