PCDD/PCDF emissions from small firing systems in households

This report presents results of emission measurements of polychlorinated di benzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) in the flue gas of seven oil, nine gas, and two wood firing systems under laboratory c onditions. The burn rate of the combustion was in the range of the rated us eful heat output. Two additional test series varied the amount of combustio n air and thus the heat output. The PCDD/PCDF emissions for oil- and gas-fi red boilers are in the range of 0.0020-0.0142 ng I-TEQ/m(3) (referring to 3 % O-2 in the dry flue gas). No correlation between the combustion technique and the PCDD/PCDF emissions could be established. In the tests with the wo od-fired furnaces PCDD/PCDF concentrations in the flue gas ranging from 0.0 14 to 0.076 ng I-TEQ/m(3) (referring to 13% O-2 in the dry flue gas) were f ound. A significant correlation between the firing rate of the heating inse rt and the measured PCDD/PCDF concentrations was found. On examination of t hree typical 2,3,7,8-CDD/CDF congener profiles, a comparable pattern could be observed with natural gas and light fuel oil. The congener distribution for wood combustion is considerably different. (C) 1999 Elsevier Science Lt d. All rights reserved.