CITY-CENTER CONCENTRATIONS OF POLYCYCLIC AROMATIC-HYDROCARBONS USING SUPERCRITICAL-FLUID EXTRACTION

A method has been developed to allow routine quantitative analysis of polycyclic aromatic hydrocarbons (PAH) in urban dust particulates with a 12 h sampling time. Supercritical CO2 with polar modifier was used for extraction from sampling media and subsequent sample clean-up and analysis was performed using on-line HPLC-GC. Recoveries of PAH from a NIST certified urban dust sample SRM1649 were comparable with those quoted by NIST. A sample of data from three continuous monitoring programs of particulate phase PAH is presented along with accompanying results from ambient gas analysis of NOx, SO2, O-3, and CO. One sampling period includes a meteorological temperature inversion, when PAH levels rose to 6-7 times their mean values. Pearson correlation coefficients have been calculated to test for correlations between PAH levels and other atmospheric pollutants. The PAH show a very strong correlation within a given ring group and strong correlation between ring groups. The temporal variations of the PAH are also quite closely correlated with NOx and CO.