I clean the air because my lungs capture car particles.
That's why I have an e-bike, so I breathe less when cycling/commuting into the city.
There was a study [0] in Paris that demonstrates a signifiant positive benefit/risk ration of bicycling even in polluted air: the effect on physical and psychic health benefits largely outweighs (sometimes to x30) the risk of accidents and pollution disease.
My city attempts to promote cycling, but hasn't bothered to first take care of the problem with people heating their homes with solid fuels like coal dust and whatnot.
It's frustrating, because cycling during the heating season is not only unpleasant, but also unhealthy.
Technically we all disinfect the water through our kidneys too
Excluding those recently punched hard in the kidneys.
Some diesel engines can clean the air, but only if the air coming in is very polluted. They'll catch and burn particulates, and they'll chemically scrub NOx. This only applies if the air outside is very polluted, though