Concentrations of chlorine, PCDD/PCDF and dl-PCBs in ash from domestic wood-burning (small combustion plants) and medium-sized biomass combustion plants

PCDD/Fs and dioxin-like PCBs (dl-PCBs) are persistent organic pollutants regulated under the EU POP Regulation. Due to their similar toxicological properties, both groups are subject to common, stricter limit values introduced in 2019. This report provides German data on their occurrence in ash from small-scale and biomass combustion plants. Results show that bottom ash is generally low in contamination, while fly ash contains higher but usually non critical levels. Elevated concentrations mainly occur when treated wood is burned. A further reduction of limit values appears feasible if only untreated wood is used and fuel control is improved.