Atmospheric pollution by PAHs, PCDD/Fs and PCBs simultaneously collected at a regional background site in central Italy and at an urban site in Rome

Concentrations of PAHs and PCDD/Fs were measured throughout one year, and PCBs during the second semester, at a rural site in a natural park representative of background pollution in central Italy; results were compared with simultaneous measurements performed at an urban site in Rome 60 km away. Twenty-four daily samples were collected at each site by a high-volume PM10 sampler from February 2000 to January 2001. After ultrasonic extraction and clean-up by TLC, samples were analysed by GC–MS. Mean concentrations of benzo[a]pyrene (BaP, as a marker of carcinogenic PAHs), ∑PCDD/Fs and ∑64 PCBs in Rome were, respectively: 1.1 ng m−3, 65 fg WHO-TEQ m−3, 553 pg m−3. The background concentrations were, respectively: 0.016 ng m−3, 3 fg WHO-TEQ m−3, and 94 pg m−3. Hence, BaP, and the other PAHs, showed the highest urban-background gradient (two orders of magnitude) and PCBs the lowest. The background pollution levels of BaP and PCDD/Fs were in agreement with the few available background/remote measurements in Europe. In Rome PAHs and PCBs, but not PCDD/Fs, were clearly seasonal; the PCDD/F TEQ was moderately correlated with BaP (P < 0.001). At the background site, the seasonality of PAHs was less marked, while it could not be assessed for PCDD/Fs and PCBs. The PCB TEQ accounted for 4% and 15% of total (PCDD/Fs + PCBs) TEQ at the urban and background site, respectively. Mean PM10 concentration was 54 μg m−3 in Rome and 15 μg m−3 at the background site.