title: Modelling the impact of room temperature on concentrations of polychlorinated biphenyls (PCBs) in indoor air.
abstract: Buildings contaminated with polychlorinated biphenyls (PCBs) are a health concern for the building occupants. Inhalation exposure is linked to indoor air concentrations of PCBs, which are known to be affected by indoor temperatures. In this study, a highly PCB contaminated room was heated to six temperature levels between 20 and 30 C, i.e. within the normal fluctuation of indoor temperatures, while the air exchange rate was constant. The steady-state air concentrations of seven PCBs were determined at each temperature level. A model based on Clausius-Clapeyron equation, ln(P) = -ΔH/RT + a(0), where changes in steady-state air concentrations in relation to temperature, was tested. The model was valid for PCB-28, PCB-52 and PCB-101; the four other congeners were sporadic or non-detected. For each congener, the model described a large proportion (R(2)>94%) of the variation in indoor air PCB levels. The results showed that one measured concentration of PCB at a known steady-state temperature can be used to predict the steady-state concentrations at other temperatures under circumstances where e.g. direct sunlight does not influence temperatures and the air exchange rate is constant. The model was also tested on field data from a PCB remediation case in an apartment in another contaminated building complex where PCB concentrations and temperature were measured simultaneously and regularly throughout one year. The model fitted relatively well with the regression of measured PCB air concentrations, ln(P) vs. 1/T, at varying temperature between 16.3 and 28.2 °C, even though the measurements were carried out under uncontrolled environmental condition.
authors.affiliation: Danish Building Research Institute, Aalborg University Copenhagen, A.C. Meyers Vænge 15, DK-2450, Copenhagen SV, Denmark. Electronic address: nal@sbi.aau.dk.
authors.forename: Nadja Lynge
authors.initials: NL
authors.lastname: Lyng
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100, Copenhagen Ø, Denmark.
authors.forename: Per Axel
authors.initials: PA
authors.lastname: Clausen
authors.affiliation: Scandinavian Bio-Medical Institute (SBMI), Rungstedvej 21, DK-2970, Hørsholm, Denmark.
authors.forename: Claus
authors.initials: C
authors.lastname: Lundsgaard
authors.affiliation: Danish Building Research Institute, Aalborg University Copenhagen, A.C. Meyers Vænge 15, DK-2450, Copenhagen SV, Denmark.
authors.forename: Helle Vibeke
authors.initials: HV
authors.lastname: Andersen
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D003718:Denmark; D004784:Environmental Monitoring; D006798:Housing; D019570:Inhalation Exposure; D008962:Models, Theoretical; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D013696:Temperature
chemical_list: D000393:Air Pollutants; D011078:Polychlorinated Biphenyls
keywords: Enthalpy of evaporation; Indoor air; PCBs; Polychlorinated biphenyls; SVOCs; Temperature dependency