The AP got a hold of some federal data to create an interactive database of industrial air pollution in the country, and it turns out that the Giants Stadium is more polluted than Manhattan. The NY Post went through and plugged a couple areas in, finding out that - Fifth Avenue in the 50s is 1.4 times more polluted than the average US neighborhood, whereas Gracie Mansion/Yorkville is 1.2 times more polluted; City Hall is 1.2x, Harlem, 1.1x, and Yankee Stadium 1.3x..and Stuyvesant is 1.7 times higher! Giants Stadium is 6.9 times the national average. However, the pollution in the study is only from industrial sources, not necessarily cars and trucks.
Gothamist checked a few other neighborhoods: Park Slope is 0.09 times the national average, Jackson Heights is 1.1x. Plug in a neighborhood and see how it stacks up against the nation for air pollution: The AP's Inteactive Database on National Pollution. It seems like the database requires a zip code, so here's a PDF of NYC zip codes.