Concentrations of polychlorinated dibenzo‐p‐dioxins and dibenzofurans in outdoor air of North‐Rhine‐Westphalia, Germany

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Abstract
Measurements of polychlorinated dibenzo‐p‐dioxins (PCDD) and dibenzofurans (PCDF) in outdoor air of North‐Rhine‐Westphalia were carried out. Fifty‐six samples were taken at different sites in areas of different land use and emission structures. A special filter system allowed analysis of the gas and particle phases separately. It was found that higher chlorinated PCDD/PCDF (7 or 8 chlorine atoms) are collected on glass fiber filter and lower chlorinated PCDD/PCDF (tetra‐ and penta‐CDD/CDF) are absorbed on polyurethane foam. The following isomers were determined: OCDD, OCDF and 11 isomers with chlorine substitution in 2,3,7,8‐position as well as the sum of TCDD, PeCDD, HxCDD, HpCDD, TCDF, PeCDF, HxCDF, HpCDF and the sum of PCDD (4–8) and PCDF (4–8). No 2,3,7,8‐TCDD could be detected but 2,3,7,8‐TCDF was found at 15 sites. Mean concentration in the Rhine‐Ruhr‐District for the sum of PCDD (4–8) and PCDF (4–8) was 3.2pg/m3 and 5.5pg/m3 respectively. Detection limit for TCDD and PCDD/PCDF (5–8) was 0.1–0.2 pg/m3 and 0.005–0.015 pg/m3 respectively. There is no significant indication that 2,3,7,8‐chlorinated isomers of PCDD/PCDF are predominantly decomposed by photochemical reactions in outdoor air.