The Upper West Side boasts the worst air pollution in all the five boroughs, according to new city data. The Upper East Side didn’t fare so well either, coming in right behind the neighborhood across the park.

According to the organization NYC Clean Heat, the pollution comes mostly not from cars, trucks, and buses, but the type and amount of heating oils burned in the Upper West Side’s buildings. “The reason why [the Upper West Side] is the biggest emitter is the size of the buildings,” said Kenneth Camilleri, a manager at the organization.

The city has been working to get buildings in the neighborhood and across the city to move away from using heating oils numbers 4 and 6, “which are known for the high levels of toxins they emit,” according to DNAinfo.

 As of 2011, 700 UWS buildings are still burning dirty heat sources.

(Photo: Tom Thai/Flickr)