What if we would make such an advanced filter, and then make it mandatory in cars. That way cars would 'clean' the air. You'd need to find a process that scales though, so that the 'dirty' filters are processed in a way to get out the carbon and use it somewhere.
Or make direct fuels out of it :P /s (that would not work, otherwise you've created a perpetuum mobile). Would be interesting if you could use your car's surface as a kind of anode.
