DISTINGUISHING THE CONTRIBUTIONS OF RESIDENTIAL WOOD COMBUSTION ACID MOBILE SOURCE EMISSIONS USING RELATIVE CONCENTRATIONS OF DIMETHYLPHENANTHRENE ISOMERS

As part of the United States Environmental Protection Agency's Integra ted Air Cancer Project, air particulate matter samples collected in Bo ise, ID, were analyzed by gas chromatography with mass spectrometric d etection (GC-MS) and apportioned between their two main sources: resid ential wood combustion (RWC) and motor Vehicle (MV) emissions. The tec hnique used for distinguishing the source contributions involved compa rison of the concentration of 1,7-dimethylphenanthrene (1,7-DMP), a po lycyclic aromatic hydrocarbon (PAH) emitted primarily by burning soft woods (e.g., pines), with that of a PAH emitted in modest concentratio ns by both RWC and MV sources, 2,6-dimethylphenanthrene (2,6-DMP). The se results were then compared with the mean 1,7-DMP/2,6-DMP ratio of 4 8 samples collected in a roadway tunnel, with any enrichment in the Bo ise sample ratios over the mean tunnel ratio attributable to the RWC s ource. These resulting RWC contributions were compared with fraction R WC results obtained by radiocarbon measurements (C-14/C-13 C-13) of th e same extracts from Boise, with generally good correlations between t he two techniques observed, suggesting that the methods are comparable when used to distinguish emissions of MVs from RWC of soft woods.