Air-Ink turns pollution from your car exhaust into black ink that can be used for art. You put the device on the end of your car’s exhaust pipe and it will collect carbon soot. The soot can be created into high quality ink and be used for many things.

http://www.graviky.com/air-inktrade.html

The engineers had create a device that goes on the end of cars and the scientists had to use the carbon soot and turn it into ink.