Abstract
In an effort to assess the occurrence and sources of polycyclic aromatic hydrocarbons (PAHs) in the ambient air of Riyadh, Saudi Arabia, PM10 samples were collected during December 2010. Diagnostic PAH concentration ratios were used as a tool to identify and characterize the PAH sources. The results reflect high PM10 and PAH concentrations (particulate matter (PM) = 270-1,270 mu g/m(3)). The corresponding average PAH concentrations were in the range of 18 +/- 8 to 1,003 +/- 597 ng/m(3) and the total concentrations (total PAHs (TPAHs) of 17 compounds) varied from 1,383 to 13,470 ng/m(3) with an average of 5,871 +/- 2,830 ng/m(3). The detection and quantification limits were 1-3 and 1-10 ng/ml, respectively, with a recovery range of 42-80 %. The ratio of the sum of the concentrations of the nine major non-alkylated compounds to the total (CPAHs/TPAHs) was 0.87 +/- 0.10, and other ratios were determined to apportion the PM sources. The PAHs found are characteristic for emissions from traffic with diesel being a predominant source.