I've always imagined blimps floating around and filtering our air above all the major cities and places where air pollution/CO2 density is worst. Does anyone have any reasoning as to why this isn't really being done?
As a thought experiment - look at the average car - a Toyota Camry for example. That car emits 206 grams per kilometer. Over the course of the car's lifetime (about 200 thousand kilometers or so) that's 41 thousand kilograms of CO2. For one family car.