Distribution of PCDDs,PCDFs and PCBs in the atmosphere

Air samples were collected through the summer season using quartz fiber filter (QMF) and polyurethane foam plugs (PUF) with high volume air sampler. The QMF and PUF samples were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), chlordanes and DDE by high resolution gas chromatography with mass spectrometry (HRGC-MS). We have previously reported the concentrations of these compounds in urban air. In this study we present: (1) daily variability; (2) vapor/particulate ratio of these compounds. Daily variability of these compounds in ambient air was discussed with meteorological factors. The major parts of PCDDs and PCDFs exist in the particulate phase. Chlordanes, PCBs, and DDE exist in the vapor phase at 98%,96% and 95%, respectively.