Printer design that uses air pollution as ink.

Black printing ink is one of the most consumed products in the industry.
Most of this printing ink is produced in factories with complex chemical procedures. Companies like HP/Canon make 70 percent of their profits by selling these cartridges at 400% margin.
Just a minor itch that led me to build something cool from observations arising from nostalgia of the days back in India. There's so much soot/pollution around us, esp. in crowded cities. What if the same could be repurposed to generate ink for printers?

Rubbing alcohol+oil substrate+soot= lowtech non-uniform ink . We built a contraption that supplies the ink to HP C6602 inkjet cartridge interfaced with Arduino turning it into ~ 100dpi print platform.
Technical details on anirudh.me/2014/02/kaala-soot-printer/

However, the ink is low-tech, and okay for basic printing as of now.