| dc.description.abstract |
Polycyclic aromatic hydrocarbons (PAHs) were measured in pine needles (passive sampling) and on high volume particulate matter (PM) filters (active sampling) over a period of eight to ten months at two separate sites in the Dayton, Ohio, USA metropolitan area: Moraine and Yellow Springs. Total PAH concentrations for PM ranged from 77.4 μg/g to 837 μg/g (dry wt.) at both sites with high molecular weight PAHs being the predominant form that tended to be higher in concentration during the colder months. Total PAH concentrations for pine needles varied by tree species and location. With an average concentration of 4187 ng/g, Austrian pine (Pinus nigra) needles in Moraine ranged from 2543 ng/g to 6111 ng/g (dry wt.) with the lowest and highest concentrations occurring in October and August, respectively. The amount of phenanthrene was extremely high for August, 4200 ± 112, which could have resulted from the close proximity of the tree to the parking lot at a firehouse. White pine (Pinus strobus) needles in Yellow Springs had an average concentration of 384 ng/g and ranged from 127 ng/g to 589 ng/g (dry wt.) with September and November, respectively, having the lowest and highest PAH concentrations. The 2- and 3-ring PAHs were the predominant form in P. nigra, while the 4-ring PAHs predominated in P. strobus. Total PAH concentrations in P. nigra were an order of magnitude greater than for P. strobus. A bivariate plot of BaA/(BaA þ Chry) versus Flt(Flt þ Pyr) allowed the PM and pine needle data to be included in the same source analysis and indicated sources of PM at both sites were biomass and/or coal combustion. This plot also suggested PAHs in Yellow Springs P. strobus originated from petroleum combustion sources, whereas PAHs in Moraine P. nigra originated from petroleum combustion with some sources more aged or remote. |
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