Climate change scientist David W. Keith and his colleagues are building a simple machine from near commercial parts capable of capturing the trace amounts of carbon dioxide present in the air at any given spot. The local air mixture in non-industrial spaces is typically on the order of 0.04%. Traditional methods of carbon dioxide capture used in industrial spaces such as power plants are technically difficult even when the gas composes as much as 10% of the air and only handle the emissions created by the power source they serve.
An ambient air scrubber has several advantages. It doesn’t need to be tied directly to the sources of carbon dioxide to remove it or even located anywhere nearby. A scrubber in China would still clean the air over Europe or North America, so they can be located wherever construction and maintenance is least expensive and near the storage location for the recovered gas.