Around half of our CO2 emissions aren’t from big power plants, or even small power plants, according to researchers from the University of Calgary. They’re from diffuse sources, like car exhaust, home heating and airplanes, which can’t be easily sucked up at the source. Led by climate scientist David Keith, the Calgary group is working on technology that could soak those “diffuse emissions” right out of the air.

Their system is a kind of air scrubbing tower, which takes air and reacts the CO2 out of it by exposing it, in this case, to sodium hydroxide. Then the stuff goes through a few chemical intermediaries eventually leaving separated CO2 that can be piped away, and more hydroxide to feed back into the scrubber.

Other air-scrubbers have been developed and researched, notably at Columbia University, also with good results. But the real achievement for the Calgary group seems to be in taking the reacted CO2 and hydroxide, and separating them back out from each other—an important step to making the process whole.

With their current design, according to the university, they can capture around a ton of carbon dioxide for less than 100 kilowatt-hours of electricity. At that rate, for every bit of electricity used to run the scrubber, you’re actually capturing ten times as much CO2 as was released to create that electricity in the first place. That means that in terms of emissions, it is efficient… but financially, not-so-much-so. As far as the researchers have reported, the technology is expensive, and not near ready for large-scale development yet. But, it could potentially fill a unique role, taking on that 50 percent of diffuse CO2 emissions that no smokestack extractors will ever be able to keep out of the skies.