Characterization of non-ortho coplanar PCBs, polychlorinated dibenzo-p-dioxins and dibenzofurans in the atmosphere

Three non-ortho coplanar PCBs (Co-PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in twelve air samples at three sites were measured in summer and winter seasons in 1992. Six samples of Co-PCBs, PCDDs and PCDFs associated with the quartz fiber filter ('particle phase? and polyurethane foam (PUF) plug ('vapor phase') were analyzed to examine the distribution between vapor phase and particle phase. PCDFs were the major contributors to the toxic equivalents (TEQs) in the atmosphere in both seasons. The toxicity contribution of coplanar PCBs to dioxin toxicity was low (about 4.9%). Particle phase PCDDs and PCDFs in winter mostly contributed to the toxicity in the atmosphere. Co-PCBs existed mainly in the vapor phase in summer. The relationships between the congeners of these compounds were examined and significant correlations were found between Co-penta-CB and penta-, hexa-CDF, and between Co-hexa-CB and penta-, hexa-CDF. These findings suggested that most of the Co-penta-CB and Co-hexa-CB observed in the atmosphere originated from such a source as municipal waste incinerator.