A research team at the University of Chicago has developed a nanofiber air filter that could transform existing building ventilation systems into carbon-capture devices, while also reducing energy costs for homeowners.
The new filter, described in a paper published in Science Advances, was created by researchers from Assistant Professor Po-Chun Hsu’s lab at the Pritzker School of Molecular Engineering. The distributed carbon nanofiber direct air capture filter is designed to enable homes, offices, schools, and other buildings to contribute to reducing airborne carbon dioxide.
A life-cycle analysis indicates that even when accounting for emissions generated during manufacturing, transportation, maintenance, and disposal, the filter removes more than 92% of carbon dioxide from the air.
“Every building already has ventilation systems that move large volumes of air every day. By integrating our carbon-capture filters into these systems, we can remove carbon directly from the air without building new plants or using extra land,” said Ronghui Wu, first author and assistant professor at Nanyang Technological University who conducted this research as a postdoctoral researcher in Hsu’s lab. “It’s a practical and scalable way to make carbon capture part of everyday infrastructure.”
If widely adopted, replacing all building air filters with this model could eliminate up to 596 megatonnes of carbon dioxide annually—the equivalent of removing 130 million cars from roads for a year. On an individual level, users could see lower energy bills; previous research found potential savings could reach approximately 21.6%.
Wu explained: “Normally, air-conditioning systems need to pull in a lot of outside air to keep indoor carbon dioxide levels low. Our filter removes carbon dioxide inside the building, so the system doesn’t have to bring in as much outside air. That means less air needs to be heated or cooled, which reduces the energy consumptions in HVAC.”
Current direct air capture technologies are typically large-scale operations requiring significant investment and resources. Hsu compared their approach to solar power technology: "These rooftop panels are possible because sunlight is more or less uniform. The CO2 from air is similar,” he said. “We propose, using experiment and computation to demonstrate, that indeed we could retrofit our buildings to be part of the decarbonization effort.”
The UChicago team designed their polyethylenimine-based nanofiber material as a reusable filter compatible with existing HVAC systems—similar in installation to high efficiency particulate arresting (HEPA) filters but intended for repeated use after regular removal of captured carbon.
Hsu outlined a potential system where municipal waste management would collect saturated filters from buildings alongside regular garbage and recycling services: “They would have these saturated filters from household ventilation systems and commercial buildings, then replace them with new ones,” he said. “They’d ship the saturated one to a centralized facility to dissolve the CO2 or make it into highly concentrated CO2 to capture or, even better, convert to high-value chemicals or fuel.”
The filter material is engineered for strong solar absorptivity so it can be regenerated through solar thermal methods such as exposure to sunlight.
“It has to be able to regenerate using renewable energy,” Hsu said. “The most common way to regenerate CO2 with solvent is by heating it up. If you burn fossil fuels to heat up the solvent, then you will probably end up emitting more carbon dioxide than you capture.”
In addition to energy savings and environmental benefits on a larger scale, individuals may experience improved indoor air quality.
“This kind of air filter can also improve indoor air quality, especially in places like classrooms and offices where many people share the same space,” Wu said. “By keeping indoor carbon dioxide levels low, it helps people stay more alert, focused and healthy.”
The study was published under the title “Distributed direct air capture by carbon nanofiber air filters” by Wu et al., Science Advances (October 17, 2025), DOI: 10.1126/sciadv.adv6846.