Dangerous Substances in Building Materials — Emissions from PCB Coated Ceiling Panels — Polychlorinated Biphenyls (PCB) in Indoor Air

Abstract

The knowledge of the average concentration of persistent and toxic organic substances in indoor air is basic to estimate the hygienic effects of contaminated indoor air. It is well known that the concentration of SVOC in indoor air depends on climatic conditions as well as the ventilation habits of the occupants. Based on the physicochemical properties and the high toxic potential dioxin-like PCB and PCDD/F are appropriate substances to study these influences on indoor air quality. The present paper describes the contamination of indoor air with dioxin-like polychlorinated Biphenyls ( PCB, coplanar and mono-ortho-substituted) and polychlorinated Dibenzodioxins and -furans (PCDD/F) in buildings with PCB coated ceiling panels. A number of public buildings (schools, universities) in Germany are equipped with such PCB coated ceiling panels. The coating consists of high-chlorinated Biphenyls (Clophen A 60). Dioxin-like PCBs and PCDD/F are relevant impurities of technical PCB-mixtures [4, 5]. Dioxin-like PCBs and PCDD/F in indoor air were determined under standardised conditions (ISO 16000-1; VDI 4300 Bl. 2) and real-life conditions (short, repeated ventilation actions) in dependence on the seasonable changes. The present work proves the dominating influence of the indoor temperature [1–3, 9]. An increase of the indoor temperature from 20 to 25 °C leads to an increase of the concentration of dioxin-like PCB from 30 ng/m³ to 90 ng/m³ (sum 12 dioxin-like PCB). A comparable effect of temperature or seasonable changes can be proved for 2,3,7,8-TCDF in the indoor air of these buildings. The concentration increases from 10 pg 2,3,7,8-TCDF /m³ in winter times up to approx. 25 pg/m³ in the summer season. Normally the concentration of dioxin-like PCB and PDDD/F in indoor air are quoted in toxicity equivalents (TE). Based on the TEF established in 1998 by the World Health Organisation the calculated concentration for dioxin-like PCB ranges from 5 pg WHO-TE/m³ in the winter season up to 14 pg WHO TEQ/m³ in summer times. Normal ventilation accomplished by the occupants (short, repeated opening of the windows), reduces the concentrations of dioxin-like PCB in indoor air up to 60% in the summer season. In winter times, when normally only few ventilation actions are carried out, almost no effect of those ventilation actions can be observed. In Germany a tolerable daily intake (TDI) for dioxin-like PCB and PCDD/F via indoor air of 5 pg WHO-TEQ/m³ is discussed [7, 8]. The revision of WHO-TEF in 2005 influences the appraisal for the exposure situation in these buildings. Applying the new WHO-TEF for dioxin-like PCBs established by WHO in 2005 on the concentration of dioxin-like PCB in indoor air the WHO-TE is reduced to a level of 2 to 4 pg WHO-TE/m³.