I still wonder if this is evidence of causation or just a correlation?
I would agree that air pollution is in part responsible for causing clouded judgement and could lead to making overall poorer decisions,
On the other hand it would seem that people who live in areas of the inner city with the most smog, may also be financially much worse off, while living in the kind of food deserts in which there are overall fewer healthy options available, and so people in the most polluted regions often have little choice but to subsist on what is available within the fast food culture.