Source apportionment of polycyclic aromatic hydrocarbons in the urban atmosphere: a comparison of three methods Larsen, III, Randolph K; Baker, Joel E [University of Maryland, Solomons, MD (United States). Chesapeake Biological Lab.] 01 COAL, LIGNITE, AND PEAT; SAMPLING; MATHEMATICAL MODELS; COAL; POLYCYCLIC AROMATIC HYDROCARBONS; POLLUTION SOURCES; USA; VEHICLES; GASOLINE; DIESEL FUELS; OILS; URBAN AREAS; SEASONAL VARIATIONS; MARYLAND The sources of PAHs to ambient air in Baltimore, MD, were determined by using three source apportionment methods, principal component analysis with multiple linear regression, UNMIX, and positive matrix factorization. Determining the source apportionment through multiple techniques mitigates weaknesses in individual methods and strengthens the overlapping conclusions. Overall source contributions compare well among methods. Vehicles, both diesel and gasoline, contribute on average 16-26%, coal 28-36%, oil 15-23%, and wood/other having the greatest disparity of 23-35% of the total (gas-plus particle-phase) PAHs. Seasonal trends were found for both coal and oil. Coal was the dominate PAH source during the summer while oil dominated during the winter. Positive matrix factorization was the only method to segregate diesel from gasoline sources. These methods indicate that number and relative strength of PAH sources to the ambient urban atmosphere. As with all source apportionment techniques, these methods require the user to objectively interpret the resulting source profiles. 39 refs., 4 figs., 4 tabs. United States 2003-05-01 English Journal Article Journal Name: Environmental Science and Technology; Journal Volume: 37; Journal Issue: 9; Other Information: baker@cbl.umces.edu; PBD: 1 May 2003 Medium: X; Size: page(s) 1873-1881 https://doi.org/10.1021/es0206184 [] 9 37 Journal ID: ISSN 0013-936X; ESTHAG; TRN: 000700367 CLA; CLA-00:070367 2010-12-31 20355515