Residual oil combustion: 2. Distributions of airborne nickel and vanadium within New York City

Abstract

In an earlier paper based on PM_2.5 speciation network data, we showed that nickel (Ni) concentrations were much higher in New York City (NYC) than in New Jersey (NJ) and Connecticut (CT), and that the NYC levels, but not those in NJ and CT, were much higher in the winter than in summer. However, all of the speciation sites in NYC were in the northern half of the city. To determine the distributions of Ni and other PM_2.5 components within NYC, we collected 8-weeklong filter samples at 10 sites throughout NYC in both winter and summer, and measured the concentrations of the elements by X-ray fluorescence (XRF). The resulting data, together with speciation network site data, were used to construct seasonal average concentration isopleth maps for Ni and vanadium (V). As expected, Ni was much higher in Bronx than in Brooklyn, and much higher in winter than in summer. By contrast, V was higher in Brooklyn than in Bronx, and the winter and summer levels were similar. It appears that space-heating boilers are the major source category for Ni in NYC, whereas the Port of New York is the major source of V.