Associated Press: Few sights capture Manhattan's beauty like the grand, old apartment buildings that ring Central Park. But for decades, many of these mansions for the rich and famous have also been a literal source of urban grit. Like other pre-war buildings throughout the city, scores of the graceful towers around the park have long burned the dirtiest heating fuel around: a nasty sludge called No. 6 oil that puts more soot into the air annually than all the city's vehicles combined. This is the kind of Dickensian...