[Army Air Corps]

In smoggy cities like Los Angeles, driving one on summer days may actually clean the air...

So, the car has an air intake, air filter, and clean air exhaust to help clean the air? Oh, I see, the reporter is an idiot and thinks that somehow producing fewer emissions is the same as removing CO2 from the air.

[Gondring]

CO₂ isn't the only pollutant in exhaust. One component of LA air is, for example, products of incomplete combustion. If these are taken into a "cleaner" system, then it could be true that the local effect is to "clean" the air.