That's not as silly as it sounds I think. You could improve the air quality to be better than if your car existed, if you weren't generating carbon pollution a

That's not as silly as it sounds I think. You could improve the air quality to be better than if your car existed, if you weren't generating carbon pollution and were say removing pollutants from the air as you drive. In reality this would be really hard, but if you had solar powered car and removed nox or something. But then you get into the infinite tail of the energy and pollution used to make your car.